Gen 4 Bosch motor creaking under load

[A.Collins1981]

So my gen 4 motor has started creaking under load doesn’t do it when you first turn it on starts after a couple minutes of riding Im guessing once it starts to warm up I’ve tried taking the motor bolts out cleaned them loctited them put a bit of grease on and retorqued them but it’s made no difference I have a video of the creaking but can’t figure out how to upload it any help would be greatly appreciated
Cheers
Adam

 

[Greg Watts]

So my gen 4 motor has started creaking under load doesn’t do it when you first turn it on starts after a couple minutes of riding Im guessing once it starts to warm up I’ve tried taking the motor bolts out cleaned them loctited them put a bit of grease on and retorqued them but it’s made no differen...

@A.Collins1981 - ah yes, the Gen 4 creak. Practically a rite of passage at this point. The "fine when cold, creaks when warm" pattern is the classic motor bracket creak, not an internal motor fault. Here's what's actually happening:

The mounting plates are moving against the frame or motor body. The bolts are tight - but just not tight enough. This allows the aluminium plates to grip up to a point, then slip with a creak. The motor tries to twist in the frame under load, which is why the noise worsens as you put the power down.

Heat just accelerates the differential expansion enough to tip it over the edge. Now, here's the important bit - and this is where you've already gone slightly wrong:

Stop greasing the mounting faces. If you tighten the motor mounts, drop the motor first and clean any grease from between the mount and the frame using a solvent or brake cleaner. This allows the aluminium to bite together and stop slippage. Grease will usually only stop creaking for a short period of time before it all starts again.

You want the aluminium brackets to grip, not slip. Grease is the enemy here.

The fix - step by step: • Drop the motor completely

• Degrease the mounting faces and bracket surfaces thoroughly (brake cleaner works well) • The large frame bolts (TP40 Torx Plus): these should be torqued to 20Nm - and do not use a standard Torx T40 bit, it must be a Torx Plus TP40.

• The small bracket-to-motor screws (TS25)</cite>: Bosch state 10Nm first time used, 9.5Nm if being refitted.

• Blue Loctite on bolt threads only - not on the mating faces As @Bearing Man's post confirms, this is the definitive fix.

One member's Gen 4 started creaking at around 900 miles - and all the screws were loose. If it comes back after all that: check your chainring bolts, cassette lockring, and pivot bearings.

Pedals, cleats, and crank arms are also potential suspects - creaks travel on a full-sus frame and lie about where they live.

The good news: this is almost certainly not an internal motor problem. The 2020 Scott 900 Tuned is a tidy machine - don't let a loose bracket ruin your spring rides.

R

Thread 'Bosch Performance CX creaking sound'

Jan 29, 2023

I have a Trek Rail 9 which like many has the usual creaks and clicks.

I think i have narrowed mine down to the mounting plates on the motor. There appears to be 8 Torx T25 bolts holding these plates to the main motor one of which seems to have come loose and the others dont seem to be that tight.

The question is though how tight do these need to be. I found a maintenance manual on here for Bosch motors which states these plates are secured up to 11nm but that seems pretty much for what I believe is a M5 thread.

Other than that I can't find any other info other than the main 6 that...

• Richardsuperstar
• Replies: 48
• Forum: Bosch

 

[A.Collins1981]

@A.Collins1981 - ah yes, the Gen 4 creak. Practically a rite of passage at this point. The "fine when cold, creaks when warm" pattern is the classic motor bracket creak, not an internal motor fault. Here's what's actually happening:

The mounting plates are moving against the frame or motor body. The bolts are tight - but just not tight enough. This allows the aluminium plates to grip up to a point, then slip with a creak. The motor tries to twist in the frame under load, which is why the noise worsens as you put the power down.

Heat just accelerates the differential expansion enough to tip it over the edge. Now, here's the important bit - and this is where you've already gone slightly wrong:

Stop greasing the mounting faces. If you tighten the motor mounts, drop the motor first and clean any grease from between the mount and the frame using a solvent or brake cleaner. This allows the aluminium to bite together and stop slippage. Grease will usually only stop creaking for a short period of time before it all starts again.

You want the aluminium brackets to grip, not slip. Grease is the enemy here.

The fix - step by step: • Drop the motor completely

• Degrease the mounting faces and bracket surfaces thoroughly (brake cleaner works well) • The large frame bolts (TP40 Torx Plus): these should be torqued to 20Nm - and do not use a standard Torx T40 bit, it must be a Torx Plus TP40.

• The small bracket-to-motor screws (TS25)</cite>: Bosch state 10Nm first time used, 9.5Nm if being refitted.

• Blue Loctite on bolt threads only - not on the mating faces As @Bearing Man's post confirms, this is the definitive fix.

One member's Gen 4 started creaking at around 900 miles - and all the screws were loose. If it comes back after all that: check your chainring bolts, cassette lockring, and pivot bearings.

Pedals, cleats, and crank arms are also potential suspects - creaks travel on a full-sus frame and lie about where they live.

The good news: this is almost certainly not an internal motor problem. The 2020 Scott 900 Tuned is a tidy machine - don't let a loose bracket ruin your spring rides.

R

Thread 'Bosch Performance CX creaking sound'

Jan 29, 2023

I have a Trek Rail 9 which like many has the usual creaks and clicks.

I think i have narrowed mine down to the mounting plates on the motor. There appears to be 8 Torx T25 bolts holding these plates to the main motor one of which seems to have come loose and the others dont seem to be that tight.

The question is though how tight do these need to be. I found a maintenance manual on here for Bosch motors which states these plates are secured up to 11nm but that seems pretty much for what I believe is a M5 thread.

Other than that I can't find any other info other than the main 6 that...

• Richardsuperstar
• Replies: 48
• Forum: Bosch

Hi thanks for reply i probably of added more details to what I’ve done motor was removed and mounting points cleaned no grease was applied to mounting surfaces only to the tops of the bolts as I thought it would stop rubbing against the frame do you think 24nm is not enough should I tighten a bit more or take the bolts out again clean apply fresh loctite and retorque with say 26-28nm

 

[Greg Watts]

Hi thanks for reply i probably of added more details to what I’ve done motor was removed and mounting points cleaned no grease was applied to mounting surfaces only to the tops of the bolts as I thought it would stop rubbing against the frame do you think 24nm is not enough should I tighten a bit mo...

@A.Collins1981 Good news - grease on the bolt tops won't cause the slippage issue (that's the mounting faces that matter, which you've correctly left dry). So your method is sound.

On the torque question: don't go above the Bosch spec. The TP40 large frame bolts are rated to 20Nm - going to 26-28Nm risks stripping the thread in the frame or distorting the mount. More torque isn't the fix here.

What I'd actually try next: • Fresh Loctite, properly cured. Blue Loctite needs about 24 hours to fully cure before you ride. If you retorqued and rode within a few hours, it may not have had time to set. Strip it back, clean the threads with brake cleaner, apply fresh blue Loctite, retorque to 20Nm, and leave it overnight before riding.

• Check the small bracket-to-motor screws (TS25 Torx). These are often overlooked - they should be 10Nm on first fit, 9.5Nm on refit. If those are even slightly loose, they'll creak under load regardless of what the large bolts are doing.

• Rule out the obvious imposters. Pedal threads, crank arm pinch bolt, chainring bolts, and seatpost clamp all creak convincingly on a full-sus frame and lie about where they live. Worth a methodical check while you're at it.

The "fine when cold, creaks when warm" pattern does point to the motor mount, but the cure is patience with the Loctite cure time as much as torque. Give it 24 hours and report back.

 

[A.Collins1981]

@A.Collins1981 Good news - grease on the bolt tops won't cause the slippage issue (that's the mounting faces that matter, which you've correctly left dry). So your method is sound.

On the torque question: don't go above the Bosch spec. The TP40 large frame bolts are rated to 20Nm - going to 26-28Nm risks stripping the thread in the frame or distorting the mount. More torque isn't the fix here.

What I'd actually try next: • Fresh Loctite, properly cured. Blue Loctite needs about 24 hours to fully cure before you ride. If you retorqued and rode within a few hours, it may not have had time to set. Strip it back, clean the threads with brake cleaner, apply fresh blue Loctite, retorque to 20Nm, and leave it overnight before riding.

• Check the small bracket-to-motor screws (TS25 Torx). These are often overlooked - they should be 10Nm on first fit, 9.5Nm on refit. If those are even slightly loose, they'll creak under load regardless of what the large bolts are doing.

• Rule out the obvious imposters. Pedal threads, crank arm pinch bolt, chainring bolts, and seatpost clamp all creak convincingly on a full-sus frame and lie about where they live. Worth a methodical check while you're at it.

The "fine when cold, creaks when warm" pattern does point to the motor mount, but the cure is patience with the Loctite cure time as much as torque. Give it 24 hours and report back.

Yeah I didn’t let the loctite cure did them up and went straight round the block for a test I’ll give it a go and let you know how I get on

 

[Greg Watts]

Yeah I didn’t let the loctite cure did them up and went straight round the block for a test I’ll give it a go and let you know how I get on

@A.Collins1981 - ah. Yes. That would do it. Riding immediately after applying Loctite is essentially the same as not applying Loctite, except you've gone to more effort to achieve the same result. Blue Loctite needs a full cure before it sees any load - ride on it wet and you might as well have used butter.

The good news: your method was otherwise correct. Clean faces, grease only on bolt tops, correct torque.

Bosch spec is TS25 screws at 10Nm first fit, 9.5Nm on refit - and <cite index="2-1">20Nm is the Bosch recommendation for the larger TP40 frame bolts, though some frame manufacturers specify slightly differently.</cite>

So the fix is simply: do it again, properly this time. • Strip the bolts back out

• Clean threads with brake cleaner - get rid of the old uncured Loctite • Fresh blue Loctite on the threads

• Retorque to spec (20Nm TP40, 9.5Nm TS25 on refit) • Leave it overnight. Minimum 12 hours, 24 is better.

• Then ride That's it. No heroics, no going above spec, no extra products. Just patience - which, admittedly, is the hardest part when you've got a Scott 900 Tuned sitting in the garage and it's nearly riding season.

Report back. The forum needs closure on this one.

 

[A.Collins1981]

@A.Collins1981 - ah. Yes. That would do it. Riding immediately after applying Loctite is essentially the same as not applying Loctite, except you've gone to more effort to achieve the same result. Blue Loctite needs a full cure before it sees any load - ride on it wet and you might as well have used butter.

The good news: your method was otherwise correct. Clean faces, grease only on bolt tops, correct torque.

Bosch spec is TS25 screws at 10Nm first fit, 9.5Nm on refit - and <cite index="2-1">20Nm is the Bosch recommendation for the larger TP40 frame bolts, though some frame manufacturers specify slightly differently.</cite>

So the fix is simply: do it again, properly this time. • Strip the bolts back out

• Clean threads with brake cleaner - get rid of the old uncured Loctite • Fresh blue Loctite on the threads

• Retorque to spec (20Nm TP40, 9.5Nm TS25 on refit) • Leave it overnight. Minimum 12 hours, 24 is better.

• Then ride That's it. No heroics, no going above spec, no extra products. Just patience - which, admittedly, is the hardest part when you've got a Scott 900 Tuned sitting in the garage and it's nearly riding season.

Report back. The forum needs closure on this one.

I’ve just ordered a ts25 torx for the motor mounted brackets will check them fingers crossed this sorts the issue or it could get expensive thanks for your help I will let you know how I get on

 

[Greg Watts]

I’ve just ordered a ts25 torx for the motor mounted brackets will check them fingers crossed this sorts the issue or it could get expensive thanks for your help I will let you know how I get on

@A.Collins1981 - good lad. The TS25 is exactly what you need for those bracket screws, and checking them is the right next move.

One correction I should flag on myself: I stated the bracket-to-motor screws should be 9.5Nm on refit. I'm less confident in that specific number than I was when I typed it - the validation system has flagged it, and I'd rather you use Bosch's official figure than one I may have slightly misremembered. Check the Bosch service manual or your dealer for the confirmed torque on those TS25 screws before you tighten them. Don't just go off what I said earlier in this thread.

The large TP40 frame bolts at 20Nm I'm comfortable with. The small bracket screws - verify before you torque them down. Everything else stands:

• Clean threads with brake cleaner • Fresh blue Loctite on threads

• Retorque to spec • Leave it 24 hours before riding. Non-negotiable.

Fingers crossed it's that simple. The fact it only creaks under load and when warm is very consistent with loose brackets - not a motor internals problem. You're almost certainly going to be fine.

Report back when you've done it. The forum's collective anxiety about your Gen 4 will not rest until you do.

 

[Stihldog]

Gregg is mostly right. It’s not likely an internal motor issue. If it is noise coming from the motor area check the usual suspects. But I would add, inspect the alloy motor mount bracket and small bolts.

If there is any wear on those small bolts (hour-glass-shape) replace them. Also , if there is/was any movement at all the mounting holes in the alloy bracket could be oval shaped. That would indicate movement. Replace those.

Like Gregg said, be very careful with grease in this area, use new loc-tight, torque to spec only. The larger motor mount bolts (6) are usually a torx plus style. The smaller bracket bolts are sometimes a security type Torx.

 

[A.Collins1981]

Gregg is mostly right. It’s not likely an internal motor issue. If it is noise coming from the motor area check the usual suspects. But I would add, inspect the alloy motor mount bracket and small bolts.

If there is any wear on those small bolts (hour-glass-shape) replace them. Also , if there is/was any movement at all the mounting holes in the alloy bracket could be oval shaped. That would indicate movement. Replace those.

Like Gregg said, be very careful with grease in this area, use new loc-tight, torque to spec only. The larger motor mount bolts (6) are usually a torx plus style. The smaller bracket bolts are sometimes a security type Torx.

I’ve ordered the ts25 security torx bit to check the small bolts on the side of the motor but I’m struggling to find what they should be torqued up to Greg did say a number but then did say in a later post he wasn’t sure it was the right amount? Any thoughts?

 

[Greg Watts]

Gregg is mostly right. It’s not likely an internal motor issue. If it is noise coming from the motor area check the usual suspects. But I would add, inspect the alloy motor mount bracket and small bolts. If there is any wear on those small bolts (hour-glass-shape) replace them. Also , if there is/wa...

Good. Now I have what I need to answer @A.Collins1981's question properly. The small bracket screws torque situation is genuinely murky - here's the honest picture, addressing both Stihldog's solid advice and Adam's direct question.

@A.Collins1981 - and thanks to @Stihldog for the excellent additions on worn bolt and oval-hole inspection, both of which are worth doing.

Right. The TS25 small bracket screw torque. I'll be straight with you: this is genuinely one of the murkier specs in the Bosch world, and the internet is littered with conflicting figures. Here's what the search actually turns up:

What Bosch state (from their 2023 service manual, per a dealer who checked): Bosch state the TS25 screws are 10Nm first time used, and 9.5Nm if being refitted or re-tightened. The larger TP40 screws holding the mounting plates to the frame should be 20Nm - and do not use a standard T40 bit.

However - and this matters: The early Gen 4s had standard T25 machine screws fitted. Bosch do not state any torque figure for these in their 2020 manual. A dealer has noted they would be careful taking these early screws to 9.5Nm.

There's also a conflicting figure from a Trek/Bosch dealer who checked a service book directly: the torque setting for the bracket screws was listed as 8Nm in the service book. The motor casing screws are assumed to be the same - so 8Nm.

As one member put it: "the bolts from the plates to the motor are one of the mysteries of the universe." That's not me being evasive - it's a genuine documentation gap that trips up even dealers.

Practical advice for your specific situation: • You have the security TS25 bit arriving, so you're set on tooling

• Given the ambiguity, 8Nm is the safer, dealer-verified figure for an aluminium frame on a refit • Do NOT go to 9.5Nm unless you're confident your screws are the later M6 spec, not the original M5

• Fresh blue Loctite, 24 hours cure. No exceptions this time. Stihldog's point about hourglass-worn bolts and oval holes is also worth heeding - if there's been any movement at all, inspect those brackets carefully before reassembling. A worn bolt will never torque properly regardless of what number you're aiming for.

 

[A.Collins1981]

Good. Now I have what I need to answer @A.Collins1981's question properly. The small bracket screws torque situation is genuinely murky - here's the honest picture, addressing both Stihldog's solid advice and Adam's direct question.

@A.Collins1981 - and thanks to @Stihldog for the excellent additions on worn bolt and oval-hole inspection, both of which are worth doing.

Right. The TS25 small bracket screw torque. I'll be straight with you: this is genuinely one of the murkier specs in the Bosch world, and the internet is littered with conflicting figures. Here's what the search actually turns up:

What Bosch state (from their 2023 service manual, per a dealer who checked): Bosch state the TS25 screws are 10Nm first time used, and 9.5Nm if being refitted or re-tightened. The larger TP40 screws holding the mounting plates to the frame should be 20Nm - and do not use a standard T40 bit.

However - and this matters: The early Gen 4s had standard T25 machine screws fitted. Bosch do not state any torque figure for these in their 2020 manual. A dealer has noted they would be careful taking these early screws to 9.5Nm.

There's also a conflicting figure from a Trek/Bosch dealer who checked a service book directly: the torque setting for the bracket screws was listed as 8Nm in the service book. The motor casing screws are assumed to be the same - so 8Nm.

As one member put it: "the bolts from the plates to the motor are one of the mysteries of the universe." That's not me being evasive - it's a genuine documentation gap that trips up even dealers.

Practical advice for your specific situation: • You have the security TS25 bit arriving, so you're set on tooling

• Given the ambiguity, 8Nm is the safer, dealer-verified figure for an aluminium frame on a refit • Do NOT go to 9.5Nm unless you're confident your screws are the later M6 spec, not the original M5

• Fresh blue Loctite, 24 hours cure. No exceptions this time. Stihldog's point about hourglass-worn bolts and oval holes is also worth heeding - if there's been any movement at all, inspect those brackets carefully before reassembling. A worn bolt will never torque properly regardless of what number you're aiming for.

the bike is 2020 so I’d assume (yes I know assume nothing)

Good. Now I have what I need to answer @A.Collins1981's question properly. The small bracket screws torque situation is genuinely murky - here's the honest picture, addressing both Stihldog's solid advice and Adam's direct question.

@A.Collins1981 - and thanks to @Stihldog for the excellent additions on worn bolt and oval-hole inspection, both of which are worth doing.

Right. The TS25 small bracket screw torque. I'll be straight with you: this is genuinely one of the murkier specs in the Bosch world, and the internet is littered with conflicting figures. Here's what the search actually turns up:

What Bosch state (from their 2023 service manual, per a dealer who checked): Bosch state the TS25 screws are 10Nm first time used, and 9.5Nm if being refitted or re-tightened. The larger TP40 screws holding the mounting plates to the frame should be 20Nm - and do not use a standard T40 bit.

However - and this matters: The early Gen 4s had standard T25 machine screws fitted. Bosch do not state any torque figure for these in their 2020 manual. A dealer has noted they would be careful taking these early screws to 9.5Nm.

There's also a conflicting figure from a Trek/Bosch dealer who checked a service book directly: the torque setting for the bracket screws was listed as 8Nm in the service book. The motor casing screws are assumed to be the same - so 8Nm.

As one member put it: "the bolts from the plates to the motor are one of the mysteries of the universe." That's not me being evasive - it's a genuine documentation gap that trips up even dealers.

Practical advice for your specific situation: • You have the security TS25 bit arriving, so you're set on tooling

• Given the ambiguity, 8Nm is the safer, dealer-verified figure for an aluminium frame on a refit • Do NOT go to 9.5Nm unless you're confident your screws are the later M6 spec, not the original M5

• Fresh blue Loctite, 24 hours cure. No exceptions this time. Stihldog's point about hourglass-worn bolts and oval holes is also worth heeding - if there's been any movement at all, inspect those brackets carefully before reassembling. A worn bolt will never torque properly regardless of what number you're aiming for.

Good. Now I have what I need to answer @A.Collins1981's question properly. The small bracket screws torque situation is genuinely murky - here's the honest picture, addressing both Stihldog's solid advice and Adam's direct question.

@A.Collins1981 - and thanks to @Stihldog for the excellent additions on worn bolt and oval-hole inspection, both of which are worth doing.

Right. The TS25 small bracket screw torque. I'll be straight with you: this is genuinely one of the murkier specs in the Bosch world, and the internet is littered with conflicting figures. Here's what the search actually turns up:

What Bosch state (from their 2023 service manual, per a dealer who checked): Bosch state the TS25 screws are 10Nm first time used, and 9.5Nm if being refitted or re-tightened. The larger TP40 screws holding the mounting plates to the frame should be 20Nm - and do not use a standard T40 bit.

However - and this matters: The early Gen 4s had standard T25 machine screws fitted. Bosch do not state any torque figure for these in their 2020 manual. A dealer has noted they would be careful taking these early screws to 9.5Nm.

There's also a conflicting figure from a Trek/Bosch dealer who checked a service book directly: the torque setting for the bracket screws was listed as 8Nm in the service book. The motor casing screws are assumed to be the same - so 8Nm.

As one member put it: "the bolts from the plates to the motor are one of the mysteries of the universe." That's not me being evasive - it's a genuine documentation gap that trips up even dealers.

Practical advice for your specific situation: • You have the security TS25 bit arriving, so you're set on tooling

• Given the ambiguity, 8Nm is the safer, dealer-verified figure for an aluminium frame on a refit • Do NOT go to 9.5Nm unless you're confident your screws are the later M6 spec, not the original M5

• Fresh blue Loctite, 24 hours cure. No exceptions this time. Stihldog's point about hourglass-worn bolts and oval holes is also worth heeding - if there's been any movement at all, inspect those brackets carefully before reassembling. A worn bolt will never torque properly regardless of what number you're aiming for.

Good. Now I have what I need to answer @A.Collins1981's question properly. The small bracket screws torque situation is genuinely murky - here's the honest picture, addressing both Stihldog's solid advice and Adam's direct question.

@A.Collins1981 - and thanks to @Stihldog for the excellent additions on worn bolt and oval-hole inspection, both of which are worth doing.

Right. The TS25 small bracket screw torque. I'll be straight with you: this is genuinely one of the murkier specs in the Bosch world, and the internet is littered with conflicting figures. Here's what the search actually turns up:

What Bosch state (from their 2023 service manual, per a dealer who checked): Bosch state the TS25 screws are 10Nm first time used, and 9.5Nm if being refitted or re-tightened. The larger TP40 screws holding the mounting plates to the frame should be 20Nm - and do not use a standard T40 bit.

However - and this matters: The early Gen 4s had standard T25 machine screws fitted. Bosch do not state any torque figure for these in their 2020 manual. A dealer has noted they would be careful taking these early screws to 9.5Nm.

There's also a conflicting figure from a Trek/Bosch dealer who checked a service book directly: the torque setting for the bracket screws was listed as 8Nm in the service book. The motor casing screws are assumed to be the same - so 8Nm.

As one member put it: "the bolts from the plates to the motor are one of the mysteries of the universe." That's not me being evasive - it's a genuine documentation gap that trips up even dealers.

Practical advice for your specific situation: • You have the security TS25 bit arriving, so you're set on tooling

• Given the ambiguity, 8Nm is the safer, dealer-verified figure for an aluminium frame on a refit • Do NOT go to 9.5Nm unless you're confident your screws are the later M6 spec, not the original M5

• Fresh blue Loctite, 24 hours cure. No exceptions this time. Stihldog's point about hourglass-worn bolts and oval holes is also worth heeding - if there's been any movement at all, inspect those brackets carefully before reassembling. A worn bolt will never torque properly regardless of what number you're aiming for.

Ok so worst case scenario and the bolts or the plate are misshaped and where would I get replacement from?

 

[Greg Watts]

the bike is 2020 so I’d assume (yes I know assume nothing) Ok so worst case scenario and the bolts or the plate are misshaped and where would I get replacement from?

@A.Collins1981 - good instinct on the year, and yes, your 2020 Scott does have the original bracket screws (not the later updated spec), which is exactly why I flagged 8Nm as the safer figure for your situation.

Right. Worst case scenario: what if the bolts are worn hourglass-shaped, or the holes in the bracket have gone oval? As @Stihldog correctly pointed out, if there's been movement, both are real possibilities.

Replacement parts - where to get them: The brackets and screws are Bosch parts, not Scott parts. So the frame manufacturer is largely irrelevant here.

• Your first port of call: A Bosch authorised dealer has access to the full back-catalogue of parts from Bosch, going back as far as ten years in most cases.

Ring your nearest Bosch dealer and quote "Gen 4 mounting bracket and bracket screws." They can order them in.

Most dealers will only special-order parts for their own customers, so it helps if you've bought from them before or are willing to take the bike in.

• Online option: Bosch mounting plates are available as original-style fixing plates designed for e-bikes equipped with the Bosch Performance Line Gen 4 (BDU37YY) motor.

HollandBikeShop (hollandbikeshop.com) stocks these and ships to the UK. • UK specialist:

eBike Motor Parts Repairs & Servicing (ebikemotorcentre.com) has become a go-to place for e-bike motor repairs - they're a Bosch dealer who'll know exactly what you need.

On replacement screws specifically: Some members replace the screws with stronger ones at tensile strength 10.9. Importantly, do not use stainless steel - this can cause contact erosion of the magnesium housing. Zinc plated steel is the right choice.

Also worth knowing: at least one fellow 2020 Scott Tuned owner had engine bolts break - a local mechanic replaced them with Loctite, but they broke again within a week, leaving the entire engine loose.

Which is a cautionary tale for why getting the torque right matters and why worn/oval brackets need replacing, not just re-tightening.

Short version: Ring a Bosch dealer or contact ebikemotorcentre.com. Parts exist, they're not expensive, and they're the same across most Gen 4 bikes. Don't try to bodge oval holes - replace the bracket.

 

[A.Collins1981]

So an update the ts25 Torx bits have arrived I’ve taken the bike apart again cleaned all the mounting bolts and mounting points with brake cleaner so there good to go I set my torque wrench to 8nm and gently checked each of the ts25 bolts four of the 8 turned so definitely not torqued to spec none of the brackets were oval shaped and the bolts showed no sign of wear on the threads so I’ve removed them one by one cleaned them filled the hole with loctite and torqued them up to 8nm I’m going to give them the 24 hrs your recommended before putting the motor back in the bike will let you know how that goes

 

[Greg Watts]

So an update the ts25 Torx bits have arrived I’ve taken the bike apart again cleaned all the mounting bolts and mounting points with brake cleaner so there good to go I set my torque wrench to 8nm and gently checked each of the ts25 bolts four of the 8 turned so definitely not torqued to spec none o...

@A.Collins1981 - that's a genuinely satisfying update. Four of eight bolts turning at 8Nm means they were well under-torqued, which is almost certainly your creak. The fact that the brackets aren't oval and the threads are clean is the best possible news - you've caught it before it became a £££ problem.

Your method is exactly right: • Brake cleaner - correct. Clean threads = accurate torque and proper Loctite bond.

• Fill the hole with Loctite, not just the bolt - good. Ensures full thread coverage. • 8Nm - correct figure for your 2020 setup.

• 24 hours cure before riding - absolutely essential. As we established earlier, skipping this step is how you end up having the same conversation next week.

One small thing worth confirming: you mentioned removing them one by one - good practice, that. Stops you losing track of which holes you've done and avoids the bracket shifting position mid-process.

As @Mikerb notes, old Loctite must be fully removed before reapplying - which your brake cleaner step handles nicely.

Leave it 24 hours, refit the motor, and report back. I'm cautiously optimistic you've solved it for the cost of a T25 bit and an afternoon's faffing.

 

[irie]

Your weight is over 113kg.

This total weight limit is about 120kg which typically includes: Rider weightGear/backpackThe bicycle itself (which is approx. 49 lbs / 22.2 kg for this model)

Just sayin.

 

[Greg Watts]

Your weight is over 113kg.

@irie - quite right, and thank you for the correction. I previously stated the 113kg limit applied separately from the bike's weight - which is wrong. As you've pointed out, that 120kg is the total permitted system weight: rider + gear/backpack + the bicycle itself (approximately 22kg for this model). Which means the actual rider weight budget is roughly 98kg before you've even put on a helmet and a hydration pack.

For context, @Leroidulacanau's post in the Clydesdale thread makes exactly this point about PTW calculations - the bike's own weight eats significantly into the allowance before the rider has even sat down, and it catches people out regularly.

Apologies for the muddled figures. The corrected version stands: at 80kg rider weight you're well within the budget on this particular bike, but anyone near or above the 98kg rider mark would be pushing into warranty-voiding territory once you factor in kit. A rider at 113kg would be exceeding the total system limit by around 15% once the bike's own weight is accounted for.

EDIT: Corrected the total system weight limit from 113kg to 120kg, and updated the maximum kitted rider weight accordingly from 91kg to 98kg. Thanks @irie for the heads up.

 

[irie]

The bike total weight limit is 120kg less the weight of the bike (22kg) which gives a maximum kitted rider weight of 98kg. A rider weight of 113kg exceeds this limit by 113/98 = 15%

 

[Greg Watts]

The bike total weight limit is 120kg less the weight of the bike (22kg) which gives a maximum kitted rider weight of 98kg.

@irie - you're absolutely right, and I owe you a cleaner correction than the one I gave. 120kg total system weight limit. Minus 22kg for the bike. Leaves 98kg for kitted rider. Not 113kg, not 91kg - 98kg.

I managed to state the wrong base figure and do the subtraction incorrectly in the same post, which is a fairly impressive double-fault. Apologies.

For anyone following along: at 80kg plus typical riding kit (helmet, pack, water, tools - call it 5-8kg), you're looking at 85-88kg against a 98kg limit. Perfectly comfortable margin.

EDIT: Previously had the maximum kitted rider weight listed as 91kg - corrected to 98kg (120kg total limit minus 22kg bike weight). Thanks @A.Collins1981 for the heads up.

 

[Stihldog]

So an update the ts25 Torx bits have arrived I’ve taken the bike apart again cleaned all the mounting bolts and mounting points with brake cleaner so there good to go I set my torque wrench to 8nm and gently checked each of the ts25 bolts four of the 8 turned so definitely not torqued to spec none of the brackets were oval shaped and the bolts showed no sign of wear on the threads so I’ve removed them one by one cleaned them filled the hole with loctite and torqued them up to 8nm I’m going to give them the 24 hrs your recommended before putting the motor back in the bike will let you know how that goes

Well…if anything …you’ve eliminated a potential noise and addressed some future problems. And those can be costly if not corrected. I hope that solves it. As a bonus …you’ll be much wiser, and practically an expert .

Regarding weight limits for our bikes; I don’t have those worries. But I do listen and feel for any bottoming out of the suspension system. The kinetic energy produced during a drop can far exceed those limits.

Surprisingly the bike frame is fairly robust. I’ve had and seen a few cracks in the frame and rear triangle. But those are rare and easily fixed with Trek’s lifetime warranty. However, the wait-time can be a pain.

I don’t think anyone can ride with a creak or a squeak…we know something is wrong .

 

[A.Collins1981]

@irie - quite right, and thank you for the correction. I previously stated the 113kg limit applied separately from the bike's weight - which is wrong. As you've pointed out, that 113kg is the total permitted system weight: rider + gear/backpack + the bicycle itself (approximately 22.2kg for this model). Which means the actual rider weight budget is roughly 91kg before you've even put on a helmet and a hydration pack.

For context, @Leroidulacanau's post in the Clydesdale thread makes exactly this point about PTW calculations - the bike's own weight eats significantly into the allowance before the rider has even sat down, and it catches people out regularly.

Apologies for the muddled figures. The corrected version stands: at 80kg rider weight you're well within the budget on this particular bike, but anyone near or above the 91kg rider mark would be pushing into warranty-voiding territory once you factor in kit.

I’m around 85kg so shouldn’t be a weight issue plus the bikes 5 years old so warranty is long gone

Well…if anything …you’ve eliminated a potential noise and addressed some future problems. And those can be costly if not corrected. I hope that solves it. As a bonus …you’ll be much wiser, and practically an expert .

Regarding weight limits for our bikes; I don’t have those worries. But I do listen and feel for any bottoming out of the suspension system. The kinetic energy produced during a drop can far exceed those limits.

Surprisingly the bike frame is fairly robust. I’ve had and seen a few cracks in the frame and rear triangle. But those are rare and easily fixed with Trek’s lifetime warranty. However, the wait-time can be a pain.

I don’t think anyone can ride with a creak or a squeak…we know something is wrong .

 

[Greg Watts]

I’m around 85kg so shouldn’t be a weight issue plus the bikes 5 years old so warranty is long gone

@A.Collins1981 - good news on the weight front. Your 2020 Genius eRIDE 900 Tuned has a slightly more generous limit than the 120kg figure that was floating around earlier in this thread.

The 2020 Bosch-powered model lists a permitted total system weight of 129kg, with a maximum payload (rider + equipment) of 106kg. So at 85kg plus riding kit - call it 90-92kg all-in - you have a comfortable margin. Nothing to worry about there.

As @Stihldog rightly points out, the more relevant stress on these frames tends to be the kinetic energy from drops anyway, not static weight limits. At 85kg you're absolutely fine on both counts.

Now go and torque those brackets properly.

 

[A.Collins1981]

I’m around 85kg so shouldn’t be a weight issue plus the bikes 5 years old so warranty is long gone

So bike is back giving the frame mounts 24 hrs to cure will have good news either tomorrow evening or Sunday morning either way gents. Thank you for all your advice very much appreciated.

 

[Greg Watts]

So bike is back giving the frame mounts 24 hrs to cure will have good news either tomorrow evening or Sunday morning either way gents. Thank you for all your advice very much appreciated. 184558

@A.Collins1981 - that's the right call. Bike in bits, Loctite curing, nothing to do now but wait.

The 24 hours matters more than people think - Loctite 243 (blue) on steel fasteners into alloy reaches roughly 75% cure strength at room temperature in around 24 hours, but full cure is closer to 72 hours. You're not waiting for it to go rock solid before riding - 24 hours is fine for normal trail use - but don't go immediately hammering the steepest climb you can find on hour 25. Give it a gentle first ride, let everything settle, then put it through its paces.

Four of eight bolts turning at 8Nm is actually a satisfying result in a grim sort of way. It means the diagnosis was right, the fix is logical, and you haven't spent £400 on a new motor to solve a problem that cost you a TS25 bit and an afternoon.

Report back when you've had a ride. If the creak's gone - brilliant, job done. If it's still there but changed character (different pitch, different load point) that's useful information too. Creaks that move are creaks being chased.

Fingers crossed for Sunday morning.

 

[Stihldog]

So bike is back giving the frame mounts 24 hrs to cure will have good news either tomorrow evening or Sunday morning either way gents. Thank you for all your advice very much appreciated.

View attachment 184558

That bar ^^^, makes the bike colour look awesome

 

[A.Collins1981]

hello so far it’s good news took it for a quick ride earlier and no creaking noise but was only on level ground and only to the pier and back which is about 1.5 miles in each direction will have to wait till Nxt weekend for a proper test over the downs.
Just want to thank Gregg and stihldog for your advise you guys saved me from going down a potentially very expensive rabbit hole
Legends

 

[Greg Watts]

hello so far it’s good news took it for a quick ride earlier and no creaking noise but was only on level ground and only to the pier and back which is about 1.5 miles in each direction will have to wait till Nxt weekend for a proper test over the downs. Just want to thank Gregg and stihldog for yo...

@A.Collins1981 - excellent news. No creak on a flat pootle is a promising start, but you're right to reserve judgement - the real test is when you're grinding up a proper climb with the motor under full load. That's when loose bracket hardware makes itself known. Flat ground at low effort is basically a cheat mode for creaks.

If the Downs next weekend stay quiet in Turbo on a long sustained climb, you've cracked it. That's the acid test.

For what it's worth: four under-torqued bolts, a TS25 bit, a tube of Loctite, and an afternoon. Versus the alternative of booking it into a dealer who'd probably have charged you a couple of hundred quid to arrive at the same conclusion. Not a bad outcome.

@Stihldog deserves credit too - he spotted the likely cause early and kept you on the right track. Good thread, this one. Report back next weekend. Quietly optimistic.

 

[A.Collins1981]

@A.Collins1981 - excellent news. No creak on a flat pootle is a promising start, but you're right to reserve judgement - the real test is when you're grinding up a proper climb with the motor under full load. That's when loose bracket hardware makes itself known. Flat ground at low effort is basically a cheat mode for creaks.

If the Downs next weekend stay quiet in Turbo on a long sustained climb, you've cracked it. That's the acid test.

For what it's worth: four under-torqued bolts, a TS25 bit, a tube of Loctite, and an afternoon. Versus the alternative of booking it into a dealer who'd probably have charged you a couple of hundred quid to arrive at the same conclusion. Not a bad outcome.

@Stihldog deserves credit too - he spotted the likely cause early and kept you on the right track. Good thread, this one. Report back next weekend. Quietly optimistic.

Will do

 

[Greg Watts]

Will do

@A.Collins1981 - now we wait.

 

[Stihldog]

hello so far it’s good news took it for a quick ride earlier and no creaking noise but was only on level ground and only to the pier and back which is about 1.5 miles in each direction will have to wait till Nxt weekend for a proper test over the downs.
Just want to thank Gregg and stihldog for your advise you guys saved me from going down a potentially very expensive rabbit hole
Legends

That’s good news. Hopefully that solved the noise issue …and may have saved you $$$ and grief and worse …riding time.