220mm Rotor

[Husky430]

Just wondering if anyone has gone down this road? Reading a brake comparison and they were talking about stopping efficiency being so much better as the rotor size goes up. Seems a relatively simple way to get more out of your existing brakes. Would be keen to give it a go next time I replace my rotor and just add in an adapter as well.

 

[urastus]

If it's for the front, it might be wise to see what size limit the forks are safe using; there will be a lot more torque. It wouldn't be wasted on the rear, which generally does the most braking, albeit light breaking.

 

[Husky430]

Yeah was thinking for the front and the forks are Fox Factory 36's that can take a 27.5 or 29 inch wheel, they came standard on the bike, though not sure if this is any help

 

[GrandPaBrogan]

I could be wrong but I was always under the impression that the 220mm rotors came about because of the larger diameter 29" wheel - has made the former largest 203mm rotor standard, inadequate.

If your 4pot calipers are already capable of locking up your front wheel, then going up to 220mm rotors at the front may not be such a good idea?

 

[Husky430]

certainly can lock it up but was thinking more about brake modulation with the bigger rotor, maybe I'm just dreaming

 

[GrandPaBrogan]

certainly can lock it up but was thinking more about brake modulation with the bigger rotor, maybe I'm just dreaming

A larger diameter rotor would likely end up with less modulation.
The larger contact area I guess would make the rotor less prone to 'bluing' or burning up under prolonged braking. Although prolong braking situations would be abnormal in a well designed track with flow... more likely if you were exploring virgin territory and found yourself in a pickle.

 

[Husky430]

Contact area would be the same, it must be something like more leverage/torque(?) that's being exerted apon the wheel with the larger diameter rotor?

 

[Olof Bike Adventures]

I think larger rotors are great for several reasons. Have upgraded my brakes recently and it is a big difference in performance obviously, more leverage.

Larger rotors mean better heat dissipation which is important when going downhill (like in bike parks) => Less chance of overheating and destroying the brake pads. I recently reviewed a Cannondale Moterra with 220 mm rotors with 2 interlocking rings which I think is the future.

I also find that it is easier to modulate the braking power, especially when it gets steep. It is not about being able to lock the front wheel or not, it is about maintaining (and improve) control with less effort.

You need an adapter for the larger rotors, going up 20 mm is often ok as long as the fork can take it.

But even cheaper and easier is to change brake pads to start with, makes a lot of difference too (depending on what is fitted to the bike from the start of course).

 

[JetSedgwick]

Just wondering if anyone has gone down this road? Reading a brake comparison and they were talking about stopping efficiency being so much better as the rotor size goes up. Seems a relatively simple way to get more out of your existing brakes. Would be keen to give it a go next time I replace my rotor and just add in an adapter as well.

i went from 200mm to 220mm and it was money well spent. Noticeable difference.

 

[Olof Bike Adventures]

For the sram the 200 - 220 was a must and 180 - 200 rear as well.

my TRP DHR evo are solid at 203/203

I hope to hear about my trickstuff max before the parks open back up.

I find it really odd that bike manufacturers still insist on 180 mm in the rear, even on analog trail bikes. There is absolutely no reason not to have 200 mm.

 

[Olof Bike Adventures]

Here is an interesting article on the subject: Ending the rotor size myth – Why you should have a bigger brake rotor at the back than the front | ENDURO Mountainbike Magazine

One of the editors actually went down from 220 mm to 200 mm because the brakes where too strong, or 200 mm was good enough. But that is analog bikes, a heavier eMTB is a completely different thing and I still think 220 mm in the front is the way to go (if you don't have monster brakes as @BAMBAMODA ).

Larger rotors in the rear makes sense if going downhill a lot, btw.

 

[GrandPaBrogan]

Contact area would be the same, it must be something like more leverage/torque(?) that's being exerted apon the wheel with the larger diameter rotor?

The brake pads contact area is the same, but the rotor contact area will be larger (same contact height but longer total circumferential area) which theoretically might give the surfaces more time to cool. A larger 29 wheel will also be spinning at a slightly slower RPM compared to a 27.5 wheel - at the same bike speed.

And yes the larger 220mm rotor diameter creates more stopping leverage if the 27.5 wheel size remains the same, but would reduce modulation (make it more abrupt). However, when combined with a larger 29 wheel size the previous modulation should be maintained.

There are also other factors that affect modulation other than rotor size, like:
• Pad material
• Rotor material
• Air bubbles in the system
• Brand or construction type of the brake lines themselves (how flexy they are under pressure)
• Length, shape, and pivot location of the brake levers
• The sizes of the caliper pistons
• Heavier weight of eMTBs and the riders waistline

 

[Jackware]

Yeah was thinking for the front and the forks are Fox Factory 36's that can take a 27.5 or 29 inch wheel, they came standard on the bike, though not sure if this is any help

Explore 36 Mountain Bike Forks | FOX

FOX redefines ride dynamics for ATVs, mountain bikes, motocross, off-road vehicles, snowmobiles, trucks, and UTVs.

www.ridefox.com

 

[Husky430]

Thanks for all the great info fellas, think I'll give it a go when it comes time to replace the front rotors, brakes are Saints with the Ice tech rotors and I've never had brakes as good as these just looking to make a great thing better. Anyone who has done this already I'd be interested in a link to the adapter. It already has one which I'm assuming is one that takes it from a 180mm rotor to a 200mm one, so again I'm assuming that I'll need one that is 10mm higher again to take it up to 220mm? So by my calculations that would mean that the adapter is 20mm in height to take it from 180 to 220mm? Can't seem to find an Ice Tech rotor in 220mm either, thinking that any 6 bolt 220mm rotor will be ok but happy to hear what others think.

 

[Dan63]

I was going to go with a Magura MDR-P 220mm 6 bolt rotor. Looks great, thicker and floating type. You will need a +40mm post mount adapter such as this - Cleanskin Post Frame Or Fork To Post Caliper Brake Mount

Largest that Shimano make is 203mm, so you're basically looking at 220mm from SRAM, HOPE or MAGURA, or 223mm from Galfer - with a +43mm adapter

The larger rotor will improve braking in these ways -
Outright power - more leverage
Better modulation - less lever force required
Less heat generated - higher efficiency from the increase leverage
Less heat soak - larger rotor can absorb and dissipate more heat

 

[Husky430]

Thanks for that Dan, still a bit confused on the caliper mount as mine has one already between the fork leg and the caliper. So does the Cleanskin one eliminate the existing one or do you run the two together to make up the difference between the rotors?

 

[Husky430]

oh just reread your post and see that I need a 40mm one which will get rid of the existing one.

 

[jbrown15]

The brake pads contact area is the same, but the rotor contact area will be larger (same contact height but longer total circumferential area) which theoretically might give the surfaces more time to cool. A larger 29 wheel will also be spinning at a slightly slower RPM compared to a 27.5 wheel - at the same bike speed.

And yes the larger 220mm rotor diameter creates more stopping leverage if the 27.5 wheel size remains the same, but would reduce modulation (make it more abrupt). However, when combined with a larger 29 wheel size the previous modulation should be maintained.

There are also other factors that affect modulation other than rotor size, like:
• Pad material
• Rotor material
• Air bubbles in the system
• Brand or construction type of the brake lines themselves (how flexy they are under pressure)
• Length, shape, and pivot location of the brake levers
• The sizes of the caliper pistons
• Heavier weight of eMTBs and the riders waistline

I've seen you mention the less modulation point twice now, why do you think it would have less modulation?

I switched from 203mm Shimano Icetech rotors to Galfer 223mm rotors to go with my XTR calipers and have experienced the exact opposite. I have even better modulation and the larger thicker rotors deal with heat and warping far better than my 203mm rotors did.

 

[GrandPaBrogan]

I've seen you mention the less modulation point twice now, why do you think it would have less modulation?

I switched from 203mm Shimano Icetech rotors to Galfer 223mm rotors to go with my XTR calipers and have experienced the exact opposite. I have even better modulation and the larger thicker rotors deal with heat and warping far better than my 203mm rotors did.

It is an over-simplified blanket statement based on increased leverage due to the larger diameter rotor. In hindsight, I should've been more careful with such a statement because of todays modern and sophisticated braking systems - now standard on our high end bikes.

It can still hold true for simpler brake designs that have 1 piston (the second and opposite brake pad is fixed and stationary), or for 2 piston systems where the pistons are inherently larger. Depending on the pad material (organic or sintered metallic), swapping to a larger rotor could cause abrupt wheel locks - depending on the terrain conditions, the type of tyres, and if its dry or raining.

But yeah, most eebs have 4 piston systems these days, which most likely activate in progression (first two then the next two pistons follow) in order to produce better modulation. I think some high performance 4 pot systems also engage 2 smaller pistons initially and then followed by 2 larger pistons.

We don't have a unit of measure to quantify the amount of modulation (that I know of), but suffice it to say that brakes that flip like a switch from nothing to sudden full lock - has zero modulation... but from then on, a lot of factors come into play besides just the rotor diameter alone - so pretty careless on my part. I have a bike with 185 rotors at the rear that locks-up by just me looking at the lever ? and yet my eMTB needs a decent squeeze for the rear 203 brakes to start drifting. The difference? Two different brake brands and the weight of the bikes.

As an example, the same brake system could be hardly manageable and lock-up too easily for a lighter bike/rider with narrow sparsely treaded tyres, but be perfect for a heavier bike/rider with burly DH tyres. People also have varying hand strength... some just slam them on without even knowing, and others are naturally light handed.

I can only guess that in your case, your former 203 rotors needed a firmer finger pull on your part to stop the bike, therefore this could dull your perception of its stopping 'bite.' When you changed to 220 rotors, it permitted you to stop without having to pull your fingers so much, and so therefore you can now sense a greater degree of progression before your wheel would lock.

 

[Olof Bike Adventures]

Another advantage with more powerful brakes is the possibility to use 1-finger braking. More fingers to grip the bar when it gets messy. Personal preference maybe...

 

[jbrown15]

It is an over-simplified blanket statement based on increased leverage due to the larger diameter rotor. In hindsight, I should've been more careful with such a statement because of todays modern and sophisticated braking systems - now standard on our high end bikes.



It can still hold true for simpler brake designs that have 1 piston (the second and opposite brake pad is fixed and stationary), or for 2 piston systems where the pistons are inherently larger. Depending on the pad material (organic or sintered metallic), swapping to a larger rotor could cause abrupt wheel locks - depending on the terrain conditions, the type of tyres, and if its dry or raining.

But yeah, most eebs have 4 piston systems these days, which most likely activate in progression (first two then the next two pistons follow) in order to produce better modulation. I think some high performance 4 pot systems also engage 2 smaller pistons initially and then followed by 2 larger pistons.

We don't have a unit of measure to quantify the amount of modulation (that I know of), but suffice it to say that brakes that flip like a switch from nothing to sudden full lock - has zero modulation... but from then on, a lot of factors come into play besides just the rotor diameter alone - so pretty careless on my part. I have a bike with 185 rotors at the rear that locks-up by just me looking at the lever ? and yet my eMTB needs a decent squeeze for the rear 203 brakes to start drifting. The difference? Two different brake brands and the weight of the bikes.

As an example, the same brake system could be hardly manageable and lock-up too easily for a lighter bike/rider with narrow sparsely treaded tyres, but be perfect for a heavier bike/rider with burly DH tyres. People also have varying hand strength... some just slam them on without even knowing, and others are naturally light handed.

I can only guess that in your case, your former 203 rotors needed a firmer finger pull on your part to stop the bike, therefore this could dull your perception of its stopping 'bite.' When you changed to 220 rotors, it permitted you to stop without having to pull your fingers so much, and so therefore you can now sense a greater degree of progression before your wheel would lock.

I believe most of the high end 4-piston brake setups have a larger and a smaller set of pistons with the smaller pistons engaging the rotor first, cars are designed the same way I believe. At least with the systems I've looked at when I was heavily into modded Euro cars.

I would argue that a larger rotor is less likely to lock up and have better modulation because you don't need as much braking force from your finger to slow down. Further to that I can tell you with the larger rotors I no longer use two fingers for braking and just use my index fingers. I also ride allot of speed technical terrain when modulation is very important to me and allot of fast high speed terrain too which requires extremely strong brakes. I also have less fatigue in my hands from having the larger rotors because I can stop better, sooner and faster with having to use less force to slow down.

Before I switched to 223mm rotors I thought 203mm was all I'd ever need with my XTR's, its safe to say I was wrong. I also don't run organic pads and never would.

Also, my rear wheel only locks up when I want it too. Again due to great modulation, have you personally used 223mm rotors to have first hand knowledge or is your opinion theory?

 

[GrandPaBrogan]

I believe most of the high end 4-piston brake setups have a larger and a smaller set of pistons with the smaller pistons engaging the rotor first, cars are designed the same way I believe. At least with the systems I've looked at when I was heavily into modded Euro cars.

I would argue that a larger rotor is less likely to lock up and have better modulation because you don't need as much braking force from your finger to slow down. Further to that I can tell you with the larger rotors I no longer use two fingers for braking and just use my index fingers. I also ride allot of speed technical terrain when modulation is very important to me and allot of fast high speed terrain too which requires extremely strong brakes. I also have less fatigue in my hands from having the larger rotors because I can stop better, sooner and faster with having to use less force to slow down.

Before I switched to 223mm rotors I thought 203mm was all I'd ever need with my XTR's, its safe to say I was wrong. I also don't run organic pads and never would.

Also, my rear wheel only locks up when I want it too. Again due to great modulation, have you personally used 223mm rotors to have first hand knowledge or is your opinion theory?

I’ve always used one finger for braking. My opinion was based on changing to 203 rotors and then having to go back to 185 again because I lost modulation at the rear. No, I haven’t used 220 rotors at the front and I’ve already owned up to my indiscretion. No need to keep riding me about it.

 

[jbrown15]

I’ve always used one finger for braking. My opinion was based on changing to 203 rotors and then having to go back to 185 again because I lost modulation at the rear. No, I haven’t used 220 rotors at the front and I’ve already owned up to my indiscretion. No need to keep riding me about it.

No sorry that wasn't my intention, I wasn't trying to call you out. Just giving my point of view from my personal experiences.

Sorry really didn't mean for it to come across that way. Opinions are like arseholes, everyone has one....lol I didn't mean to act like one....lol

 

[Cisco]

Tried the 220 Galfer disc last April
Have ridden about 1000 miles on it now.
Real improvement on an already good set up. Recommended.

 

[Husky430]

Couldn't find a Magura anywhere in Oz, so ended up getting a Hope and one of the Cleanskin adapters. Hopefully I don't have any dramas with the Hope fittment that a few people seem to have had with the rivets on the rotor hitting the caliper. Time will tell, only bummer is that it won't turn up before Christmas so will have to wait impatiently.

 

[HORSPWR]

Contact area would be the same

Not really, with a larger rotor you have more meters per second passing through the brake pads for the same rpm, therefore braking efficiency is improved because you increase the contact area within a given time frame.

For example, with a 180mm rotor and the brakes applied for 6 seconds you could have 3392mm of rotor passing through the brake pads but with a 203mm rotor you could have 3826mm of rotor passing through the pads in the same time.

There's no downside to going to bigger brakes, whether it's on a bike or a car.

 

[Dan63]

Couldn't find a Magura anywhere in Oz, so ended up getting a Hope and one of the Cleanskin adapters. Hopefully I don't have any dramas with the Hope fittment that a few people seem to have had with the rivets on the rotor hitting the caliper. Time will tell, only bummer is that it won't turn up before Christmas so will have to wait impatiently. View attachment 48027

Let me know your feedback. I'm tinkering with me bike while injured and unable to ride, might pop the bigger rotor on ?

 

[Levo Laland]

Galfar disks are well made, not too bling and less than £50 with the adapter.

 

[Eddy Current]

I could be wrong but I was always under the impression that the 220mm rotors came about because of the larger diameter 29" wheel - has made the former largest 203mm rotor standard, inadequate.

If your 4pot calipers are already capable of locking up your front wheel, then going up to 220mm rotors at the front may not be such a good idea?

The main improve and I can confirm is not the more power but the modular feeling with bigger rotor and proper pads. Also bit better cooling. Go with float rotors in bigger sizes is more noticeable the lack of twist

 

[Husky430]

Definitely have more feel with it, same awesome stopping power with better modulation, and doesn't it just look the biz... now tossing up whether I need one for the rear end too? Looks like it would fit easily with the same adapter.
Didn't get any of the hitting the rivets issue that was talked about in the reviews when I ordered it, which was a bonus.