38t chainring on Amflow
- Thread starter SimonG
- Start date
Why are you starting a 3rd thread on this issue?
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Can I put a bigger chainring on it? Does it fit?
I bought a 2nd amflow spider. I’m popping down to a local engineering shop and getting 1.7 mm of material removed from the spider arms to increase the distance from the suspension arm. Wow, I've seen crazy things, but this takes the cake. So you're purposely making the material weaker on 120Nm...
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Chain ring swap
Hi, Has anyone swapped the standard 34 chainring to a 36 ?, is it possible without remove the spider which requires a specific Amflow tool. I was hoping to avoid that. Also, it looks like the crank arms are self extracting, i.e. you just unwind the bolt against the end cap and the arm is...
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- Thread starter
- #4
Because I’m a food technologist, built a company and employ engineers but I haven’t a clue how to work a phone forum thing.Why are you starting a 3rd thread on this issue?
Can I put a bigger chainring on it? Does it fit?
I bought a 2nd amflow spider. I’m popping down to a local engineering shop and getting 1.7 mm of material removed from the spider arms to increase the distance from the suspension arm. Wow, I've seen crazy things, but this takes the cake. So you're purposely making the material weaker on 120Nm...Chain ring swap
Hi, Has anyone swapped the standard 34 chainring to a 36 ?, is it possible without remove the spider which requires a specific Amflow tool. I was hoping to avoid that. Also, it looks like the crank arms are self extracting, i.e. you just unwind the bolt against the end cap and the arm is...
If you can't figure out basic reply to threads functionality, I would question how other decisions are made by you.
But I'll rest my case, you shaved material of the critical component on the bike. You don't have to say anything else.
- Thread starter
- #6
I had another no nothing with an opinion the other day. Show me your maths on bearing load/material fail. Mine says it won’t fail and been out 2 hour this afternoon and had no issues. Gonna run the figures past material strength experts for validation then flog the solution on eBay for £149 a pop.
Pentti
New Member
Just confirming on this thread that I fitted a HOPE R22 38T Chainring to a silver Amflow without any mods, it physically fits and there have been no problems whatsoever in use. I tried flexing the bike with my foot against the crank and there is no detectable movement in the clearance between the chainring & chainstay. When you ride the bike the clearance increases, the point where the chainring is closest to the chainstay is very close to the pivot point of the chainstay. 38T is an option in the software and the chain guide bracket can be adjusted around it's pivot to fit the ring without any further mods too.
Pentti
New Member
Now I'm thinking 40/42T might fitGonna run the figures past material strength experts for validation then flog the solution on eBay for £149 a pop.
- Thread starter
- #10
I used a sram 38t it snagged.
D
Deleted member 37410
Guest
I wish I could run a 38 on my Kenevo
To the OP. You have done 2 things.
1) Chainline is pushed out. This will impact low gear cross chaining. Impacting shifting, cassette, chain and chainring wear. Side loads will be greater.
2) As someone who has bent a spider arm from impact, with a spider arm that hasn't had half it's material removed. Your chainring now hangs lower, making it more susceptible to impact. And when it does impact. It will bend a spider arm far more easily.
I would not do this, unless this was just going to be a gravel and tar cruiser.
1) Chainline is pushed out. This will impact low gear cross chaining. Impacting shifting, cassette, chain and chainring wear. Side loads will be greater.
2) As someone who has bent a spider arm from impact, with a spider arm that hasn't had half it's material removed. Your chainring now hangs lower, making it more susceptible to impact. And when it does impact. It will bend a spider arm far more easily.
I would not do this, unless this was just going to be a gravel and tar cruiser.
D
Deleted member 37410
Guest
I would love +2 mm chain line as well, I spend 90% of my time in gears 8+ and maybe 1% in gear 1.
I have an ochain and there could be quite a bit of material since it is very thick. Will investigate this for sure
I have an ochain and there could be quite a bit of material since it is very thick. Will investigate this for sure
D
Deleted member 37410
Guest
The reduced clearance is a downside for sure, already feeling that with a 36 chain ring. Smashing the chain ring = smashing the motor axle. So trading good gear ratios for being careful over logs and stuff
D
Deleted member 37410
Guest
Radius should be 4 mm more for a 38 then a 36, so 2 mm lower is a bit optimistic. With the angle of the stays I would probably also need the 2 mm offset for clearance, got to measure that
- Thread starter
- #17
For other who read this….. the above poster is a know all-know f all troll with an opinion. Despite repeated requests for material fail calculations I have received nothing. The shop I used did the engineering calculations and do work for aerospace industry. It’s sound.
Pentti
New Member
You are correct, however Amflow torque means 1-7 are not used, the whole point of a bigger chainring is to try and get away from the smallest sprocket and in this case the 2mm chainline change actually helps centre the chain better around the gears you use.
Pentti
New Member
Thanks for the info, interesting, the steel teeth must be longer than the Alloy ones? If anything you would expect an alloy ring to be thicker than a steel one.
- Thread starter
- #20
Don’t know in the diameter difference on steel vs alloy….. the steel ring is 4mm thick, I have a 36t alloy and it has a 5mm spine at its widest but the steel is really hard, obviously.
- Thread starter
- #21
You are correct, i confuddled radius with diameter. The ring sits 4mm lower.
- Thread starter
- #22
Yeah im sticking with the SRAM 11-50, I find 10 is too fond of slipping when biking in New Zealand. I was out this morning; it's fast... obliterated trail times....Strava would not validate my time and sent me a message about a suspected vehicle.
I may not use 1st gear much. But 2nd and 3rd I use all the time when climbing technical areas. And I'm only on the 34T chainring.
Another example for me is stairs. To climb normal stairs, I use 3rd. But steep or long stairs I use 2nd. Pushing your bike up stairs is for the peasants ......
As I said. It comes down to your use. But the Amflow has been rated one of the best climbing bikes currently available. That is 90% of why I bought it. And it out climbs my Merida E160 with the Shimano EP801, hand over fist. It's not even close.
And it's when you are climbing and decending technical areas, that I want the most BB clearance. Giving up 4mm would be a huge issue in technical areas.
The other thing. Impacts are not always directly into the chainring. If you hit something at a slight angle. There is significant sideways loading on the chainring, which transfers directly to the spider arms. I have personally bent a spider arm this way. So removing material from the arm only makes this a higher probability.
I have now added a timber skid block to the bottom of the motor, which protudes 1mm higher than the 34T chainring. This has fixed all the issues I have been having with chainring strikes. But if you don't ride trails where chainring strikes are a problem. Then I guess the 38T upgrade shown here, shouldn't cause you too many issues.
But if you are only riding trails where BB clearance doesn't matter. Why did you buy an Amflow ? .......
Silent1
New Member
What cadence are you cycling at? Your comment suggests you're never below 9mph-ish?
I'd say I ride every gear with a near bell curve mileage distribution centred on gear 8 but nearly every ride I'll be down to 2nd and up to 11 depending on terrain.
Pentti
New Member
Mullet 27.5 rear wheel and USA bike, lightweight rider and yes, low cadence when possible.
Silent1
New Member
34 tooth front would get you the 6% ish you lost back from the mullet.
I’m impressed, I’d either break a chain or wear out my cassette quick if I was putting the torque in a low cadence requires, I presume you’re on trails/fire roads for your uphill sections?
I’d give my left arm for gravel vs the mud I’m on, I’d save probably 200W too
- Thread starter
- #27
70-80 rpm. I’m using the center gears most and am hitting 49kph on flat flat fire roads.
Silent1
New Member
I aim for an 80-90 cadence, so I think that makes sense, you’re adjusting your ratios up by 18% over a 32T so if I’m doing 88rpm you’d be doing 74/75rpm, all about where you’re comfortable
ozzybmx
Active member
Just did the 34t to 36t swap.
Anyone unable to order from Amflow, AliExpress has the tool to fit. $19.49au with whatever currency conversion that may be to your country.
For a chainring swap, the chainring tool is required to remove the spider, also not a bad idea to have it in your spares anyway, just in case. My Bosch gen4 lockring used to mysteriously loosen itself regularly.
Tool is the B29.
www.aliexpress.com
Anyone unable to order from Amflow, AliExpress has the tool to fit. $19.49au with whatever currency conversion that may be to your country.
For a chainring swap, the chainring tool is required to remove the spider, also not a bad idea to have it in your spares anyway, just in case. My Bosch gen4 lockring used to mysteriously loosen itself regularly.
Tool is the B29.
Fahrrad-Mittelwellen-Innen sechs kant werkzeug b23/26/29/30 41mm 16 Zähne 46mm 12 Zähne Keil verzahnung Acht Zähne Schnapp-Zentr ier wellen werkzeug - AliExpress 18
Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com
Charley_Phogg
New Member
Just did the 34t to 36t swap.
Anyone unable to order from Amflow, AliExpress has the tool to fit. $19.49au with whatever currency conversion that may be to your country.
For a chainring swap, the chainring tool is required to remove the spider, also not a bad idea to have it in your spares anyway, just in case. My Bosch gen4 lockring used to mysteriously loosen itself regularly.
Tool is the B29.
Fahrrad-Mittelwellen-Innen sechs kant werkzeug b23/26/29/30 41mm 16 Zähne 46mm 12 Zähne Keil verzahnung Acht Zähne Schnapp-Zentr ier wellen werkzeug - AliExpress 18
Smarter Shopping, Better Living! Aliexpress.com
Thanks. Ordered. I've been looking for one of these and so has my buddy with an Amflow. They aren't available from Amflow USA yet.
