Dropouts

minde28383

minde28383

10 kW
Joined
Apr 2, 2010
Messages
700
Hello Gents,
Yesterday I started to put my e-bike together and encountered very disappointing issue with shallow dropouts. Hub's axle does not go into dropouts entirely, only ~70% axle's slides into dropouts. I have found that some lads do some filling to deepen dropouts, also puts some torque arm which supposedly would stop axle from spinning in case dropouts would go crack. I don't mind to do some filling but not sure how it will affect frame's strength and reliability. Have you encountered such dropout issue and managed solve it and how? Or maybe you even had issue with Trek's 4300 dropouts.

yes, pics quality is not good, only cheap camera was on hand.
 

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im confused by the photos,it does not look stable. i just put a 9c rear on a trek 4300,i thought my axle was in my dropouts well enough,maybe a clearer pic might help,my frame is 2001.i just cut some steel dropouts from a old bicycle rear triangle with a hacksaw and handfiled them to fit.then made a bracket to bolt on to the frame eyelets.i will try to get a picture.
 
Over the years, bicycles have used different dropout spacings. The two most common spacings that are in general use are 130mm for road bikes and 135mm for mountain bikes. I'll bet you're using a road bike axle on a mountain bike hub. Learn more by reading about dropouts at http://www.sheldonbrown.com/gloss_sp-ss.html#spacing

:)ensen.
 
velias said:
You don't need new dropouts you need a new camera
Click to expand...

If the camera doesn't have a macro mode (the little flower symbol), such as those on phones or laptops, then just put a magnifying glass in front of the lens to change it's focus distance.

:)ensen.
 
purplepeopledesign said:
If the camera doesn't have a macro mode (the little flower symbol), such as those on phones or laptops, then just put a magnifying glass in front of the lens to change it's focus distance.
Click to expand...

Like this?
8)
penny1.jpg
 
The large size axle on 9c and 5300 clyte motors usually require the dropouts to be deepened, or at a minimum, have the bottom widened to a bigger radius.

Alu frame? if so you definitely need torque arms or plates or something. Steel frames maybe not, just depends on the thickness of em.
 
purplepeopledesign said:
Over the years, bicycles have used different dropout spacings. The two most common spacings that are in general use are 130mm for road bikes and 135mm for mountain bikes. I'll bet you're using a road bike axle on a mountain bike hub. Learn more by reading about dropouts at http://www.sheldonbrown.com/gloss_sp-ss.html#spacing

:)ensen.
Click to expand...

130mm and 135mm are axles' lengths. The bug is that axle does not slide deep enough into dropouts. There is no issue with axle length.
 
beast775 said:
im confused by the photos,it does not look stable. i just put a 9c rear on a trek 4300,i thought my axle was in my dropouts well enough,maybe a clearer pic might help,my frame is 2001.i just cut some steel dropouts from a old bicycle rear triangle with a hacksaw and handfiled them to fit.then made a bracket to bolt on to the frame eyelets.i will try to get a picture.
Click to expand...

You are right; it’s not stable at all. Some reinforcement is needed for sure. Your solution to use old bicycle dropouts sounds effective. It would be nice to see picture of it.
Yesterday I was staring at dropouts for quite long time and have come up with some solution.


Currently I have cut this torque arm from card paper just to see how it would look visually. When it will be cut from steel it will be quite big and strong support for axle. I’ll stick to this solution unless something better will come up. My idea is quite simple and not very nice for the eye but hopefully will give enough support.
See pic.:
Those two black dots will be holes for bolts. On the other side of this plate will be another plate. Both plates will be fixed by bolts; between these plates will be squeezed frame.
Actually I have never seen anyone do such torque arm, I hope it will work.
 

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dogman said:
The large size axle on 9c and 5300 clyte motors usually require the dropouts to be deepened, or at a minimum, have the bottom widened to a bigger radius.

Alu frame? if so you definitely need torque arms or plates or something. Steel frames maybe not, just depends on the thickness of em.
Click to expand...

Radius is fine but dropouts’ indeed are very shallow and needs to be deepened, the problem is that it needs to be deepened about 4mm and frame is made from alloy, also so called dropouts' ears are casted in a such way that filling 4mm out of dropouts would really weaken the frame, so I think I have no other option but to use effective torque plates.
 
I’ve filed down 2 torque plates from 3mm steel. It took 3 to 4 hours of intense filing and drilling, but I hope these plates will help in case alloy dropouts would break.
 

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i have 2 trek 4300 frames and none have shallow dropouts like that bike,is it a full size mine are 22.5 and 23 inch.whatever you do dont stress the original dropouts with force from new torque arms IE tightening.make sure everything sits flat.i wont have pics of mine till next week,i dont have a camera,i borrow one when i can.good luck and no wot at first.
 
3mm mild steel is very borderline, on the BMX I had 5 pieces on one side and it still let go, ok there was a lot more torque at the drops than you have, check http://www.eikes.ca for their version 3 torque arm, you need 6-8mm steel preferably case hardened once you have cut the hole to shape.

The plate your using doesnt look enough and unless you get the fit really snug it will still be working on the drop outs before the arm.

I made my own

http://endless-sphere.com/forums/viewtopic.php?f=14&t=4539&hilit=+torque+arm

That as 2 years ago and it hasnt moved :D alloy drop outs using an X5 running at 60V, this bike has done well over 12,000 miles 8)

Looking again at your picture you have a replaceable hanger on the rear mech, check what its made from on My trek its steel, however id still go with something with a tight snug fit, you really dont want the back wheel coming out for the sake of a few bucks getting the right arm fitted. I only run 1 arm on the 1 side, the side opposite the hanger,you can see this from the pictures in my post.
 
Isn’t it true that any torque arm/plate starts to do its job only when axle starts to spin? In other words: any torque arm helps only when drop outs brake. Otherwise torque arm/plate just sits there and does nothing. When you give some acceleration axle puts tension on drop outs, not torque arm. No matter if you use your arm or not, it does not give drop outs any strength, it only helps to keep wheel in frame in case if drop outs brake, right? Torque arm is just safety/support in case drop outs brake, wheel does not go out of forks and you don’t hit the ground.
So if arm is 3mm or 7mm it will do its job only when arms are broke?

Or do you think that torque arm overtakes tension from axle when you accelerate?

ps. I don't wanted to prove some one wrong, but want to find if my understanding is correct.
 
Hi

Yes the torque arm must be a snug fit so that it takes up the strain before the drop outs do it is not designed to save the wheel if the drops break although it will help in this instance.

With ally drop outs they will crack and break if they are going to go, with steel you will at least get some warning, on my steel Raleigh I dont run a torque arm as both axle and frame are a snug fit not seen any movement in 2 years
 
My trek 2010 frame's drop outs also provides snug fit (I've filed them to be snug fit), that's why I'm thinking that no torque arm/plate will provide any support to drop outs. Axle may break snug alloy drop outs before getting any strain on torque arm.
I believe that axle may get support from torque arm/plate when drop outs are not snug. Otherwise torque arm only kicks in when axle gets loose.

In my case drop outs are much snugger with axle then axle with torque arm/plate. But the problem is that drop outs are alloy and they may brake and then put strain on torque arm. In my believe torque arms are designed to give support before axle puts strain on drop outs, but if axle is snug with drop outs then torque arm/plate is idle.
 
beast775 said:
i have 2 trek 4300 frames and none have shallow dropouts like that bike,is it a full size mine are 22.5 and 23 inch.whatever you do dont stress the original dropouts with force from new torque arms IE tightening.make sure everything sits flat.i wont have pics of mine till next week,i dont have a camera,i borrow one when i can.good luck and no wot at first.
Click to expand...

Mine is 2010 or 2009 year model frame 24 inch. I bought this frame for my e-bike project. I never though that I would have considerations with drop outs.
 
This is the thread you need to read to understand torque arms. http://endless-sphere.com/forums/viewtopic.php?f=2&t=14195
 
I went through some discussion in the link and still think that:
Torque arm/plate starts to do its job when drop outs brake; otherwise it just sits there idle.
Initial spin out is prevented by axle inside snug drop outs tightened with nuts. After this tightening looses then torque arm/plate kicks in and keeps wheel inside spinned out dropouts.
Torque arm is preventive part and gives no strength before drop outs crack or spin out.
 
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