Author Topic: Rear Dropout width adjusting  (Read 1253 times)

Rear Dropout width adjusting
« on: June 30, 2012, 08:09:58 pm »
My Dawes Horizon (reynolds 520 steel) is 135mm spacing, has anyone got any links for someone that would be able to adjust it to 130mm please.

Also does anyone know what it would cost.

Thanks

Re: Rear Dropout width adjusting
« Reply #1 on: June 30, 2012, 09:05:34 pm »
Don't know about reducing the width exactly but I have run a 130mm hub perfectly well in a 135mm dropout. Basically add some washers each side. You can still take up a small amount of slack by compressing the dropouts a mm or two with the QR; the axle only needs a couple of mm's in the dropouts for integrity, with a QR.

I've also gone the other way and spread a Dawes Audax dropouts to 135mm, simply by using a Tubus Cargo rack, which actaully pulls the droputs apart enough to make popping the wheel out a doddle.
I know the dropouts aren't perfectly aligned. I'm still waiting to see what happens, but the gear changes are good.

robgul

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Re: Rear Dropout width adjusting
« Reply #2 on: July 01, 2012, 07:40:15 am »
The classic "threaded rod" method normally used to spread the dropouts can be used the other way to reduce the width.   There are some notes in The Briefings in my ramblings at  www.beewee.org.uk  - just do it the other way!

However, there's probably enough spring in the dropouts to simply pull the frame up to the axle width with the QR skewer?

Rob

Biggsy

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Re: Rear Dropout width adjusting
« Reply #3 on: July 01, 2012, 10:38:28 am »
Is always enough travel possible with the threaded rod method to work before the stays reach each other?

The distance I had to push mine going the other way was amazing.
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robgul

  • HoECC & Cycle:End-to-End webmaster, S Warwickshire Bike Shop in Wellesbourne
  • . . cyclist, Cytech accredited, manages an LBS
    • Cycle:End-to-End
Re: Rear Dropout width adjusting
« Reply #4 on: July 01, 2012, 12:40:04 pm »
Is always enough travel possible with the threaded rod method to work before the stays reach each other?

The distance I had to push mine going the other way was amazing.

I've only done it once (reducing the width) but it seemed to need less "over stretch" than when spreading the dropouts which as you say can be quite startling ... no idea why?

Rob

Re: Rear Dropout width adjusting
« Reply #5 on: July 01, 2012, 02:50:07 pm »
Don't know about reducing the width exactly but I have run a 130mm hub perfectly well in a 135mm dropout. Basically add some washers each side. You can still take up a small amount of slack by compressing the dropouts a mm or two with the QR; the axle only needs a couple of mm's in the dropouts for integrity, with a QR.

If it's a normal shimano-style axle, even just replace the whole axle with one of the correct length and some axle washers - I think they come in 2 or 2.5 mm - I've gone longer>shorter by a similar process.

Re: Rear Dropout width adjusting
« Reply #6 on: July 01, 2012, 07:45:14 pm »
Thanks all, not sure if I want to risk adjusting it myself so will have a think.

Biggsy

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Re: Rear Dropout width adjusting
« Reply #7 on: July 01, 2012, 07:57:52 pm »
Any frame builders near you?  It'll cost just one hour of their time, I'd expect.

You'd do a better job yourself than an average local bike shop.  The threaded rod method is beautifully easy, though it would be good to get it checked by a professional afterwards if you want perfect alignment.
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Re: Rear Dropout width adjusting
« Reply #8 on: July 01, 2012, 08:01:40 pm »
Any frame builders near you?  It'll cost just one hour of their time, I'd expect.

Well SJS Cycles is very close but not sure if they have a frame shop as such.


You'd do a better job yourself than an average local bike shop.  The threaded rod method is beautifully easy, though it would be good to get it checked by a professional afterwards if you want perfect alignment.

I may still do it this way but I am worried about breaking something.

Re: Rear Dropout width adjusting
« Reply #9 on: July 01, 2012, 08:10:05 pm »
I don't like the threaded rod technique as it presupposes the two sides are equally bendable, which they rarely are.  Put a cotton thread round the dropout slots and head tube; the distance between the thread and the seat tube has to be the same on each side, or one side has been squeezed more than the other. 

I would put the frame on some cushions, ensuring the main triangle is supporting it, and push each side in independently.  Keep checking the side-to-side alignment and the spacing.

If you're running a hub gear, which can malfunction due to the slightest bend in it (causing internal components to bind), you also need to return the dropouts to parallel afterwards, and this is very hard to do with cast or forged dropouts.  For anything else, it doesn't matter too much.
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Biggsy

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Re: Rear Dropout width adjusting
« Reply #10 on: July 01, 2012, 08:20:05 pm »
breaking something.

Nah, nothing's going to break unless it's already on the verge of breaking.  The worst that will happen is ending up with wrong dimensions - that you or someone else will be able to correct afterwards.
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Re: Rear Dropout width adjusting
« Reply #11 on: July 01, 2012, 08:23:58 pm »
I don't like the threaded rod technique as it presupposes the two sides are equally bendable, which they rarely are.  Put a cotton thread round the dropout slots and head tube; the distance between the thread and the seat tube has to be the same on each side, or one side has been squeezed more than the other. 

I would put the frame on some cushions, ensuring the main triangle is supporting it, and push each side in independently.  Keep checking the side-to-side alignment and the spacing.

If you're running a hub gear, which can malfunction due to the slightest bend in it (causing internal components to bind), you also need to return the dropouts to parallel afterwards, and this is very hard to do with cast or forged dropouts.  For anything else, it doesn't matter too much.

WHS

You are welcome to come and avail yourself of my karrimat and very large piece of wood, which is kept for this very purpose.  Cold-setting isn't for the feint-hearted though so you might want to just take it to SJS and let them get on with it out of you gaze!

Re: Rear Dropout width adjusting
« Reply #12 on: July 13, 2012, 09:48:41 pm »
Just to update this, all sorted, SJS cycles could not help, however Argos in Bristol did it all ok and in less than 45mins.