Author Topic: Thorn Audax Mk3 - MTB to Road Hub Rear Wheel  (Read 260 times)

SurreyFan

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Thorn Audax Mk3 - MTB to Road Hub Rear Wheel
« on: May 30, 2020, 09:13:31 AM »
Hello all

In swapping a rear wheel with the original Deore MTB 135mm hub, for a road 105 (I assume) 130 mm hub, will derailleur require adjusting at all ? 'Do it and see' I hear you cry.

I believe that the critical dimension is from axle lock nut face to 'high gear' sprocket face - if that doesn't alter, derailleur functions as before as cassette width is a constant (using same cassette)  ?

I'm rather hoping that the Shimano to Shimano swap will be 'seamless'.

Haven't tried my Mavic Aksiums yet....bet they're different dimension to Shimano !

Regards

Kevin

leftpoole

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Re: Thorn Audax Mk3 - MTB to Road Hub Rear Wheel
« Reply #1 on: May 30, 2020, 10:16:32 AM »
Hello all

 'Do it and see' I hear you cry.



I'm rather hoping that the Shimano to Shimano swap will be 'seamless'.



Regards

Kevin


I never said a word!  ;D ;D ;D

PH

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Re: Thorn Audax Mk3 - MTB to Road Hub Rear Wheel
« Reply #2 on: May 30, 2020, 01:49:38 PM »
I'd be inclined to take it off, clean it, grease the threads and the jocky wheels, check all the adjustment screws are moving freely, then start from scratch.
It might not need any of that, I do it as part of a general service, usually annually depending on use.  Sometimes, because it's gradual, I don't notice how shifting has deteriorated, but do notice the improvement when serviced. 

leftpoole

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Re: Thorn Audax Mk3 - MTB to Road Hub Rear Wheel
« Reply #3 on: May 31, 2020, 10:52:40 AM »
Hello all

In swapping a rear wheel with the original Deore MTB 135mm hub, for a road 105 (I assume) 130 mm hub, will derailleur require adjusting at all ? 'Do it and see' I hear you cry.

I believe that the critical dimension is from axle lock nut face to 'high gear' sprocket face - if that doesn't alter, derailleur functions as before as cassette width is a constant (using same cassette)  ?

I'm rather hoping that the Shimano to Shimano swap will be 'seamless'.

Haven't tried my Mavic Aksiums yet....bet they're different dimension to Shimano !

Regards

Kevin

I have something to add!
I have been looking at this. It is pretty obvious you are concerned because the change and any adjustment is maybe beyond present ability? Forgive me if I am incorrect.
As far as I can work out, swapping the wheel for a different OLN providing you keep the same cassette, I think should simply match up as though you had taken the original wheel off for when the tyre goes down on its own (I will not say pun****e)
Try it.
John

PH

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Re: Thorn Audax Mk3 - MTB to Road Hub Rear Wheel
« Reply #4 on: May 31, 2020, 11:36:10 AM »
I think should simply match up as though you had taken the original wheel off for when the tyre goes down on its own (I will not say pun****e)
Not quite - You've changed the chainline, the stays move in through an arc rather than in parallel and the cassette on some MTB hubs sits slightly inboard of some road hubs.
All these differences are very minor, will they add up to enough to make a difference?  I don't know and as you say you could try it and see. 
The advantage of starting from scratch is you get it perfect, the disadvantage of just trying it is that you my find it works good enough but you don't know if it could be better.

SurreyFan

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Re: Thorn Audax Mk3 - MTB to Road Hub Rear Wheel
« Reply #5 on: June 01, 2020, 08:47:23 AM »
Well I have done it (because the bearings were kaput on the front Deore hub, not the back, and I haven't been able to source cones for the front one) - lovely 'new' wheels and hubs but there must be a fractional difference in alignment as indexing not now 'perfect', and it was pretty good before.

Must, as we all surmise, be slight dimensional differences in the MTB and road hubs, (other then the 130/5 difference) leading to sprockets being 'not quite where they were before'.

So will as you suggest clean derailleur and re-index, which is worth doing from time to time anyway.

thanks for input

Kevin

leftpoole

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Re: Thorn Audax Mk3 - MTB to Road Hub Rear Wheel
« Reply #6 on: June 01, 2020, 10:33:56 AM »
I think should simply match up as though you had taken the original wheel off for when the tyre goes down on its own (I will not say pun****e)
Not quite - You've changed the chainline, the stays move in through an arc rather than in parallel and the cassette on some MTB hubs sits slightly inboard of some road hubs.
All these differences are very minor, will they add up to enough to make a difference?  I don't know and as you say you could try it and see. 
The advantage of starting from scratch is you get it perfect, the disadvantage of just trying it is that you my find it works good enough but you don't know if it could be better.

PH
Yes of course! But by just how little? I think the opening poster asked because he was concerned that his gears would not work after changing the wheel over.
I think now the job he intended is now done, he has to learn the easy job of adjustment (same as you and I once did)
John
John