Converting a 130mm hub to 135mm

[slowster]

I intend to respace an unused 130mm rim brake hub to 135mm. I already have a longer axle and various axle spacers, and I think the existing quick release skewer will accommodate with the extra width. The rear dropout spacing of the frame measures 136.2mm, and with two 3mm spacers placed over the axle and locknuts (one on each side) of the 130mm hub, it just fits in the dropout.

I could therefore respace the hub to 135mm (with a 5mm spacer), or to 136mm (with both 3mm spacers installed on the non-drive side). Are there any compelling reasons to choose one option over the other?

[cycle tramp]

For me the difference of using a spacer either side of the axle vs a spacer on just one side would depend on which option would put the rear wheel/tyre directly in line with the front wheel/tyre (and therefore achieve better handling characteristics)

[pwa]

If the rim is slightly to one side after the spacing, you can still re-dish the wheel to bring the rim back to central. Putting more spacer on the non-drive-side would mean having to bring the rim further that way, which would confer some notional mechanical benefit by reducing dish.

[Brucey]

I would always go for the 'spacers on the NDS' option, then redish the wheel to suit.

[slowster]

I have not explained well what I meant. The hub has not yet been built into a wheel. The spacer(s) will be added to the non-drive side to reduce dish. I can respace the hub to either 135mm or 136mm. It's not a bike which is heavily laden, so am not particularly bothered about the extra 1mm less dish with 136mm.

I am wondering if those who have similarly respaced or fine tuned the width of hubs, have found that it's better to leave the ~1mm gap to make wheel insertion and removal easier, or whether to maximise the width and have a very close fit.

[cycle tramp]

I have not explained well what I meant. The hub has not yet been built into a wheel. The spacer(s) will be added to the non-drive side to reduce dish. I can respace the hub to either 135mm or 136mm. It's not a bike which is heavily laden, so am not particularly bothered about the extra 1mm less dish with 136mm.

I am wondering if those who have similarly respaced or fine tuned the width of hubs, have found that it's better to leave the ~1mm gap to make wheel insertion and removal easier, or whether to maximise the width and have a very close fit.

Ah, right.. well in which case - can you put the 5mm spacer on the non drive side of the axle and still have enough space for the sprockets and chain?

[pwa]

It is easy enough to play around with whatever spacers you have, even before making the hub up into a wheel. So why not see which arrangement (136 or 135) appears to end up with the faces of the dropouts meeting the hub squarest? And does the smallest sprocket have decent clearance from the stay?

[slowster]

It is easy enough to play around with whatever spacers you have, even before making the hub up into a wheel. So why not see which arrangement (136 or 135) appears to end up with the faces of the dropouts meeting the hub squarest? And does the smallest sprocket have decent clearance from the stay?

I've placed the single 5mm spacer on the axle and offered up the hub to the dropout, and then repeated the exercise with the two 3mm spacers. Both fit. There is no need to spring the droupouts apart for the 136mm configuration, but the play between hub and dropouts is virtually negligible, i.e. ~0.2mm. My instinct is to choose 136mm, but it occurred to me that others who have done similar might have concluded after they had built the hub into a wheel that slightly narrower, i.e. 135mm, would have been a bit better for easier wheel insertion.

At the end of the day I appreciate this is a pretty trivial consideration. I've never tried altering the hub spacing before: in the past if the dropouts were slightly narrow I just pulled them apart, and if a bit wide I just relied on the QR to squeeze them together. This is the first time I have respaced a hub, and I find I have the luxury of being able to fine tune the fit.

(If the wheel was for heavily laden riding, I would probably increase the spacing to ~137mm and spring the dropouts apart by ~1mm to absolutely minimise dish, but that is not the case in this instance.)

Smallest sprocket will be 13t, not 11t, and I will double check clearance, but it should not be an issue. I am not altering the drive side axle spacing.

[Brucey]

I am wondering if those who have similarly respaced or fine tuned the width of hubs, have found that it's better to leave the ~1mm gap to make wheel insertion and removal easier, or whether to maximise the width and have a very close fit.

good question; I guess I was always pretty firmly in the latter camp. BITD I'd use 7s 128mm OLN in frames meant for 126mm. And I used to be dead fussy about what hubs/freewheels I used, lest I wound up with too much wheel dish.

[pwa]

Presumably a little less of the axle sits in the drop-out with it spaced for 136mm.

[slowster]

Thank you all for the replies.

I was always pretty firmly in the latter camp.

That's good enough for me. 136mm it is then.

Presumably a little less of the axle sits in the drop-out with it spaced for 136mm.

IIRC something like 4.5mm of axle usually protrudes beyond the lock nut. I read that some people have successfully converted hubs from 130mm to 135mm using the existing axle and relying on the dropouts resting on just 2mm of axle on each side. I have a longer axle to fit, and I figure a reduction from 4.5mm to 4mm (or even a bit less) should not be a problem.

[MartinC]

I think either of the options would work so it's down to what suits you best. I've been respacing NOS 7 speed freehubs to fit 130mm and 135mm dropouts for a while.

Shimano's standard for axle lengths is: 126mm OLN 137mm, 130mm OLN 141mm, 135mm OLN 146mm; (141mm axles of decent quality are hard to get hold of at the moment it seems). As you say this represents an ideal of 4.5mm protrusion in each dropout but IME a couple of mm is enough 'cos t's the friction generated by the QR cam that's holding the wheel in position. We managed to get wheels to hold in place on chromed horizontal drop outs in the past with no contribution from the axle protrusion (as long as they were done up tight), verticals should be even more secure. If the protrusion is too long the cam may bottom out before it's tight enough even with the spring removed (thickness of the dropout will affect this).

So my rule of thumb is to use the right length axle or the size below but not the size above. IME redishing from 130 to 135 or vice versa requires about half a nipple turn each side.

If it were me I'd respace it to 135mm simply because it would then likely fit any of the nominally 135mm or 132.5mm OLN frames I have or may acquire. Your objective may be to aim for the minimum dish possible which is very sensible too. Apologies for the length of the post but it may be of value to others too.