Rear Hub Spacing Question

[stev0]

Rebuilding my late-model Poprad Disc and I had the random compulsion to measure the rear frame spacing while all the parts were stripped off.

Spacing measures 135 on the dot. Rough measurement of the hub suggests 130. :confused: Never noticed that the hub doesn't fit snugly in the frame without screwing down the QR until today (rarely get flats or remove the rear wheel). Everything on the internet suggests that they only built these in 130mm spacing.

I have some questions which I hope someone can help me answer:

Does anyone know if Trek ever made 135mm spaced Poprads?

Assuming that only 130 spaced Poprads were made, do I have to worry about structural integrity now that it seems the frame had bent itself out of shape?

Do I need to run the hub with spacers? If so, in what configuration? (2.5mm axle spacers on each side? 5mm on one side? - will this affect my chainline/rotor alignment enough to be a problem?)

If I keep squeezing the frame onto the 130mm hub, will the potential flex on the axle be dangerous? Or affect the ride otherwise? (I haven't noticed anything 'bad' but will it ride any better on spacers?)

Can I just ignore the spacing issue if I replace the hub with a 135mm spaced hub? (I guess this is the same as the first question - Is it okay that the frame now has 135mm if it was built at 130mm?)

Looking forward to hearing some input. Thanks

[Peter P.]

Your main concern would be the dropouts being out of parallel when cinched down to 130mm to accommodate the hub.

My choice would be to add spacers to only the non-drive side of the hub as that will not disturb the chainline. You will need to re-dish the wheel.

Today's cassette hubs are less likely to suffer bent axles in a situation such as you're in so I wouldn't be too concerned about that occurring.

I'd be less inclined to re-space the rear end because some heat treated steels don't like cold setting and cracking or premature failure can occur.

I do not know if the Poprad was originally 130 or 135mm. It could very well be just sloppy construction. For peace of mind, at least have the dropouts and derailleur hanger checked for alignment.

Again, the easy, non-invasive solution is to re-space the hub. It may affect your disc alignment but you can always shim out the caliper if necessary.

Hope this answers all your questions.

[markie]

I would not worry about it. I would out the wheel back in and worry about something else... Why I am old and slow... Why England suck in the World Cup...

[oldpotatoe]

Rebuilding my late-model Poprad Disc and I had the random compulsion to measure the rear frame spacing while all the parts were stripped off.

Spacing measures 135 on the dot. Rough measurement of the hub suggests 130. :confused: Never noticed that the hub doesn't fit snugly in the frame without screwing down the QR until today (rarely get flats or remove the rear wheel). Everything on the internet suggests that they only built these in 130mm spacing.

I have some questions which I hope someone can help me answer:

Does anyone know if Trek ever made 135mm spaced Poprads?

Assuming that only 130 spaced Poprads were made, do I have to worry about structural integrity now that it seems the frame had bent itself out of shape?

Do I need to run the hub with spacers? If so, in what configuration? (2.5mm axle spacers on each side? 5mm on one side? - will this affect my chainline/rotor alignment enough to be a problem?)

If I keep squeezing the frame onto the 130mm hub, will the potential flex on the axle be dangerous? Or affect the ride otherwise? (I haven't noticed anything 'bad' but will it ride any better on spacers?)

Can I just ignore the spacing issue if I replace the hub with a 135mm spaced hub? (I guess this is the same as the first question - Is it okay that the frame now has 135mm if it was built at 130mm?)

Looking forward to hearing some input. Thanks

I would first go see a LBS to check rear triangle alignment..or do the string test...string tied to RH dropout, around head tube, to LH dropout..see if the distance from the string to the seat tube is the same on each side.

If it is indeed aligned and not just bent out 5mm on one side..I do the above..add 5mm spacers on right side of hub(may need a new axle..depends)..redish wheel to left..adding tension to LH side of wheel(a good thing)..go ride.

I wouldn't just shove the 130mm wheel in it..'may' brake a dropout when you force the dropouts flat with the QR..

Quick research shows the frame is indeed 130mm..strange for a disc compatible frame..

[ultraman6970]

Most disc hubs are 135mm, would not be weird that the frame comes in 135 mm from the factory instead of 130..