Bicycle Mechanics - 130 vs 135mm with a 7s
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09-29-12, 03:57 PM
I went to purchase a used MTB wheelset. Deore hubs. Supposed to be, according to the seller, 130mm with a 7 speed cassette. First thing I did was measure it and it was a regular 135mm, not 130mm. So did not take it. Otherwise they were good.
Then I was thinking if I took 5mm spacers from the non-drive side and cut 5mm off the axle, would it be just the same if it was made as a 130mm with 7 speed cassette? Adjust the rim so it would be centered again, of course.
So I am asking if I did that would the dish be OK, just like as if it were made as a 130mm in the first place? Is there some data base with distances of flanges to the centerline for different hubs so I could figure that out?
As it was it did not look like it had very much dish, which I guess you would expect since a 7s cassette body would be narrower than a 8/10s. So making the change to 130mm by cutting the non-drive side would add more dish but might still be OK?
Yes, if you respaced from the left, and redished the wheel you would have been fine.
Also, if it was a 135, it might have been spaced for 8s, and if a freewheel hub, you could have trimmed from the right. Freehub systems however cannot be changed on the right side.
The other option (if you have a steel frame) is to spread the frame to 135mm. My commuter is set up that way, 7s freewheel on 135mm hub, and the rear wheel is almost centered between the flanges, almost eliminating the right/left spoke tension difference. If the wheel is still available, and frame spreading is an option, that would be a great option.
09-29-12, 05:19 PM
Yes, thanks. Wheels are still available. I was not going to give him full asking price anyway. Seemed like a nice reasonable guy who just wanted to get rid of them and would be very flexible on price. I think I will get them.
Going to 130mm would be stretching my frame already. That would be stretching a 126mm frame to accommodate 130mm. Don't want to stretch to 135mm anyway. Would not want to have to fight with it too much when taking the wheel off/on to fix flats which I seem to get a lot of.
It would be a nice matched wheelset for me, instead of the mismatched set I currently have.
He had first claimed they had come from a 1988 Stumpjumper, but after meeting him it seems he doesn't really know what they originally came from. He got them from someone else and who knows what they had originally come from.
09-29-12, 09:00 PM
Simple enough to respace the hub for 130mm. Will have slightly more dish, but that's not a black & white all-or-nothing quality. Actual dish measurement in mm will give you a better idea of how durable the wheel will be.
Personally, I also like to remove spacers from the right side as well to place the smallest cog about 4mm away from the inner-dropout face. Typically I can remove 2mm from the right and 3mm from the left and the resultant change in dish is only 1mm instead of 5mm. This makes for a much stronger and durable wheel.
09-30-12, 12:51 AM
Wider axle will be less dish. as the centered rim is also shifted left
more in the direction of centered between hub shell flanges
I think getting to 145 the rim between hub flanges Is centered..
Would not want to have to fight with it too much when taking the wheel off/on to fix flats which I seem to get a lot of.
I'd suggest using a narrower tyre at higher pressure (say bike & rider <85kg - 23mm, <100kg - 25mm), with a smooth tread with no sipes. More likely to ride between stuff or spit it out the side.
Oh hang on, we're talking MTB. If on the road, use the narrowest slicks you can find, if offroad, I have NFI.
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