Originally Posted by
aaronmichael
The rear rim on my 1989 Trek cracked and I wanted to replace it. The rear rim had a 126mm 7 speed freewheel hub on it. The bike is indexed shifting for the rear. I was told that I would have problems even switching to a 7 speed cassette because the spacing in between the actual gears is different -even when going from a 7 speed freewheel to a 7 speed cassette. Therefore, to keep things "easy", I wanted to use my current hub and put it on a different wheel. The rim that is already built up is cheaper than the non built one which is why I asked If I could strip it down and use it for a rear wheel build. I suppose I'll call around the LBS's and ask them what they could do.
Ah...now it makes sense.
1. You can spread a 126 out to 130. I did it for 10 years or so. If the frame is steel you can get it cold set at any shop that has been around for more than 5 years. if aluminum you should be fine spreading it each time,
2. You can put a spacer on an 8/9/10 freehub body to allow you to use a 7spd cassette. Read up on it
here. "The wider 8/9/10-speed freehub body requires a 4.5 mm spacer behind a 7-speed cassette. You might as well stay with the larger number of sprockets if the hub already has this freehub body."
You can get the spacer or you can run your 7's in friction mode and run an 8 or 9 spd cassette....or pick up cheap 8 or 9 spd shift levers and you now have an 8 or 9 spd system.
3. all you need is the rim and requisite spokes if you want to actually move your 7spd hub. Sure buying that front would allow you to take it and cut out the front hub and just utilize the rim. May be cheaper than just buying the rim, but who is going to build it? Personally I seldom have a problem with using other people's parts, but most shops won't want to do it or could end up charging you more in the end.
So - focus on what you want to achieve - you want a new wheel. Question is how to get it working in an old frame and 7spd system. I would buy a cheap prebuilt catalog wheel from a local shop, get the 4.5mm spacer and install your current cassette. It will be the cheapest option.
....actually I lied about what i would do. i would use that as an excuse to go get a whole new bike and setup. ....but I am like that.