mountain parts + old road parts compatibility
 

Hey guys,

I have some random questions and i hope you guys can help.

I have an '87 Schwinn road frame which i like a lot and i'm fixing it up. It came w/ 27" wheels and 2x6 gearing w/ stem mounted clicky-friction (sorry, i don't know anything about road bikes) shifters.

My plan is to put some new 700c road wheels on it w/ bigger cx tires if they fit. The new wheels would have a modern freehub and the old wheels have a free wheel cassette therefor making the old cassette incompatible w/ the new rear wheel.

But i do have lying around an old 8speed mountain cassette and rear deraileur. Am i correct in assuming a mountain cassette will fit on a road hub? I wonder because a road hub is 130mm wide and a mountain is 135mm... but it seems this is often done to get lower gearing. So i hope that will work and the 8speed rear deraileur should be fine as well. I'll keep the old double rings up front for now.

The next question is about shifting. what would happen if i hooked up the old clicky-friction shifters to the modern 8 speed RD? the derailer is dumb in that it depends on the shifter for indexing, right? So could i feel around w/ the friction shifters for the shift points? I just wonder if there is enough range in the old shifters to span the 8 gears.. probably not.

Assuming that won't work, i wonder if i could stick the 8speed mountain thumb shifter on the upper drop bar for now. reach for that wouldnt be much less convenient than reaching to the stem as is.

Also, how do bar end shifters work? Would they be compatible w/ my mountain 8speed stuff?

Thanks!

You might want to post this over in the mechanics forum. The only thing that you have that has anything to do with CX is the tires you're thinking of using. You might get better/more responses over there.

My thinking is that you'd need to replace your shifters with the bar end one's you're thinking about, but they are cheap. They will work fine with mountain bike components. If you put the modern 8 speed RD on, you'd also have modern index shifting available. You can also use the mountain cassette on a road hub, but you might not be able to fit the 8 speed cassette on a 6 speed hub. A new wheelset may be in order. Shouldn't have any problems fitting a new wheelset as you most likely have a steel frameset and it should spread the couple mm you need.

stolen from Sheldon Brown's article on Shimano freehub systems:

so yes, assuming i read your post correctly and you're using a new wheelset with an old 8-speed cassette, you're fine.

the shifters should work the derailer as well, as you are correct in the deralier being "dumb," but the amount of cable pull might be an issue. i'd try it and see anyway, however, as it might work just fine. you never know.