BiNumber3

Hi,
Just wondering if there was any significant difference between mountain groupsets and road.
I'm putting together a road bike for a friend, and will need to replace the cassette, and found 2 by SRAM, 8spd one for mountain and the other for road. I might also need to replace the derailleur as well.
The mountain components I found are more aestheticly pleasing (to me, the cassette's all black) and a bit cheaper, so if possible I'd want to get those.

blacksquid

Isn't the rear spacing different? 135mm for mountain groups and 130mm for road groups.

Steev

Makes no difference for the components.
"Road" cassettes will have tighter ratios like 11-25 where a "mountain" cassette will be typically something like 11-32. Assuming Shimano/SRAM (not Campy) the spacing will be the same as long as the number of cogs match. The spline pattern and freehub body is the same for 8, 9 and 10 speed. You will need to check the size of the largest cog if you go with a "mountain" cassette and are running a rear derailleur from a "road" group as they a typically specified for a 27 or 28 tooth largest cog.
For rear derailleurs, you can use them interchangably, with the exceptions that SRAM x series are not compatible with Shimano shifters and I believe the new Shimano 10 speed mountain stuff is not compatible with their other groups.

STP

Just make sure the rear derailleur will work with the combination and the chain width/length is right. Everything else is just hub style (shimano/sram vs. campy)

BiNumber3

awesome thanks everyone