mr,grumpy 

Assuming that I have two sets of 7-speed shifters and one wheel with an eight speed cassette, can I swap the 8 for a 7 or is the spindle too large for that? Or should I just run the 7 smallest gears until I can fins a set of 8 speed shifters?

(purple Cannondale M-500. I'm not sure of the year but all but one year of M-500 have 7 speeds and the sifter only clicks 6 times so I am am guessing that I do NOT have a '98)

zzyzx_xyzzy

You need a 4.5 mm spacer to run a 7sp cassette on an 8sp hub.

https://www.jensonusa.com/store/produ...te+Spacer.aspx

Steev

If your C'dale has 7 speed shifters, it probably will have 126mm rear drop-out spacing. You'll need to be pushing the chain stays apart to fit the 8 speed wheel in, which will have 130mm OLD.

mr,grumpy 

Hum. The eight-speed hub sipped right in there!

Al1943

Yeah, many of the later 7-speed frames were 128 or even 130 mm dropout spacing. But you'll need new shifters and new chain and if you need to buy those you could just as easily go 9 or 10-speed. I wouldn't buy 8-speed shifters, 8-speed components are becoming too rare. 9 or 10-speed Shimano cassettes will fit the same hub as 8-speed Shimano.

Al

mr,grumpy 

I think that I'm going to be picking up a Kona Blast for off-road and then I'll strip the Trek that I have been building and have plenty of parts for the 'Dale. That thing is, perhaps, the LARGEST MTB that I have ever seen! I intend to put slicks and baskets on it and use it for an errand bike.