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adjustments after changing 7 speed cassette body to 8 speed(12 posts)

adjustments after changing 7 speed cassette body to 8 speedkeeshadog
Jan 17, 2003 7:50 PM
had old wheelset that had seven speed cassette. got an 8-9 speed cassette body and replaced the old 7 speed cassette body. it appears to fit on the axle fine. i'm using a 9 speed cassette now. it did not smoothly fit into the frame, but it did fit. the frame is a 2001 khs team cyclocross frame. test rode it today and noticed that while it shifted fine from the 11th to, say, the 16 or 17 tooth cog, once it got beyond that gear, the chain slipped and when i inspected it i noticed that the chain was not sitting on the cog flush but was angled and straddled over 2 cogs in those upper ranges. obviously i need to adjust something, but what, i dont know. add a spacer to the drive side? longer axle? any ideas?
more parts required???C-40
Jan 18, 2003 5:55 AM
Hopefully you did more than just change the cassette body and cassette. You need a 9 speed chain and shifters at the minimum. You may need a 9 speed rear derailleur, although some shimano rear deraileurs will work with 9 speed by changing the position of the derailleur cable on the clamp bolt.

The rear hub spacing should be 130mm. That's the standard for road bikes. Unless the wheelset was really old, it won't have 126mm spacing, which phased out about 10 years ago.
more parts required???Rusty Coggs
Jan 18, 2003 8:49 AM
Any shimano sis road, or MTB deraileror will work without messing with cable mount,other than pre 9 speed DA.
Hey, C4012x23
Jan 18, 2003 9:40 AM
Wasn't 7-speed spacing 126mm? I got into cycling a year or so before 8-speed (my experience all being with Shimano) and was thinking the change in rear spacing to 130mm came along with the change from 7-sp to 8-sp. Also, replacing the freehub (7-sp to 8-sp) required the wheel to be redished.
sort of...C-40
Jan 18, 2003 10:13 AM
Yes, the rear spacing was increased from 126 to 130 when 8 speed was introduced, but cheap bikes were and maybe still are made with only 7 speed cassettes, but with 130mm spacing.

I've got a 1992 model hybrid that has a 7 speed shimano cassette with 130mm spacing. Only older 7 speeds would be spaced 126.
more parts required???keeshadog
Jan 18, 2003 9:54 AM
the set up on the bike was with a nine speed shifter and chain and xt mega 9 rear derailleur. so everything was set up for the 9 speed cassette. i just switched wheelsets because i just started using this bike to commute on and instead of trashing a very nice aero wheelset, i put this older wheelset to use. dont know exactly how old the wheelset was, but it came on a trek 720 multitrack with a parallax shimano hub. my guess is that the bike was about 7 or 8 years old, although that is definitely just a guess.
Need more information.Spoke Wrench
Jan 18, 2003 6:42 AM
What-all have you done so far? You can almost never change just one part on a bicycle. Everything works together. Sometimes you can force fit a mismatch and get it to kind'a work, but that sometimes depends on how high your standards are. I'd rather not insult you by going through a laundry list of possibilities that you have already considered.
Need more information.keeshadog
Jan 18, 2003 10:02 AM
the setup on the bike was for a nine speed. everything else, chain, derailluers, and cassette were 9 speed. i simply changed wheels because i wanted to put to use a set of servicable wheels and not trash a nicer set by commuting on them.
i'm just trying to get as much info as possible. any that you could provide would be much appreciated. my guess is that redishing the wheel and adding/moving around/tossing spacers will be the key. there are at least 2 rather large spacers on the non-drive side. my guess is that those arent as necessary because of the increased length of the cassette body.
Couple'a things.Spoke Wrench
Jan 19, 2003 10:19 AM
I assume you have enough axle sticking out to rest securely in the dropout.

It's better to use the correct, 9-speed axle set. As you have already guessed, the cones and spacers are a little different. I think that the biggest advantage is that it allows you to switch with any other standard Shimano hubbed wheel and only have to make minimum, if any, derailleur adjustments. You will have to redish the wheel, but that's not a big deal.

I'm guessing from what you've told me that your current shifting problem is probably just a derailleur adjustment issue. Since you are using a non-standard wheel, your 12 tooth cog has probably been moved and everything else indexes from that. I suspect that if you reset both limit screws and adjust your cable tension it will probably shift OK but you'll have to move everthing back when you switch back to your good wheelset.
Couple'a things.keeshadog
Jan 19, 2003 11:04 AM
thanks for the advice. i rode it yesterday again, and after looking at how its operating i think your analysis is pretty much right on target. i will look for a 9 speed axle set. there are a couple of shops around town that sell used stuff and i should be able to find the correct axle there. but until then, i will go ahead and make the derailleur adjustment, redish the wheel and i think that will do the trick until i get the right axle.
Axle SETSpoke Wrench
Jan 20, 2003 6:11 AM
It includes not only the axle but also the cones, spacers and locknuts. Regular retail is about $25.00. I'm not the kind of guy who measures the individual differences in all of those parts, but I do know the individual part numbers are different for 7 and 9 speed hubs.

Again. I'm pretty confident you will be able to make your bike work with the stuff that you have. But if you'd like to be able to swap wheels withoug having to fool with your derailleur, that's what I would do.
Axle SETkeeshadog
Jan 20, 2003 4:12 PM
just made the slight adjustments you mentioned. it worked out fine on my test ride. the xt rear derailleur shifts fine now. thanks for the info.