fuzzymemory

I currently own a stock 2005 Giant OCR3 that has Shimano Sora-level components. I purchased a 2007 Mavic Ksyrium Equipe wheelset from someone locally. The wheels are a takeoff set and came with tires and and a rear Shimano 10-speed cassette installed. My question is, can I just install the rear wheel with 10-speed Shimano cassette or will I have to put a 8-speed cassette on the wheel? Basicly, Are Shimano cassette's interchangable? If not, can I use a spacer? If so, will I have to adjust the rear derailleur or chain?

krusty

Not sure exactly what you're asking. Your shifters will undoubtedly be 9 speed only (correct?), and as such won't work with a 10 speed cassette. You won't simply be able to use 9 of the 10 cogs with your existing shifters, if that is what you were thinking. If you're willing to buy new shifters and chain, you will be able to use the new wheel and its cassette. If you wish to keep your old shifters, you can put the 9 speed cassette on the new wheels for now until you decide on a future drivetrain upgrade.

roccobike

If your 05 OCR-3 is original, you have an 8-speed casette. You can remove the cassette from your old wheel and replace the cassette on the new wheel. You do not need and should not use a spacer. The freehubs are the same size so this is an easy swap, however, you may need to purchase a few tools to make the swap, like a chain whip and cassette removal tool.
Unless you make many, costly changes as krusty described, you can not use the 10 speed cassette with your 8 speed SORA brifters. You will have to purchase Shimano 10 speed brifters. They are NOT cheap!

Psimet2001 

You're dealing with a Shimano 8-9 (10) compatible freehub body (the part of the wheel that the cassette mounts to). Take your current cassette off of your "old" wheel.

You could also buy a new cassette if the original is worn (btw - most, including me, would recommend a new chain if buying a new cassette).

As mentioned you can not run a 10 spd cassette with 8 or 9spd shifters - although someone on here will say that they do....

fuzzymemory

Thanks for the advice. I'll just install the stock cassette on the new wheels or get a compatible 8 speed cassette. I was hoping to be able to switch between wheelsets and leave everything as is... but I'd rather do things the right way than mess everything up.

TassR700

If you do get a new 8 speed cassette and put it on the new wheel, you can then interchange new and old wheels (unless the old cassette is worn out as mentioned above). 8 speed cassettes are cheap, so I would highly recommend this.

fuzzymemory

The stock cassette still has a bit of life left in it.
That said, if I purchase a new 8-speed cassette, do I have to specify any special model numbers within the Shimano lineup or can I use any Shimano and/or SRAM cassette? I would like to have the option of switching between wheels, so running 2 similar cassettes sounds good.
Also, if given a choice, should I change the range of gears used in the cassette?
Thanks again for your help & advice

Psimet2001 

All Shimano or SRAM 8 spd cassettes would work.

As for gearing it would depend on what terrain you like to ride, what you have been riding and what your fitness level is. In the end no one outside of you can really determine what the appropriate gearing is for you.

fuzzymemory

Fitness level is low, but getting better. I still have about 20lbs to drop before I reach my target weight.
The area I live in is very hilly. Maybe I should go for something like a 25 or 27 on the back.

Treefox

When removing the 10sp cassette, remember to remove the very thin little spacer behind the cassette (right in picture) - it doesn't tend to come off with the cassette when you pull it off and can be easily missed.

But you should have a slightly thicker Mavic spacer with the wheels (with some notches in - left in picture). Keep that on.

redspoke

Glad to see someone spending all of their time riding instead of learning everything there is to know about bikes instead.