Bicycle Mechanics - Wheel help.

New to cycling.

I currently have the following rear wheel:
700c Mavic MA40. Shimano 600 hub. 7sp hyperglide cassette. I believe its 126mm.

I want to convert the wheel to 8sp but not sure how that works. Can i just get a compatible 130mm hub and keep the wheels? Or do i need to buy a whole back wheel/hub? What hub should i look for that is compatible with Shimano 600 parts (except for shifters which are 8sp Shimano Sora)?

Im aware of the 126/130mm spacing issues and the shifter upgrade which i have taken care of already. Just dont understand if wheel/spokes can take any size hub.


Thanks in advance!

You COULD relace the rim and spokes onto a new hub. Or you COULD get an 8 speed freehub to transplant onto the wheel. With that you'll also need a new longer axle meant for 130mm spacing as well as the nuts, spacers and cones unless you can fiddle and fudge the old stuff onto the new axle and work up the new spacing. Otherwise the least expensive way is to just get a new wheel. Especially if you would be paying for the new hub to be built into the old rim and spokes... IF the spokes are the right length. Frankly at that point it's either new freehub and axle or just get a new wheel.

And of course you're also looking at what sort of frame you have. Only steel frames should be cold set (fancy name for "bent") to fit the new axle spacing. Otherwise the whole upgrade is a non starter. And really that ain't so bad. There's very little "wrong" with 7 speeds for anything but the most serious of racing. Or if you have a frame that isn't steel and want to do this upgrade anyway then adjust the spacers or even make your own by opening up the holes in flat washers to allow the cassette to sit very close to the inner face of the dropout on one side and set up the other side with only enough spacers to require you to spring out the frame just a little to make the wheel fit. Likely you'd end up with a "custom" spacing of 127 to 128 mm but with some care you'd be able to use your old axle and still have it stick out enough to set in the dropouts OK. But this custom wheel will need to be re-dished to center the rim in your seat stays to get the tire and rim centered again. And obviously this wheel would only ever work in that frame really well due to the custom dishing.

Sounds like a very nice wheel... a 7 speed free hub will not accommodate an 8 speed cassette but a freehub can can be swapped and you may have enough axle to add the needed spacers without having to replace that... the axle does not have to go right to the outer face of the dropout to function properly with a QR.

If not... a new axle and a few spacers won't break the bank.

A more complex solution is to fit 9 speed cogs and spacers on the 7 speed freehub to make an 8 speed... but will need a 9 speed shifter set to shift 8... this is a solution when you cannot cold set your frame.

I think im going to just look for a complete 8sp wheel (hopefully w/cassette).

What would be a good price to sell my wheels? Mavic MA40. They were trued by a mechanic like 2mo ago.

I think im going to just look for a complete 8sp wheel (hopefully w/cassette).

What would be a good price to sell my wheels? Mavic MA40. They were trued by a mechanic like 2mo ago.

Wheels with MA40 rims will fetch a good price if they're in good shape. There's a forum for classic/vintage appraisals:
http://www.bikeforums.net/forumdisplay.php?273-Classic-and-Vintage-Bicycles-What-s-it-Worth-Appraisals-and-Inquiries
, or you might want to try Craigslist or Ebay.

You have to pry the frame wider to add #8, why not stick with the 7 speed? get the ratios right , new cluster..
I think the ratios matter more than how many there are

what gear ratio do you feel is missing ?

I run a 130 mm hub in an aluminum frame spaced at 126 mm without any problems, YMMV. Installation/removal is a bit of a pain, however.

Brad

I run a 130 mm hub in an aluminum frame spaced at 126 mm without any problems, YMMV. Installation/removal is a bit of a pain, however.

Brad

And that's why I like to fiddle with the spacer stack and maybe grind down the end of the axle a little even if it means ending up with a very non standard axle spacing for that one bike. It's fine as long as the wheel is used in the narrower spaced frames then. Even removing 2mm to get it to 128 would make the springing out of the dropouts that much easier.

BCRider, I agree wholeheartly that your's is a better way, I just have another 8S and I want the swapability, if needed.

Brad