smoss

Hi all,

I recently had a cross-country move where I was forced to ditch the rear rim of my bike, since it was beginning to crack. Stupidly, I threw out the cassette as well! Live and learn.

So, now I'm trying to replace the rear rim + cassette (Ideally, I'd like to buy a complete rear wheel), but not sure what type I need. Primarily, I don't know the spacing, and the tooth count of the cassette. The bike in question is a Centurion Dave Scott Master 1998 (purple/white color combination, 700c rim-size), the specs for which can be found online.

The relevant info seems to be:

Crank: Shimano 6400 bio-pace 53-42T

Gears: Shimano UG 13-14-15-17-19-21-24T 7 speed cassette

Shifters: Shimano 6400 SIS

Hubs: Shimano 6400 28f/32r except 60-64cm frames = 32f/32r

Rims: Araya CTL-370


If I add up the gears above (13-14-15-17-19-21-24T) that comes out to 123. Does that mean I need a cassette with 12/23 tooth count? I visited the local bike shop and was told 12/25 is more common for bikes like mine.

I have an opportunity to buy a rim online which is 7-speed, but the seller has told me the tooth count is 12/28. (Unable to post pictures, as this is my first post). Will this be an issue? Will the spacing be right? Thanks in advance, I'm relatively green when it comes to this type of stuff! Any advice greatly appreciated.

Soody

Your old hub will have been 126mm wide
If you bought a modern 130mm wide wheel, you could just open the dropouts a little wider with your hands and it would fit in fine.

You don't -need- a 7 speed specific hub either. A modern 7 speed cassette will fit on any 8,9,10, or 11 speed road wheel with a spacer
you'll just need to adjust your derailer limits and indexing

It is ideal to buy a -good- old 7 speed wheel with 126mm spacing, however i would avoid any with freewheels rather than cassette hubs, and also avoid hubs with UltraGlide freehubs rather than Hyperglyde, unless they come with a mint cassette, as all of the cheap new 7 speed cassette replacements will be hyperglide.
With an old wheel it's also very likely that atleast the cones are worn and the hub needs overhaul and potentially new parts or is outright dead. So i'd probably want to buy one that is either very cheap, smooth as already, or from someone who has opened it up and whose word you trust that it's not pitted.

As for the gearing of the cassette, within a conservative 28t max big cog, it doesn't matter. If you have hills to ride, you may want wide. Retaining 3 straight gears at the top end like you had before is very nice though. Or atleast 2. So try to avoid cassettes with 11t cogs. 53x12 or 53x13 is a fine top gear and the 12-13 or 13-14 shifts are much nicer than 11-13

Soody

That would be all good yeah

https://www.sheldonbrown.com/k7-7.shtml
you can see ratios here


12 14 16 18 21 24 28

is what the 12-28 probably is
12-14-16 is awful like dropping off a cliff when you want a minor change in cadence compared to your old 13-14-15

This is all totally moot if you're just messing around and not doing semi serious road riding. If you don't care about gaps between gears, just go as wide as you can. 12-28 is perfect then. And maybe anyway.

smoss

Thanks! Sounds like 12/28 shouldn't be an issue. Also, one minor consideration I just realized:

As I did some more research, a late 80's Dave Scott centurion would've had bolt-on rims. I believe so, anyways, and pictures seems to verify this. However, I've always had quick release on this bike. I've always used those skewers with the levers, rather than nuts and bolts. Is this bad? Dangerous? I bought it second-hand, so the previous owner must've changed things to quick-release.

The rim I'm considering buying is quick-release.

Soody

no that doesn't matter at all
also i doubt it had bolt on wheels, it's a nice bikes, nice bikes have qr

Soody

also, if you end up with a cassette/freewheel that your shifters don't index (ie not a 7 speed shimano-esque one), you can just spin the thingo on your shifter to go to friction mode, set the limits on the derailer, and it will work fine.
so 8 or 9 speed or campy or 5 or 6 speed or whatever that doesn't have over a 28t big cog.