Mountain Biking - Can somebody point me to a wheelset that would work for a 7-speed 90's mtb?
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12-27-10, 05:25 PM
I have a 93 (or 94?) trek 970 which has a worn out rear rim (concave, brake grabbing, etc).
I'd like to replace the wheel with a sealed bearing hub good quality wheel that allows for rim braking (wayyyy before disk brakes) and stay at 7 speed so I don't have to upgrade the shifters, etc.
I am a little confused in reading the posts on a couple of items
(1) if the wheel is a disk brake wheel (and I obviously skip installing the disk), is it still OK for rim braking (i.e. do they make rims different now?)
(2) Assuming it has a free hub (my current wheel has a freewheel), can I find a seven speed cassette, and will it fit OK, as most cassettes are 8+ speeds now.
If anybody could point me to the correct wheel to order I'd much appreciate it. I'm willing to pay a bit for this, because I hate cheap parts, but don't want to break the bank for this older bike.
1. A disc brake hub will work fine, but there are disc-only rims (no brake surface on the sides of the rim). Rim brake compatible rims are still available.
2.The spacing between the rear dropouts should be 135mm, but to use a seven speed cassette on an eight or nine speed freehub, you'll need a 4.5mm spacer behind the cassette.
You have an issue that needs addressed FIRST. In the early 90's the mfg's were changing the spacing so you need to know what your rear spacing is BEFORE you go buy a new wheelset. The rear spacing between the dropouts can be either:
126.5mm (commonly called 126 mm)
If you have the early 126.5 spacing - good luck finding decent hubs. Everything I've seen is JUNK.
If you have 130mm spacing, use an aftermarket road bike rear hub (like the Hope Pro 3) and have wheels built. If you go this route, use Mavic 517 rims as they are ultra durable and these rims can be used with rim brakes. DT Swiss spokes of course.
You will be upgrading to a Hyperglide cassette and 7 speed cassettes are still available in most tooth configurations. You may have some issues with shifting in the middle ranges of the cassette as your freehub is UniGlide and the cassette will be Hyperglide and there are some miniscule spacing differences.
As was said, you will need the 4.5 mm spacer behind the cassette with the 7 speed. You can get one at your bike shop and they will know what you need and can tell you where to stick it. (:D )
If you have 135 mm spacing, you can use any new wheelset on the market with a rim which can be used for rim brakes. Google to find the mfg's websites and learn which rims are OK for both disc and rim brakes. Ceramic rims need special ceramic pads (which are more expensive).
It is my belief that, since you have a freehub setup, that your spacing is 126.5 mm. You would be better off replacing the rim/spokes only as this would be the most cost effective way to go. Provided of course, that your hubs/bearings/cones are still in good shape. if you need hubs you're better off replacing the entire bike.
12-27-10, 08:24 PM
I have a Trek 9800 of the same vintage. IIRC your 970 shipped with an XT build, same as my bike. If that's the case, you've got 135mm spacing and a 7s Hyperglide drivetrain already.
IMO your best bet is to rebuild/reuse your existing hub and just build a new wheel.
12-28-10, 11:31 AM
OK! Thanks for the info. I'll measure it today (bike is kept at work not home). If it's a 135mm I'll price a new wheel/cassette/spacer combo vs. having a new rim and spokes installed on the existing (deore DX) hub.
I don't feel comfortable rebuilding my own wheel.
12-28-10, 01:09 PM
OK, I just measured it at 135mm, and also noted that the 7 speed gear cluster is a cassette not a freewheel, so one less thing I'll need to buy. Performance has a rear wheel with their own brand (Forte) hub/rim and a rim-brake comparable rim for $70 on sale. I'll either go with that, or a Sun/Deore combo at Harris for $150 (two wheels).
So it looks like I need to buy
Thanks for the replies
12-28-10, 03:37 PM
If your frame is steel, respacing the dropouts to 135mm is easy as pie. That would let you use any modern hub, with the necessary 4.5mm spacer. Unless your current hub is crazy-nice, in my opinion, it's a much nicer way to go.
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