Upgrading a 12 speed to STI's - what to do?

cleeve hill reject

I've just bought a 12 speed raleigh bike with SIS downtube shifters which I want to upgrade to STI's for riding this winter - my question is, am I right in thinking I can put a 7-speed freewheel on the 6 speed hub, and what will I need to do regarding downtube stops etc to link it all up with some 7 speed Sora shifters? Any help much appreciated.

Slow Downcp

Depends what hubs are on - if Uniglide then cassettes are like Rocking Horse ****. Just gone through the same exercise myself, ended up using the original DT shifters as only going to be used for commuting.

For the downtube, you'll need some of these:

http://www.byercycles.co.uk/32R0908.html (third item down)

rickhotrod

Try fitting a 7 speed HyperGlide freehub. You can tell the difference between a HyperGlide and a UniGlide freehub because the HyperGlide freehub has an internal thread on the end for the HyperGlide cassette lockring. Also, one of the spines is a different width to the others on the HyperGlide freehub.

Once you've fitted the 7 speed HyperGlide freehub, you can fit either a 7 speed HyperGlide cassette or 8 sprockets from a 9 speed cassette. If you use the 9 speed cassette you will need 9 speed shifters. It should also be possible to use an 8 speed cassette if 9 speed spacers are used and the 1mm spacer normally fitted before the smallest sprocket is omitted.

cleeve hill reject

Thanks guys, I hadn't really consiedered the UniGlide/Hyperglide options so you've given me plenty to think about! I'll let you know how I get on!

jrab

First question is whether the sprockets are a cassette or a freewheel? (On cassette the sprockets slide onto splines on the freehub clamped by a lockring, the free-wheeling mechanism is separate to the sprockets. On a freewheel the sprocket assembly contains the free-wheel mechanism and the whole assembly is screwed onto a threaded hub.).

Chances are a 12-speed Raleigh will be a freewheel type.

You can fit a 7-speed freewheel, even 8-speed although these are very rare (and fragile, hence the move to freehub+cassette). You can use 7-speed STIs fine, although again pretty rare but do come up on eBay now and then. I can't remember whether you'd need a new 7-speed rear mech as well, I think from memory 6 & 7-speed have the same spacing, 8-sp is narrower so I don't think you can use 8-speed shifters with 7-speed freewheel.

However you can research all the variations on Sheldon Brown (Google him - real goldmine of info).

Cable-stops already mentioned work fine.

I have an old 12-speed Raleigh. I upgraded the wheels on my Giant, put the Giant's old wheels (9-speed cassette type) onto the Raleigh along with a 9-speed 105 mech and STIs off eBay for about £50. Makes a great winter bike and much more future-proof than trying to find old 7-speed bits. There isn't a lot of clearance between the sprocket & chain and the frame in top gear, I may have been lucky on this so be careful if you try this.

Rich

Slow Downcp

JRAB wrote:

First question is whether the sprockets are a cassette or a freewheel?

Chances are a 12-speed Raleigh will be a freewheel type.

Rich

My Raleigh Triathlon is 12 speed and has a freehub.

jrab

Yeah, some do, some don't. Does make a big difference to the possibilities for STI upgrades though, so hopefully the poster knows how to tell them apart.....

Rich