10 spd Ultegra STI w/ 8 spd rear?



thatracer

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Mar 29, 2012
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Hey guys,

Have a pair of 10 spd Ultegra STI shifters and 8 spd rear dura ace cassette. I've had bar-cons on my bike for sometime. Eventually will upgrade rear to 10 spd.

In the meantime can I install the 10 spd shifters and set the stop screw on the derailleur until i get my 10 spd rear cassette?

~mike
 
Nope. The spacing is wrong. To use 10-speed STIs you need a 9-10-speed hub and a 10-speed cassette.
 
Bob,

Thanks for the reply.

I have a Cannondale Caad5 frame. Currently has Mavic open rims with the 8 spd rear. I take it my wheels will not accept a 9/10 spd cassette...

I guess I'm in for an upgrade to 10 spd wheels, cassette and derailleur.

How can I be sure this will fit my frame?
 
Originally Posted by thatracer .

Have a pair of 10 spd Ultegra STI shifters and 8 spd rear dura ace cassette. I've had bar-cons on my bike for sometime. Eventually will upgrade rear to 10 spd.

In the meantime can I install the 10 spd shifters and set the stop screw on the derailleur until i get my 10 spd rear cassette?
FWIW. The conventional wisdom suggests that there is no difference between 8-and-9-speed AND 10-speed SHIMANO rear derailleurs ...

  • I disagree ...
  • No matter, either way
Shimano tries to avoid creatng outright orphans of its components ...

While I haven't checked the following, by my reckoning IF you install the 10-speed Shimano shifters + IF you attach the rear derailleur cable at the ALTERNATE rear derailleur cable anchoring ([COLOR= #0000ff]at 9 o'clock ... it's what the "hook" is for[/COLOR]) then with your 8-speed Shimano rear derailleur you ([COLOR= #ff0000]¿[/COLOR]) should ([COLOR= #ff0000]?[/COLOR]) have close-to 8-speed Shimano indexing ...

  • If THAT works, then attaching the rear derailleur cable in the "normal" position at 6 o'clock should yield 9-speed indexing with a 8-/9-speed rear derailleur ...
  • And, if you attach the cable at 3 o'clock (with an 8-/9-speed rear derailleur, then you will achieve 10-speed Shimano indexing.

Maybe, maybe not.

You can replace the Freehub body with a newer Freehub body by either buying the Freehub body, separately ([COLOR= #ff0000]this can be costly if bought from an LBS -- information for swapping Shimano Freehub bodies is available from Sheldon Brown's website ... basically, you need a 10mm Allen Wrench[/COLOR]), or by cannibalizing another Shimano hub (presuming the current rear hub is a Shimano hub).

FYI. If you opt for anything other than an 8-speed setup, then you will want to change the chain ...

  • 9-speed chain with a 9-speed Cassette + 9-speed front derailleur
  • and, with a 10-speed Cassette, you will need a 10-speed Shimano chain + a 10-speed Shimano front derailleur.

BTW. More recent 8-speed Cassettes from Shimano & SRAM are ramped ... ramping is a good thing.
 
thatracer said:
Bob, Thanks for the reply. I have a Cannondale Caad5 frame. Currently has Mavic open rims with the 8 spd rear. I take it my wheels will not accept a 9/10 spd cassette... I guess I'm in for an upgrade to 10 spd wheels, cassette and derailleur. How can I be sure this will fit my frame?
You're in luck because the current road rear dropout spacing (130mm) was brought out to accommodate the then new to market 8 spd hubs. A 10 speed hub, then, will fit perfectly in your rear dropouts. Assuming that your rear Mavic rim is still in good shape, you could simply get that rim laced to a new hub with new spokes. A new Shimano 105 hub will run between $60-80 or so, while a new Ultegra rear hub is going to be in the area of $100-140. A Dura Ace rear hub would a bit more. Any of them is a good choice. Of course you'll need to get a hub with the same number spoke holes (i.e., the same "drilling") as your rim. If you can't find such a hub, then you'll need a new rim. It's a cheap way to get in the 10 speed door (105 hub, spokes, and building would cost on the order of $150ish, give or take a few tens. I'm not certain if you'd need to replace the RD, but doing so wouldn't cost a lot. A 105 RD goes for about $45-70. So with that you'd be looking in the ball park of $200-230ish dollars to join the 10 speed club.
 

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