SRAM Apex 10spd with 8spd Shimano shifters?

[williamskg6]

I have a Jamis Allegro 1 with a double chainring crank (50 & 34 teeth) and a Shimano Sora short cage rear derailleur. The rear gearing is an 8 speed (12-26 teeth) cassette. I am frequently finding that in order to keep the chain from extreme angles, I have to shift from my big chainring to the small one, resulting in going from just a bit too high a gear to way too low a gear, which then requires up-shifting a couple of gears in the rear. This has become bothersome.

I went to a bicycle store for a suggestion thinking they'd suggest switching to a triple crank & new front derailleur/shifter. They suggested I should get a different cassette (11-32) and a different rear derailleur so I could keep my shifters. They suggested a Sora GS or Tiagra GS. I have done some research and found that neither can handle the 32 tooth cog (they both max out at 27 teeth for biggest cog). I don't particularly like the MTB rear derailleurs Shimano currently offers - they're designed for triple cranks.

I did some digging around and found that the SRAM Apex medium cage is designed to work with a 11-32 cassette and a double crank, which sounds perfect except for one thing - it's a 10 speed derailleur and SRAM's website says something about exact actuation ratio shifters.

So, the question: will a SRAM Apex 10 speed rear derailleur work with an 8 speed cassette and an 8 speed Shimano shifter? I suspect it will, but I don't want to spend the money on this derailleur unless I am sure it'll work.

Any opinions would be greatly appreciated, especially if you have experience with the SRAM Apex. Thanks!

[nfmisso]

It will work fine with the 8 speed cassette.

It will not work with the Shimano shifter because SRAM uses a different amount of cable pull.

Do you use the 34/26 combination? I would suggest getting a larger chain ring to replace the 34, like 42 or 44 if your hills are not too severe.

Or if you don't use the 50/12 combo, consider changing the 50 for a 46.

If you need/want the 34 and 50, you'll need a triple; and will probably have to get one or more of the chain rings separately. You will also need a new front derailleur and probably a new BB.

With any of these changes, you should replace the chain.

If you do elect to change the cassette, and go with a SRAM derailleur, you should change to a 9 speed at the same time, about the same cost either way, and you'll be happier with the closer ratios.

[williamskg6]

(08-06-2011, 04:20 AM)nfmisso Wrote:  If you do elect to change the cassette, and go with a SRAM derailleur, you should change to a 9 speed at the same time, about the same cost either way, and you'll be happier with the closer ratios.

So, it's safe to assume that I can put a 9 speed cassette in place of my current 8 speed cassette? Are any other modifications required to the hub to do this?

Thanks for the advice so far. Keep it coming!

[nfmisso]

No mods required to the hub for a 9 speed cassette or spacers where an 8 speed was.

You do need:
* a 9 speed chain
* a 9 speed or greater rear derailleur
* 9 speed shifter

Good idea to replace the shifter cable at the same time, most shifters come with cables, so no big deal. Make sure that you lubricate the cable; light oil followed by a quick light wipe to remove the excess.

See: http://www.sheldonbrown.com/speeds.html

[williamskg6]

I guess it might be less work to simply switch to an 8 speed 11-32 cassette and replace my rear derailleur with a Shimano Deore XT (RD-M771-GS). Then I wouldn't have to basically change everything (shifters, brake levers, derailleur, cassette).

[nfmisso]

(08-08-2011, 10:54 AM)williamskg6 Wrote:  I guess it might be less work to simply switch to an 8 speed 11-32 cassette and replace my rear derailleur with a Shimano Deore XT (RD-M771-GS). Then I wouldn't have to basically change everything (shifters, brake levers, derailleur, cassette).

you'll need a new longer chain. New for the new cassette; longer for the bigger cog and long cage derailleur.

[williamskg6]

(08-08-2011, 08:56 PM)nfmisso Wrote:  you'll need a new longer chain. New for the new cassette; longer for the bigger cog and long cage derailleur.

I had assumed that I'd need a new chain but I really appreciate the guidance. It doesn't pay to forget things!

Thanks so much for the advice!