Swapping from Twist-shift to Thumb-shift

Semple · 8 Sep 2012 at 21:13

I've had my mountain bike for a couple of months now and looking to swap out the twist-shift gears for thumb-shift.

I've had a look at quite a few on the web and from what I can see, there's 2 different types, gear-shifts on their own or gear-shifts with brakes. Now I would rather keep the installation as simple as possible so I would prefer to steer clear of installing new gears and the brakes.

It has 21 gears (3x7).

Firstly, any recommendations on thumb-shifts to look at, or shops to buy these from.

Secondly, how easy is it to install over the existing twist-shift gears? Is it just a case of swapping out the cable. Or do the thumb-shift require any extra components to be installed.

Cheers

ins0mn1ac · 8 Sep 2012 at 22:25

It's just a simple swap, brake/gear combo jobs are probably best at a budget I guess? depends on what you're doing/what bike its going on.

Only tricky bit is getting the cable to match the gear but it's pretty simple. I think you need to match the derailleurs with the gear shifter though? so shimano whatever to shimano.

semi-pro waster · 8 Sep 2012 at 23:09

I'd say it might be a simple swap rather than it definitely will be, generally if you're sticking with the same manufacturer it will help but be aware that they're not always interchangeable depending on what system you've got. Some SRAM shifters use a 1:1 ratio while others from SRAM will work with Shimano which is 2:1 (i.e. it pulls less cable to change gears) - if you go and speak to your local bike shop then they should be able to advise you if they're any good.

Semple · 9 Sep 2012 at 13:33

Thanks for the advice so far guys.

The specs from my bike are..

Front Mech: Logan LY-0818MJ
Rear Mech: Shimano RD-TX31D
Gear Shifters: SRAM MRX 204

I'm looking at a pair of Shimano ST EF51 brake & gear shifters. I read from one review that the Shimano's have a pull ratio of 2:1. As the rear mech is also made by Shimano the ratio shouldn't be any issue? But what about the front mech?

semi-pro waster · 9 Sep 2012 at 15:14

I can't say I've ever heard of Logan as a brand of front mech (or indeed anything) but it must be Shimano compatible since the SRAM MRX shifters use a 2:1 pull ratio and are designed to be Shimano compatible. On that basis it should be the simple swap that ins0mn1ac suggested.