Bicycle Mechanics - Replacing barcons with gripshift ?

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kipibenkipod
05-20-09, 10:16 AM
Hi,
I have a touring bike with barcons shifters.
I have replaced the handlebar to a trekking bar.
The handle bar clamp size about 22mm.
It is Shimano RSX 8 gears, and I will install a cassette of 32.
Will every grip shift work?
I'm looking on the SRAM X.7 ESP Shorty Twist Shifting Lever (http://www.bike24.com/1.php?content=8;navigation=1;product=7668;group=43;page=1;pid=116;menuid1=2;menuid2=0;mid=0;pgc=0).

Thanks for your help,
Kfir


bikeman715
05-20-09, 11:06 AM
yes they will.

kipibenkipod
05-20-09, 11:08 AM
yes they will.

Is it something general that all the gripshift will fit?

Thanks,
Kfir


hernick
05-21-09, 12:19 PM
All gripshifts that I know of are designed to fit MTB-diameter (22.2mm) handlebars, which includes flat bars, riser bars, trekking bars, north road bars... So, all gripshifts will physically fit on your handlebars.

However !

While the left (front derailleur) gripshift can be of any type, the right (rear derailleur) has to be of Shimano 8-speed type.

The rear SRAM shifter you linked to will **NOT** work, because it is of the 1:1 actuation ratio type. In the "compatiblity" section, it says: "SRAM 1:1 9 or 8-speed rear derailleurs". You do not have such a rear derailleur. Do not purchase these gripshifters.

What you need is a Shimano-compatible (2:1 actuation ratio) rear shifter. Like this (http://www.bike24.com/1.php?content=8;navigation=1;product=756;group=43;page=4;pid=116;menuid1=2;menuid2=0;mid=0;pgc=0) or this (http://www.bike24.com/1.php?content=8;navigation=1;product=755;group=43;page=4;pid=116;menuid1=2;menuid2=0;mid=0;pgc=0).

As I said, the front (left) shifter doesn't matter, it's all compatible.

kipibenkipod
05-21-09, 01:03 PM
Hernick,
Thanks for taking the time and show me what will fit my bike.
I really appreciate it.

Thanks,
Kfir

JiveTurkey
05-21-09, 05:31 PM
Front derailleurs and shifters are NOT all compatible.

Generally speaking, the only time everything's compatible is when it is in friction mode, not index.

Shimano road vs MTB front shifter/derailleurs utilize different cable-pull ratios. Shimano and SRAM flat-bar/MTB front shifters/derailleurs are compatible though.

If you go with the Shimano or SRAM shifters, you may need a Shimano MTB-compatible front derailleur.

What size chainrings are you using? There are MTB front deraillaurs rated up to 48T.

Edit: Upon further research, it appears grip-shifters may have a micro-indexing which allows the shifter to be in more positions than just the 3 marked on it. If that's the case (and it's been a while since I've had my hands on a grip-shifter), it should work similar to a friction set-up.

hernick
05-21-09, 10:57 PM
Indeed, the actuation ratio of road and MTB front derailleurs is a bit different. The MTB front derailleurs need a bit more cable pull.

However, all the SRAM front grip shifters that I know of are not indexed, but instead operate in a friction-like mode with tons of little clicks. They call it "micro-indexing", which is functionally equivalent to friction shifting. The " 1 2 3 " printed on the SRAM front grip shifter are for reference only.

Since the SRAM front grip shifter is designed to pull enough cable for a MTB front derailleur, and those need more cable pull than road triple front derailleurs, the SRAM front grip shifter can certainly pull enough cable to shift correctly through all front gears of a road triple FD.

Any SRAM front grip shifter with "Micro Index" (and to my knowledge, every SRAM front grip shifter is indeed Micro Index) will work just fine with your front derailleur. The "1 2 3" printed on the shifter may not line up perfectly, but that will have no impact on your shifting performance.