Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Bicycle Mechanics (https://www.bikeforums.net/bicycle-mechanics/)
-   -   7 spd Grip shifters with SunTour XCM ? (https://www.bikeforums.net/bicycle-mechanics/1206424-7-spd-grip-shifters-suntour-xcm.html)

jacksbike 07-02-20 06:35 PM

7 spd Grip shifters with SunTour XCM ?
 
Hi folks,
I have a bike with SunTour 7 speed XCM derailleurs and triple crankset. Can I replace the existing shifters with a set of SRAM 7 speed Grip Shifters ? I know that there are different pull ratios using Grip Shifters with either a Shimano or SRAM rear derailleur, but I don't know if this will work. Open to any and all mechanical suggestions ! Thanks.

bikeaddiction1 07-02-20 07:40 PM

SRAM, Shimano, and Suntour 7 speed cassettes all have 5.0mm center to center gear spacing so it should work. Personally I would not go to twist grip shifters as in my experience they may work when new but soon they all work poorly and are much harder to maintain than other types of shifters. They typically only come on lower end bikes.

Just my opinion, but I fix up a lot of cheaper donated bikes for a couple local charities and I have seen many twist grip shifter thrown in the garbage.

dmark 07-02-20 07:55 PM

No. The derailleur pull is different. Grip Shift had Sun Tour models 30 years ago but not anymore.

70sSanO 07-02-20 08:15 PM

You need to check eBay and save a Suntour Gripshift search so if one comes up you can go after it. But one may never show up. Other option would be Suntour thumb shifters.

Or you can go to Shimano RD and Shimano compatible twist shifters “if” your freewheel/cassette has the same cog spacing as Shimano. I think the left front twist shifter is not indexed so it might work with your Suntour FD.

John

Andrew R Stewart 07-02-20 08:35 PM


Originally Posted by bikeaddiction1 (Post 21566418)
SRAM, Shimano, and Suntour 7 speed cassettes all have 5.0mm center to center gear spacing so it should work. Personally I would not go to twist grip shifters as in my experience they may work when new but soon they all work poorly and are much harder to maintain than other types of shifters. They typically only come on lower end bikes.

Just my opinion, but I fix up a lot of cheaper donated bikes for a couple local charities and I have seen many twist grip shifter thrown in the garbage.

I think your claim of 5mm c-c cog spacing for SunTour cog sets is not correct. Perhaps for the more current ST stuff that does mimic Shimano's lead. But the ST stuff from the 1990s had cog spacing that varied across the cog set. Andy

bikeaddiction1 07-02-20 08:45 PM


Originally Posted by Andrew R Stewart (Post 21566494)
I think your claim of 5mm c-c cog spacing for SunTour cog sets is not correct. Perhaps for the more current ST stuff that does mimic Shimano's lead. But the ST stuff from the 1990s had cog spacing that varied across the cog set. Andy

Sheldon says they are the same. https://www.sheldonbrown.com/cribsheet-spacing.html

Synack42 07-02-20 08:55 PM

If you're just looking for a cheap solution and don't care about indexed shifting...go retro with friction shifters: https://www.amazon.com/dp/B007QMJH86/

They're totally my go-to for any budget project. And because they're friction they basically will work with anything...

Andrew R Stewart 07-02-20 09:36 PM


Originally Posted by bikeaddiction1 (Post 21566512)

This is news that thousands of riders will find hard to believe as they have lived with poor indexing with Shimano freewheels replacing their worn out SunTours. Sorry but shop experience proves this claim is not correct often . SunTour made many different versions of their freewheels with evolving indexing attempts over the years. Cog to cog spacing, tooth profiles, chain plate shaping, pulley wheel profiles all changed as ST tied to catch up to Shimano. ST's initial design on cable tension "steps" as opposed to pulley movement amounts is said by some to be their mistake. Andy

bikeaddiction1 07-02-20 10:36 PM


Originally Posted by Andrew R Stewart (Post 21566557)
This is news that thousands of riders will find hard to believe as they have lived with poor indexing with Shimano freewheels replacing their worn out SunTours. Sorry but shop experience proves this claim is not correct often . SunTour made many different versions of their freewheels with evolving indexing attempts over the years. Cog to cog spacing, tooth profiles, chain plate shaping, pulley wheel profiles all changed as ST tied to catch up to Shimano. ST's initial design on cable tension "steps" as opposed to pulley movement amounts is said by some to be their mistake. Andy

Good to know, thanks.

jacksbike 07-04-20 03:49 PM

Thanks to all who replied. I figured that it would be a problem because I have had previous problems with SRAM grip shifters not working with Shimano rear derailleurs ( pull ratios). I am fully aware that Suntour made very many different freewheels with different spacing. I know that I can use friction thumb shifters but I would rather use indexed. Most likely the solution is to use 7 speed grip shifters and change to Shimano indexed rear derailleur, front derailleur and , most importantly, shimano indexed and correctly spaced freewheel. I do not believe, in this case, that I would have to change the SunTour XCM triple chainwheel set, but I am open to opinions on that also.

Andrew R Stewart 07-04-20 04:55 PM

Re front set up- If you use a "micro index" GripShift unit it will work with pretty much any ft der and crankset as it isn't indexed. Much like Campy Ergo front shifters.

Grip Shift makes Shimano compatible rear shifters too. Under the MRX name.

There's a lot of miss information and confusion out there concerning cog spacing and shifter/der/spacing/cable pull ratios stuff. Andy

FelixScout 07-11-20 05:22 PM

Do you have a source for "micro index" grip shifts? I keep finding microShift stuff instead unless that is what you meant?

70sSanO 07-11-20 05:44 PM

Micro index is a non-index shifter. It just has ratchets/clicks as you turn the shifters. For a number of people the little ratchets, micro adjust, make it easier to shift.

You just need to find a non-index left shifter that has micro index/adjust. I think most left Gripshift front shifters are micro index.

John


All times are GMT -6. The time now is 08:16 PM.


Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.