Gears

For discussions about bikes and equipment.
BitBroken
Posts: 3
Joined: 12 Jan 2021, 5:44am

Gears

Postby BitBroken » 12 Jan 2021, 6:02am

I was given a tricycle and it has grip shift on it. I want to covert that to triggers as I get on better with them.

I have an SRAM MRX shifter, an SR Suntour derailleur and an un-labelled freewheel but it looks standard.

Does anybody know what to use that would be compatible ?

Brucey
Posts: 42204
Joined: 4 Jan 2012, 6:25pm

Re: Gears

Postby Brucey » 12 Jan 2021, 6:59am

SRAM MRX uses the same shift ratio as shimano 6,7,8,9s. SR suntour rear derailleurs have also used shimano shift ratio in recent years.

So I think it is mainly a question of seeing how many sprockets you have at the back, and then buying a shimano compatible trigger shifter that is meant for that number of sprockets.

If you want a different number of sprockets at the back, now might be a good time to change this, and get a shifter that matches whatever new number of sprockets you end up with. However not all conceivable changes are practical; 'it depends'.

hth

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

BitBroken
Posts: 3
Joined: 12 Jan 2021, 5:44am

Re: Gears

Postby BitBroken » 12 Jan 2021, 7:06am

Thanks for the info. I am not familiar SRAM at all.

Given the info I could find 'Can of Worms' springs to mind.

I have a very cheap Shimano shifter on order to try.

Ta.

Brucey
Posts: 42204
Joined: 4 Jan 2012, 6:25pm

Re: Gears

Postby Brucey » 12 Jan 2021, 7:30am

I'm guessing you may have a screw-on freewheel...? FWIW currently available 6s freewheels from nearly all manufacturers use 5.5mm sprocket spacing, 7s (freewheel or cassette) uses 5.0mm spacing and 8s (freewheel or cassette) uses 4.8mm spacing. This means that 6s 7s and 8s index shifting has one less worry; it is mainly a question of making sure the number of clicks in the shifter is correct and that the rear derailleur is a match for the shifter (in terms of shift ratio).

However in 5s there are variations in available sprocket spacing and this can mean that 5s indexing doesn't always work quite as well as it should do. Kind of ironic, because that ought to be the simplest arrangement of all. In fact 5s indexing usually only affects gears 2,3,4, because the mech limit screws (should) determine the alignment in gears 1 and 5. So it is only three gears that the indexing has to get right, and that isn't always possible....

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

BitBroken
Posts: 3
Joined: 12 Jan 2021, 5:44am

Re: Gears

Postby BitBroken » 12 Jan 2021, 8:56am

Didn't say, apologies, it's a 7.

The trike is not very old, besides I am not sure how you'd get the freewheel off and the chain is from new, so I intend to heave it as is.

The trike is about 6 years old and I assume low mileage.