A couple of quick questions about mechs

Mattharrier
Mattharrier Posts: 173
edited June 2016 in MTB workshop & tech
I'm riding a Rockrider 8.0, which has SRAM shifters, a SRAM X5 rear mech and a Shimano front mech. The questions:

1) I was under the impression that SRAM shifters and Shimano mechs weren't compatible, and vice versa, so how come I've got a Shimano front mech that works? Would this explain why I can never adjust it so it's absolutely perfect?

2) I can pick up a 9 speed X9 rear mech for pretty cheap, if I do so can I simply swap one mech for the other and keep using the original shifter? What do I need to know about cage length? Is it worth going for an X7 or X9 mech over my X5?

Many thanks.

Comments

  • cobba
    cobba Posts: 282
    edited June 2016
    1) I was under the impression that SRAM shifters and Shimano mechs weren't compatible, and vice versa, so how come I've got a Shimano front mech that works?
    Rear shifters/derailleurs from different brands is where you run into the problem with compatibility, front shifters/derailleurs from different brands can work together fine.
    Would this explain why I can never adjust it so it's absolutely perfect?
    Without knowing your problem, that question can't really be answered.
    For all we know, you might be having these problems in a cross chaining gear combo.
  • larkim
    larkim Posts: 2,474
    I'm riding a Rockrider 8.0, which has SRAM shifters, a SRAM X5 rear mech and a Shimano front mech. The questions:

    1) I was under the impression that SRAM shifters and Shimano mechs weren't compatible, and vice versa, so how come I've got a Shimano front mech that works? Would this explain why I can never adjust it so it's absolutely perfect?

    2) I can pick up a 9 speed X9 rear mech for pretty cheap, if I do so can I simply swap one mech for the other and keep using the original shifter? What do I need to know about cage length? Is it worth going for an X7 or X9 mech over my X5?

    Many thanks.

    Ref 1 - its just that front mechs are a bugger to get "absolutely perfect". Fettle, tweak, etc. But absolutely perfect might not be achievable, I suspect thats why many go to 1x or 2x up front vs 3x.

    Ref 2 - I'd first be asking why you want to upgrade. Is there something wrong with the X5 setup at the back that means it needs updating? Cage length depends on the cassette at the back.
    2015 Canyon Nerve AL 6.0 (son #1's)
    2011 Specialized Hardrock Sport Disc (son #4s)
    2013 Decathlon Triban 3 (red) (mine)
    2019 Hoy Bonaly 26" Disc (son #2s)
    2018 Voodoo Bizango (mine)
    2018 Voodoo Maji (wife's)
  • Mattharrier
    Mattharrier Posts: 173
    The issue I have with the front mech is minor, it rattles slightly in either the top or bottom chain ring (i.e. if I adjust it so it doesn't rattle in the top ring, it will start to rattle in the bottom and vice versa). I rarely use anything but the middle ring so it's not too much of an issue, but I was curious.

    Regarding the rear mech, there's nothing wrong with it, but an X9 mech would, presumably, offer quicker and smoother shifting, which would of course be advantageous. There's no problem to fix as such, but I've read varying reports that suggest X5 or X7 is the minimum that can be considered a "proper" mountain bike mech, and improving my bike by only spending a few quid and some time doesn't seem like a bad idea.

    Cage length - presumably I need to keep the same length I have now?
  • Unless you change the rear cassette then mech length stays the same. Regarding the rear derailleur I wouldn't be in a hurry to change it. If you really want to spend money I would say changing the shifters would give you more improvement .you would need to stay with sram . X9 shifters just feel better. They don't do anything differently. Enjoy what you have and upgrade as bits wear out.
  • The Rookie
    The Rookie Posts: 27,812
    The mech of itself doesn't offer smoother and faster shifting, the benefit is that the X9 will stay offering the same quality of shift for longer than the X5 as the lower end SRAM models tend to wear faster and get a bit 'sloppy'. Shifters generally have more effect on perceived shift feel than the mech.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • larkim
    larkim Posts: 2,474
    I suppose it depends how cheap the X9 is. £10, probably worth spending for a new experience of changing and setting up a RD as a bit of self-teaching maintenance. £50, I'd be questioning whether replacing functioning RD with slightly better but still equally functioning RD was good VFM for me.

    If I was spending money on a bike I'd look at performance or comfort areas first, and mechanical gubbins later. So tyres, fork, cassette ratio, wheels, brakes, pedals for performance. Seat, stem, bars etc for comfort.
    2015 Canyon Nerve AL 6.0 (son #1's)
    2011 Specialized Hardrock Sport Disc (son #4s)
    2013 Decathlon Triban 3 (red) (mine)
    2019 Hoy Bonaly 26" Disc (son #2s)
    2018 Voodoo Bizango (mine)
    2018 Voodoo Maji (wife's)