single front ring with no chain device?

joshtp
joshtp Posts: 3,966
edited October 2009 in MTB workshop & tech
iv just set up my second (spare) bike with 1x9 (well 8 but.....) is it OK to run it with no chain device? will the chain come off all the time? im gonna put a bash on, i went for a local ride yesterday and it seemed fine, but there was no major jusmps and drops/rocky stuff. most air was prob about 2ft.
I like bikes and stuff

Comments

  • junglist_matty
    junglist_matty Posts: 1,731
    edited October 2009
    When you ride on bumpy ground your chain will come off all the time.
  • joshtp
    joshtp Posts: 3,966
    When you ride on bumpy ground your chain will come off all the time.
    OK, so how do i stop it coming off, can i bodge a chain device? this is a LOW budget(free) project, i dont want to drop £40 on an MRP when i dont even know if ill keep the 1x8
    I like bikes and stuff
  • When you ride on bumpy ground your chain will come off all the time.
    OK, so how do i stop it coming off, can i bodge a chain device? this is a LOW budget(free) project, i dont want to drop £40 on an MRP when i dont even know if ill keep the 1x8

    Use an old front mech and fix it into position using the hi-lo position adjust screws.

    Or get something cheap like this DMR chain cage:
    http://www.chainreactioncycles.com/Mode ... elID=21874

    Any cheap front mech would do.... Its because your running a rear derailleur, on bumpy ground the cage will spring about and can spring lots on bigger bumps, jumps, drops etc... which would completely slacken your chain and cause it to come off the bottom of the front ring, without a chain cage or anything on top the ring (to guide the chain back onto the ring) you'll have to keep getting off and putting it back on manually (a real pain in the arse).
  • BeardedDave
    BeardedDave Posts: 1,977
    If you're looking for a cheap fix, try one of these: http://www.billys.co.uk/english/group.php?prod=chng-js
    I ran 1x9 for about 6 months, with one of these and a bashguard, and only dropped the chain once.
    East Anglia Biking Collective!
    http://www.easternbikemonkeys.co.uk/forum/
  • joshtp
    joshtp Posts: 3,966
    OK, so old mech it is, but any idea on bodjing old mechs to fit with the jockey wheel under the chain ring, like a proper guide? would be soooo cool to do it properly for free!
    I like bikes and stuff
  • Northwind
    Northwind Posts: 14,675
    You should find the mech pretty much does the job, plus it means you can sometimes pedal it back on if it drops.

    I saw a guy with 2 cardboard discs cabletied to his, like a pair of bashrings, looked awful but seemed to work.
    Uncompromising extremist
  • joshtp
    joshtp Posts: 3,966
    in the end i bodged something like the little thing one of you recomended, that cost £9 and was for bmx/...... its a jubily clip around the frame with a padle instead of a screw, and onto that is zip tied a pice of metal from an old cage pedal that i worked into shape, ill get a photo up soon. it works really well, i went for a ride yesterday and was ragging it really hard trying to drop the chain and it only droped once, and then i pedaled it back on! so im realy happy! its also a lot lighter than a mech and looks much better becouse its small, simlpe and looks like something designed for the job, which a front mech doesnt!
    I like bikes and stuff
  • weeksy59
    weeksy59 Posts: 2,606
    Look forward to the pics. I'm debating this myself as i have no use for the smaller or big rings.
  • joshtp
    joshtp Posts: 3,966
    weeksy59 wrote:
    Look forward to the pics. I'm debating this myself as i have no use for the smaller or big rings.
    its actually suprising how little i use those two rings! i use the samll ring for the killer climbs that litter my trails in swansea, and the big ring is good for the flat seafront, but a bit more muscle in my legs is a good thing, and the seafront is boring anyway, im totaly loving running my second"thrash" bike as 1x8 at th mo, its great. dont think ill change my main bike tho.
    I like bikes and stuff
  • The Rookie
    The Rookie Posts: 27,816
    Considering the same for my Hybridised commuter, I've crunched the gearing numbers I use for my old heavier bike (3x7 but never use the small ring) and it looks like if I put my large ring in the middle position I can run 1x9, dropping to the 1st (32t) or 2nd (28T) for the hills.

    The weight saving on mech/lever/ring (then cables to add) is 341g and I'll just need something to tidy up the spider where the outer would be (cheap bashguard maybe - maybe 2 discs of black polypropeline will do the job of tidying chain guide!) although I'm hoping not to need a chain guide/device as its all on road apart from my bunnyhop over a sleeping policeman (don't want it to slow me down - LOL)....

    Simon
    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.
  • Hello.
    This is how I secured my chain.
    A DMR chain device doesn't reach the middle or outer chainrings. It's ok for a proper single ring. My bike was being thrown away so thought I'd recycle! Didn't have a front mech so I bought a DMR. I used long bolts (M5 stainless hex heads on order) and to make the device reach the outer 42t 'ring I used two 9mm sockets. No multitude of washers, it's secure and works a treat. Chain fell off at least once each ride-now it hasn't fell off once. Job done.

    http://www.flickr.com/photos/43998582@N ... otostream/
    and a close up,
    http://www.flickr.com/photos/43998582@N ... otostream/