Chain Coming Off

getonyourbike

I've been doing quite a bit of DH on my hardtail and the chain keeps coming off mid run so when I next try to pedal, I can't and also I've managed the literally bend the chain like this. It's happened twice now and both times I've had to take a link out and replace with a KMC Missing Link. My chain's getting a bit short now, it's a KMC X9L if that matters, if anymore links need taking out then it's new chain time.

I was just wondering it's a problem with my derailleur setup. The front and rear seem to be set up fine.

You can't run a chain guide with a triple set up can you? Can you with a 2X9 and if so what changes would I need to make other than chainring sizes? Would I need to mess around with spacers and need a medium cage rear mech? I know you sort the front derailleur by bringing in the high limit screw.

Cheers
Pete

nicklouse

ride slower. chose a better line. and have the chain on the middle front cog and middleish rear cogs.

getonyourbike

Ride slower isn't really appropriate as i'm riding a DH track and the whole idea is to be as fast as you can. If I went slower I'd also not have enough speed to the clear the landings on the some of the step downs etc. I've already got the best line so I can't do that either and there's really only one line. The drops and jumps may also have made it come off and I can't avoid those either.

If I have the chain on the largest chainring and the middle of the cassette the chain jumps off completely and if I have it on the middle chainring and the smallest sprocket (which I need to for a high enough gear) then it jumps down onto the inner chainring and stays there until teh end of the run.

I'm really looking for a prevention, so different setup really

andrewjoseph

try the chain on big ring and middle of cassette, more tension on the chain, more chain on the chainring.

i don't do DH, but I nearly always put the chain on the big ring for descents.

tom_howard

this should help http://www.chainreactioncycles.com/Mode ... elID=50905

try to focus on riding smooth rather than fast. Riding light will help, where you do a series of bunny hop actions but dont leave the ground, this unweights the suss so you arent crashing through the terrain.

kdawg74

You need a chain guide really, have you thought about running a single ring up front?.
With the right ring you could still get up the hills if you need to.

You can run a chain guide with a double and a medium or even a short cage would help with chain tension too not sure about needing spacers but i'm sure some one will have the answer to that one, the tip of unweighting the suspension of course does not apply as your on a hardtail.

tom_howard

kdawg74 wrote:

the tip of unweighting the suspension of course does not apply as your on a hardtail.

So what is that thing attaching his front wheel to his frame? As he is unweighting the rear of the bike too meaning the bike won't be smashing into the terrain as much thus reducing the likelyhood of the chain being rattled off.

kdawg74

Fair enough but the front is there to take the hits as you are supossed to ride the forks on a hardtail, and with good set up wont transfer so much of the jolts to the rear, and you cant always try to lighten the bike over everything just not possible on a DH track.

Was'nt trying to diss your answer it just seemed as if you had missed the hardtail part of his question that was all

tom_howard

I hadnt, thats how I used to ride my hardtail DH like that (still dabble now if I fancy giving myself a kicking!) at places like Wharnecliff and local DH trails at Storthes Hall. In fact I did it much more than I do now because now I just let the travel soak everything up, because ive got lazy. (note to self, start attacking DHs harder)

nicklouse

getonyourbike wrote:

Ride slower isn't really appropriate as i'm riding a DH track and the whole idea is to be as fast as you can. If I went slower I'd also not have enough speed to the clear the landings on the some of the step downs etc. I've already got the best line so I can't do that either and there's really only one line. The drops and jumps may also have made it come off and I can't avoid those either.

If I have the chain on the largest chainring and the middle of the cassette the chain jumps off completely and if I have it on the middle chainring and the smallest sprocket (which I need to for a high enough gear) then it jumps down onto the inner chainring and stays there until teh end of the run.

I'm really looking for a prevention, so different setup really

then you need to either change the bike or change the set up.

After all your bike is an XC Bike and is speced accordingly.

getonyourbike

That's what I'm asking about really, changing the set up.

So I could run that e Thirteen Heim 3RS with all 3 chainrings? I'd need the BB mounted version? I'm a bit of a newb to chain retention tbh.

If I was to change to a double chairing set up with something like an e Thirteen Heim 2 what else would need to be changed. I'd need different sized chainrings obviously but would I need a shorter cage rear mech or would the current one be fine? If I wound in the high limit screw on the front mech would that be fine?

Cheers
Pete

nicklouse

sorry I would change the bike.

or go single ring at the front and cripple the bike for anything else.

getonyourbike

Changing the bike and crippling the bike for XC etc is not possible for me.

I know it isn't ideal but what would I need to do to make the double set up work? New, different sized chainrings, a medium cage rear mech and a chain guide. So would that work? It's got to be better for DH and DJ than my current setup surely?

rhialto

At the risk of repeating myself (I posted something similar earlier today), here's my attempt to answer your questions:

Replace the big ring with a bashguard (optional). I run 22 and 36 tooth chainings. The 36 helps cover some of the gear ratios that I lost when I got rid of the 44 chainring. I run a long cage XT derailleur. You could run a medium but it's not necessary - if you have a long cage that will work fine.

I installed a Blackspire Stinger, ISCG05 mounted, but they come in BB mount as well. If you choose a BB mounted chain retention device, make sure you have a drive-side spacer that you can be replaced by the retention device plate otherwise you may have crankset spacing issues (as detailed in other forum threads). Another popular retention device is the SuperStar Double Chain Device (http://superstar.tibolts.co.uk/product_ ... cts_id=336). Same mounting options.

I use a double SLX front derailleur but lots of people on the forum have reported using triple derailleurs with the limit screw set appropriately.

My setup, 22/36 and bash with long cage derailleur and Stinger chain retention device works great. It shifts well and the chain hasn't come off in 6 months, including a descent in the mountains of southern France that had hundreds of rock steps. Good times, good times...

getonyourbike

That's kinda what I was thinking of doing tbh but I'd probably go for a 24/38 chainring combination.

Just a general question to someone that's tried it. Does changing to a medium cage rear mech make a noticable diffference in reducing noise and keeping the chain on better?

Also, the spacers much need to be moved around other than that one that is replaced with the chain guide as if I was using like a normal 2X9 or 2X10 setup then I'd use all the rear sprockets with either of the chainrings. If I was to do this without moving around the spacers then it'd be like using the smallest sprocket with the granny ring which is a no go due to chain crossover. Any thoughts on this?

Cheers
Guys

nicklouse

Just a general question to someone that's tried it. Does changing to a medium cage rear mech make a noticable diffference in reducing noise and keeping the chain on better?

mope and nope.

Also, the spacers much need to be moved around other than that one that is replaced with the chain guide as if I was using like a normal 2X9 or 2X10 setup then I'd use all the rear sprockets with either of the chainrings. If I was to do this without moving around the spacers then it'd be like using the smallest sprocket with the granny ring which is a no go due to chain crossover. Any thoughts on this?

nothing changes. you dont need to use all the cogs like that.

and re the spacers it is often not possible due to crank make and BB width.

getonyourbike

Thanks. So I'd use the gear in the same way as I would with just the granny ring and middle ring on a triple set up. So middle=whole cassette and granny ring=half of cassette, largest sprockets