T-Limburn Posted August 16, 2012 Report Share Posted August 16, 2012 Hi guys, basically I have never had such bad luck with chains - as of tonight I have snapped 5 this year! Luckily the snaps have all happened whilst I'm kicking to get on the rear wheel rather than when I'm doing a big move! I need to get to the bottom of this so here goes: At the beginning of the year i was using: Middleburn super pro trials ti bash (been good for years but very stretched and worn teeth), cheap crappy mech that did the job, KHE collapse chain (one year old at time of snap so I thought yeah, fair enough), and a chain line that was way off but that had worked for years (if it aint broke, don't fix it?) Once the KHE died I got a Sram 9 speed chain as it was all I could get hold of on a Sunday, and I really wanted to ride that day! The Sram lasted a week but are in no way designed for the stresses of trials, so that was fine. Next I bought a KMC Z510 and fitted a Rohloff that I'd had laying around for a while. This too lasted one week. I bought a Z510HX next, and sorted my chain line out when fitting it as it was out and I figured this may be a factor. This lasted a while but then snap! At this point I was getting pretty pissed off with snapping chains and bashing up my knee, so when I bought my new chain (another Z510HX) I also bought myself new front and rear cogs as mine were pretty knackered. I replaced the super pro trials bash with a TNN Super Comp 16t and got a 14t Trialtech for the rear. This setup lasted a while, but the chain snapped tonight. This is a picture of my setup before I fitted the new cogs: The Rohloff is at pretty much full stretch, but I've definitely seen them run like this before... and plus it looks awesome haha. Obviously I'd rather not replace my massively overpriced chain tensioner, but can it really be the problem?! Other people have run Rohloffs nice and taught like this with no troubles! When the first 4 chains snapped it was in the middle of the link, suggesting it was stretched but most have only been a matter of weeks old! The 5th just ripped the plate away from the pin! Cheers, Tom 2 Quote Link to comment Share on other sites More sharing options...
N.Wood Posted August 17, 2012 Report Share Posted August 17, 2012 I'd probably say its something to do with the 16t front chainring. The more teeth, the more the load is spread around the chain and lessens the stress on each link. Pretty sure loads of people who used to run the super pros snapped tonnes of chains. Seems like upping it to 18t makes alot of difference. 2 Quote Link to comment Share on other sites More sharing options...
craigjames Posted August 17, 2012 Report Share Posted August 17, 2012 As Nick said, also the fact the chain is run silly tight won't help. Quote Link to comment Share on other sites More sharing options...
SunnyBoy Posted August 17, 2012 Report Share Posted August 17, 2012 Probably a combination of super tight chain and the 16t front sprocket...I'm just about to start using a similar set-up with 16 / 13 ratio and an Atomz tensioner so I guess I'll see how well it copes! Quote Link to comment Share on other sites More sharing options...
Jake. Posted August 17, 2012 Report Share Posted August 17, 2012 If you can squeeze the chain and it touches the chainstay or nearly touches it then that's good, shouldn't run your chain as tight as you can. I agree with the 18t comment. Quote Link to comment Share on other sites More sharing options...
Al_Fel Posted August 17, 2012 Report Share Posted August 17, 2012 Hows your chain tool looking? That could also be your problem. The 16:14 ratio isn't ideal either but maybe if your chain tool is damaging the chain as you are fitting it that could be where the problem lies. Quote Link to comment Share on other sites More sharing options...
MATRIAL Posted August 19, 2012 Report Share Posted August 19, 2012 18 / 15 ,, kmc koll chain and you can pull a train whit out any chance of snap Quote Link to comment Share on other sites More sharing options...
onza pro series guy Posted August 19, 2012 Report Share Posted August 19, 2012 i ran a sram 8speed for ages with my rohlofff super tight with no problems. Currently running a Z510 and a tight rohloff no probs so far, touch wood. I'm running a 22t front sproket though so could be your problem as metioned above. Quote Link to comment Share on other sites More sharing options...
T-Limburn Posted August 21, 2012 Author Report Share Posted August 21, 2012 Cheers guys. I know that a 16t sprocket has more stress than an 18t, but I used my superpro for years, with badly stretched teeth and never had a problem before this year, so I only changed to the tnn on the off chance that this could be the problem. I've always run my chains as short as possible too, but never with such a strong tensioner I guess. Think I might try it with a slightly longer chain so that the rohloff isn't at full whack like pictured above and hopefully it'll last a bit longer! Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted August 21, 2012 Report Share Posted August 21, 2012 The chain length won't make a difference. The KHE lasted cos it's a very strong chain, when I had 16t up front it was the only chain I could use that didn't break almost instantly. Unfortunately you need a stronger chain or a bigger front ring... 1 Quote Link to comment Share on other sites More sharing options...
T-Limburn Posted August 22, 2012 Author Report Share Posted August 22, 2012 (edited) Thanks Adam! Well I repaired my chain last night and put my crappy old mech back on, everything is running very nicely! I think the chain was well over tight with the rohloff at full stretch, hopefully this will last a little longer - as I said, I've never had this problem before now and I've been running 16:14 for about 5/6 years now. If it does start happening again I guess I'll have to suck it up and get a bigger cog up front, but fingers crossed I'll be ok now! Edit: The only thing is that my old mech is quite big whereas the rohloff was nicely tucked out the way. If this solves my problem, what tensioner would you suggest that is slimline and not as powerful as a rohloff? Edited August 22, 2012 by T-Limburn Quote Link to comment Share on other sites More sharing options...
N.Wood Posted August 22, 2012 Report Share Posted August 22, 2012 Could you not just run the Rohloff and add a link to the chain? Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted August 22, 2012 Report Share Posted August 22, 2012 The tension provided by the chain tensioner is nowhere near the tension applied to the chain when you stomp on the pedals - trust me, the chain tensioner does not make a difference in terms of your chain snapping. 2 Quote Link to comment Share on other sites More sharing options...
T-Limburn Posted August 22, 2012 Author Report Share Posted August 22, 2012 (edited) Yes Nick I think I will try that too, it was just nice to be able to go out riding last night knowing that my chain was at a decent tension without being over tight like it was with the Rohloff. Running it as tight as it is in the top picture the cranks wouldn't even rotate backwards very nicely it was that tight. With the mech on they spin nice and freely. I'm now wondering whether the rear jockey wheel was catching a little on rear sprocket where I was trying to run a nice slimline set up when the Rohloff arm isn't very long. But that'll teach me for choosing aesthetics over function Oh and Al_Fel I've used various chain tools on the multiple chain replacements so I don't think its that, but cheers I'll keep a closer eye on it next time just in case! Edited August 22, 2012 by T-Limburn Quote Link to comment Share on other sites More sharing options...
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