Firebird breaking chain... a lot
6th broken chain this morning on the firebird, starting to feel a bit angry about it. Currently using a XTR (7701), which I also use on the commuter, road bike and DH (Phoenix) without any problems. A month ago I also managed to tear 6 teeth of the saint 22T granny.
All 9spd except for XT front derailer 10spd
XT ****fifter / Mid cage deraileur / XTR chain
Saint crankset 22/36 / XT casette (12-32)
So far every break has occurred during a slow ascent in the granny and either the 28t or 32t cog on rear. What normally happens is I crest a water bar or lift the front onto an obstacle, the bike comes to near a standstill, I shift my weight forward (so the front doesn't lift), as I am doing this the back end compressors into the water bar or obstacle. As I start to peddle again to regain some momentum, the chain snaps, I swear loudly.
I understand in this situation there is a lot of torque going through the drive train, low gearing + steep hill, starting from near a stand still. I do not change gears during this and do not mash the pedals, I consciously peddle gently at the start of the pedal stroke.
The chain is long enough, always replace the broken links with new.
The chain is always repaired with proper shimano connection pins.
The chain does not break in the same spot (have been marking the breaks).
The chain is clean and oil, in gear, no bent cog teeth.
After the last break (5th one, not this morning), i checked the obvious things, the deraileur bolt was a little loose, along with the hanger bolt, tinny bit of play (perhaps enough for a ghost shift underload?) Tightened, still have a broken chain.
The chain is long enough, DW said there is little chain growth, which I have checked with the coil removed from the shock. Another post, on the turner forum, said to make the chain a lot longer than needed, I have, but I couldn't be arse'd going for a ride to find out.
Last thing I can think of is a new chain? I have never broken a Rohloff chain, might be worth spending the money? Wipperman seems to have a good reputation? have I got a dud XTR?
Last edited by Uphill=sad; 08-25-2012 at 10:19 PM.
I used to break alot of xt chains (hg-94)
moved to sram, and even with the lowest model (1031) - never broken again.
I've never had any problems with chains on the Firebird, running 1x10 or 2x9. I've always run XTR chains.
Is the chainline/bb spacers right? Is the cassette lock ring tight? Are any of the links twisted slightly? That's about all I can think of.
This is the same chain broken six times? Or six different chains?
If it's the former, that might be the issue. I have no scientific explanation, but I never run a chain that's been broken, aside from (hopefully) using it to get off the trail.
yeah, since you already cycled it through the travel without the coil and all, it's got to be the chain... that said if it is the same chain, i've had the same thing happen with 7701s where once it breaks once, it just keeps beaking... even in different spots.
i need to develop my crashing skills...
You probably got a dud. I had a sram chain (maybe a pc971) that after the first break it kept going crazy breaking all the time. I made sure that the chain wasn't too short, too long or twisted. I changed out the chain and no problems after that. It was a new chain by the way. Im not suprised when stuff like this happens with fairly new stuff. I bought a 2012 Pivot 5.7 and the Fox Float 150 came with a bad air seal that let oil from the lowers migrate to the top air chamber. Thats a very expensive top of the line "Pro" fork. WHen I researched it there were 100's and 100's of customers with the same issue. Sucks but sometime boosting profit means skimping on quality control.
Only type of shuttle I ride....the ambulance!
It's the same chain (with extra links used from the spares).
The chain links look pretty good and the chain has no twists or kinks, checked every link individually.
I am presuming it's a dud, since I have never had a problem with the same model on all my other bikes. I first thought it was breaking in the same place (dodgy fix), but it's definately a different spot each time.
Anyone have a recommendation for a 9spd chain to suit XT? I don't think I'll buy another 7701
Big Test Icycles
I have had great results with SRAM 990 chains. I have only broken one and it was after a derailleur hanger broke, bending the derailleur and twisting the chain. I rode it for a week with a kink, it finally gave out and snapped. I have used them with both SRAM and Shimano (Saint) set ups.
I have some new XTR 9 speed chains I'll sell you if you PM me.
Maybe you just have some super human strength in your legs that make"s the chain go ping.
I've snapped a 3 chains now both going dh not up, one was old and the others may have been to short. That was before I had thought about setting the chain length with the suspension fully compressed.
Since I've done that i haven't had a problem.
Just thought I'd update this.
Threw the XTR chain out and bought a KMC X9 chain - been riding it now for 6 months without a single break. Still riding up the same technical up hills which require some bursts of power, but no problems at all.
I either had a dodgy XTR chain, was not connecting it properly (was using shimano replacement pins - it also did not break in the same place twice) or an XTR chain is simply not up to Clydesdale/power lifting quads. I do still run an XTR on the DH bike without fault, but the gearing is completely different.
I haven't changed anything else on the bike, I don't shift under load, so far I am happy to recommend KMC chains... but undoing the quick link should have bought the tool for it.
That quick link tool is money well spent
Desert Sunset Calls/Upward, Pain, Perseverance/Welcome Solitude
And I only run KMC chains on all my rigs.
Which KMC chain? the extra light seems to be not too sturdy for firebird>? How is shifting on Dynasys 10 speed that is designed for directional chain?
What about Wippermann Connex 10SX 10-SPEED Chain, has anyone tried it yet?
I went the standard X9 93 - avoided the lighter versions, I think from memory, would have saved 30-50g (?), didn't think it was worth the risk - also a little cheaper. I have just upgraded to 10spd XT dynasys, with a KMC X10 93. After some careful looking around the KMC chains are not directional, and while I cannot compare the shifting to another chain - the KMC shifts nicely - smooth and snappy, for lack of better terminology.
Originally Posted by Ilyam3
Ordered the KMC tool this morning, hopefully will result in less tool rage in my shed.
I use the lighter KMC with the cutouts and the gold colored plating on it for my AM bike with a 1x10 setup and it never, ever breaks and shifts like a dream.