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Chain breaking

fartloud1

fartloud1

Chimp
Oct 5, 2011
12
0
Lake Havasu City
So my chain has broken 3x in the past month or so. It's always when standing and torquing up short steep hills. (Which consequently results in a hard fall and cursing). The chain was new this past spring, but I ride 3-4x a week. Also, I have smooth shifting and no chain skip/suck. And since a couple of chains-ago, I've been pretty religious about inspecting the chain when cleaning/lubing. The chain is a Sram PC991 with Sram x9 drivetrain. Bike is full suspension XC, but use mainly all-mountain. The outside plates of the link appear to be spreading and popping off the link. Questions: How many breaks before a new chain? Once it starts breaking, is it toast? I don't remember chains breaking on my hard-tail. Does anyone else? I assume it just keeps breaking where it was put back together? Any of you willing to sacrifice some weight for a sturdier chain? (I don't race.) How much life do you get out of a chain? I thought a chain should last a full season, but maybe not?

Cheers and Happy New Year
 
BikeMike

BikeMike

Monkey
Feb 24, 2006
784
0
You're right that chains usually break where they have been repaired, but are you repairing with a master link or does SRAM have a special pin now?

Shimano chains have been solid for me. You just have to make sure to use the special pin (provided) when putting them together.

If it's broken a few times it's worth it to get a new chain and start again. Chain wear depends on conditions and the state of your drivetrain, so chainstretch is usually a better indicator than time. It's better (for the rest of your drivetrain) to replace a chain a bit early than it is to replace a chain a bit late.
 
fartloud1

fartloud1

Chimp
Oct 5, 2011
12
0
Lake Havasu City
Sounds like I've been doing it wrong by not using master links. Time to buy a new chain and handfull of masterlinks. I usually use a chain tool and take off the link that failed and then use the chain tool to reconnect the chain to get me home. I'm not aware of a special pin by SRAM. My shade-tree ways usually made me assume the outside plate was failing because it's always bent when it breaks. Thanks for the advice.
 
ltr450rider

ltr450rider

Chimp
Jun 17, 2010
43
0
Goleta, CA
Proper length chain might be an issue here. Some f/s bikes have a small amount of chain growth when the suspension cycles. If you are powering up in your big/big gears, or running a single ring up front, that could pull your chain apart if youre chain is too short.

BTW, I see your in Havasu. I might hit you up about some trail info sometime, If I ever make it out during the winter months that is.
 
woodsguy

woodsguy

gets infinity MPG
Mar 18, 2007
1,083
1
Sutton, MA
If you don't use a powerlink and just put the chain back together it will break again. That method should only be used in an emergency. I also have found that a dry chain will break so make sure it is properly lubed. That is the main reason I stopped using White Lightning. I like the lube but it needed to be applied before every ride and if I forgot there was a good chance of a broken chain. To make it worse sometimes it wouldn't even last one ride. I used to break chains every week or so with WL and no powerlink.
 
fartloud1

fartloud1

Chimp
Oct 5, 2011
12
0
Lake Havasu City
ltr450rider said:
Proper length chain might be an issue here. Some f/s bikes have a small amount of chain growth when the suspension cycles. If you are powering up in your big/big gears, or running a single ring up front, that could pull your chain apart if youre chain is too short.

BTW, I see your in Havasu. I might hit you up about some trail info sometime, If I ever make it out during the winter months that is.
Click to expand...
Yeah, hit me up. There's quite a few trails here now, and they're not on the map.
 
fartloud1

fartloud1

Chimp
Oct 5, 2011
12
0
Lake Havasu City
woodsguy said:
If you don't use a powerlink and just put the chain back together it will break again. That method should only be used in an emergency. I also have found that a dry chain will break so make sure it is properly lubed. That is the main reason I stopped using White Lightning. I like the lube but it needed to be applied before every ride and if I forgot there was a good chance of a broken chain. To make it worse sometimes it wouldn't even last one ride. I used to break chains every week or so with WL and no powerlink.
Click to expand...
Seriously, I just started using WL a few weeks ago. Noticed my chain was obviously dryer at the end of each ride.
 
BikeMike

BikeMike

Monkey
Feb 24, 2006
784
0
Yeah, mostly chains break because they were connected without a master link or the special pin. Most people learn that lesson at some point.

Quick test for if a chain needs lube (especially if using a dry lube) is to tap it. If it rattles it needs lube.

Cross chaining (big chain rings up front and in back --or small in both) can put a bit of lateral stress on the chain, but usually that accelerates wear more than breaks the chain. Running totally dry isn't great for the chain, but it doesn't usually send the chance of breakage through the roof for an otherwise good chain. If you're not happy with WL and still want a dry lube, I'm a fan of Rock-n-Roll Gold (on the mountain bikes, runs clean but still requires fairly frequent application). Dumonde Tech Original is my favorite wet chain lube.
 
R

roel_koel

Monkey
Mar 26, 2003
278
1
London,England
if you are regularly breaking chains I would first inspect your CHAINTOOL

I have seen many riders with ongoing problems with their chains, and they use the same chain tool each time to install the chain, or to install a new chain

using a cheap chain tool can also cause this problem, as the chain is not installed properly to correct tolerances

if the chain tool (bushing pin) is damaged (sometimes it is slightly flared from an off-centre contact with the chain bushing) it will deform the chain structure just enough to cause a failure under extreme pressure

I always use Park chain tools on my bikes (and my customers bikes) and regularly replace the bushing pin to avoid these issues


also, inspect your drivetrain components (typically the chainrings and cassette teeth) to make sure you don't have a damaged chainring or cassette cog tooth that is deforming your chain
 
baca262

baca262

Monkey
Aug 16, 2011
392
0
do you check if the pin is protruding outside the outer link a little after reconnecting? if it's flush, it'll snap. i've reconnected at least 5 chains on random links in the last 3 years and i've only had a single snap, that was when i forgot to check the aforementioned.

the chains were the cheapest variety though (i can't be arsed to shell out more than 20$ for a part that will wear out after 3 months of winter riding), i've noticed that the more expensive chains have recesses in pin faces so you might really need a different pin to reconnect the chain. either way, powerlink is the way to go.
 
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fartloud1

fartloud1

Chimp
Oct 5, 2011
12
0
Lake Havasu City
Gee-whiz update: Bought a new 990 chain AND a 990 cassette. (New Race Face cranks/bb last month) The new drive-train has such a night & day difference that I feel like a squid for not replacing parts sooner. Didn't think they were that bad prior to the new parts.
 
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