Granny sucking my chain

[stratus5]

Could have worded the title a lot better

 

I have a XT (2008) crankset which is fairly new (~1500km) which is chain sucking. It only the granny gear (single gear suck) and happens once the chain is a bit sandy/dirty/wet.

 

I took the granny gear off last night and it does show signs of wear. There are clear notches where the chain has worn into the gear, but its nothing like a cresting wave, just a noticable notched point on the pressure faceof three or four teeth rather than the original smooth profile. Other two blades look like new and chain has about 200km on it.

 

I have seen a web site or two, where they suggest just filing the tooth smooth again,  but not happy altering the profile on such a highly loaded gear.

 

I will replace the gear, but hesitant to go the XT route again since this one wore so quickly. Is there a better more wear resistant sprocket I can use instead of the current XT version? I am not worried about a slight increase in weight.

 

I would also like to apologise to Lilo (I think?). I was going up the second very steep climb at Wolsely when she came steaming up behind me (I am faster downhill). As she caught me the granny gear sucked and I called it a 'Bitch!' before I realised there was a pretty girl alonside me. Sorry Lilo I was really swearing at the gear

 

 

[Saffa_G]

thats a serious communication problem... chuckle 

[Tumbleweed]

i've hear the bbb ones are pretty tough. never used one though.

[AndreZA]

So basically what you are saying is that your granny sucks.

[slowpoke]

hmmmm.... i also ride XT.... and if it weren't for I_Fly coming to my rescue i'd have been carrying my bike home after my last ride... because of chain suck in granny gear!!!

[AndreZA]

You guys did not read the user manual did you? XT and XTR do not make "granny" gears. That little toothed wheel on the inside of the crank is a chain catcher and not a chainring.

 

 

[Overlord]

 

You guys did not read the user manual did you? XT and XTR do not make "granny" gears. That little toothed wheel on the inside of the crank is a chain catcher and not a chainring.

 

 

 

Ain't that the truth.

 

[Johan Bornman]

Chainsuch is due to one of three problems.

1) Tooth profile.

2) Mud and dirt clenching the chain onto the gear and it therefore cannot release the chain.

3) A chain that's so rusted and stiff, it just follows the gear instead of exiting in an orderly fashion.

 

In other words, if your chain is clean and free rolling, it is the tooth profile.

 

I find it strange that your granny has croacked after so few miles but then again, perhaps you did all 1500 those k's in the granny, in bad mud. Who knows?

 

File the teeth. Don't worry about a highlyloaded gear. You'll have to file them to stumps before it slips and as a sensible guy, you wont do that.

 

Eventually you'll have to replace it of course, but nothing wrong with filing it at least once.

 

 

[WorcesterWheelers]

Chainsuch is due to one of three problems.

1) Tooth profile.

2) Mud and dirt clenching the chain onto the gear and it therefore cannot release the chain.

3) A chain that's so rusted and stiff' date=' it just follows the gear instead of exiting in an orderly fashion.

 

 [/quote']

 

I'm sure plenty of people had chainsuck on Sat in Wolseley's race.

 

We crossed plenty of streams and several muddy sections, and even a fair bit of sand.

[stratus5]

Thanks for all the advice/suggestions

 

Bought the bike from Albert (Probike). I think he weighs 96 Kg and is a strong guy. The crankset  may have done the Epic?

 

I weighed 98 when I bought the bike, but now down to 94  and dropping... Fairly strong rider as well, but go downhill over technical sections on my face more often than I care for.

 

Done most of this years PP fun rides including Robertson, which was a mud fest.

 

The wear is not bad, but it is noticable. I think if you are pushing 90 plus kilos up a steep hill you will chainsuck far more than lighter guys given the same trail/and bike conditions. It only sticks when I have to peddle slightly harder than normal, like over a short steep rocky section.

 

Not all teeth are equaly worn. Some are perfect. When I tried filing some of them, it would appear that some are softer than others. Not sure if the XT small blade is hardened (can you harden alu?). Could be one or two areas were not correctly treated.

 

What I have noticed is that the granny seems particulary noisy under load. Admittedly the chain often has sand/mud/snot on it, but it sounds very much like the front deraileur is touching the chain (which it isn't) and grinding away. Previous cranksets I have owned were definitely quieter.

 

Know there were lots of previous threads on chain lube, but i am a bit frustrated in that the wet lubes seem to be sticky and encourage sand to stay on the chain for longer. The dry lubes shed dirt better, but also dont stay around for more than 40 km.

 

Guess if it was too easy, we would all get bored and have nothing to talk about

[Johan Bornman]

Thanks for all the advice/suggestions

 

Cut cut cut

 

 

The wear is not bad' date=' but it is noticable. I think if you are pushing 90 plus kilos up a steep hill you will chainsuck far more than lighter guys given the same trail/and bike conditions. It only sticks when I have to peddle slightly harder than normal, like over a short steep rocky section.

 

[/quote']

 

Weight doesn't come into play on the sucking part, only on the wear part. Since chainsuck happens on the chain's return cycle, it is purely a function of spring tension and the stickability of the chain/ring combo.

 

 

 

Not all teeth are equaly worn. Some are perfect. When I tried filing some of them' date=' it would appear that some are softer than others. Not sure if the XT small blade is hardened (can you harden alu?). Could be one or two areas were not correctly treated.

[/quote']

 

Anything is possible. What you describe is quite weird. The aluminium on there is not hardened afterwards but the blade is cut from a hard aluminium alloy which makes it considerably harder than pure aluminium. I doubt the alloy wasn't uniform. You're experiencing some other phenomena here. Are you sure you aren't looking at teeth that have a different profile to begin with?

 

 

 

What I have noticed is that the granny seems particulary noisy under load. Admittedly the chain often has sand/mud/snot on it' date=' but it sounds very much like the front deraileur is touching the chain (which it isn't) and grinding away. Previous cranksets I have owned were definitely quieter.

 

[/quote']

 

Worn chainrings are noisy, since they force the teeth into the chain on entry. You have a worn chainring there.

 

 

Know there were lots of previous threads on chain lube' date=' but i am a bit frustrated in that the wet lubes seem to be sticky and encourage sand to stay on the chain for longer. The dry lubes shed dirt better, but also dont stay around for more than 40 km.

 [/quote']

 

This is a topic as explosive as religion. But I'll tread carefully.

 

The type of lubrication you're using when lots of mud involved is irrelevant. The lubrication gets overwhelmed by the dirt and no matter how wet or dry, cheap or expensive it is, severe mud will overwhelm it. Any further water will then wash it completely clean. The only solution is to turn to road biking. This is an attractive option in spite of the taxis. I'll dodge taxis rather than wash a bike after each ride.