smead
08-16-2012, 02:46 PM
Teaching my newbie niece how to ride her guru -
http://forums.thepaceline.net/showthread.php?t=108644&highlight=guru
Last weekend she did OK, but of course ended up cross chaining a lot, and there were so many other issues I was telling her about I didn't want to further confuse her about cross chaining. We'll get there later ...
Here's the problem though - On all my other road bikes (9 and 10 speed shimano/sram), if I cross chain big big, while not good, the chain stays on, even when I pedal backwards.
Twice on her ride last weekend she stopped while in the big big or big w/ 2nd biggest cassette cog. Pedaling forward while cross chained is OK (well we know it is not ideal, but the chain stays on..), but when she goes to start out again, she rolls the pedals backwards to position the crank for a start, and both times the chain comes off, and not only that, it misses the inner ring and ends up on the bottom bracket. I don't want this to happen to her when I'm not around.
The drivetrain is installed and tuned perfectly. It is a new SRAM S550 Crankset 34/50 w/ GXP BB, sram 1050 chain, and sram 1070 11-28 cassette. The chainline on the big ring is about 45mm which is about where most shimano doubles are .. Visually it doesn't appear any more cross chained compared to my other 10 speeds with shimano or FSA cranks, yet on those I can pedal backwards big/big all day w/o throwing the chain.
The only thing I can come up with is that the ramping on the SRAM chainring must be different such that going backwards, it wants to throw the chain down when cross chained big/big?
Any ideas/thoughts? I can't even correct this with a chain catcher because that's only going to help in the other direction ..., so I'm at a loss how to fix this, I guess I need to move the cross chaining lesson up in her list of upcoming ride lessons?
http://forums.thepaceline.net/showthread.php?t=108644&highlight=guru
Last weekend she did OK, but of course ended up cross chaining a lot, and there were so many other issues I was telling her about I didn't want to further confuse her about cross chaining. We'll get there later ...
Here's the problem though - On all my other road bikes (9 and 10 speed shimano/sram), if I cross chain big big, while not good, the chain stays on, even when I pedal backwards.
Twice on her ride last weekend she stopped while in the big big or big w/ 2nd biggest cassette cog. Pedaling forward while cross chained is OK (well we know it is not ideal, but the chain stays on..), but when she goes to start out again, she rolls the pedals backwards to position the crank for a start, and both times the chain comes off, and not only that, it misses the inner ring and ends up on the bottom bracket. I don't want this to happen to her when I'm not around.
The drivetrain is installed and tuned perfectly. It is a new SRAM S550 Crankset 34/50 w/ GXP BB, sram 1050 chain, and sram 1070 11-28 cassette. The chainline on the big ring is about 45mm which is about where most shimano doubles are .. Visually it doesn't appear any more cross chained compared to my other 10 speeds with shimano or FSA cranks, yet on those I can pedal backwards big/big all day w/o throwing the chain.
The only thing I can come up with is that the ramping on the SRAM chainring must be different such that going backwards, it wants to throw the chain down when cross chained big/big?
Any ideas/thoughts? I can't even correct this with a chain catcher because that's only going to help in the other direction ..., so I'm at a loss how to fix this, I guess I need to move the cross chaining lesson up in her list of upcoming ride lessons?