shifting problems

smnw10

err...this looks like a good forum to put this.
A year ago I bought a Moser frame on Ebay for cheap and got all the other parts and pieces new for quite cheap actually and assembled the bike myself...road bike. The parts I got are all Shimano Ultegra, double ring cranks and 12-25 cassette.
The problem I am having is if I go into my 13 or 12 gear while in my 39 ring my chain literally rubs against the inside of my 53 ring. I tried for hours adjusting everything to allow me to use my 12 and 13 with my 39 ring but couldn't ever get it to work. I even shortened up my chain and that was better but still didn't solve the problem. Shortening the chain anymore and I'll be putting a ton of strain on it when i'm in my 53 ring.

Does anyone have any ideas? I'm getting a new chain and cassette (11-21) by christmas but that won't make a difference will it? Unless I can shorten my chain that much more that it will make a difference?
The frame size is 61cm if that helps anyone.

I suppose I could take it to a mechanic but don't feel like paying anything or having my bike gone for a couple days cause the LBS for some reason never gets around to things quick. This past racing season I just wouldn't use those gear combinations and called it good. But I was looking to race in a "Lil Ring" race where your gears are restricted to 39-11 I believe. If I can't use those last two gears there is no hope for me!

anyways lemme know what you all think could solve the problem

thanks

bikeguy2004

Add the links that you took out of the chain, back to the chain. You probably made the chain too short.

There are some chain ring and cassette combination that you just should not use. 39X12, and 53X25 are the 2 worst conditions. Each of these combinations has extreme chain angles and should not be used. The chain angle is why the chain is rubbing on the 53 ring, when you are using the 12 cog. Just don’t use that combination. Problem solved. That's how it's designed.

Now.... for the race... You could take the 53 ring off the crank, no more rubbing. But the chain angle is still going to stress your chain more than usual. Put the ring back after the race. And you may want to disconnect the FD cable, just so you can't shift from the small ring to no ring, just in case you do shift the FD in the race by mistake.

Julian Radowsky

As mentioned, the rubbing sound is the chain rubbing on your 53 tooth ring, and extreme chain angles are not good for your drivetrain. The gearing of extreme chain angles can often be closely duplicated by using other combinations.
eg:

Use 53/16 instead of 39/12
Use 53/17 instead of 39/13

Use 39/19 instead of 53/25
Use 39/17 instead of 53/23

boudreaux

err...this looks like a good forum to put this.
A year ago I bought a Moser frame on Ebay for cheap and got all the other parts and pieces new for quite cheap actually and assembled the bike myself...road bike. The parts I got are all Shimano Ultegra, double ring cranks and 12-25 cassette.
The problem I am having is if I go into my 13 or 12 gear while in my 39 ring my chain literally rubs against the inside of my 53 ring. I tried for hours adjusting everything to allow me to use my 12 and 13 with my 39 ring but couldn't ever get it to work. I even shortened up my chain and that was better but still didn't solve the problem. Shortening the chain anymore and I'll be putting a ton of strain on it when i'm in my 53 ring.

Does anyone have any ideas? I'm getting a new chain and cassette (11-21) by christmas but that won't make a difference will it? Unless I can shorten my chain that much more that it will make a difference?
The frame size is 61cm if that helps anyone.

I suppose I could take it to a mechanic but don't feel like paying anything or having my bike gone for a couple days cause the LBS for some reason never gets around to things quick. This past racing season I just wouldn't use those gear combinations and called it good. But I was looking to race in a "Lil Ring" race where your gears are restricted to 39-11 I believe. If I can't use those last two gears there is no hope for me!

anyways lemme know what you all think could solve the problem

thanksJust don't use them combinations you shouldn't be in the small small anyway and can live without the small and second cog. Possilble solutions if you insist is a thinner chain, chainring spacers or a BB shim. The cahin should be long enough to handle the big/big,so don't frig around with that.

smnw10

thanks for the posts, my main concern was wanting to do this lil ring race, and not being able to use those gear combinations was going to hurt me in that race

i guess I'll jus tgo ahead and remove my big ring for that race so i can use those gear combos

thanks

artmichalek

Even after you take the big ring off, there's still going to be a lot of cross on those gear combinations. If you're going to be sticking to the small end of the cassette during the race, you might be better off removing the big ring and moving the small one to the outside of the spider. You're also probably going to need some washers for the crank bolts.

boudreaux

Even after you take the big ring off, there's still going to be a lot of cross on those gear combinations. If you're going to be sticking to the small end of the cassette during the race, you might be better off removing the big ring and moving the small one to the outside of the spider. You're also probably going to need some washers for the crank bolts.Then you have a crossover and extreme angle problem on the big cogs.

artmichalek

Then you have a crossover and extreme angle problem on the big cogs.
That's why I said to do it if he's going to be sticking to the small end of the cassette. There's going to be a crossover problem either way, so you might as well put it on the gears that get used the least.