I just bought a Trek 2100, it is about three weeks old. I' not sure, but I think I've put around 180 miles on it. In the last couple of weeks, I have encountered some unwanted shifting while in certain gear combos.

I'm still a bit of a newbie when it comes to do it yourself bike maintanence, but I gotta learn. What is this a symptom of? I've been considering converting the bike to a double (Right now it has a 52/42/30 Bontrager Race crankset), probably ultegra. Would this make the bike shift better?



The whole double converstion thing is a little off topic. School is starting, and I will be riding less, but I'm just curious. Will I need to change the bb? Derailers? Chain?

I'm a noob, I know....but I love the bike, and that has to count for something, right? :D

I just bought a Trek 2100, it is about three weeks old. I' not sure, but I think I've put around 180 miles on it. In the last couple of weeks, I have encountered some unwanted shifting while in certain gear combos.

I'm still a bit of a newbie when it comes to do it yourself bike maintanence, but I gotta learn. What is this a symptom of? I've been considering converting the bike to a double (Right now it has a 52/42/30 Bontrager Race crankset), probably ultegra. Would this make the bike shift better?



The whole double converstion thing is a little off topic. School is starting, and I will be riding less, but I'm just curious. Will I need to change the bb? Derailers? Chain?

I'm a noob, I know....but I love the bike, and that has to count for something, right? :D

One thing that pops out of my head right now is probably the cable tension is too tight. what gears were you using when you have that ghost shifting?

One thing that pops out of my head right now is probably the cable tension is too tight. what gears were you using when you have that ghost shifting?


I cant remember. I think it is probably a smaller gear because some of the time when this happens is when I drop a few to get out of the saddle in a climb. The most frequent (and annoying) place it happens is relatively flat...so the gear probably isnt that small. I dont turn a very big gear if you know what I mean :rolleyes:

Oh, and it is always in the middle chainring. I've only used the 30 a few times (and not for the last couple of weeks....progress!), and it hasnt happened in the 52. I dont spend a bunch of time in the big ring...but I dont think it is a problem right now.

Very common occurance on new bikes. Typically you can fix this problem by doing some fine adjustment on the little twisty adjuster thing that is located where the cable enters the derailleur.

Turn the bike upside down if you have no stand, slowly pedal and shift up and down, while watching how the chain tracks. You'll most likely see that the chain is brushing against a neighboring sprocket. Twist the nut a couple times while continuing to pedal, and you will see the chain move. Do that until the symptoms go away.

Or, you could just take your bike back and have the shop do it.

I cant remember. I think it is probably a smaller gear because some of the time when this happens is when I drop a few to get out of the saddle in a climb. The most frequent (and annoying) place it happens is relatively flat...so the gear probably isnt that small. I dont turn a very big gear if you know what I mean :rolleyes:

Oh, and it is always in the middle chainring. I've only used the 30 a few times (and not for the last couple of weeks....progress!), and it hasnt happened in the 52. I dont spend a bunch of time in the big ring...but I dont think it is a problem right now.

I think you are using 42/12 with a little tight cable. the result is the chain may skip one gear up under load. even under normal pedalling, you may hear the chain making noise rubbing against the 13 cog. This happens when the derailleur is not aligned properly to the 12 gear.

You can try turning the cable adjuster on the downtube anticlockwise 1/4 turn when you are on the bike, and that should take care of the problem. Also you are going on an extreme chain angle when using 42/12 gear combo. Always do a chainring shift when you are going to spend time in the upper or lower gear ranges. Try to keep the chainline as straight as possible.

I cant remember. I think it is probably a smaller gear because some of the time when this happens is when I drop a few to get out of the saddle in a climb. The most frequent (and annoying) place it happens is relatively flat...so the gear probably isnt that small. I dont turn a very big gear if you know what I mean :rolleyes:

Oh, and it is always in the middle chainring. I've only used the 30 a few times (and not for the last couple of weeks....progress!), and it hasnt happened in the 52. I dont spend a bunch of time in the big ring...but I dont think it is a problem right now.
How new are you and is this your first bike with STI shifters? It takes some practice to nail the shifting -- especially under a heavy load like when you jump out of the saddle. (I apologize if you're not a noob :))

It sounds like it could be a simple rear der adjustment too. Check out the Park Tools website for tuning instructions. If you bought the bike from your LBS, take it in for an adjustment if you're not comfortable doing it yourself -- they should do it free of charge on a bike that new.

I'm noob to road/bike mechanics...but not biking. I know not to put the bike in extreme gear combos. I know the bike isnt happy in 42/12, and I usually stay out of that selection.

This isnt happening in one specific gear either. The shop i got the bike from has been very good to me so far (they fixed a BB click a week or so ago for me), but I think I'll give these adjustments a try myself. I just dont like going to the shop too much. The time I spend waiting for my bike fills my mind with destructive thoughts of buying stuff :p

Thanks for all the help. :)

Your LBS should be able to trade in your triple for a double at no charge. My GF had tons of problems with her triple it was just a pain. Probably not your problem but give it a try.

Kyle

The shop i got the bike from has been very good to me so far (they fixed a BB click a week or so ago for me), but I think I'll give these adjustments a try myself. I just dont like going to the shop too much. The time I spend waiting for my bike fills my mind with destructive thoughts of buying stuff :p

This is an adjustment that would literally take a LBS mechanic a couple of minutes at the most. One good way to learn is to have him show and tell you how to do it while he adjusts it.