Issues with gears jumping

[lbraasch]

So I'm realatively new to road bikes, so I'm having issues diagnosing the source of my problem.

When doing a climb, or sprint, the chain jumps in the casset from one gear to another, and then back to where it originally was, all without input in the shifter (downtube shifters).

When this occurs, I would not say that I'm mashing, however, the input is greater than when just spinning along. I also weight 155lbs, so I doubt I'm overloading any of the parts.

Is the issue coming from the rear-derailer, chain, or casset?

I'm planning on giving the casset and chain a good cleaning, hoping to alleviate the issue. I've got bruises on my leg from when the chain jumps, and my foot slams down.

Thanks

 

[xxamr_corpxx]

So I'm realatively new to road bikes, so I'm having issues diagnosing the source of my problem.

When doing a climb, or sprint, the chain jumps in the casset from one gear to another, and then back to where it originally was, all without input in the shifter (downtube shifters).

When this occurs, I would not say that I'm mashing, however, the input is greater than when just spinning along. I also weight 155lbs, so I doubt I'm overloading any of the parts.

Is the issue coming from the rear-derailer, chain, or casset?

I'm planning on giving the casset and chain a good cleaning, hoping to alleviate the issue. I've got bruises on my leg from when the chain jumps, and my foot slams down.

Thanks

http://sheldonbrown.com/autoshift.html

I think this might be it.

 

[lbraasch]

http://sheldonbrown.com/autoshift.html

I think this might be it.

Sounds like the issue. So, since i have friction shifters, the wing nut/screw that needs to be tightened... where is it? Is it on the shifter itself?

 

[gclark8]

A nice new inner cable may help, a $ or 2.

The friction tension is on the shifter, the little bolt with the ring in the midddle.

 

[lbraasch]

degreased everything, tightened the friction cable, everything seems to be running smoothly after a test ride. We'll see how it holds up on a longer ride.

Are there any how-to websites out there that will show my basic bike maintence? I'm very mechanically inclined, and work on my cars and motorcycles, but bikes are a forgien field to me, and I don't want to use my only bike as a gunnie pig if i don't have to.

 

[Scotty_Dog]

Are there any how-to websites out there that will show my basic bike maintence?

http://www.sheldonbrown.com/

http://www.parktool.com/repair/