Roughness when pedaling fast
 

Hey Guys,

I can't quite figure out if this is a problem or not given my inexperience, but it is bugging me not knowing what it is. When I'd pedaling slowly (even hard up a steep hill) everything is very smooth; however, when I'm pedaling quickly I feel a roughness or bumpiness at certain times. I'm not sure if this is normal or an indication of a problem. Sorry for the vague description, it's difficult to describe. I don't think it's a grinding feeling, and feels more like a bumpiness or roughness. For all I know, it could be the bumpiness of the road that I'm feeling - but it's really only as I'm pushing the pedal downward.

My bike: http://devinci.com/bikes/browse_10#10_33_105

Thanks in advance!

What gearing are you in when it occurs? 50-11 ?
What psi do run in the tires?
How many miles are on the chain?

I was also going to ask about the gearing and chain condition.

IME, riding in the smallest cogs, particularly with a higher mileage chain, may not feel as smooth as riding on larger cogs. I believe this may be due to fewer rollers engaging the cog during any point of rotation.

Thanks for your responses.

Excuse my poor terminology here. On the left handlebar gear, I'm on the highest of the three settings (i.e. most resistance). On the right handlebar gear, I'm around the middle setting.

Sorry, I should have also mentioned that this is a brand new bicycle with about 100km on it.

As for the tires, I haven't yet filled them myself, but I think they're around 70 or 75 psi.

Get a floor pump w a guage and air up your tires before each ride.

New bikes should get a free tune up from the dealer after a few miles.
Take it back to the dealer for questions and a tune up.

By gearing we mean what is the teeth count on the front ring and rear cog.

Yeah, I was planning on going in to ask based on the responses here.

As for the teeth count, I'm still not 100% sure as to which parts you're referring to exactly (sorry!). The link I posted above has a picture of the bike which you can mouse-over to zoom in on around the gears. Does that help any?

Thanks again,

Chain rings:

http://i256.photobucket.com/albums/h...39-24001-1.jpg

Cassette with cogs:

http://i256.photobucket.com/albums/h...5-39-24002.jpg

if it is brand new bike off the showroom floor it may just need some fine tuning. It could be a bike that was hastily assembled by mechanics and needs some adjustments in the drivetrain.

I would suggest taking it back to the shop where you bought it and ask them to test ride it. It can be difficult to diagnose things like the roughness you describe without having the bike in person. If you are lucky the shop should be willing to tweak things a bit free of charge.

Thanks for the visual. It looks like I'm on 50 - 21T (or so the engraving on the cog says). Though, I also go 1 or 2 up (more resistance) on the front gear as well (which is probably where I'm pedaling fastest at times).

It will take a while to get shifting and everything else figuerd out.
Took me about 2,000 miles to get it down.
Just have fun learning.

Thanks 10 Wheels (and everyone else who has replied). Do you suggest I take it in and have them look at it? It was tuned by the mechanic before I picked it up, but who knows.

Air up your tires to Max psi.
Find a smooth road and practice with different gears.

Ok - I'll give it a shot, but what do you mean by practice?

Thanks again,

Practice shifting gears and knowing what gears you are in.

I think it is likely that it is a gear selection issue. If you are changing most of the time between rear cogs and usually leave the bike in one chairing then you might be 'cross-chaining,' which will usually result in poor performance.

http://sheldonbrown.com/gears.html