009jim

My second bike is a Trek 7100. I've not ridden it very much. Got it in a swap deal from an ex. I took it out for a long ride last weekend and became aware that when I let go of the handlebars, they will always turn right by a few degrees. It is almost impossible to ride no hands (not that I do this).

Whilst I was riding I looked for reasons for this. The bike is a multi-purpose bike but with shocks on front. I sighted the frame and can see no sign of it being bent. The bike has had little use (still has original tires and brake pads).

The problem is not misalignment between the bars and the wheel, because the front wheel turns right. I see this as I sight down over the top tube and down tube.

Can anyone suggest reasons, or what I should check (and how).

hueyhoolihan

of course the first thing is to look for obvious misalignment of the front wheel. and maybe the back wheel. it can also be bent fork... i've had tires that could cause it. some from being so new and narrow that they acted like a knife edge, never letting the front wheel track a straight line.

but your problem, seeing that it always veers to the right could be caused by the crown in most roads. riding on the right as we do, the road will always be slanted slightly in that direction. maybe try riding on the other side of the road as a test.

rpenmanparker 

OP rides on the left! "Whilst" is an obvious clue, but he also lists being located in Oz.

rpenmanparker 

Are the cables long enough to not pull on the bars?

BikeWise1

Is the front wheel all the way up in the dropouts?

mrrabbit 

Besides any obvious frame misalignmentm have you verified that:

1. Both front and rear wheels are properly dished using a dishing tool?

2. THENNNNN made certain that both wheels are properly inserted all the way into the drop outs and centered under the front fork crown and rear seat stays and chain stays?

=8-)

009jim

Yes - just checked. If I hold frame up, it easily goes to either side.
Yes - seems to be, I just loosened and tightened. (it has quick release).

009jim

It appears by my eye to be dished ok. Both front and rear wheels are centered nicely in their respective forks. One thought:- what if the front shocks have different spring constant, i.e. when depressed with my weight, one fork depressed an additional 1/8" causing front wheel to tilt? If the case, it's not apparent to the eye!

Can you give me some tips on how to check as per item 2. please?

mrrabbit 

You don't check dish by eye...

1. Dishing tool.
2. Flip-flop in stand with axle turn and compare distance to reference point each time.

Improperly dished wheels installed centered in the frame will cause alignment, tracking and handling issues.

For example, centering a so-called "zero dish" or "no dish" rear wheel (there's no such thing) in a frame will cause not just tracking problems, but also shifting problems ranging from an increase in drivetrain noise to misshifts.

=8-)

1 Miyata Biker

Make sure the tires are inflated to the proper PSI. Even a few pounds over the maximum won't hurt anything. A low air pressure can make some tires get "squirmy". You can also prove to yourself there either is or isn't a problem by carefully moving to the opposite side of the roadway when there's no traffic, and see if the bike still wants to drift to the right. If it drifts to the left, like it should if all things are equal, then you know it was just the crown of the roadway causing the drifting. If it still wants to drift right, then you may want to take it to the LBS for an inspection.