LHT swaying while riding...
 

Hi,

I just bought a new 2010 Surly Long Haul Trucker. It rode fine for a week and then I installed a pair of Planet Bike hardcore fenders and a Tubus rear rack. Now when I ride, I notice a weird swaying, both when pedaling and coasting. It's like the bike is pulling to the left slightly and then back to the right, and it changes back and forth every few seconds. If I take my hands off the handlebars, I'll for sure crash which wasn't the case before. I didn't mess with any of the bike components when I did the installs, and everything is symmetrical. The wheels are both true--nothing obvious there. Any ideas as to what the deal is? Maybe that's just how the bike is, but that doesn't seem right. I've never felt this on any bike before.

Thanks,
Bob

Any chance the wheel(s) are not completely in the dropouts? Headset a little loose? Squeeze the front brake and rock the bike back and forth, any noise or play from the fork/handlebars would show up.
Tires at a reasonable pressure? Are they seated properly, or maybe not quite round? Tires that aren't built straight can cause the steering to swerve as the contact patch goes off center.

Did you load stuff on the rack? Even a few pounds of stuff loaded on that rear rack will make a bike sway somewhat.

Bob, Sometimes all it takes is a couple of short rides on a new bike to loosen mated parts. Your dealer will likely give it a free service and I'll guess it's the rear hub.

Brad

Sounds like loose/worn head set, loose/worn bearing cones on one or more wheel, wheel incorrectly installed in drop-outs, or even too much weight loaded at the rear of the bicycle, or even the fender rubbing on the downtube as it comes by Full-Straight-On position.

Some of these issues could have been induced while installing fenders -especially the wheels not being in the drop-outs correctly and even the cones getting out of adjustment. Check that the wheels are fully seated in the drop-outs and are straight. Check for wobble in the tires (grab the tires/rims and wiggle from side to side). Check for head loosness by putting the front brake on and grabbing the stem and head with one hand and wiggling (you should feel NO vibration, clickig, or movement other than rotation when you put force into the front end with the brake locked). Check that the rear rack is mounted solidly to its mounting points and not wiggling or flexing too much.

If you have any of these issues they need to be corrected by a competent bike mechanic or you will continue to have an issue that may become worse and damage components further and even be unsafe..

I would remove the add ons-all three.
Then ride it again- if the swaying is gone, them install the add ons one at a time-re-test it.
You might find that one add on is responsible.

It is possible you "changed something" when installing them in which case the problem will still be there when you remove them.

I wouldn't fool with anything else until I removed the parts and retested the bike.
Luck
Charlie

Fixed!
 

Hey thanks everyone for the suggestions. I reset the front wheel and the problem still persisted.

Turns out the little loop on the front fender that connects to the fork via a screw was rubbing, causing the slightest bit of friction. I bent it down so it no longer rubs, and presto, no more swaying.

Crazy that such a little bit of contact could cause something so noticeable.

Thanks again for the help!

It makes perfect sense and what I was getting at when I mentioned to check if the fender was hitting the downtube.

If the wheel/forks can't center properly then it is pushed either left or right, then the geometry of the bike tends to want to correct for this and push the wheel back towards straight -just like a caster of a shopping cart (this is why you can ride no-handed or "ghost-ride" a bike without a rider on at all).

So the bike's geometry pushes the wheel straight but because something is hitting it can't STAY straight and goes too far to the other side just a tiny bit. Then the bike tends to push the wheel straight again. You feel this as an oscillation or wobble at the bars -just like when that shopping cart caster is wobbling around and can't stay straight.

This can also happen with a bad headset if they are binding up at one spot or annother and not able to move smoothly for minute automatic rake/trail geometry adjustments that the bike makes all by itself..