Bicycle Mechanics - bike rides "wobbly" or "not straight"...

i just built up a single speed/mountain *** street bike for my girlfriend. i used an old "diamondback outlook" frame that i found in a friends garage. it was a cheesy old beater but it had nice long horizontal dropouts and was just my girlfriends size so i took the plunge.

anyway, things were going really good. i got the frame powdercoated cheap, and reassembled it with good quality parts i had lying around. when we were just about done i decided we should take it out for a test ride. she rode it down the street and i noticed she was kinda swerving a little bit, from side to side, and making lots of corrections with the handlebars. she came back and told me that it felt "weird". i tried it too and she was right. for some totally unapparent reason the bike is just sorta all over the road. with each pedal stroke it swerves slightly to the left, and then to the right. if you even tried to take you hands off of the handlebars you'd eat **** instantly. it's that unstable. keep in mind this bike rode FINE before we took it apart. i know i put it back together right.

this problem is driving me crazy. maybe the frame was damaged at the powdercoater? is something out of alignment? i just put on a brand new pair of geax streetrunners 26x1.25 tires. any ideas???

thanks!

ps - the rear wheel is a little untrue.

Is the headset too tight?

Is the headset too tight?

+1. That's what I was going to ask too.

Or maybe the bearings notchy?

Look to the headset Grasshopper. :)

Or maybe the cones are backed off a little and giving the wheel too much play. Try to wiggle the wheel side to side. Does it feel loose? If so, it's in the hub.

If not, turn the wheel. Do you see the wheel go side-to-side towards one brake pad then the other? If so then the wheel is out of true. If it goes side to side ALOT, then the rim might be bent, and need to be replaced.

Yeah, the headset is tight. I thought maybe the fork play was the problem so I kinda overtightened it. I am having trouble with the headset. It doesn't seem to want to go back together just right. I guess I could try to install a brand new one. Never done that before, just overhauls.

The rear rim is a little untrue but I don't know if it's bent. I really don't think so.

Have a drink and try it out again. Bet it smooths right out.;)

Is the powder coat interfering with the cups for the headset? You may have to scrape away some of the power coat to get the cups back in place correctly.

It's also possible that the frame isn't straight. If the rear wheel doesn't track the same line as the front it can cause all kinds of problems.

But I'd agree, so far it sounds like it's a problem in the headset area. It'd take a REALLY out of round (like visually obvious) rear wheel to cause those problems, and being out of true would only become a real problem at speeds over 20mph or so, and even then only if it was pretty bad.

Check for broken axles.

Rode good before, rides not so good now. My money is on an assembley issue.

hey all. i took it to my local bikeshop and they all pretty much concurred that it was the headset. the powdercoater did powder the inside of the headset cups too. they're putting a new headset in for me now and it should be done when i get off in about 10 mins or so. thanks for your input!!!