A little history: $6 garage sale 10 speed. I bought it after it had been sitting for quite some time. I've converted it to single speed, for what its worth (nothing lol). New rear wheel w/ suzue basic hub and the front wheel is the original rebuilt with new bearings. I had to buy a new seat post and stem for it.

Why did I have to buy a new stem? Well, the old one, besides being severely corroded, was bent. When looking at the bike from the front center, the handlebars were rotated to the right so that when you were ON the bike, the left side of the handlebars were marginally lower than the right side. It was enough to notice. So, I replaced the stem. I figured somebody wrecked the bike and that was all the damage.

Now I'm not so sure.

The bike rides beautifully in general, except that it has quite a pull to the left. I've examined the bike and I can't find anything obviously bent or anything. I figured maybe the front fork was bent, but I checked it out and the fork legs are straight, and when viewed from the side, neither fork leg is ahead of the other. They seem symetrical.

The only really iffy thing on this old bike is the headset. It squeeks. I know, I know, I need to repack it at the least.

Can anyone offer any suggestions, based on what info I gave? I'd really like to fix this as the frame fits me quite well, really, and I'd hate to have to shop for a new frame.

Thanks in advance, and sorry for the book!

Stem straight, rear wheel straight, rear triangle aligned properly?

Stem straight - check. rear wheel straight- check. Rear triangle? It *looks* all normal.

How can I be sure?

Also the bike rides normally, its not like I have to constantly correct for it. Its just that if I were to let go of the handlebars, it will invariably turn left.

Hm is the headset tight? I assume its a threaded style and 9x out of 10 they are loose it seems.

You should take it in to have the alignment checked on both ends. Have them check the fork centerdness as well. It's all pretty simple and shouldn't take long or cost much.

Are the axles centered in the dropouts? This would cause the wheel to be skewed.

Try shifting your butt cheeks to the left.

Lift up the bike by the top tube, let it hang there, see if the front wheel is pointing forward or turned to the side. There might be something bent biasing it to the left.
Or check the local map, maybe there is a gravimetrically massive object like a black hole somewhere due left.

Totally.

Try riding in the opposite direction and see if it pulls right.

Take a look at this thread. I has a similar problem that turned out to be a lateral bend that was hard to see unless you kneel down and sight down the wheels.

https://www.bikeforums.net/bicycle-mechanics/79546-straightening-bent-fork-blades.html

the wheel dish may be off

I don't remember where it is, but Sheldon Brown talks about a home frame alignment technique. It works like this, I think:

Take a string and run it through the rear dropouts and around the head tube, making a triangle. Pull it tight. Take a ruler and measure the distance from the string to the seat tube on each side of the frame. This should tell you whether your frame has a lateral bend.

I'm not sure how to check for other bends except by eyeing it.

I hope the bike's at least rideable. I've ridden bikes that rode just great as long as you kept a hand on the bars, and hopefully that's the case with this one.

Thanks for all the suggestions, I'll check it out in the morning. The bike IS rideable. The one thing I thought of after reading this is that I DID rebuilt the front hub myself, so I may have messed up the spacing of the hub, so I'll check that. I'll flip the front wheel around and see if it then pulls to the right. Thanks!

Any cables pulling the bike to one side? I guess not if you are running a single speed. Deffinately have a look at the headset.

FOUND IT. Frame is bent. After looking at it very carefully, my wife and I both came to the conclusion that when viewed from the front, the head tube is twisted to the right. Which of course would put the wheel to the right of the center, making it pull left.

Thanks for all the suggestions.

A good LBS should be able to atleast straighten it up a bit. Ask, question is free...

Thanks. I'll call some bike shops on my lunch hour today, hopefully someone can realign the frame cheaply.

Well at the very least, I found a shop that won't charge anything to LOOK at the bike and see what needs fixing. Hopefully, the repair price won't be too expensive.