# Bent rear triangle



## duotone (Dec 31, 2006)

I have a GT frame (steel) that I love.

Noticed the wheel not setting quite right so I put a fish line through the drop outs around the head tube and measured the distance from the line to the seat tube.

Right side = 1"
Left side = 1.25"

What to do?

Thanks > Tony


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## duotone (Dec 31, 2006)

Oh, I forgot to mention it's a single speed. I only weigh 155lbs so I didn't think I had the power to bend the frame, but now that I think about it that's what I've done.

The torque of being a SS probably shifted it.

Can I straighten it and run a tensioner to relieve some of the torque?


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## Walt (Jan 23, 2004)

*Quick questions*

So I'd guess that this frame has been out of alignment the *entire time* you've owned it. Riding it SS is not nearly enough to bend the rear triangle, and you're not a big guy. So I think Occam's Razor says that it's always been this way (at least since you've had it).

You love the bike, right? Did you notice the alignment problem when riding, or when looking at it? If the former, yes, you should try to do something about it (probably just re-dish the wheel). If the latter, pretend you never noticed and keep riding that beast until you *really* destroy it.

Alignment only matters to the extent that it affects the ride of the bike. I've seen, ridden, and owned many hilariously out-of-alignment frames from various manufacturers, and I've never had one that didn't basically track straight and ride fine. That's not to say poor alignment is a good thing - just keep the old "if it ain't broke, don't fix it" maxim in mind when deciding whether or not to make an effort to fix an alignment issue.

-Walt


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## Zoke2 (Nov 16, 2007)

any shop worth its salt should have this tool and the know how to help you fix it


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## duotone (Dec 31, 2006)

I bought the frame NOS and just noticed this in this spring.

Does it effect the ride? Don't think so.
Does it effect my mind? Yes, I'm annal.

I noticed when looking at it. I'll try bending the triangle a bit with a 2x4.


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## Walt (Jan 23, 2004)

**sigh**

Great plan.

-Walt



duotone said:


> I noticed when looking at it. I'll try bending the triangle a bit with a 2x4.


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## duotone (Dec 31, 2006)

Walt said:


> Great plan.
> 
> -Walt


Well, I was going to jump on it.


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## TortugaTonta (Jun 14, 2004)

The problem is that you don't know what is out of alignment without one of these










what if the rear triangle is fine and the seat tube is out of plumb?

The seat tube really doesent matter, its the relationship between the dropouts and head tube. The string trick tells you something is wrong but not exactly what is wrong.

You should listen to Walt, he knows more about this than you, otherwise you wouldn't have asked.


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## duotone (Dec 31, 2006)

I know Matt, and have more respect for his work than most builders. But I use the tools I have, and though I love the frame I don't have the money to have it worked on by anyone.

That is unless Matt wants to pay me a visit in Michigan. Weather's nice here!


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## Schmitty (Sep 7, 2008)

Leave it alone. You say you love the bike, therefor you don't need to worry about it's state of alignment. It's a GT.. was likely built a bit out. Keep in mind it's really only out .125 assuming your measurement is correct. And as stated, that method only indicates that *something* is ascew.. it doesn't tell you what exactly.Not a big deal for a prodcution bike.

If you're really that anal, better start interviewing custom builders.

-Schmitty-


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## Blaster1200 (Feb 20, 2004)

Schmitty said:


> Leave it alone. You say you love the bike, therefor you don't need to worry about it's state of alignment. It's a GT.. was likely built a bit out. Keep in mind it's really only out .125 assuming your measurement is correct. And as stated, that method only indicates that *something* is ascew.. it doesn't tell you what exactly.Not a big deal for a prodcution bike.
> 
> If you're really that anal, better start interviewing custom builders.
> 
> -Schmitty-


True.

You don't know of the rear end is 'bent' relative to the bottom bracket/seat tube, or if the front end is bent relative to the back end. The back end may be perfectly straight, but the front end may not be perpendicular to the centerline of the bottom bracket.

You have a greater risk of screwing up the frame than you do making it right...unless you have an alignment table like the one shown above.

And considering my experiences with mass produced frames, especially those from GT, I bet it came that way.


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## duotone (Dec 31, 2006)

Thanks for all your insight, I am seeing this much differently than I did before I posted this thread. Anal is relative, I think I'm going to pretend I never saw the bent / mis-aligned frame.. ;-)


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