how to check a tweaked frame

[Uncle Stretch]

I had a frame that once I put the chain on it looked like the back of the frame was bent and it made the chain run funny on the sprocket. I read on sombodys post how they checked it with a piece of string. I hooked some nylon line from one dropout on the outside ...around the front neck ..and back to the droupout on the other side. Pulled it tight and then measured from the string in to the seatpost tube on each side and it was about an inch off. The fix was almost as simple. I put my frame crank housing in my vice and then pushed the rear tubes, that were too close to the outside. then I pushed the other side in some to match. Checked again measuring to the seatpost and they were right on. If you measure the rear hub distance from outside to outside you can get that distance right as you push it in. It is easy on a frame with small chainstay tubes . It might take a little more force with ones that are bigger.Dont get too carried away bending them at first till you measure a little and see where you need to be.

 

[user 135]

That is the way, good that it worked out. It is handy to have an extra axle around with nuts set inside and out. I did this for a major bend or also to ship frames, just as precaution.

 

[Uncle Stretch]

Humm I never thought about putting an axle in there to keep the distance. Good idea clancy.

 

[thatismytruck]

I did something similar when I needed to fit my Thick Brick into my Murray frame.

In my basement I have large hooks hanging from the joists. I hung the frame from the head tube then grabbed the frame just near the dropouts and pulled them apart. Then I put a 2X3 slightly above the spot where the tire needed clearance and squeezed the frame back together. I made sure the wheel and tire fit in. Then let the frame hang free from the head tube. Tied a plumb bob to the seat post and measured from the dropouts to the string. Luckily, each measurement was very close.

Woo Hoo!! big tire spins!!

 

[Walker]

Back at the bike shop we sent quite a few aluminum frames back because the alignment was off. Steel frames were relatively easy to straighten the way you outline. Using a caliper to measure between the seat tube and the string will ensure that your alignment is spot on.

 

[Uncle Stretch]

I guess all the frames I have run into have been close, but from now on Ill check them all before I start because its so easy.

 

[B607]

That is the way, good that it worked out. It is handy to have an extra axle around with nuts set inside and out. I did this for a major bend or also to ship frames, just as precaution.

Putting an axle in the frame dropouts to ship it is a must. I use a piece of all-thread instead as it's cheaper than an axle. I also put a wooden plug in the top and bottom of the head tube to keep it from getting damaged. I used a dowel that was the right size but you could just as easy use a tree branch cut to plug shape. Gary