How to Set a Welded Metal Frame
Many classic steel bicycle frames can be "cold set" or expanded to accommodate larger or more modern drivetrains. Riders may want to update their older, more comfortable and familiar frames with easier shifting mechanisms or replacements for worn out drivetrains. The process of expanding the frame is fairly simple, but the decision to proceed involves some risk to the frame and the brake bridge. A successful cold set of a steel frame can give new life to a favorite steel framed bicycle and save it from the scrap heap.
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Things You'll Need
- Steel bicycle frame
- Metric ruler
- New hub size in millimeters
- 3/8-inch threaded rod, 8 inches long with two washers and two nuts
- Tape or strong string
Instructions
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1
Wrap the brake bridge (near seat post) with tape or string.
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2
Turn the nuts onto the threaded rod until they are spaced closer than the rear dropouts (rear axle slots).
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3
Add washers on both sides.
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4
Slide the threaded rod into the rear dropouts and turn the nuts until they are pressing the washers out against the dropouts.
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5
Turn one nut counter-clockwise and slowly expand the frame.
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6
Keep expanding until the frame is just a few millimeters wider than the desired width.
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7
Loosen the nut and measure the width of the frame at the rear dropouts.
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8
Repeat the process in small amounts until the frame is spread the required amount.
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9
Remove the brake bridge tape.
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1
Tips & Warnings
Use a magnet to ensure that the frame is steel if you are not sure.
Lightly lubricate the threaded rod for easier nut rotation during the spreading operation.
Spreading can also be accomplished by using leverage, but this method uses more controlled force.
Do not continue if a high degree of force is required to turn the nut. Certain varieties of extremely rigid steel tubing as well as aluminum and carbon tubing do not respond well to this method.
References
- Photo Credit Jupiterimages/Comstock/Getty Images
