need help with tire / chainstay clearance issue. pics included.

So I am putting on Maxxim Hookworms (26 x 2.5), mounted on Husky 26 x 2.125 rims, on a 1955 AMF Roadmaster frame.

The issue is that the tire needs more clearance near the front of the bottom chainstay where it tapers in to the bottom bracket. The tire was rubbing but I trued it up a little and now there is 1-2mm of clearance. I need a little more clearance.



chainstay_prb

So option 1 is to grind/notch the inside of the chainstay tubes, and weld in some kind of reinforcement.

Option 2 would be easier but wanted to get some feedback. If I could just move the tire back 1/4" it would help quite a bit with the clearance issue. So I thought I could just drill some holes and elongate the slot where the hub mounts, like this.

slot (unmodified)

chainstay_orig


proposed modification:


chainstay_mod


Anyone see any problem elongating this dropout slot a bit?

yeah i have considered that but making new dropouts is a lot of work considering i only need to move the tire back less than 1/2"

thanks guys, i measured back 0.25" on each drop out, center punched, then drilled it out with a step bit to 7/16" to match the existing size. cleaned up the slot with a cutting wheel on an angle grinder. Tire to chainstay went from "really tight" to "comfortable" with 4-5mm on each side now.



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yeah, hindsight being 20/20 and all... that probably would have been the better way to go. but after dropping the cash for the hookworms and the husky wheels, sturmey archer hub, etc. got to make it do.

On to the next problem!

Thanks Scotto. Finally got my tubes in and tires mounted and the seat came in. starting to look like a bike again. as soon as my sportsman crankset comes in i can start getting the engine mount figured out.


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Love these hookworms! They have some amazing grip.