Sjtaylor

I have a vintage bike frame with horizontal dropouts. The existing rd mount hole has no threads and no tension screw stop tab. The outside of the hanger had been ground in such a way that the tension screw would wedge against the hanger in just the right location (I guess). I’m going to run the rear axle to the rear of the drop outs to lengthen the chainstay and allow larger tires to be used. It’s my try at a homemade gravel road bike.

In the photo you can see with the axle in place the hanger hole is threadless, no stop tab and in the wrong location. Another photo shows the drive side dropout of a donor frame. I intend to cut the hanger off that donor drop out and tig weld it to my project frame in just the right location.

I have measured a few different drop outs and I figure the center of the hanger hole should be about 1-1/8” to 1-1/4” away from the center of the axle and a bit to the rear. I’m going to make appropriate cuts and weld chamfers and jig up the replacement hanger for tig welding.

I’ve included a photo of the derailleurs of which one will likely be used in the build. My question is do I have the hanger hole location figures correctly or is there something that I’m missing with this plan.

Thanks.

Andrew R Stewart 

It's almost sad to see a classic frame modded in such a way. What's the frame? A Peugeot?

That drop out is designed for a Simplex rear der. It has a threaded backing nut on the mounting bolt to hold it all in place.

Many had just ran a 10x1 tap through the hole and cut a notch and/or added a peg to act as a B screw stop in these drop outs. Perhaps a visit to the C&V forum before doing anything would provide some context and ideas. Andy

dedhed

Lots of threads on simplex dropout modification/workaround in C&V

https://www.bikeforums.net/classic-v...r-favor-2.html

Sjtaylor

The frame is a 1978 PX10LE that had been stripped of the original components and replaced with Suntour and Shimano components. The rd was a SuntourV-GT mounted through the clearance hole but no place for the tensioning screw to land. The down tube shifters had been replaced with cable stops, top tube clamps replaced with Velcro, etc. I had decided it was not feasible to try to bring this bike back to factory original. Someone here commented that the frame wasn’t so collectible to feel too guilty about modernizing the frame.

With the rear axle placement I’m planning 700-38c will easily fit. I’ve been looking but not too many quality road bike frames my size with tire clearance like this.

I haven’t done any surgery yet.

Thanks.

Sjtaylor

The derailleur advice porfavor thread was good info but my idea is to move the axle to the rear of the drop outs as in my photo. This idea might be crazy but when I see 40c tires mounted in the frame I feel I just have to make the mods.

Thanks.