Cannondale large down tube.

Tube

See attached photo . I measured the circumference = 7 /3.14 tape measure in photo just to give you an idea
 

Attachments

  • P1010056.JPG
    P1010056.JPG
    120.4 KB · Views: 277
I've found it best to first get the proper size u-bolt (or muffler clamp) when mounting a HT to a bike with a really fat downtube. After that it will almost always involve drilling/cutting of a steel plate to accommodate for the wider-than-average u-bolt.

That's the most simple scenario laid out for you. If you have the ambition & the means you can trim & bend that plate into a z-shape or whatever suits your needs. It's got to be functional first, and then you can deal with making it look as pretty as you need it to be.
 
See attached photo . I measured the circumference = 7 /3.14 tape measure in photo just to give you an idea
All I can do is suggest one again the very first step I suggested you take, get an accurate diameter and you simply won't get one with that metal tape measure.

A tool I find I use all the time is just a cheap ($15) linear caliper you can get at Harbor Freight.
http://www.harborfreight.com/6-inch-digital-caliper-47257.html

image_21602.jpg


All you need is muffle clamp that size and something between it and engine base with front studs out.
 
mine has the RST front fork and the top tube drops lower at the seat post - I could do it, but the carb would need to be outside the frame to either right or left, and I think I'd make the rear motor mount block much thinner

I'm not a hobbyist, but rather a maker of cheap transportation, so for me it isn't worth the hassle to make something that I would get about $2 per hour for all the extra labor involved

I've done similar before tho. so I know it can be done.
 
Back
Top