Please ID this Cannondale frame

[mullinino]

Ah...worked it out, it's for the non-driveside crank arm to clear....funny solution. Still say it's a weakness.

 

[retrobikeguy]

I see what you are saying, to think of literally denting a tube on opposite sides you would think that structually its a bad idea, early aluminium pioneers though ...... still learning at this point

 

[mullinino]

Yeah, agreed....I've never heard of any actual weaknesses reported either so must've been grand...ta

 

[2manyoranges]

Yep - had a late 80s M600 which had exactly that on each chain stay for crank clearance and thus smaller Q with the oversize tubes.

Method:

Cut tubes
Bend tubes (including big creases in each chainstay)
Weld tubes
Place frame in humungous oven for heat treating to restore crystal structure and reduce massively the weaknesses from bending
Paint
Hang bits on
Ride

Find out that super stuff aluminium frames beat you to pieces off road.
Buy something made out of something sensible - like 853 or ti

 

[BearValley9196]

Few more pictures

 

[2manyoranges]

Few more pictures View attachment 629908View attachment 629910

It looks like a very nice project. Nice large size, and in good shape. Do you have a serial number from the bb?

 

[BearValley9196]

It looks like a very nice project. Nice large size, and in good shape. Do you have a serial number from the bb?

The serial number is actually on the chainstay but it's in awful condition and hard to make out any of the important numbers

 

[trailwright]

Bargain for a tenner...as long as there are no hidden cracks. Look forward to seeing the build.

 

[2manyoranges]

Indeed bargain for 10gbp - and the longer head tube was more dependable - they are mighty strong frames. I suspect 1987 M series - note the flat plate rear dropouts rather than the later cantilever dropouts. I had a teal M in 18 inch with the complex welding at the short head tube. This bigger frame is much nicer.

 

[jimo746]

Is it for 26" wheels?