Over the weekend I acquired an '83 ST500 in all original spec down to the bar tape. With 650a 26 X 1-3/8 wheels and tires... Perusing through the catalog on vintagecannondale I don't see this specification. Can anyone shed some light on this?

Smallest size listed in catalog is 19" with a 40.9" wheelbase and 18" chain stays

ST C2C: 18-1/4"
WB: 41" -ish
CS: 18" -ish
Stand over: 27.5" -ish

That's a new one on me. I've had 83's before (AA frameset, number on bottom of BB) and they were ST's, but had 27" wheels.

AA serial... Second set of bottle bosses buried way down under the DT by the crank...that'd be one grubby water bottle.

Wow, what an odd ball. How are the clearances? Continental still makes some HP 650a's and maybe Bontrager (ugh).

Clearances are excellent. Unfortunately the rims are NOT hook bead therefore pressures are limited!!

Is it possible that's not the original wheelset? I've run into a few 19" early 80's C-dale bikes and I don't remember them with anything other than 27" rims.

The '83 catalog states the ST500 would have come with Wolber Super Champion 58's in 27x1-1/4" with frame sizes 19, 21, 23, & 25. I don't see a footnote stating the 19" came in a different wheel size.

There's an off chance that a 700c wheel might work in the frame but you might not be able to adjust the brake pads low enough for the smaller rim. So a 700c could theoretically work with longer reach brakes and would certainly make a wider range of tire and tube choices available.

I looked at one of them and it's rated for 70 psi so they'd be OK for those rims. I'm now thinking the Continentals are really not worthy of that frame. 650b wheels perhaps?

Brake pads are mid level in the calipers, no way will a 700c work out front. As far as I can tell its not a 19" frame. Engineering diagram pictured in '83 catalog appears to show a C2C measurement for ST. Maybe C2T is 19" but C2C is clearly closer to 18". 622-590/2 = 16mm height difference. No way!!

650B would probably fit.

Hi, Here's a couple shots of my '83 ST500, with original 27" Wolber's.
cdst-1.jpg

cdst-11.jpg

I recall that was where most people carried their stove fuel bottle, so if it leaked, it wouldn't get on the rest of the bike.

Can't remember for sure whether the shop I worked in at the time ever brought in any of those 26 X 1 3/8" Cannondales, but I do remember them being available for at least one production run. We definitely stocked Cannondale SM500 mountain bikes with a 16" frame size and 24 X 1.75 wheels front and rear (and I still ride an 18" version with 26 X 1.75" front and 24 X 1.75" rear wheels).

miamijim, The frames are measured C-T and even then it may not be exact. The 650A wheel's reason is unknown. Cannondale did make compact road frame sets for that wheel size, but AFIK not in the early '80s.

Brad

Panaracer comes to mind for 650A... Harris Cyclery might have a couple other choices.

the brake block position appears "as designed".
It is a small frame, they should have placed sub 27" wheels on that size.

A few common uses for that cage location...

With fenders it stays cleaner.
Fuel bottles can go there when camp cooking for touring.
Bulk water bottles for water storage(to then be poured into a drink bottle) go there.

Whichever is selected, a velcro strap is usually helpful to both ensure the bottle doesnt pop out AND to keep the cage from fatiguing. Bottle cages werent designed to support weight with the front lip down and that stresses the cages, so a strap helps reduce downward stresses from bumps.

I'll add another.
My Blackburn mini pump came with a snap in holder clip predrilled for bottle mounts and I mounted it there. Works great.