[bikin]

Do I have this right?

The way I understand it to be, and as measured from center of BB to top of tube:

XL= 22"
L =19.5"
M=18"
S=17"

SuperGo in Oceanside, CA is advertising the 17" on the showroom floor (I measured them myself) as Medium. I thought the 17" is a small frame(???).

What's wrong and right here.....????

 

[tscheezy]

I think it's more like:
XL=21.5"
L=19.5"
M=17"
S=15"

The top tube height (standover) is roughly the same on the medium and small. Only the top tube length and the distance the seat tube extends above the top tube differ (there are other small diffs like head tube length, etc).

Did the frame have the brace between the top and seat tube? Yes = medium, no = small.

 

[bikin]

Yes, there was a brace.

If indeed that was a medium then it was very surprising. I hadn't rode a medium until today. Big difference between the large and medium. Medium felt very cramped in the cockpit. Large felt top heavy and slow... not as whippy.... or responsive.
I liked the feel of the med. but too crampy.

For some reason I had the idea that there was an 18" seat tube.

 

[tscheezy]

There used to be an 18" (M). Back in the days (XCE, RFX) when Turner had 5 sizes (XS, S, M, L, XL) it was 15, 16.5, 18, 19.5, and 21. Now (Spot) they have the new 4 sizes scheme plus sasquatch. They seem to have dropped the 18 (M), made the 16.5 (S) a touch bigger and called it a medium. Or something like that.

I'm not sure why the length of the seat tube would cause the bike to feel small or large per se, that feeling usually comes from the top tube length. You sound like you are right between sizes tho. Who knows, maybe neither will work...

 

[bikin]

The seattube length didn't make a difference. It was just an indication of frame size.
I don't know why it felt cramped, but there was one hell of a difference between the two.
Top-tubes are almost the same lengths. Thanks for the information on sizes. Maybe the setup wasn't quite right on the medium....short stem...saddle too low. I will have to go and try them out again. The biggest difference to me is the snappier movement of the medium over the large. Which I liked. Though the large was the most comfortable.