help me understand this Serotta??

[AngryScientist]

this might fit me? is this TT geometry? could that top tube quoted be correct? anyone know anything about the cx II bikes? could be a fun fixed gear bike with 120 rear spacing, but if that TT is truly 47mm, forget it.



http://www.ebay.com/itm/Serotta-CXII-Frame-and-Fork-48cm-Columbus-Colorado-Steel-/281274449501?&_trksid=p2056016.l4276

http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/2TcAAOxydlFSvvYU/$_57.JPG

[tiretrax]

Everytime I saw that model, it was a tt bike.

[christian]

CXII was their name for the tri-bike, but nominatively it denoted the use of shaped tubing. So I would just think of this as a shaped-tube track bike. It's pretty clearly a dedicated track bike - 120mm spacing, fork-ends, no bottle cage mounts. Also note no provision for rear brake.

Given it's for 700c wheels, it's hugely unlikely that the top tube is 47cm long. Unless the STA is 80d...

I'd ask the seller to mount wheels and take a profile shot. From that, we can probably collectively figure out what's what.

[christian]

btw, I think that's pretty sweet.

[ergott]

Seller says 48cm nominal which I interpret to be horizontal. The actual 47cm is measured C-C along the tube which slopes.

Without the seattube angle it will be real tough to figure out what the fit is like.

[RedRider]

The CXII tubing was stiff and relatively light. It made a great TT or Tri bike and Serotta did many custom CXII tri bikes for the West Point Tri Team who rode them to many podium positions.
I built a track bike using the CXII downtube.
If you're considering a used model check the seat clamp. I don't remember the specifics but there was a year or two that they used a unique clamping method that if broken can not be replaced or repaired. The one pictured above is the "good" seat clamp.

[thegunner]

buy it nick, and let me borrow it.

[RedRider]

I found a photo of the custom Serotta CXII Tri bikes that were made for the West Point Tri Team.

[AngryScientist]

very cool.

Serotta was such a unique company, with so much done over the years. their ending really was sad.

[RedRider]

This is my Serotta CXII Track bike...

[Black Dog]

1. Ask for the serial number. It may have the size as the 1st 2 digits.

2. Use the diameter of the steerer 1-⅛" (28.575mm) as a basic benchmark and measure the length of the TT on the screen. You can estimate the TT this way even with the frame not square to the camera you will get a decent estimate. Being that it slopes you can be sure that the ETT it is actually longer than your estimate.

(EDIT: holy crap…I did this and it came to around 40cm actual and 42 ETT (very loose estimate). Get a photo from the seller with the measuring tape on the TT.


(EDIT 2: I remeasured and this time I calculated the TT as the Hypotenuse of a right angle triangle measuring the set back from the camera and the rough estimate came in at ~44cm)

(TAKE WITH A GIANT GRAIN OF SALT)

3. Given the size of the head tube I would be shocked if the TT was that short.

[mhespenheide]

This is my Serotta CXII Track bike...

Purdy.

[nahtnoj]

Nick,

I think the HT length offers a clue. There is a CM or so top and bottom, maybe 5CM for the height of the DT, 3CM for the top tube, and 2-3CM between the top tube and down tube. A 13CM HT on a frame that is otherwise nearly 48 square should be impossible, right?

Probably the TT has more slope that advertised, and its closer to 51 or 52 effective. But Christian is right, need to see it with some wheels.

[christian]

Couple of things of note - track bikes generally have little drop. This would make the head tube shorter. But this one is pretty long. I think nahtnoj is pretty close. Heck, compare it to the 368 a-c fork and you'll think it's longer. Let's call it 12cm minimum.

Now tilt the picture in your head a little bit; so that the rear fork ends and fork tips are level. Looks like a bog-standard STA maybe even .5d slacker than the HTA, so let's call it 74, because it's a little bike; maybe even 74.5.

Take that STA data, add the fact that it has 700c wheels and the top tube is somewhere around 51.8 - 52.5cm measured c-c. Otherwise, the front wheel would be in the downtube.

Actually, I bet he's measuring weld-to-weld or something.

[93legendti]

Seems to me the bottom bracket denotes its a 48, fwiw.

http://www.ebay.com/itm/Serotta-CXII-Frame-and-Fork-48cm-Columbus-Colorado-Steel-/281274449501?&_trksid=p2056016.l4276

[AngryScientist]

well,

thanks for the replies. i've heard back from the seller, and i have an offer in on the frame. we'll see where this goes, i guess.

cheers.

[Black Dog]

well,

thanks for the replies. i've heard back from the seller, and i have an offer in on the frame. we'll see where this goes, i guess.

cheers.

And the size is???

[Brian Smith]

The CXII tubing was stiff and relatively light. It made a great TT or Tri bike and Serotta did many custom CXII tri bikes for the West Point Tri Team who rode them to many podium positions.
If you're considering a used model check the seat clamp. I don't remember the specifics but there was a year or two that they used a unique clamping method that if broken can not be replaced or repaired. The one pictured above is the "good" seat clamp.

The seat tube collars for all the "CXII" steel-tubed frames made for tri- or tt or track are the very same used for all of the other steel-tubed frames. The proprietary seat post fastening system to be wary of was only used on the "CXII Ti" model and the "HSG" variant of it. The tip-off would be a titanium seat tube with a teardrop profile.

Christian, a frame with a smaller amount of BB "drop" has a taller head tube for an equivalent seat tube length than a typical frame, so that's the opposite of what you were saying.

The Columbus multi-shape down tube had the reputation for being "stiff" somehow, but the round tube that Columbus used to create it would be more "stiff" in the ways that contribute to forward motion than the resulting tube. People enjoy the look and the extra weight wasn't much of a detraction for them.

That particular frame on offer is attractively finished, if it fits you, I can easily understand the temptation to buy it.

[nooneline]

Couple of things of note - track bikes generally have little drop. This would make the head tube shorter. But this one is pretty long.

Hmm - not exactly. Or, "sort of, but."

Track bikes often have higher bottom brackets than road bikes. So if you take a 52x52 track bike and a 52x52 road bike and stick 'em next to each other, the track bike, with its higher bottom bracket, it gonna have a top tube that's higher - and, thus, a head tube that is longer.

However, some track bikes are built with short head tubes to facilitate both a pursuit (aero bars) and a mass-start position - very deliberately without square geometry. These are usually more modern track bikes intended for competition rather than, say, track bikes with more traditional styling.

[Ozz]

CXII = 112

As in 112 miles...the distance of the bike leg of an "Ironman" triathlon

That said, obviously the bike above is a track bike

:beer: