Frame Sizing (Seat/Top Tubes)
Hello -- a very friendly forum. I'm looking at a track frame but have a couple of questions about sizing. My current bike has a seat tube of 55 and a top tube of 54.3. It's a Colnago ML and has a very typically short TT. I run a 120 stem and am happy with this configuration. Now for track. I'm not asking for track: am I going to want to run a longer TT? It seems that I'm going to need to as most of the stems seem to be 95 or so. Can anyone give me any advice regarding geometry, fit, etc. (Say) does a "typical" track bike normally run a longer TT? Oh, I should mention that I'm planning on riding this on the street as well. I'm eager to get to the track we have in LA! Thanks very much for any suggestions.
hmm... 55 seat tube.. but c-t? or c-c? some manufacters use cc on their seat tubes and other c-t seat tube. Old italian frames are usually measured C-C so I bet if u do that with your Colnago u have an squared frame of 54 cms or so. Years ago manufacturers started using seat tubes measured C-T, so basically it depends. Im quite sure Colnagos are CC... maybe not now but in the past they did.
Well apparently all u need is a regular surly or a bianchi pista (steel) or a fuji steel or a KHS, even raleigh came up a few months ago with a track bike with road angles... maybe thats what u need, ull be able to run in the track and in the street with no problems. The problem will be the size because a colnago is a quite classic geometry and I have no clue how old is your frame to start with. the other factor is that nowadays basically u have to guess the right size. In some brands u'll use 55 or a 54, on others maybe even a 53 os a small frame... so now u have to figure it out depending on how comfortable u fell more than if the size it match with the Colnago. In the past was easy... everybody was using the same tubes but know oversize tubes, integrated headset, no lugs... even if the angles are the same with a modern bike u'll have to get a different size for sure.
Since u dont have for sure what u'll need, maybe u'll continue using the same stem or maby get a shorter one or maybe a longer one. It depends..., my sugestion is guess the size of the new frame taking more care of the tt than the seat tube... but do not abuse because u might end with a frame too big for u maybe. Sadly evrybody is using different ways to measure frames so there is no starndar anymore...
I'd suggest you start with the stem length that gives you the same overall reach as your road bike. Then get on the track and see what you need. Three different aspects of your riding will determine changes to your stem length: 1. At speed at the pole, you'll find there's an optimal speed (not necessarily your fastest) at which you'll be glued to the pole, but faster than that you will feel increasingly unstable. This is a result of the optimum speed your track is designed for. To go faster, you can get a bit of an improvement with a different stem length (for most people, a longer one). 2. If you have to dive down to the pole at speed, you'll be doing some radical direction changes where the track wants to throw you. You may find that a different stem will give you better balance -- for me a longer stem helps a bit. 3. Your event also determines upper body extension -- you may get the fastest acceleration in a kilo or 500m with a shorter extension, and may find the same for sprints as well. Pursuit may need a longer stem and I definitely find that for madisons I like to ride a centimeter or so longer because it helps stability during handslings, while also opening my chest and diaphragm a bit for long chases. Overall, I used to head toward a shorter upper body position, but with a power meter and a lot of motorpacing I've found that I was giving a lot away. Now, riding a longer position, I do better and I feel stabler as well, which also permits me to work closer to my limit.