Tri bike geometries - can they be generalized?
Bike gurus,
This one popped into my head while reading Chris's fit options post. Are there good general characterizations for the various bike geometries from different manufacturers? I.e., Brand X typically has long top tubes, similar to Brand Y, but totally different from Brand Z
For instance, I have a long torso for my height / short legs. Does that point me in any certain direction? I have yet to buy a tri bike, but had an aero fit test done about 18 months ago at (Cronometro in Madison) to help me pick a bike that would work. They had me set up on a P2C and it felt great by the time I was done, though we had to move the seat all the way forward.
So now I'm looking for a Cervelo or something with similar / compatible geometry. That's where I wondered if there is a chart somewhere that might help me limit my search without having to dig through the detailed specifications of every bike out there.
Thanks!
Comments
@Scott - that is a great repository of data. Nice to have it all together in one place. But looking at all the numbers makes me a bit dizzy
.
What I was really hoping for is a layman's summary of what all those numbers mean, or for my own case, at least an idea of which ones are roughly equivalent to a cervelo p2c. Or maybe there is no way to make those sort of statements?
Here's a link describing them long/low and short/narrow in more layman's words:
http://www.slowtwitch.com/Bike_Fit/...w_613.html
Unfortunately, while some makes are consistent, others vary the stack and reach based on what size. Here's a link that maps the stack and reach numbers of various tri-bike makers graphically:
http://www.slowtwitch.com/Bike_Fit/..._1321.html
I had similar questions when I bought my tri-bike 18 months ago. I had a FIST certified guy set me up on the fit bike, take measurements, and then we looked at the various bikes that matched those coordinates. It wasn't free, but if you are going to spend $2,000 or more on a bike, I think it's worth it. With a list of 2 or 3 bikes in hand, I called my local shop, had them set up the bikes based on my desired specs and test rode them for about 20 minutes each. One bike just felt better than the other, and I bought that bike.
And why do I say that...
I'm a bit more legs than I am torso so I need a bike that is a little bit taller but a little more narrow. Not knowing jackshit about fit two years ago I went and bought a Felt B2 (after selling a Trek Equinox that also probably didn't fit me right). I didn't know that all 56cm bikes weren't created equally. Felts are notoriously long and low (like Cervelo). Pretty much one of the worst choices I could make. I have never been really comfortable on it and I have had it fitted three times. The last fit was high tech with all the computer images and video captures and angle measurements and the whole nine yards. The fitter told me the Felt was "not the bike I would have recommended for you" (her words for "way to pick out a bike, dumbass.") She got it fitting as best she can but it still sucks. I did what any other person with more money than sense would do and ordered a new bike. The Trek Speed Concept is more along the tall/narrow lines (which I need) but it's also very configurable with different bar/stems combos.
Brian if you have short legs and a long torso then yes, you need long and low. Cervelo is good for that (P3 and P4 even more so than P1 and P2), as are Felt, Fuji, and other brands.
What are you riding now? A road bike?
My opinion:
LBS:
FIST:
My larger point is to not limit yourself to the local resources you may or many not have. This is why we work with Todd at TTBikeFit.com, because he's knows his stuff and is not in the business of selling you the 56cm P2C that's been on his floor for 3yrs...
@Michael - Thanks for the references. I'll look those over and see if I can figure out which bikes are good candidates.
@Bob - That's some expensive learning you did! Yikes. I'm trying to avoid that very scenario, that's what I was thinking with the fitting at least. I think I have good measurements from my fitting and now trying to figure out how to apply them to find the proper bike. Thanks for sharing your experiences.
@Chris - current bike is an old Lemond road bike. This is a good bike to casually cruise the countryside, but no good for more aggressive riding. At the least, the size and/or fit is wrong for me. Tried clip on bars and even a forward lean seat post, but just can't make it work - hip angle too sharp. Works well enough for indoor trainer, but I need something else for races or I spend the whole time in the hoods going backward through the field like I did at the Pigman HIM last year.
@Rich - point taken about LBS. They have an excellent reputation around here and I felt good because they did not actually try to sell me on anything, they just did the fitting. But that certainly doesn't mean it was actually correct. In the end I felt good about it because the setup I had felt great, but I wasn't convinced the bike I was on was the best way to get that fit. $$ are short or I would go to Todd right away. In the meantime I'll have to learn what I can on my own and through all of you.
Now it looks like I just need to sit and stare at the numbers until I can figure out how to convert my fitting measurements (like saddle to HB, saddle HB differential, and grip height) to stack and reach data. At least with your help it looks like I can narrow it down considerably
Thanks all!
Look up your frame online and figure out the frame stack/reach. If this isn't available just get a tape measure.
Measure the spacers you have under the stem and the stem length and angle.
Plug it in here: http://alex.phred.org/stemchart/Default.aspx
Add the stack/reach from the stem to the frame to get your current handlebar stack/reach.
Once you have that you can now figure out exactly what stem and spacers are required to have the same fit on different frames. All you have to do is start to play with different frame/stem/spacer combos until you get the same handlebar stack/reach.
The catch to this approach is that you have to stick with the same aerobar stack/reach. You can adjust that as well but that gets a little hard and requires you to measure things as the stack/reach of most aerobars is not documented and can vary based on how you adjust them.
With all of the help received here, hopefully I can get the right bike and get it set up in time for the race.
Thanks everyone,
Brian
Yes, use the knowledge and experience of the rest of us and avoid that costly mistake. Granted, the Trek Speed Concept wasn't out two years ago so I would've been lusting after that bike anyway.