I posted this question on another biking forum and it was suggested I try here.
I am starting to enter some Triathlons and TT’s and have the opportunity to pick up a TT bike, but unfortunately will not have the ability to try a bike for sizing /fit. I will need to get a frame based entirely on published geometry specs. Can anyone here with some TT bike sizing experience offer some suggestions on sizing??
I’ve been an avid cyclist for 20+ years now (racing for 15 of those) and have no issues with sizing up a road, mountain or cyclocross bike…but a Tri/TT bike is a whole new cycling world to me so I need to ask for some expoert advice here. I started reading thru the Fit section here and was pretty overwhelm’d so I thought I’ ask first here to possible get an initial frame size and then get set up with a professional fit on I have the bike.
I’m 6’1", 185lbs with a 33" inseam, kind of longish extremities
Currently I am riding a 57cm Obea Orca road bike, 100mm stem, seatpost with a 25mm offset
and here is the geometry of the TT frame that I’m getting
You think the second from the largest? If you do races where you have to meet the uci setback requirment, it may be an issue when you run a small frame with lots of seatpost.
I’ll let some smarter people help. Your road bike is smaller than mine, I ride a 58.7 top tube and have similar build to you and ride a 56 size tt bike
If you look at this picture, this is me on a bike I borrowed to do this race, it’s a cheaper felt with in a size 56 with a toptube just under 56. I have the seat jammed pretty far forward and the drop from the top of the saddle to the top of the aero bars is about 4 inches, I could have used more but would need to use different bars. As it sits, it’s too far forward to be legal, but I could slide the seat back enough to pass with the frame. I ride with the seat 31 inches from bb center to saddle top with a cockpiy of about 23 inches on my road bike if that helps for comparison
So your saying your 56cm TT was too long I assume?
My current road bike set up is 30.5" from center of the BB to the top of the saddle straight up thru the seatpost - not angling back thru the setback. My cockpit drop is probably close to 4" as well.
I’m leaning toward the 55cm frame which has the 547.9 ETT
if you look at the picture I linked to, I’m riding a 55.7 top tube and have 4 inches of drop to the bars. I’d like more drop, but that’s life. I guess a shorter top tube would give me a better angle at my elbows, but perhaps it would be too scrunched. I’ll let you decide, but at least you have some numbers to get you started.
I am just under 6’1", 185lbs, with a 36" inseam. Seat hight is 83cm
Road bike is a 63cm Trek
TT bike is a 58cm Cervelo P3.
The real question is how low do you want to go in front (drop=seat top to arm rest top). My body would fit on a 61cm Cervelo P3, but I would not be able to get the 18.5cm of drop without a seriously negative stem (I do run a negative stem, but only slightly). So, how steep do you intend to ride? If you take a look at the whole Stack and Reach stuff on the site. You want to find a frame that will work with the Stack and Reach you expect to have.
I had that exact same issue trying to get on a 58 cervelo and on a specialized transition (the old model) in those sizes I couldn’t get the bars to drop enough
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I am just under 6’1", 185lbs, with a 36" inseam. Seat hight is 83cm
Road bike is a 63cm Trek
TT bike is a 58cm Cervelo P3.
The real question is how low do you want to go in front (drop=seat top to arm rest top). My body would fit on a 61cm Cervelo P3, but I would not be able to get the 18.5cm of drop without a seriously negative stem (I do run a negative stem, but only slightly). So, how steep do you intend to ride? If you take a look at the whole Stack and Reach stuff on the site. You want to find a frame that will work with the Stack and Reach you expect to have.
Good luck.
That is a bit of my problem since I don’t have an TT experience…knowing “how low I need to go”. I think what I’m looking for to start is which frame size will offer me a good neutral position that I can gain some fit experience with to see what works for me and over time how I may want to change it. So down the road if a new frame would be in my plan I could purchase it with a bit more experience under my belt. I’m still reading thru the fit info here and trying to gather some more info, but always looking for real world experience from those that have “been there done that”.
