So I am buying a bike for my 17 yr old daughter. She is the high school triathlon team, I will get her a road bike as they will be training for ITU draft legal races.
I have narrowed it down to Specialized Amira Comp and Orbea Onix Dama, they are both equally equipped (Shimano 105). I can see the geometry sheets are very different, and I don’t know what is a better fit for her body composition, as they are sold at different shops she cant get advise from the shop, they both say they fit. She has ridden both and likes both, mentioned the Orbea felt more stable when pedaling standing up (I guess this meant stiffer ride?), so I appreciate anybody who knows about fitting bikes can advise.
She has a 31.5 inseam and 5’4.5" height. I did the fitting guide on The competitive cyclist and it gave me some measurements I don’t know how to read across into the bike geometry charts. The fit sheet gave her: seat tube range c-c 52.0, seat tube range c-t 53.6, top tube length 61.7.
The specialized Amira (size 51) indicates the following: Seat tube length, B-B Center to top: 450mm, Top-Tube length horizontal: 518mm.
The Orbea Onix Dama (size 49) indicates the following: Seat tube length: 2 measurements, H: 430, HST: 490 (don’t know the difference), L: 510
Great to see a high school that has a tri team. You got some skewed numbers with the fit calculator. The top tube measurement cannot be right. With her inseam and considering she is still growing the 49 is too small. Also you cannot really get an accurate view of seat tube length when comparing bikes with sloping top tubes as the real measurement actually exists somewhere in space above the tube intersection. You would be better served by getting her a professional bike fit from someone well versed in tri bike fit, fully understanding the need to run off the bike. Using those measurements then look for frames that have the corresponding stack and reach measurements, not seat tube and top tube and you will come away with a better fitting bike. There is plenty more to it than this but it is a start.
I have an Orbea Onix Dama from '08 or '09 and it is a 51. Looking at size chart they go from 49 to 53 now.
I’m just under 5’ 6" but have shorter inseam than your daughter which I would guess she has shorter torso than I so for her shorter top tube women’s bike have is important. Appears the Orbea has shorter top tube than Specialized 510 vs. 518.
51 specialized sounds appears from not seeing like the right size. 49 to 53 seems like a big jump, they don’t make a 51, or perhaps they don’t have in stock?
Yes, its awesome the HS has a tri-team, I hear its the only one in the district that offers a semi private PE program.
The Orbea is only made in 46 (S), 49(M) and 53(L), so I think it makes sense she would be a Medium (definitely not a large)… Specialized is available in many more sizes, but the shop said she would be a 51.
She is leaning slightly towards the Orbea (for her based purely color scheme! :-))
Any additional comments on geometry fit to her body type or experience with either bike would be greatly appreciated. Will be purchasing next week.