Do you Err on the smaller or larger frame size?

Triathlon Forum
1

buying a bike for my better half the is 5ft6 inseam 79cm

bike shop recommended 53 sm frame road bike for her. but now buying elsewhere and am between a 54 cm and a 52 cm

should I err by going larger or smaller? I figured the smaller of the two will be easier to get a good tri position with clipone once she is more confident or am I thinking the wrong way here?

2

Without knowing her body dynamics or anything else, it’s a bit of a vague question. However, asking a few of the guys I ride with, we’re all riding tri/tt frames smaller than our road frames. (ie: my road bike is a 60, and my TT frame is a 56). Much of this depends on the geometry of the chassis and her actual riding position though.
Try using the Competitive Cyclist Fit Calculator http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO
and after having gone through that. Take a closer look at the two frames, take some measurements, and see which looks as if it would fit fit her in her riding position better.

3

If only someone would write an article this topic, oh wait Slowman did
http://www.slowtwitch.com/Bike_Fit/General_Fit_Articles/In_between_bike_sizes__1173.html
.

4

Neither, try a different shop/brand until yall find one that fits correctly.

5

good article and the first sentence kind of answers my question. but it is mainly about tri bikes this is more for a road bike fit really.

6

As a rule of thumb, size up for tri bikes (for aerodynamics) and down for road bikes (for standover height, the eurocool longer stem and seatpost extension, and the lighter/stiffer setup). Note, many of these rules for road bikes are obsolete due to carbon fiber frames, sloping TTs, etc. , but tradition remains. From a practical standpoint it’s better to have a smaller bike and longer stem/post than a bigger bike you can’t fit properly on.

FWIW, my tri bike is a 52, my road bike a 49.

7

They don’t make large enough frame sizes to fit me. BAH

8

to small can always be fixed with more seat post or more stem or more spacers.

sometimes too big can not be fixed.

with a first bike where you don’t know yet what position you really want to be in, erring on the small side guarantees you won’t at least run into an unsolvable problem.

9

I agree with Jackmott–better a bit shorter.

Having had a too short tri bike, I would go the other way with a Tri bike.

10

Thanks for the advice everyone that was very helpful think will go with the 52 cm frame and take it from there.

11

I’m same height and ride 51 or 52 in my tri, road and cross bikes.

For me road bikes that are for men with top tube of over 530 are to long like Specialized Tarmac in 52 is 537. I do better with top tube of about 520-525.

12

I’m same height and ride 51 or 52 in my tri, road and cross bikes.

For me road bikes that are for men with top tube of over 530 are to long like Specialized Tarmac in 52 is 537. I do better with top tube of about 520-525.

Thanks KathyG nice to have a female response to give a picture that makes sense thanks!

13

She is giving good advice about top tube length. Different companies measure differently. A 53 from on company maybe the same as 52 from another