Sizing help please

JonEdwards
JonEdwards Posts: 452
edited September 2012 in Road buying advice
So i'm trying to get my missus, who's a keen mtber with a couple of very flash bikes to give roadie-ing a try.

She's 5'6".

Previous experiences with drop bars have either been ancient "10 speed" hacks, or a Spesh Tarmac that we borrowed from a femalefriend (ex world cup mtber)who's the same height as her, but it turned out to be longer than my bike. She managed 10 minutes on it before giving up. "Couldn't see, couldn't steer, couldn't brake. Torture machine" were her words, IIRC.

She'd probably head towards more audax-ey kind of riding, rather than flat out racy stuff. So I'm thinking a carbon sportive bike would be the right sort of thing to demo, with at least a 105 group on. (her MTBs are all XO/XTR). For choice I suspect she'd rather go for a nice steel frame, guards etc, but there ain't many of them available to try for more than a quick once round the carpark.

So I arranged to demo a small Look 566 from a local shop. In typical bike shop fashion, they forgot to do anything about ordering the demo bike in, and have failed to return calls when asked to chase up on it. Can't be bothered to make any more effort with them.

So, we're looking at Wiggle's "30 day demo" policy. Now it only applies to bikes with 15% or less discount, so we're quite limited in choice. Best option seems to be a Pinarello FP due 105. However we're not sure what size to order. The sizing guide for her height suggests a 51cm, but the TT length is only 13mm shorter than my 55 cm bike (I'm 5'10" and use a 110mm stem on it), and I feel pretty stretched on that, so we'd be down to a 47cm with a 528mm TT.

Your thoughts...?

Yes I know getting a proper bike fit done by a shop would be the correct answer, which is why we tried to demo the Look, as they could have set it up correctly for her. However that failed utterly which leaves us with buying semi-blind online.

Cheers,

Jon

Comments

  • styxd
    styxd Posts: 3,234
    The top tube lengths are fairly meaningless without seat tube and head tube angles
  • 71/74 on the 47, 72/73.5 on the 51 (HA/SA)

    So next to chuff all in it. 0.5° on the seat angle will be easily within the range of the saddle fore/aft adjust. The HA difference will be more about tyring to get a sensible wheelbase and toe clearance on the baby one.