Here's a question. My girlfriend is a marathon runner and has talked about how she'd like to do some riding, with the thought of eventually doing tri's and iron (wo)man's.

I was thinking of going to garage sales and CL to find her a nice old road bike that I can fix up for her. It would never be the one she'd ride if she got into tri's and the like. But it would allow her to do some cross training, and ride.

She has an inseam of 30 inches, but she's 5'3. I'm 6'3 and have an inseam of 34.

Since I'd like this to be a surprise, any thoughts on how to figure out the proper bike size for a woman? Obviously the online 'fit' calculators may give a bad answer. What might be the right height will likely be the wrong length.

Thanks!

The Fit Calculator on CompetitiveCyclist.com takes into account both inseam and upper body measurements. The hard part would be trying to get the upper-body measurements of your gf without telling her why. Or you could just guesstimate.

My wife has a 30" inseam and is 5'4. She generally rides a 50cm with 90-100mm stem and standard setback seatpost. She prefers a compact frame for the greater standover.

5'3" is one of those tough heights. Depending on her ratio of inseam to torso, she might fit some manufacturers 47 cm frames. I'd be reluctant to presume that she could fit anything bigger... maybe a 49 if it was WSD and measured C-T.

It will be a crapshoot... you know how particular bike fitting can be, so a "surprise" non-returnable bike is a risk. But I would hazard a guess that at 5'3" most 47s can be made to work with changes in stem and perhaps seatpost.

I'm 5' 3.5" and have ridden everything labeled from a 48 to a 52. You need to focus on the top top length. With long legs she can stand over anything but the top tube could be too long. 50.5-52.5 cm top tube might be workable but then you're taking a big risk not knowing more about her comfort on a bike. Flexibility, injuries, etc,, will affect her position. You can't assume ahything.

Am just going through the fit issue, it can be a bit of a minefield. (I'm nearly 5'6", yet my ideal toptube length is 51.1cm as I have a really short reach. So I need a smaller frame than usual for someone of my height)

Since you really want this to be a surprise for your gf, why don't you see if you can buy the wheels only, wrap them with a big bow and write in the card that you can choose the rest of the bike together. Win, win.

Yeah I just got my GF a Dolce as a surprise. But I measured her a long time ago because I told her one day I would like to build a bike for her. I really hope I got all the measurements right! I'm so nervous. It comes next week.

Perhaps you can buy a bike from a LBS and tell them about it. Then give it to her as a gift but go back to the store soon and have them help you check the fit. They may exchange it for a different size or order one if necessary.

The "fix up" part of the old bike and shopping around could cost considerable time and money. And still leave you with a bike perhaps not as nice (and perhaps nicer as with some steel frames), as something new that starts around $600 with warrantee and service plan.

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I agree with SK. I'm just under 5'3" with a 30" inseam, and my bikes w/traditional geometry are all 52 cm and one is 51 cm. A frame with compact geo in size Small might work, as long as top tube isn't too long. Most bikes are designed for guys. Most women have shorter arms proportionally, and it's critical to get the TT measurement right to avoid her encountering shoulder, neck and back pain. A short stem can help but is no substitute for a TT that fits. If this is going to be a throwaway bike, maybe look for a old touring model, a Terry, or something shorter on the TT that will provide a shorter reach. And in the meantime get her a good professional bike fit and then take her to ride different bikes. Part of the fun of cycling (IMO) is test-riding, anticipating and searching for the next bike :-) . Good luck!

I'm so happy! My girlfriends bike came and it fit her perfectly!

Here's a question. My girlfriend is a marathon runner and has talked about how she'd like to do some riding, with the thought of eventually doing tri's and iron (wo)man's.

I was thinking of going to garage sales and CL to find her a nice old road bike that I can fix up for her. It would never be the one she'd ride if she got into tri's and the like. But it would allow her to do some cross training, and ride.

She has an inseam of 30 inches, but she's 5'3. I'm 6'3 and have an inseam of 34.

Since I'd like this to be a surprise, any thoughts on how to figure out the proper bike size for a woman? Obviously the online 'fit' calculators may give a bad answer. What might be the right height will likely be the wrong length.

Thanks!

completely unrelated-- kinda.

make sure it's a color she likes. my girlfriend would never ride a bike in a color she hated (and neither would I).

I'm 5'3" and I have a 47cm trek....
buying a bike is kind of one of those things that you have to be there for.. well it is in my opinion,

so how about surprising her by taking her to a bike shop and helpign her pick one out?

I'm 5'3" and I have a 47cm trek....
buying a bike is kind of one of those things that you have to be there for.. well it is in my opinion,

so how about surprising her by taking her to a bike shop and helpign her pick one out?

I like this idea best! I know us guys like to surprise our SOs with things, but I think having her go to the LBS with you and finding the fit and color she likes would be better than surprising her with something not as nice. Even if you surprised her with the perfect bike somehow, I think she might enjoy the process of working out exactly what she likes at the LBS.

Just my opinion! :-)

Here's a question. My girlfriend is a marathon runner and has talked about how she'd like to do some riding, with the thought of eventually doing tri's and iron (wo)man'. She has an inseam of 30 inches, but she's 5'3.
Thanks!
I am 5' & have 30 inseam. Get her a a 46-49cm bike. Anything w/ Shimano 105 is beyond great for a starter & more than she needs. Get her a new lesser Shimano-equiped bike for $500. Don't worry about details on a starter bike & just buy the thing.