Asking about road bike size

sin_ozono said:

Hi!!!!

I've been looking for a road bike for my girlfriend. A second-hand bike has been offered to me, the 2007 Ruby comp specialized but I'm not sure if it will be the right size. It's a 51 and the geometry is in the next link:

Specialized Bicycle Components : Ruby Comp

My girlfriend height is 163 cm (63,6"😉 and 73cm (28,5"😉 scrotch measurement.

Thanks you for your help

It could be pretty close, but we're closer to curing cancer than we are doing bike fits over the internet. If you can arrange it, have your girlfriend ride the bike. Be very careful, however, not to spend more on her bike than you would on your own. The ratio of spending should be something like this: (10 + ζ ) * hers = yours, where ζ is much greater than hers.

The problem is that the bike is in another city so It's impossible for her to ride the bike ant the geometry for de 2009-2010 is quite different that's why I'm force know If at least the size could be the right one.

I wasn't thinking about spend more money in her bike than in mine not even close 😄

sin_ozono said:

Hi!!!!

I've been looking for a road bike for my girlfriend. A second-hand bike has been offered to me, the 2007 Ruby comp specialized but I'm not sure if it will be the right size. It's a 51 and the geometry is in the next link:

Specialized Bicycle Components : Ruby Comp

My girlfriend height is 163 cm (63,6"😉 and 73cm (28,5"😉 scrotch measurement.

Thanks you for your help

It's pretty close, but I think it would be too tall.

Figuring the bottom bracket height at 10.5" (26.5cm) or so, and adding the 51cm frame size, it would have a stand-over height about 77cm, too tall for her, expecially when you also factor in the sloping toptube.

The only way it would fit is the 51cm were to a point above the top tube, and even then it would be too close.

If you want to give it a bit more careful consideration, ask the seller to measure the true stand-over height at the center of the top tube, and compare that to her crotch to floor length. Ideally she should have no less than 2cm of clearance.

In any case don't let the deal blind you to the importance of good fit.

sin_ozono said:

Hi!!!!

I've been looking for a road bike for my girlfriend. A second-hand bike has been offered to me, the 2007 Ruby comp specialized but I'm not sure if it will be the right size. It's a 51 and the geometry is in the next link:

Specialized Bicycle Components : Ruby Comp

My girlfriend height is 163 cm (63,6"😉 and 73cm (28,5"😉 scrotch measurement.

Apparently, I'm the only one who looked at the frame's geometry ... for those who didn't, the frame has a sloping top tube.

So, the bike's frame will fit ... you may have to change the stem to a shorter one (BMX stems are the stubbiest) AND you may have to find a different handlebar with a shorter reach, but if the price is right, then it's probably a pretty good "first" bike for your girlfriend.

alfeng said:

Apparently, I'm the only one who looked at the frame's geometry ... for those who didn't, the frame has a sloping top tube.

Congratulations. You've won an extra 5 minutes at recess. Your parents must be proud.

alfeng said:

Apparently, I'm the only one who looked at the frame's geometry ... for those who didn't, the frame has a sloping top tube.

So, the bike's frame will fit ... you may have to change the stem to a shorter one (BMX stems are the stubbiest) AND you may have to find a different handlebar with a shorter reach, but if the price is right, then it's probably a pretty good "first" bike for your girlfriend.

Pardon my ignorance, but how does a sloping top tube help? it slopes up from the seat tube, and even if level would already be too tall.

FBinNY said:

Pardon my ignorance, but how does a sloping top tube help? it slopes up from the seat tube, and even if level would already be too tall.

All a sloping top tube is give some or more stand over clearance. It doesn't make a bike fit.

If, however, the standover height is as tall or taller than the cycling inseam, that presents problems. In the case of the OP, it's unclear whether the inseam given is a cycling inseam or not. If it is, the frame is too big. If it's not, it might work (a cycling inseam is longer than a regular inseam), but it's impossible to say without a bike fit. That's why bike fits, over the internet, are as reliable as Italian trains. You don't use shorter stems just to make a frame that's too large fit.

alienator said:

All a sloping top tube is give some or more stand over clearance. It doesn't make a bike fit.

This is a perfect example of why one measurement is worth 1,000 opinions

Sloping top tubes offer more stand-over clearance when compared to a level top tube with an equal head height, but when compared to a level top tube of the same seat tube length, it offers not more, but less stand-over clearance, because it rises from the seat lug and thus is higher than a level top tube would be coming from the same place.

The improved stand-over clearance rational applies because with sloping top tubes it's allows one to build frames with shorter seat tubes than would otherwise be possible on full size wheels. With a level top tube the smallest size possible is about 49cm, but with sloping top tubes, frames can be built down to 43cm or even less.

That isn't the case here because we know it's a 51cm frame. The real question is what the nominal 51cm measures to, and how much heigher the top of the seat tube is over the seat tube/top tube joint. Which why I suggested getting a true standover measurement from the seller.

Given her overall height I suspect he did give us a crotch to floor inseam, otherwise she'd have incredibly long legs for her size. And by way of comparison, my 47cm commuter bike with a level top tube has a stand-over height of 29" and the bike he's looking at would be taller yet.

FBinNY said:

Pardon my ignorance, but how does a sloping top tube help? it slopes up from the seat tube, and even if level would already be too tall.

OMG! You still haven't looked at the frame's geometry ...

On the 51cm SPECIALIZED RUBY frame, the seat tube is 41cm (c-c), 45cm (c-t) ...

The (virtual) top tube is 51.8cm ...

While some people who are the height of the 'girlfriend' could probably ride the particular bike as-is, if the cockpit is a bit too long, then installing a shorter stem and/or a handlebar with a shorter reach can effectively make the bike feel smaller.

FRAME FIT should be done based on the distance between the saddle & the handlebars AND NOT between the saddle and the ground.

[quote="alfeng"]OMG! You still haven't looked at the frame's geometry ...

It isn't that I haven't looked, but because I couldn't open the link to the published geometry. It's why in each post I said that there was an unknown factor, being the difference in the seat tube length (nominal size) and height of the seat tube/top tube junction. It's also why I suggested getting a true measurement of the stand-over clearance.

Your latest reply had me go to another site to pull down the published spec's, and based on that the frame is still too large for her, with borderline standover clearance. Depending on the other factors she's be far better off with one of the two smaller sizes offered.

I apoligize for the confusion.

alfeng said:

While some people who are the height of the 'girlfriend' could probably ride the particular bike as-is, if the cockpit is a bit too long, then installing a shorter stem and/or a handlebar with a shorter reach can effectively make the bike feel smaller.

FRAME FIT should be done based on the distance between the saddle & the handlebars AND NOT between the saddle and the ground.

I've been fitting Specialized road bikes to women for some time and, unless this woman's proportions are unusually extreme, she should have no trouble straddling the 51, but she could find the 51.8 top tube to be a bit of a stretch. A stem one or two centimeters shorter would remedy this.

By the way, the stock bar on the Ruby has a pretty short reach already.

My only caveat is that if her legs are exceptionally short for her height, she may have trouble straddling the top tube, a deal-breaker. If her legs are exceptionally long, then she might need the extra head tube height of the 51 anyway.

Would, could, might, maybe......all great words to accompany a purchase based on internet advice.

Why can't you borrow the bike so your girlfriend can take spin? Or....why can't she go with you to check out the bike?

See, you're down to a roll of the dice. You could choose to buy the bike, anyway, based on the "information" you've culled in this thread, and it's possible the bike would be a fit. It's also possible that the bike won't be a fit and your girlfriend won't feel comfortable riding it. It's also possible that it could fit, but she doesn't like the way it rides.

It's all up to you.

If it were my girlfriend, first, I'd make sure my wife didn't find out about her. Second, I'd find a way to get my girlfriend at least one test ride on the bike.

Thank you all for the answers.

She can't test a similar bike because It was suppouse to be a surprise, and the actual ruby is different than the 2007 ruby, but after all I'm completely sure that would be impossible to fit a bike without test it.

Anyway I've got a lot of answers telling me that the bike will be too tall so I'm not going to risk so much money. I didn't buy mine by Internet even if there was better values so I won't do it with her bike... But I've been tempted to do so.

sin_ozono said:

My girlfriend height is 163 cm (63,6"😉 and 73cm (28,5"😉 scrotch measurement.

I like to think of myself as being intimately familiar with a woman's anatomy, but I've never heard of a "scrotch". Wonder if my wife will help me locate her's this weekend? 😉

You can post your doubt in another thread. You don't need to be too intelligent to notice that I'm not a native english speaker and some words are difficult to know or learn just because you don't use them often. I try to write the best way I can but sometimes (more usual than I'd like) I make mistakes but I think that most of the people understood what "scrotch" is so maybe the problem is yours.