Is 50cm frame too small for a 5'9"/175cm person?

BiggMakk

Based on my build, longer legs and short torso, a custom frame was recommended by my bike fitter. An ideal C-C top tube for me is 52cm (kinda weird considering a 54cm seat tube was recommeded). Needless to say custom frames are expensive and apparently there's no guarantee that it will ride properly considering the odd dimensions.

My research shows that 50cm frames tend to have 52cm top tubes. Will this be too small for me making the ride skittish? I test rode a smaller frame once and I felt like I was physcially falling forward when climbing uphill out of the saddle. My other problem would be my thighs hitting the handlebar when riding out of the saddle. Add to that my shoes hitting the front wheel during sharp turns.

The more I research, the more flummoxed I get. May be I should just get an off-the-rack 52cm frame and just accept its limitations. I currently ride a 54cm with a super-short stem.

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oldbobcat

Gosh, 50 is tiny. My 5'4" daughter with legs up to there sits very nicely on a 50 (with 53cm top tube and super short stem). And If you're hitting your knees on the handlebar, that has to be too small no matter how long your stem is.

It would help to know the ratios of your leg length and arm span to total height. If we're talking about 50% and 100% or less, than you're in the range of normal lankiness. You might be able to get comfortable by splitting the difference on a stock bike and using a slightly shorter stem, flipped or with maximum spacers. For example, my legs say 60 but my torso says 56, so my main bike is a square 58 with 11cm stem and maximum spacers. You can also shop for frames with shorter top tubes. Also, try a second opinion from another fitter to confirm that 52cm top tube. What's the top tube length of your 54?

Another route would be the "comfort" geometry. Generally, these bikes have shorter virtual top tubes, and the longer head tube would let you size down without getting too low. Check the geometry charts for the Giant OCR and Trek Z-series to get an idea.

I know one freak whose legs are considerably longer than half his height. His old standard geometry bike has an extra long straight tube seatpost and Nitto Technomic stem. He's a candidate for full custom or a comfort bike with short stem and maximum spacers.

kdelong

Your shoes hitting the front wheel is a common occurence on a bicycle with standard racing geometry. It doesn't matter too much because most steering on a racing bike is done by leaning into the turn anyway. You just have to be careful to have your feet positioned right at slow speeds when you will turn the front wheel more controlling your bike.

As for your other issues, I would check with another bike fitter to get a second opinion. If he agrees with the first, I would just bite the bullet and start researching custom frame builders. There are some very reasonable builders out there, especially if you want a steel frame.

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alfeng

FWIW. I am sure you are not alone in getting a questionable fit by a "bike fitter" -- did you pay for the fitting?!?

So, can you touch your toes and/or place your palms flat on the ground without bending your knees? Or, presuming a possible lack of fitness on your part, could someone with your proportions theoretically touch their toes and/or place their palms flat on the ground without bending their knees?

If so, then you would have proportionally longer arms. Is that right? THIS IS TRUE FOR SOME WOMEN, too!

BUT, just how long is your super-short stem? Is it a DH stem? How long is the current top tube?

Just WHY are you looking to buy a new frame?

To state what may not be obvious, different handlebars have different shapes AND consequently different forward reach & drop ... and, the "fit" can also be adjusted by choosing a different handlebar.

In the end, you COULD choose a 50cm frame if you really wanted a 52cm top tube ... you would want to use a hi-rise stem (hi-rise stems appear to have about a 90mm forward reach) ...

OR, look at the back of various "catalogs" where the specs are & select a "comfort" bike ... they seem to have proportionately shorter top tubes. Strip the components off, and put your own on.

IMO, if you really want a new ROAD frame, then you should probably get the 52cm frame with ~54cm top tube + a 110mm-to-120mm stem (depending on the handlebars & their installation) ...

oldbobcat

I meant Felt Z-series.

Peter@vecchios

I think the biggest issue may be how short the headtube will be and how low the handlebars will be below the saddle on such a small bike. A competent custom frame builder CAN guarantee the frame will ride fine and dandy or they wouldn't build it, Waterford, for example.

http://www.waterfordbikes.com

scirocco

Not weird at all. In fact, precisely what you would expect if you have long legs and a short torso. Seat tube length is largely irrelevant (as long as you know the other bike dimensions.)

What the fitter most likely envisaged with the shorter top tube (52cm) was that you could use a longer stem. This would keep the overall reach to the bars about the same, so you would have no more problems with your knees hitting the bars than with your current bike. The longer stem would be more in the range for the bike that its designers intended, so it would probably handle better (or at least more like its designers intended it to.)

Like others have said, you don't have to go custom. Pick a so-called "comfort" geometry bike like a Serotta Fierte or Avanti Cadent, and the size with a 52cm top tube will have a head tube long enough for someone your height.

swampy1970

Just how short are your legs? I'm 5ft 11" and ride a 60cm frame and it fits fine and dandy. 3" difference in height shouldn't normally equate to a 8cm difference in frame size....


... maybe you're best suited to a uni-cycle.

melslur

At 5'9" with a shorter torso you should be on a 53 or so. Just sit on a 50/52/54 in a bike shop and see which feels most natural. If your instincts say 50 is too small, then trust yourself.

swampy1970

At 5' 11", with 34.5" inside leg I have a shorter than normal torso too - but find a 60cm frame, with 12cm stem a good fit. I used to ride a 14cm stem until recently.