PandaExpress

Went into the shop and got my measurements taken for bike fitting. Either the guy helping me out was the worst at explaining things or I just didn't understand his explanation, because I'm still confused about what size I am. I'm primarily interested in road bikes, but figuring out mountain bikes would be nice too.

Here's what I got form the shop:

I'm 5'11, with slightly shorter legs/longer torso than most people my height.

Standover max: 32.3 inch (82 cm). I've been told the bike should be an inch less, so something 31 inches tall?

Top tube with downstem: 66 cm

According to the guy taking my measurements, I should be riding 54 cm road bikes. Does this sound about right based on the other information?

RonH

I'm 5'-11" and my bikes are 57 cm and 56 cm. I think a 54 cm may be a bit small. Try dealing with manager/owner or go to another shop. Buy the bike from the shop that seems the friendliest, most knowledgeable, helpful, etc.

Yo Spiff

I'm a lot shorter than you at 5" 7", but what I have in common is that my legs are short relative to my height and my upper body is longer. This results in the frame with the correct reach for me being one that is in my crotch if I am standing over the top tube. I believe Doesn't present any problem to me. Shouldn't be as much of an issue on a sloping tube design. What matters is the riding position being right for you.

I just measured the frame on my road bike and the seat tube measures just about 20" from center of the bottom bracket to middle of the top tube. That comes to about 51cm. It's a fairly short frame, as you can see:



So, for a guy 4 inches taller than myself, they are recommending a bike only about 1.2 inches taller. Perhaps I'm riding the wrong size, but all my bikes have been about this size and it certainly feels right to me.

PandaExpress

I suppose a better question would be, with a 32 inch standover height, would 54 or 56 cm be a better fit?

SkyDog75

Standover height is a convenient rule of thumb measurement, but it's not the definitive way to find your best fit. It can be argued that the effective top tube length or overall reach (top tube + stem) are more important than standover height or seat tube length.

But anyway, for sake of comparison... I'm about 5'9" with a 32.5" inseam, measured from the bottom of my bare feet to snug against my unmentionables. I'm generally comfortable on road bikes with a 31"-ish standover height over a sloping top tube and roughly 54 cm effective top tube length. At 5'11" with a long torso, I'd expect you to be comfortable on something a bit longer than a typical 54 cm frame.

Have you tried any of the online fit calculators to see what kind of sizing they suggest? Competitive Cyclist has a good one HERE.

PandaExpress

I've come to the same conclusion. Unfortunately, I'm just not sure whether or not I should go for a 54 cm bike with a long top tube or a 55/56 cm bike. Anyone know what the approximate standover height is on a 55 or 56 cm bike?

SkyDog75

It varies. I've noticed some pretty big differences from brand to brand, so it pays to look at the manufacturers' web sites for geometry charts. You can find specs like top tube length and standover height on most current and recent models. For example, here's some info from the geometry chart for my 2006 Bianchi San Mateo:

Size: 53 cm
Seat Tube Length: 50 cm
Top Tube, Actual: 52.3 cm
Top Tube, Virtual: 53.5 cm
Standover Height: 30.5 inches

Size: 55 cm
Seat Tube Length: 52 cm
Top Tube, Actual: 53.8 cm
Top Tube, Virtual: 55 cm
Standover Height: 31 inches

Size: 57 cm
Seat Tube Length: 54 cm
Top Tube, Actual: 54.8 cm
Top Tube, Virtual: 56 cm
Standover Height: 32 inches

"Actual top tube" is the length of the top tube. "Virtual top tube", the more useful number, is the length the top tube would be if it was horizontal instead of slanted. Virtual top tube length is a more practical measurement of the distance between the head tube and seat tube.

Legacy2

Hi panda! I am a newbie here too and had the same problem with sizing. I am 5'7" with a 31" inseam. Bike shop said an 18" frame for me but that put the top tube right up against me. Since I am just getting back into riding, I figure I might have a few accidents and safety wise would be in pain if I came off forward with anything less than perfectly straight legs. The next size down in the bike I wanted was a 16". The reach was better for me and I feel 'safer' with more room between me and the top tube. Guess which way I went?

Incidently after riding several different models, there were some 18" that I could have been comfortable with. Those were the ones that the top tube sloped down slightly as it got closer to the saddle. It's all in what you are comfortable with. My feelings are that if someone is not comfortable with their bike, they will not ride it as often as they might. Get comfortable and get riding!

Legacy2

DX-MAN

Panda, two points:

1. I agree that a 54 sounds a bit small, so sight unseen, I'd say 56.

2. The best way to resolve this is a test ride -- try a 54, then a 56, in the bike you like. If they don't have both in your choice, you can either try the closest thing they DO have, or try another shop.

Some bike fitters, for some reason, come up on the small side when they measure somebody. Follow #2, and you should get a good feel for where you really are. HINT: a proper-sized bike just 'feels good' to sit on, coast, and pedal on. It's almost exciting, like the feel of the best pair of shoes you ever tried on.

veloronfla

"Some bike fitters, for some reason, come up on the small side when they measure somebody." Smaller is lighter or they have the smaller one in stock or they just don't know any better.