Frame Size, Center of Gravity, and Bike Handling

[Jo-n-NY]

I find you question very interesting. I am 5'2 (inseam I think, 29) and in a Specialized WDS I ride a 51cm. I felt kind of cramped on a 48. By most of the posts here of ladies about the same height as me, most of them ride a 48.

I felt this kind of odd because I do not consider myself to have long legs. I still have a good amount of seat post showing and wouldn't want any more showing. My handlebars are pretty much inline with my seat. It just always make me wonder about my fit compared to others of my height.

~ JoAnn

[Eden]

I'd definitely say that a smaller bike can help with climbing. I used to ride a bike that was too long for me and on very steep hills I would have the front wheel lift up. I'm much shorter than you, but I'm also longer in the leg and quite short in the arms and torso. What it meant was that I couldn't get my weight over the front of the bike to keep that front wheel down - now it only happened on very steep hills - we're talking up in the 20%'s here, but I also now have much, much more power now that I am not stretched out. Even at my shortness shops tend to want to put me on a bike that is too big - I'm 5' with about a 29ish inseam - they always want to put me on a 48, but my torso needs a 44. I would suggest to anyone who thinks that they are bad at climbing hills and/or has knee pain climbing that they really take a critical look at the size of bike they are riding - a too long bike with too long cranks can kill your abililty to get up hills.

I've also hear that the pros tend to ride somewhat smaller frames than are recommended to the general riding public. A lot of it is to get a super aero postition on the bike that would be hard to achieve on a bigger bike. I'm sure they wouldn't do it if it affected the handling since they are epxected to fly down mountains at crazy speeds. They can, I'm sure, get custom geometries that just are readily available to us though - super long stems are said to make a bike squirrely.

[Starfish]

This is a very interesting topic. I have to laugh...you guys don't think you have long legs, but your 29" inseams go with 5' and 5'2" heights, etc. I am 5'6", and my inseam is barely 29.5".

Anyhow, awhile back, I emailed some questions to Georgina Terry. I was wondering about whether or not a WSD frame could work for me even though I don't have long legs or short torso. I was wondering if a stem adjustment could work. Despite not having shorter arms or torso, I have wondered if my bike is too long for me. One of my questions, and her reply, follows. I'd be curious what you all think:

My question: I'm curious about what you said re: stems. Does handling, balance, center of gravity, connection with the road change when you put a longer stem on a bike to accomodate fit? I am inexperienced and curious about how geometry & fit affect handling. For instance, I like to sit back on climbs, and have been thinking I would like a bike with the seat positioned well back ... so I wonder if putting a longer stem out front puts more weight forward rather than back?

Her answer: You're right that a stem that's too long can throw off the handling of the bike - the relationship between the handlebars and the wheel axle just won't cut it. Especially on the bike you buy, because it won't be a tall bike even though it will be a long bike. Try to keep the stem 100mm or shorter.

[emily_in_nc]

I find you question very interesting. I am 5'2 (inseam I think, 29) and in a Specialized WDS I ride a 51cm. I felt kind of cramped on a 48. By most of the posts here of ladies about the same height as me, most of them ride a 48.

I felt this kind of odd because I do not consider myself to have long legs. I still have a good amount of seat post showing and wouldn't want any more showing. My handlebars are pretty much inline with my seat. It just always make me wonder about my fit compared to others of my height.

~ JoAnn

And I am 5'2.5" with a 28.5" inseam and ride a 44-46! So we're all built differently, that's for sure! One thing I know I've read about a smaller vs. larger frame if you're between sizes is that a smaller frame weighs less. And, you can always get a taller stem or seatpost, but you can only put a stem or seatpost down so far. My older road bike that I sold was a Terry in the 17.5" size (which I believe is about a 44 cm) actually fit me a bit better than my 46 cm Aegis, on which I have my stem as low as it can go, and my seatpost pretty low too. The standover is *just* adequate. But part of that is the frame geometry and how the seat tube is measured -- I test rode a Trek 5200 in the 47 cm size and could stand over it just fine, but felt a bit too stretched out up top and didn't want to put too short a stem on it for handling reasons, so I didn't buy it.

I can't imagine riding a 51 cm with my build!

Emily

[Thorn]

Thanks for the replies! Y'all have given me a lot to stew upon. Based on your comments and other reading, I suspect that the correct size for me is somewhere between the two. The 60cm frame is too long and is not as stable as I'd like on hills; the 52cm is probably a little short which is why I ended up with a long stem (see image) and may have caused my initial discomfort when standing.

Last fall I was seriously considering a custom bike, but a bad experience at the bike shop put it on hold. Then this opportunity to ride a steel frame bike with Campy parts came up and I decided Fate was controlling the timing of the purchase. I expected that the lessons I would learn from the week would be about steel and Campy. I did learn about that (oohh...how comfy are those Campy brake hoods), but now I've also seen that frame size matters as much as geometry and material.

Thanks so much!

[jusdooit]

...........but I would say a 52cm is way too small for your height. I am 5'7" with a 32+ (almost 33) inseam and I ride a 52cm very comfortably as far as seat height. My error was getting a men's frame, so while I'm fairly long legged I am short in the torso. Therefore the overall reach across the top tube is too much for me. According to my LBS changing the stem height, etc. will have a significant effect on my control over the bike. The higher the stem the less control you have because you give up some torque. the way he explained it made complete sense. So I am in the market for a better fitting bike.
Good luck, I think a lot is just trial and error.

[Thorn]

I think a lot is just trial and error.

Ain't that the truth!!!

According to my LBS changing the stem height, etc. will have a significant effect on my control over the bike. The higher the stem the less control you have because you give up some torque. .

And, ain't it the truth there there is art in the science of bike fit! The mechanic who put me on the 52 thought through the 60cm and concluded that the stem would be so short the effective "lever" wouldn't be there and I'd have no control over the bike.

Arrgggghhh....it is going to be a long, slow (albiet fun) shopping experience!