Sizing ramble
heavymental
Posts: 2,091
I'm not sure I'll ever understand bike sizing...
A guy in a bike shop was flabbergasted recently when I said I was riding a 52cm. He felt that it was way too small. It's a 2006 Scott CR1 with an effective top tube length of 530mm. He said I'd suit a 56cm Genesis with a top tube of 561mm. I had a bike fit recently and I now have an 80mm stem to bring my position back and up a bit more. It's now more comfortable so I can't see how a longer top tube is going to be a better fit?
I'm thinking of a Ritchey steel frame but the 53cm is 1.5cm longer in the top tube than my Scott so I'm considering the 51cm frame as its similar in the top tube length to my scott (532mm). I dread to think what the guy would say if I told him I was on a 51cm. But the question is... am I right to do so or is there other factors that make a difference to the fit!?
Here's a comparison between some key measurements on the 3 frames... my current ride, the Genesis that the guy thought I'd fit, and the Ritchey Logic in the larger 53cm..
___________________Scott Genesis Ritchey
Head Angle___________73______72______73
Effective TopTube_____530_____561_____545
Seat Angle___________74.5_____73.5____74
Chainstay____________405_____420_____410
BB Offset____________ 67______72______72
Head Tube Length_____130_____160_____140
A guy in a bike shop was flabbergasted recently when I said I was riding a 52cm. He felt that it was way too small. It's a 2006 Scott CR1 with an effective top tube length of 530mm. He said I'd suit a 56cm Genesis with a top tube of 561mm. I had a bike fit recently and I now have an 80mm stem to bring my position back and up a bit more. It's now more comfortable so I can't see how a longer top tube is going to be a better fit?
I'm thinking of a Ritchey steel frame but the 53cm is 1.5cm longer in the top tube than my Scott so I'm considering the 51cm frame as its similar in the top tube length to my scott (532mm). I dread to think what the guy would say if I told him I was on a 51cm. But the question is... am I right to do so or is there other factors that make a difference to the fit!?
Here's a comparison between some key measurements on the 3 frames... my current ride, the Genesis that the guy thought I'd fit, and the Ritchey Logic in the larger 53cm..
___________________Scott Genesis Ritchey
Head Angle___________73______72______73
Effective TopTube_____530_____561_____545
Seat Angle___________74.5_____73.5____74
Chainstay____________405_____420_____410
BB Offset____________ 67______72______72
Head Tube Length_____130_____160_____140
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Comments
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There are no rules on frame size. Take a look at the assortment you see in the pro-peloton.
If it works for you, it is right.
In fact, several geometries and several sizes might be absolutely fine for you.
Go with your gut and buy what you want.
I'm not sure why some cyclists feel the need to comment on choices made by others.0 -
Debeli wrote:There are no rules on frame size. Take a look at the assortment you see in the pro-peloton.
If it works for you, it is right.
In fact, several geometries and several sizes might be absolutely fine for you.
Go with your gut and buy what you want.
I'm not sure why some cyclists feel the need to comment on choices made by others.
Yes it seems to me like there is more than one way to get to a comfortable position. But it does seem silly that the first question isn't about the top tube length as that's what counts. Seems old fashioned to think about the seat tube measurement as the indicator of bike size since compact frames came in and changed the position of the point where seat and top tube meet. Saying a frame is 52cm no longer means it's a titchy frame necessarily as you can find the same top tube length on a bigger bike.0 -
Buy the bike that gives you the riding position you want. My bike is a size down from what the size charts suggest as i have a relatively long body and if stuck between two sizes i prefer the smaller.0
