Most important fit measurements?
#26
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https://www.cannondale.com/en-us/bik...napse-carbon-4
https://www.trekbikes.com/us/en_US/b...ode=white_grey
Look carefully how long the seat tube is on both of these size 56 bikes. Hint: It's not 56cm.
Last edited by Lombard; 02-01-23 at 05:43 PM.
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If you scroll down to geometry specs, you will see Cannondale and Trek don't agree with you:
https://www.cannondale.com/en-us/bik...napse-carbon-4
https://www.trekbikes.com/us/en_US/b...ode=white_grey
Look carefully how long the seat tube is on both of these size 56 bikes. Hint: It's not 56cm.
https://www.cannondale.com/en-us/bik...napse-carbon-4
https://www.trekbikes.com/us/en_US/b...ode=white_grey
Look carefully how long the seat tube is on both of these size 56 bikes. Hint: It's not 56cm.
If you don’t get that a bike is primarily sized using a rider’s height and inseam to determine a size based on seat tube length, rather than torso/arm length and top tube, then I really have no words.
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I think it's more accurate to say sizing is roughly based on the effective seat tube length, which is measured to where a hypothetical horizontal top tube would intersect the seat tube.
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#29
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Modern bikes with sloping top tubes would be misleading if they used the actual seat tube measurement. My 58 cm Cinelli (seat tube, c to c) has a 56 cm top tube (c to c). If that was the size of my bike it would be way too small.
If you don’t get that a bike is primarily sized using a rider’s height and inseam to determine a size based on seat tube length, rather than torso/arm length and top tube, then I really have no words.
If you don’t get that a bike is primarily sized using a rider’s height and inseam to determine a size based on seat tube length, rather than torso/arm length and top tube, then I really have no words.
#30
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Possibly. Though interestingly, while you see effective top tube length posted, you never see effective seat tube.
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If you scroll down to geometry specs, you will see Cannondale and Trek don't agree with you:
https://www.cannondale.com/en-us/bik...napse-carbon-4
https://www.trekbikes.com/us/en_US/b...ode=white_grey
Look carefully how long the seat tube is on both of these size 56 bikes. Hint: It's not 56cm.
https://www.cannondale.com/en-us/bik...napse-carbon-4
https://www.trekbikes.com/us/en_US/b...ode=white_grey
Look carefully how long the seat tube is on both of these size 56 bikes. Hint: It's not 56cm.
see the size chart for cervelo, it links height to size https://www.cervelo.com/en-US/bikes/caledonia
in fact the size chart for trek that you listed does the same thing , size is equivalent to classic frame size and most direct comparison is height
so to repeat, size is based on seat tube length, either actual lengths in classic designs or effective length in sloping tube designs.....
The effective seat tube length is the distance between the bottom bracket and the point at which a virtual horizontal top tube would intersect the seat tube.
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(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
#32
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agree
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#33
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#34
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Once you understand stack and reach, frame size numbers become meaningless. A lot of brands use the length of a short seat tube on a sloping TT frame as the size. It doesn't mean a thing. I do pay attention to the seat tube angle on the smaller sizes. A 75 degree STA with a proprietary 15mm setback post we be a no go for me. I'd want 32mm of setback.
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modern bike bikes use the equivalent sizing.... ie a sloping seat tube bike of 58 will fit like a classic bike of 58 cm
see the size chart for cervelo, it links height to size https://www.cervelo.com/en-US/bikes/caledonia
see the size chart for cervelo, it links height to size https://www.cervelo.com/en-US/bikes/caledonia
so to repeat, size is based on seat tube length, either actual lengths in classic designs or effective length in sloping tube designs.....
The effective seat tube length is the distance between the bottom bracket and the point at which a virtual horizontal top tube would intersect the seat tube.
The effective seat tube length is the distance between the bottom bracket and the point at which a virtual horizontal top tube would intersect the seat tube.
I would agree with this. As we all know too well, a size 56 bike from one brand can be quite different from a size 56 bike from another brand.
#36
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Effective seat tube length was common in the early days of sloping top tube frames, before stack and reach. You don't see that much today. Stack and reach makes selecting the right size so much easier.
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#38
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Looking to buy a new ride and am happy with the fit of my current ride so i'd like to keep the fit as similar as possible. in comparing the geometry of my current ride i find that naturally i am one of those in betweeners. i have this unfounded impression that the two most important measurements would be stack and reach. would that be a correct assessment? or are there other considerations i should also add emphasis to like tube angles or tube lengths?
#39
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My first consideration is the amount of fork rake with a bike. Chainstay length is also important for climbing. Bikes like the Trek Domane and Specialized Roubaix are excellent in this regard and provide a lot more control at speed on steep down hill roads. After deciding on the bike then I evaluate the size overall. For touring I would go with the larger frame but for general riding the smaller frame if on the fence.
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It's my opinion that the most crucial measurements are whichever ones you are close to the limits of. For example, my long femur and religious following of KOPS has me with a saddle slammed almost all the way back on a 25mm setback post and a 73.5 STA, so I simply won't buy a bike with a 74 or greater STA. Others may want a shorter reach to avoid needing a super short stem, or a low stack height for a super aero position. If you are really an in betweener on all those measurements, you're golden and have a lot of wiggle room. At that point you can focus on other aspects, like how the various dimensions affect handling or comfort
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#41
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Fork rake (offset) doesn't mean anything without a head tube angle to go with it and a calculation of the resulting trail. You could have 40 or 50mm of offset and the same trail.
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Stack and Reach worked for me when I got a new road bike. I wanted a similar fit to my older bike.
Got an older bike without stack and reach measurements? Here's an easy method -- see this 2017 post.
Using simple measurements with the rear tire against a wall:
Got an older bike without stack and reach measurements? Here's an easy method -- see this 2017 post.
Using simple measurements with the rear tire against a wall:
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For fit? Stack and Reach.
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Stack and Reach worked for me when I got a new road bike. I wanted a similar fit to my older bike.
Got an older bike without stack and reach measurements? Here's an easy method -- see this 2017 post.
Using simple measurements with the rear tire against a wall:
Got an older bike without stack and reach measurements? Here's an easy method -- see this 2017 post.
Using simple measurements with the rear tire against a wall:
Last edited by smd4; 02-03-23 at 08:23 AM.
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will 30mm gp5000 fit with 4mm clearance is key
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Well if it works on one person for one bike then it must be reliable