Frame size, new bike fitting, questions

[DaleRider]

My conversion says that you are 5' 8".

Cannondale has this handy chart.

http://www.evanscycles.com/product_document/file/e60/9e4/ed6/676/cannondale-road-bike-sizing-chart.pdf

Which puts OP squarely on a 54 Cannondale.

It's really more like 5'8.25". At least that is what my ego keeps telling me.

[GT56]

I plugged the numbers in to ye olde bike comparator. If it's 100% accurate, you'd need a 95mm -6* stem on a 5cm spacer to have an identical position to your current one on the CAAD8. If you went with the 50cm SLR01, you'd need a 100mm stem on 25mm of spacers. Of course, one test ride is worth a thousand internet comparisons. Good luck!

SLR01 53 (red) compared to a CAAD8 using the geo chart you posted:

thanks, but this raises a few questions:

'height at top of headset' would correspond to 'stack' , right ?

then from where is 'handlebar height with spacers' measured, also from the bb ?

is yes, then a 20 mm difference between the two is hardly possible if the stack height of a stem is 40 mm alone, then add a raise because of the upward angle

there's no spacers used in your calculation, right ?

where do we find proof that a saddle to handlebar drop of 110 mm can be achieved ?

[AGW]

I used 10mm of extra headset height (or I could have added as spacer height instead) on the CAAD8 to match the OP's bearing cover height, but SLR01 is slammed. I think you're right that it's calculating stack, and it's only about 3-4mm off from what BMC publishes, but I have no idea what the stack is for a '04-'05 CAAD8 to compare. Also, BMC didn't publish its fork rake, and I don't know if that affects the output calc for stack in the spreadsheet. Perhaps someone with BikeCAD and a lot of free time can do an overlay? That would also produce a bar drop figure.

[DaleRider]

OK, I think I can answer my question now.

I stripped the CAAD8 down to the bare frame and took it to a friends tool & die shop. We locked the frame in a jig and used the front and rear axles to ensure that the frame was sitting level. We then built a tool that inserted into the bottom bracket that had one rod going vertical and another on a 90* that we could raise and lower. While this wasn't the most accurate measuring tool in the world, we ended up with a stack of 533 mm and a reach of 382 mm.

There may be a +/- in there somewhere, but this should but me perfectly on a 50 cm SLR01.

[g32ecs]

I'm 5'7 and ride a 50. Kinda wished I went for a 48.

50 should be perfect for you.

[AGW]

That posted geo chart matches the one for a 2004 R1000 I found with the wayback machine. In bikecad. You're right on on reach (381), but I got a stack of 554. You'd fit on either frame, the difference is mostly going to be 20mm of spacers.

[GT56]

OK, I think I can answer my question now.

I stripped the CAAD8 down to the bare frame and took it to a friends tool & die shop. We locked the frame in a jig and used the front and rear axles to ensure that the frame was sitting level. We then built a tool that inserted into the bottom bracket that had one rod going vertical and another on a 90* that we could raise and lower. While this wasn't the most accurate measuring tool in the world, we ended up with a stack of 533 mm and a reach of 382 mm.

There may be a +/- in there somewhere, but this should but me perfectly on a 50 cm SLR01.

have you still got the caad 8 ? to be 'really' sure, you could measure the headtube lenght and relate that to a period cannondale geo table

[DaleRider]

That posted geo chart matches the one for a 2004 R1000 I found with the wayback machine. In bikecad. You're right on on reach (381), but I got a stack of 554. You'd fit on either frame, the difference is mostly going to be 20mm of spacers.

I typed a little to quickly. The stack was 543 mm, but its easy to see where I could be off by as much as 10 mm.

I spoke with the guy who has done my last three yearly fittings and his words were "If you plan in racing again go with the 50. If all your going to do is charity rides and Gran Fondos, get the 53".

I refuse to do another crit again, but there has been some really cool road races popping up in Michigan and Ohio lately. So I'll have the local BMC dealer order up the 50.

Thanks for all the help with what should have been a simple decision.

[GT56]

That posted geo chart matches the one for a 2004 R1000 I found with the wayback machine. In bikecad. You're right on on reach (381), but I got a stack of 554. You'd fit on either frame, the difference is mostly going to be 20mm of spacers.

I typed a little to quickly. The stack was 543 mm, but its easy to see where I could be off by as much as 10 mm.

I spoke with the guy who has done my last three yearly fittings and his words were "If you plan in racing again go with the 50. If all your going to do is charity rides and Gran Fondos, get the 53".

I refuse to do another crit again, but there has been some really cool road races popping up in Michigan and Ohio lately. So I'll have the local BMC dealer order up the 50.

Thanks for all the help with what should have been a simple decision.

you won't regret it, pls post pics when ready

[DaleRider]

WIll do. I've been wanting a BMC for a long time now so this will be like my dream bike build.

[DaleRider]

Well, last night at our local shop ride there was a gent there with a 53 cm Pro Machine that was kind enough to let me spin on it for a few miles. I am so glad that he did as ordering the 50 would have been a bad choice. His frame had a 100 mm stem slammed on to the top cap, and the reach/stack felt even better than my CAAD8. He didn't have a power meter on his bike to confirm it, but I actually felt like I was making more power with less effort (lower heart rate, same cadence).

[bikerjulio]

Well, last night at our local shop ride there was a gent there with a 53 cm Pro Machine that was kind enough to let me spin on it for a few miles. I am so glad that he did as ordering the 50 would have been a bad choice. His frame had a 100 mm stem slammed on to the top cap, and the reach/stack felt even better than my CAAD8. He didn't have a power meter on his bike to confirm it, but I actually felt like I was making more power with less effort (lower heart rate, same cadence).

Isn't that the setup I told you to go with????

[DaleRider]

Yup

[USPS]

I'm thinking about buying a new tarmac or venge. My current 8 year old Trek is a 56 - so up until now I have thought that was my size. Recently it has come to my attention that I should be looking for a 58.
What do you think?
Here are my measurements:
Bare feet
Inseam: 33
Trunk: 26
Forearm: 12.5
Arm: 25.5
Thigh: 23.25
Lower Leg: 22
Sternal Notch: 59.5
Total Body Height: 72

On paper, would a 56 or 58 fit me better?

The measurements were taken alone by myself so they may be slightly inaccurate. I also plan on going in to get sized properly. But with all that aside it would be nice to know your opinion.
Thanks!

[DaveS]

You have short legs and a long torso.

You can't compare frame size number between brands. What you really need to compare is the stack and reach, if they are listed. If not, then the next best thing is the head tube length to get an idea of the frame's true vertical size and the combination of TT length and seat tube angle to compare the reach. If the TT lengths are the same, but one frame has a numerically smaller STA, then the reach is shorter, by about 1cm per degree.

What you need to ask yourself is what is wrong with your current setup. Is your stem excessively long and/or your reach too short, due to your long torso? What makes you think that your current frame doesn't fit?