Cannondale tandem geometry charts incorrect!?
#1
Junior Member
Thread Starter
Cannondale tandem geometry charts incorrect!?
There was no way I could get my Cannondale tandem locally, so I ordered one from abroad. Buying without trying means that you need to rely on geometry charts. I'm used to that so I'm quite confident in getting the sizing right.
Once I got the tandem I didn't think more about it, but recently I started to realize that things didn't really add up so I measured the geometry of the pilot position as accurately as I could, and indeed, it does not match with the Cannondale chart.
Here's the comparison measured vs the chart (front position only, the tool doesn't support tandems...):
https://www.bikegeocalc.com/#36Canno...99F170G153H53Z
I got the chart from here:
https://www.cannondale.com/en/Intern...e-8950cc063e71
As seen the actual frame is 10mm lower and 5mm shorter, and the front wheel is 12mm closer (it was actually the toe overlap that got me thinking that something wasn't right), and the seat tube is ~10mm shorter. Not a huge difference, but as I was choosing between the M/S and L/S size, when the M/S is even smaller than the chart I would probably have chosen the L/S if the chart had been correct (I don't know what the error is with the L/S).
Cannondale did change the geometry to 2014 model as far as I know, but I got a 2017/2018. I don't know of any recent geometry change so as far as I can see the chart is just wrong, unless there is some other chart hidden away somewhere that I should have been looking at instead.
I've already got the S/M size so I'm stuck with that, and it's okay I have a good fit already as I've changed stem and bar. A heads up for anyone that's about to do the same, that is make sizing based on the geometry chart, it seems it cannot be fully trusted.
Once I got the tandem I didn't think more about it, but recently I started to realize that things didn't really add up so I measured the geometry of the pilot position as accurately as I could, and indeed, it does not match with the Cannondale chart.
Here's the comparison measured vs the chart (front position only, the tool doesn't support tandems...):
https://www.bikegeocalc.com/#36Canno...99F170G153H53Z
I got the chart from here:
https://www.cannondale.com/en/Intern...e-8950cc063e71
As seen the actual frame is 10mm lower and 5mm shorter, and the front wheel is 12mm closer (it was actually the toe overlap that got me thinking that something wasn't right), and the seat tube is ~10mm shorter. Not a huge difference, but as I was choosing between the M/S and L/S size, when the M/S is even smaller than the chart I would probably have chosen the L/S if the chart had been correct (I don't know what the error is with the L/S).
Cannondale did change the geometry to 2014 model as far as I know, but I got a 2017/2018. I don't know of any recent geometry change so as far as I can see the chart is just wrong, unless there is some other chart hidden away somewhere that I should have been looking at instead.
I've already got the S/M size so I'm stuck with that, and it's okay I have a good fit already as I've changed stem and bar. A heads up for anyone that's about to do the same, that is make sizing based on the geometry chart, it seems it cannot be fully trusted.
Last edited by torger; 08-30-19 at 02:22 PM.
#2
Junior Member
Thread Starter
I just measured the rear of the bike. The horizontal top tube length is 715mm rather than 725 as the chart says, but the rest seems to match.
#3
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Join Date: Aug 2015
Posts: 124
Bikes: 2005 CoMotion Speedster, 2014 Cannondale T2, various single bikes
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This is sort of consistent with the geo chart weirdness I've seen. Our T1/T2 frame is from 2017-a warranty replacement for what I am pretty sure was a 2015. Though I cant be sure exactly when the warranty frame was made it's the exact frame size wise. The above chart is from our original owners manual. It lists captain top tube for our L/S at 58.5 where it is actually about 56.5 or 57 at most. In fact, the chart you posted seems to match our bike. Our chart also has 71 degree ht angle for all the sizes and a 66 trail. That agrees with your number from bike geocalc but not your c-dale chart. Not sure what ours is. Your chart numbers are smaller all around, and seem to be more reasonable. 54.5 is about right for a size M, rather than the 57.1 listed above