Looking at the CF 8.0 Di2 in either medium or large. I did not have a proper fit or an old TT bike, but maybe you can help me based on the following measurements:
Height: 185 cm
Arm length: 65cm
Current saddle height on road bike: 78cm on 175 cranks
Website suggests size medium, but after reading posts #607 and #608 I might better go with a large? Many thanks. And awesome work, 30 pages of detailed replies and insight.
Strobes27, Thank you for such a sweet and thoroughly well thought out post. May I still be here helping athletes get on the right bike at 3000 pages!
I suspect your Pad Y is ~650 and your Pad X is ~500. So, for a Canyon Speedmax CF 8.0 with Di2 you should get a size Large. Both bikes will meet you in terms of Pad Y and in terms of seat height. The Medium could work as well but the Pad X maxes out at 492 with the 80mm stem that comes stock. If the the Large is out of stock you should get the Medium a simply put a 90mm stem on that (you can order it from Canyon at the same time - or, the steer tube (1 1/8th in) & handle bar diameter (31.8) are standard so many 90mm stems in the world that will fit.
I want to go a step further in this discussion to say this... the 175mm cranks on your road bike are probably fine. Both the Medium and the Large in this bike come stock with 175mm cranks and those are too long for a triathlon or time trial bike. I suspect the proper length for you is 165 or even 160mm. Currently Canyon cannot swap out parts upon order so my advice is this...when you order this bike, go else where at the same time and acquire a set of Ultegra cranks in the 165 length* and when the bike arrives do a quick swap of the cranks so that you can sell the 175s as new, never ridden.
Get back to me here with any more questions you might have.
*Since you're getting new cranks now is the time to consider getting a set with power built in if that's in your budget. Also, since were gonna make it perfect, you have to decide on chain rings for those cranks and here's my advice on that:
1) If you only train/race on flat, and you're light, and you're a masher who likes to make the bike go at 70-80rpm then you are allowed to get 53x39 rings.
2) It's far more logical that you get mid-compact 52/36 as it's a gearing that'll still let you go pretty fast in the 52x11 and still keep cadence up on climbs with the 36x??28?? 30?
3) If it's all hills all the time and you need help climbing, and you're a bigger athlete, and you simply hate going downhill fast then you get compact 50x34.
Ian Murray http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan