Current bike: 541 / 380
Potential new bike: 528 / 401
So comparing the two, if I did make the switch, the new bike would be lower and more stretched out, correct? In which case (assuming I want to keep my same position), I would need a shorter stem that has less of an angle (current stem is 120mm, 73*). SO potentially a 100mm stem @ 84*?
Are these Stack and Reach considered “close”, or would the bikes end up fitting completely differently?
Thanks in advance.
you are on exactly the right track here.
the closeness is as the math indicates. 2cm shorter stem, 1.3 cm of extra stack, whether you get that from stem angle or a spacer is up to you.
how well the new bike fits you depends on what your current setup is. If you already have 3cm of spacers on the current bike, this new bike would be a bad choice.
if you currently use no spacers or maybe 1 spacer, its fine.
You are correct across the board. If the new bike fits you will a 100/84* stem, I’d say it’s a better fit.
They aren’t really that close. 21mm of reach is a pretty significant difference. That’d be a typical S and M for many companies (or 51 / 54).
Current stem is slammed (well except for the Easton Bear Trap, which provides tension for the headset…but that is only .5cm maybe). Changed to the 73* stem to get lower.
The new potential bike has an integrated front end system, so I need to dig a little deeper and see if I can mimic my current position with their bar / stem options.
Thanks for the feedback.
You are correct across the board. If the new bike fits you will a 100/84* stem, I’d say it’s a better fit.
They aren’t really that close. 21mm of reach is a pretty significant difference. That’d be a typical S and M for many companies (or 51 / 54).
Great, thanks for the feedback.
Out of curiousity why do you feel the 100 / 84* stem would be a better fit?
Side note - my current bike is an aero road frame converted for tri’s…new frame would be a dedicated TT / Tri frame.
Tri bikes, typically, should be spec’ed with a stem that is ~2cm shorter than on a comparably sized road bike. This because a tribike has more weight up front due to position, so if you NEED a longer stem to make the bike fit, that means you are putting your weight further out in front of the bike, which is a bad idea. This assumes a given length of aerobar. I.e., an 11cm stem vs. a 9cm stem where the 11 is simply being used to achieve a more comfortable arm pad position on the forearms is not a big deal. But an 11cm vs. 9cm stem with the same arm pad position would make me a bit more critical. In other words, some aerobars have the pads behind the centerline of the pursuit bar. Some in front. And some have reversible pads. Comfort in that sense is very personal. So stem length to tweak that is fine. But an overly long stem, because of the additional weight on the front end, is more problematic on a tribike than on a road bike.
That doesn’t surprise me about your description of the frames. In that case, I revise my prior statement. The first frame is a typical size 54/M geometry road bike; the latter is a typical 54/M geometry tri bike.
Thanks for the explanation…
And yes, the road frame is a medium frame. So in your opinion, is the change reasonable (assuming a change to a 100 / 84* stem), or should I look at other frames?
Nope, it sounds reasonable to me.
In which case (assuming I want to keep my same position), I would need a shorter stem that has less of an angle (current stem is 120mm, 73*). SO potentially a 100mm stem @ 84*?
All the above makes perfect sense assuming you want to keep the same position.
The only additional thing to mention is seat angle. Your aero road bike probably has a seat angle in the region of 75/76, and the tri bike a seat angle of 78/80 depending on which brands you are looking at. So, to replicate the exact same position you would be riding the tri bike at a shallower effective seat angle than would be considered optimal.
Great, thanks, Jordan.
@ Freespeed…road bike is set up @ 76* SA and the geo on the new frame says it is 76* as well (although there is clearly a more forward position on the SP that is not detailed in the spec sheet). But as a guy coming from a road background, the shallower 76* SA is my preference anyway, so it should be a wash.
Thanks for all the input!