Looking for some feedback on the quality of shifting of Cobb cranksets. A thread on the trainerroad forum claims that the shifts are bad (https://www.trainerroad.com/forum/t/any-reason-to-not-use-super-short-cranks/28483/5), but I’m assuming that it might be a mechanical system. I’m wondering if the same limitation applies to the electronic groupset too (after tuning). Trying to decide between Cobb and Rotor, and this might swing it one way or the other.
Looking for some feedback on the quality of shifting of Cobb cranksets. A thread on the trainerroad forum claims that the shifts are bad (https://www.trainerroad.com/...short-cranks/28483/5), but I’m assuming that it might be a mechanical system. I’m wondering if the same limitation applies to the electronic groupset too (after tuning). Trying to decide between Cobb and Rotor, and this might swing it one way or the other.
I have both the Cobb alloy short cranks as well as the Cobb carbon short cranks and can’t say I have ever had an issue with them. Not sure what they mean by bad shifts as they don’t really ever define what they mean other than just complaining to complain. I read the post you referenced and it sounds like they might have just slapped on a set of cranks and didn’t adjust everything properly (especially the FD) and then complained about their shifting. FYI…mine are installed on bikes with Ultegra Di2.
Thanks Ray! That helps a lot.
Thanks Ray! That helps a lot.
Very welcome. Cheers!
One last question 
Can the 110 BCD chainrings be swapped with other standard chainrings?
It’s not the cranks it’s the chain rings that are not optimal for Di2 in my opinion.
You can put Rotor or Praxis chain rings on the Cobb cranks.
Rotor makes 110BCD 53/39
.
Yes, they can be swapped with other 110BCD 5-bolt rings.
Thank you! That puts me at ease.
It’s not the cranks it’s the chain rings that are not optimal for Di2 in my opinion.
Did you face issues shifting under tension?
It’s not the cranks it’s the chain rings that are not optimal for Di2 in my opinion.
You can put Rotor or Praxis chain rings on the Cobb cranks… Can you elaborate on that. What exactly is wrong with the Cobb chain rings that are not optimal?
Hi Ray, I am looking at purchasing the Cobb Carbon One short cranks but was wondering if the rings can be swapped out? I do not see how the rings are attached to the spider or crank arms and would like the option of changing rings if I face any problems with my electronic groups. Could you provide some insight since you have been using one? Thanks in advance!
Since you are considering the Cobb carbon cranks, you should also look at Rotor cranks.
I would, but I need a non-bb30, 150mm crankset for my speed concept. I have almost exhausted my options.
Rotor Aldhu 24 is available in 155mm.
Yes. But looking for 150
You can run the Rotor Aldhu cranks 150mm with 30mm axle and BSA30 bottom bracket if you have an English threaded bottom bracket on your frame.
I have Cobb 155mm 52/36 and Im nervous every time I shift from the small ring to the large ring. I would drop the chain 50 percent of the time. I went to Di2 hoping that would solve the problem. But it still drops, although not as much. I’ve had different mechanics make adjustments. I always thought it was a front derailer problem. But maybe it’s the crankset.
Hi Ray, I am looking at purchasing the Cobb Carbon One short cranks but was wondering if the rings can be swapped out? I do not see how the rings are attached to the spider or crank arms and would like the option of changing rings if I face any problems with my electronic groups. Could you provide some insight since you have been using one? Thanks in advance!
That is something I wouldn’t be able to help with as I haven’t changed mine. Sorry about that. But I have no doubt a quick call to Cobb would get that cleared up quickly. I ordered the chainring combo I preferred and haven’t had any issues with them so I never looked into changing the rings.
I have Cobb 155mm 52/36 and Im nervous every time I shift from the small ring to the large ring. I would drop the chain 50 percent of the time. I went to Di2 hoping that would solve the problem. But it still drops, although not as much. I’ve had different mechanics make adjustments. I always thought it was a front derailer problem. But maybe it’s the crankset.
Have you talked to Cobb about this issue? If it’s a design issue then I would assume they have heard plenty of feedback to better understand it. I have the 53/39 setup so I wonder if it’s more of an issue with the compact setup?
I have two cranksets from Cobb, a standard and a compact. Both shift fine with Ultegra mechanical. I was talking to someone at Cobb about a tribike build with an Etap setup. They recommended I change the rings to praxis rings. He said something about the stiffness of the Praxis rings providing better shifting.
I ended up using a cutdown Sram Apex from bikesmithdesign Here. The shifting wasn’t great so I change to Praxis rings and it shifts as it should now.