anyone using Rotor 3D cranks

hill_climb

Recently I've been trying out shorter cranks on my everyday road bike and am liking 165mm. Problem is that I'd like to change the cranks on my 'good' road bike which has a Campagnolo Chorus 2014 11 speed compact. Campy only go down to 170mm crank length.

It's looking like the choice here is between FSA, Sram Red and Rotor. One quest about the Rotors. Could anyone who uses these let me know how much ankle clearance these have? For example, the Campy's have less than FSA cranks I've used before but have no problems with either. I've tried contacting Rotor but without a reply? Truth is I'm liking the look of the Sram Red cranks so I could just swap out the rings for the Chorus ones.

Thanks

StillGoing

It would depend more on the protuberance of your ankle bone as the 3D crank arms are straight with no bend in them. I use them on one bike and have no problems, but then I don't get issues with ankle clearance on any crankset.

964cup

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19734212#p19734212]hill_climb[/url] wrote:

? Truth is I'm liking the look of the Sram Red cranks so I could just swap out the rings for the Chorus ones.

Thanks

Don't think you'll be able to use Chorus rings on a SRAM crankset. Campag bolt spacing is different.

philbar72

Rotor are all right. I've got 2 power2 max rotor crank sets and one is great, no hassle at all, the other is a bit creaky!!!

campag uses 135bcd usually, sram is either 110 or 130.... ?

964cup

It's not the BCD, although that does vary for standard doubles, but the bolt spacing. On a compact, the BCD is 110 for both Campag and other manufacturers, but the bolts are in different places.

I also have several Rotor chainsets (PowerLT and standard 3D+). I'm using a mixture of PraxisWorks and Rotor NoQ rings. Either would work fine with an otherwise Campag drivetrain. Can't say I've ever noticed or thought much about ankle clearance, so can't comment on that.

markyone

http://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=135977

hill_climb

Hi everyone, thanks for the replies. Some helpful information. By the way, the cranks will be fitted to a BB30 frame.

Looking at Rotor cranks first, I've attached a schematic of what I see as ankle clearance. I understand that the Rotor crank may be straight but there must surely be at least some offset angle to it? 'Back in the day', I rode many bikes with straight cranks and that were also exactly perpendicular to the bottom bracket axle. These were from Stronglight and Mavic to name two. In my opinion, one of the best ergonomic advances in bike design was the introduction of the 'bent' crank to accommodate ankle clearance. Surely the Rotors are not going back to a fully straight and perpendicular design ? That would completely rule it out in my opinion.

So what are the choices for top-end cranks with 165mm length? Would an all Sram Red (including rings) work with the Campy transmission? Understanding that even though the bolt diameter will be 110mm, the location of the bolts around this circle will not be the same as Campy.

thanks again.

StillGoing

3D do have some off-set, but it is minimal. If you're going to be putting it on a BB30 frame, then surely you're better off going for the 3D+ option to avoid the need to use adapters?

I use 165mm chainsets with SRAM Red (10 speed) on the Basso and 3D on the Merida. Weight wise there isn't enough in it to be bothered about and performance is fine from either. I use a P2M and Q rings with the 3D, and Q rings on the SRAM Red and to be honest I'd struggle to know which chainset I was using but for the lack of power data with SRAM.

If there is a LBS that stock Rotor gear, take your ND side crank arm in and ask to compare it against a 3D+ one.

964cup

I'll have a look when I get home (today's bike is on Campag SR) but if you're using Speedplay as your drawing suggests, why not just get longer spindles from J&L if you need more clearance? They do Ti spindles in a variety of lengths for about £35, look on eBay.

Anonymous

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19734904#p19734904]hill_climb[/url] wrote:

Hi everyone, thanks for the replies. Some helpful information. By the way, the cranks will be fitted to a BB30 frame.

Looking at Rotor cranks first, I've attached a schematic of what I see as ankle clearance. I understand that the Rotor crank may be straight but there must surely be at least some offset angle to it? 'Back in the day', I rode many bikes with straight cranks and that were also exactly perpendicular to the bottom bracket axle. These were from Stronglight and Mavic to name two. In my opinion, one of the best ergonomic advances in bike design was the introduction of the 'bent' crank to accommodate ankle clearance. Surely the Rotors are not going back to a fully straight and perpendicular design ? That would completely rule it out in my opinion.

So what are the choices for top-end cranks with 165mm length? Would an all Sram Red (including rings) work with the Campy transmission? Understanding that even though the bolt diameter will be 110mm, the location of the bolts around this circle will not be the same as Campy.

thanks again.

ref the pic, the answer is the Q factor in the crank arm angle.

If you cannot find a decent BB30 crank with the arm length you want, look at getting an adapter and fitting anything you like. I used to have a FSA Gossamer crank with 165mm crank arms and now I just ride 170mm and I notice no difference at all.