Curious if others have had problems with Rotor cranks. I have a Cervello S3 that came with Rotor cranks. In 2016 I snapped one crank where the pedal arm attaches to the bottom bracket. I chalked it up to a defect, and Rotor was great about paying hospital bills, sending new equipment, and paying labor to have it installed. Yesterday, I broke the pedal crank again, this time on the chain ring side where it attached to the big ring. See photo.
Has anyone had this type of issue with Rotor. I am not big powerful guy, I am 160 pounds with a 270 watt FTP, I can’t imagine why I would be snapping these cranks but others are not. Thanks for any input.
Thanks for the input. I have a couple of manufacturing engineering friends that came to the same conclusion. Now I have to figure out how it got cracked / fatigued in the first place.
Is that a 3D30 (3D+) crankset?
It looks like the lock ring bolt is on the outside in the 2nd photo. The 8mm bolt should be on the outside when the crank is installed. You would flip it to the way picture only for crank removal.
First time the crank had about 14,000 miles on it, and I ended up in the hospital for a CAT scan as the ER doc was concerned about internal bleeding, luckily it was just some hemorrhaging in the hip area.
The new crank also has about 14,000 miles on it. Winter riding does have some salt, but with Zwift, my winter riding is 80% indoors these days. Luckily, I still have my teeth, just some road rash and bruises from the latest fall. Thanks for the input.
Is that a 3D30 (3D+) crankset?
It looks like the lock ring bolt is on the outside in the 2nd photo. The 8mm bolt should be on the outside when the crank is installed. You would flip it to the way picture only for crank removal.
I could be wrong, but double check that.
Looks exactly like that to me, i.e. in the remove crank position. Here are some shots of my 3d+ with the ring in both positions:
Type of crank it is will tell the story here. Based off the bolt style, I am thinking that is not a traditional 3d+ and is instead an inPower unit? Not thinking it is a 3D as those guys attach from the other side. Anyhow, disregard my previous post if this is not a 3D+, which I am leaning to it not being.
WOW!!! That is something crazy to see in those pictures of the broken crank. I hope you are okay and road rash is healing.
I have 3 Rotor 3D cranks with 24mm axles. I haven’t had any problems at all with them. But, in looking at your broken crank arm, I wanted to just add in my .02 cents worth of thoughts…
To me (and no, I am not an ME), it looks like a stress fracture based on an inward lateral force. By this I mean (let me see if I can explain this in words well enough…), that the break looks like if the crank arm was in the 6 o’clock position, and you applied force laterally inwardly to the arm towards the BB bearing, that it then cracked off. Essentially, say when you’re standing and rocking the bike left-right-left-right (as in climbing), that when on a down stroke at the 6 o’clock position as the bike is leaning over and your leg is pushing straight down, that’s when the crack happened???
Maybe someone with an ME degree can properly explain what I’m thinking may have caused the break?? But, it still does not explain or excuse the break itself. Maybe just a bad batch of trinity drilling that got too close to tolerances???
Again, I am not throwing blame anywhere, rather just thinking about what forces may have caused such a break.
Glad you weren’t hurt too badly. Sucky situation. Goes without saying that maybe you should try a different brand of cranks. If you’re invested in the Rotor ecosystem (i.e non-round chainrings), maybe you just have to suck up the expense and proactively replace them every 10-12k miles. That hurts, but probably less than hitting the pavement every ~14k miles.
In the meantime, I’d put a ribbon through the pedal hole, wear it to the next tri-club or bike-club meeting like a medal, and brag about how I was so strong I’ve broken two of these SOB’s.
Thanks for the input. Rotor tells me that they don’t see this often and will examine the parts and try to determine why I am so unlucky.
They also offered to provide replacements and pay labor to have them installed. Maybe the third time is the charm.
That is a little concerning as I have the exact same setup 3D+ crank, rotor rings and aero spider on my road bike. I have had it on there for several years now with no issues however. I have the 3D+ with Power2max meter the same as posted pics on your thread on my tri bike and no issues either. Both have the older style removal bolt. What were you doing when the crank went? Sprints, hills?
