Kenevo SL Kenevo SL crank issue

[Scrawnyboy]

Afternoon all.
Had my Kenevo SL about 2 months. First Eeb. First Spesh. Love it.
Had a problem with my drive side crank (alloy Praxis 170mm) coming loose regardless of how often I tqd it up. Tredz replaced the cranks under warranty but I'm having the same issue again. Only on the drive side. I've raised it with Tredz again and waiting to hear back but I'm curious if anyone else has the same issue?



If I put the crank on without the bolt in, the face of the spindle is flush with the face of the crank which it isn't on the nd side.

 

[TG1971]

Did you get this sorted I have same problem

 

[G-Sport]

The way these cranks "work" is quite interesting. If you look at an unused crank-arm and the axle of the motor they are really quite different. The axle has teeth with curves between them and the arms are angular. Once you install the arm for the first time (which is much harder than any subsequent installation) the inside of the crank arm shows that the axle has "cut" little chamfers on the teeth of the internal spline.

Effectively, the axle broaches it's own fit into the crank arm!
I think that they do this so that they don't have to hold very tight tolerances on the arm, you can adjust this fit by 0.05mm or so either way and it still cuts itself a seat that will work.
I'm guessing that if you have had two sets of cranks with the same problem then maybe your motor axle is out of spec, if it is a bit small then it wont cut enough of a chamfer on the arm teeth to transmit power and it will work loose.
Maybe clean up your arm and see how big these chamfers look.

 

[TG1971]

My bike is in for warranty for a wobbly crank on drive side Specialized are swapping my praxis cranks for Sram cranks they come on new motor hopefully will stop problem

 

[G-Sport]

My bike is in for warranty for a wobbly crank on drive side Specialized are swapping my praxis cranks for Sram cranks they come on new motor hopefully will stop problem

What?!?
As far as I am aware, the Praxis and Sram cranks use very different interfaces. Just wont fit. The Praxis are for the SL1 motors and the SRAM are for the new 1.2.

 

[TG1971]

Well this is what they have told so I will update as soon as I know it’s a Specialized store so sure they would know ha ha but maybe not

 

[G-Sport]

When they arrive and don't fit just casually suggest you would be OK with them switching the motor and display to the 1.2...

 

[TG1971]

When they arrive and don't fit just casually suggest you would be OK with them switching the motor and display to the 1.2...

I don’t want the new motor tried the new Levo Sl and didn’t get the range quite happy at mtb speed up the hills with a bit of help, run 40/40 on eco and get good range.

 

[Rikvan84]

Hey, tagging into this thread.

I've got a 2023 Kenevo SL 1.1 Comp. After about 3 months the drive side crank came loose, my local dealer installed a new motor, Specialized approved the warranty claim etc.

Roughly 3 months later and I've got another shot motor / drive side crank issue. Same as before, torqued correctly but crank flops around. Putting a new crank arm on doesn't fix the problem, it's definitely another motor / spindle issue.

I also noticed on the first motor, as well as the replacement, a significant loss in power when the arm starts to flop around, which leads me to think there's definitely a bunch of damage or additional drag in the motor itself after whatever fails, fails.

I'm about 214lbs and ride a lot, 4-5 days a week usually and pretty aggressive rough terrain on the North Shore of Vancouver / Squamish.

Did any of you who had the same issue end up with the motor being replaced? When my first motor was replaced I purchased new crank arms as well just to be safe.

 

[TG1971]

So I had the same issue they have replaced motor and cranks but after 4 rides I can feel slight play, the LBS tried to fit cranks from the new motor but don’t fit

 

[Rikvan84]

Specialized giving me another new motor and new set of cranks (had to pay for cranks last time). They were not willing to supply a 1.2 motor at this time. But, they didn’t say it wouldn’t fit or integrate in the 1.1 bike, just that it’s not an option at the moment.

Last time they didn’t want the motor back for review, this time they are asking the shop to send them the motor and cranks for review.

Hoping I can get a look at the assembly when they pull it out of the bike so I can get a better idea of what’s going on.

Still think it’s just that I ride a lot, am 200+ lbs with gear, and smash into rocks and roots with no abandon on the daily. It’s a 170mm bike and should be able to take it, but maybe not?

 

[G-Sport]

Have you read my previous post (above) about how the splines on these cranks work? What did you find when you inspected the arms? My guess is that your weight/riding style puts loads through the deformed crank splines that are greater than the installation pre-load and so they are further deforming. If so, you should be able to see this. Clean them up and post a picture.

 

[Rikvan84]

Have you read my previous post (above) about how the splines on these cranks work? What did you find when you inspected the arms? My guess is that your weight/riding style puts loads through the deformed crank splines that are greater than the installation pre-load and so they are further deforming. If so, you should be able to see this. Clean them up and post a picture.

Hey - yup read through everything before posting. I had suspected this on the first motor but the shop couldn't really see any issues with the crank / spindle interface.

Funny enough, I just spoke with them prior to logging back in here and they confirmed that's the issue. Crank arm is deformed terribly and the spindle is mangled making a new crank arm unable to interface.

Non serviceable item for the motor so even though it's just a spindle the whole motor gets replaced along with the cranks.
If anyone has any ideas on stronger crank arms that won't deform as quickly that would amazing.

 

[Rikvan84]

Have you read my previous post (above) about how the splines on these cranks work? What did you find when you inspected the arms? My guess is that your weight/riding style puts loads through the deformed crank splines that are greater than the installation pre-load and so they are further deforming. If so, you should be able to see this. Clean them up and post a picture.

random thought - have your or anyone else on here tried the S Works carbon Praxis cranks rather than the alloy version on the other models? Curious if same issues persist.