Rotor 3d+ problem

rubberbullet

Hi there

During a race on Sunday, the bolt holding my Rotor 3d+ crankset together rattled loose, and so I realised that my race was over when the driveside crankset was no longer attached to both the bike and my shoes, but rather, just to my shoes.

The non-driveside is still in and unaffected. I don't think I lost any washers/spacers. The reversible silver nut which goes into the driveside is in the "receiving" position whereby the knobbly bits are on the inside, if that makes sense.

I've bought a new driveside bolt to replace the old one. The instructions for installing the 3D+ are not necessarily the clearest for a technical muppet so could I please double check what I do?

1. Attach crankset back onto the axle
2. Tighten the new driveside bolt as hard as I physically can (haven't got a torque wrench with goes up to 40nm+)
3. Check the non-driveside for play and tighten the knobbly thing if necessary

Is that right?

My problem is that the driveside side just rattled loose in the first place - I thought the whole point of the reversible silver nut and the painstaking removal process was that the driveside cranks should not just come off when one bolt works loose?

Any help much appreciated!

pilot_pete

All you need to know is here;

https://youtu.be/VbkbXl8XRXI

PP

bristolpete

Same thing happened to me just last week.

Put the crank on, torque cap to 1nm, tighten and torque pinch bolt, then re-torque the cap to 7/8nm from what I got on the Rotor website ?

rubberbullet

I'm then struggling to understand the point of the silver reversible nut?

pilot_pete

rubberbullet wrote:

I'm then struggling to understand the point of the silver reversible nut?

you've watched the video I posted a link to haven't you? It's all there...

The reversible 'nut' is used to remove the crank. You undo the hex red cap, remove the silver nut, put the red cap back on, then turn the reversible silver nut over and put that back on. Now you undo the red cap and it pushes against the back of the reversed silv nut to pull the crank off the splines. In effect it is a built in crank puller. Just make sure you put it on the right way round before tightening the red hex cap to the specified torque. If you follow the video everything will perfect, at least it has been in my experience and I have had the crank on and off a fair few times and it has never worked loose.

PP

rubberbullet

Thanks yes. The video is what I have used previously to attach and remove the cranks. Where I am lost is the following - the driveside bolt and cranks worked loose without my undoing the silver nut with a cassette tool. If it is possible to remove the cranks without going through the rigmarole of the inbuilt crank puller mechanism, what's the point of having it?

pilot_pete

rubberbullet wrote:

Thanks yes. The video is what I have used previously to attach and remove the cranks. Where I am lost is the following - the driveside bolt and cranks worked loose without my undoing the silver nut with a cassette tool. If it is possible to remove the cranks without going through the rigmarole of the inbuilt crank puller mechanism, what's the point of having it?

I am convinced you are not fitting the crank correctly then as mine has never been anything other than solidly attached when I have fitted it.

1. Make sure the silver 'puller' nut is fitted the correct way around and use your cassette tool to tighten it (doesn't need to be torqued up, just fitted).

2. Fit the red hex top cap and torque that up to spec.

3. If needs be take up any slack with the knurled nut and then tighten the tiny hex bolt to lock it into position.

Bingo. It's as simple as that. All I can imagine is that you either have the silver puller nut incorrectly fitted thus stopping the top cap from securing the crank properly or without a torque wrench you are not tightening the red top cap up enough. I would hazard a guess at that second point being the issue if you only have a short Allen key...I use my old car torque wrench for my crank, which is about 60cm long, so quite a lever arm and it takes a not insignificant squeeze to get to the required torque.

As I have said, never had any problems with that crank or my rotor flow on the TT bike coming loose, which uses the same method to hold it on.

PP

Oh and p.s. I have never been able to remove the crank by simply removing the red top cap. I have always had to remove the top cap, remove the silver puller nut with cassette tool, turn it over, refit it over the too cap and then undo the top cap to pull the crank off. It has remained solidly attached even with the red top cap removed. This is what makes me think you are not tightening the crank on properly in the first place. Good luck.