bikejack

Anyone had experience with these cranks, I believe its the same for setup the Oxala MTB cranks.

The system is a hydrid ISIS system where Stronglight have attempted to turn ISIS into a Mega or Hollowtech.

The trouble is that ISIS relies on a shoulder to locate and lock on and this system does not have one and relies on the spaced bearings to provide that function, to achieve this the non drive side has to slide in its housing which I feel might be contributing to the problem with the unit.

The cranks bind tight on install, i've tried pre compressing and respacing and nothing will free up the unit.

Any one had experience with this type of crankset Z Light or Oxala? To me its looks like the designer slept through spindle design 101.

joejack951

I have a Stronglight Fission Activ Link triple crankset on my road bike. As you say, the system uses an ISIS-like axle. There is a stop for the axle but I believe it bottoms inside of the crankarm as opposed to the crankarm stopping on a shoulder on the axle (it must, there's no other option for stopping the arm and if it pressed against the bearings it would cause them to bind). There is no adjustment for bearing preload as with Hollowtech II. The bearing spacing is set by the tube that gets installed inside of the bottom bracket shell between the two bearing cups. However, in order for this system to work the bottom bracket shell has to be faced to the correct width. If your bottom bracket shell is too wide, the second bearing will bottom out on the shell rather than stopping on the tube. Stronglight includes a small view in their instructions showing how there should be a ~1mm gap between the flange of the second bearing and the bottom bracket shell. An o-ring under the bearing flange seals the gap.

So, did you check your bottom bracket shell width before installing the bearings? Did you install the tube in between the bearings? Did you double check that the second bearing flange has a small gap between it and the bottom bracket shell?

bikejack

joejack, the short answer is yes and more.

BB is 68.1mm, I have also tried the activ link in an undersize bracket I have tried longer spacers I have tried precompressing the bearings before installing the crank. I'm now consider polishing out the bearing housing to allow the non fixed bearing to move more freely as looking at this ridiculous design the slightest resistance from the outer bearing shell would load and bind the unit.

joejack951

What do you mean by "precompressing the bearings"? Do the bearings spin freely prior to installation? Do they spin freely after being installed in the bottom bracket shell but without the crank installed? Did you have your bottom bracket shell faced prior to installation?

Looking at figure 1 in this PDF (https://www.stronglight.com/stronglig...kgauche.an.pdf), are you installing items #2 and #6? I'm not 100% certain, and would need to disassemble my crankset to find out, but it's possible that #6 prevents the bearings from being crushed during assembly by supporting the inner race of the bearings.

Drakonchik

Bumpy bump.

I got one of those Z-light triples with Activ Link, sitting and waiting in a box, waiting for the right frame to come along. Meantime I've eyeballed that bottom bracket and spotted some of the potential issues mentioned here. Waiting for some Stronglight know-it-all to shed some more light on this curious system . . .

joejack951

In reviewing the instructions again, I'm even more certain that #6 in the PDF linked above is the spacer that keeps you from overloading the bearings. The instructions mention it being in contact with the bearings and it seems to serve no other obvious purpose. Regardless of what makes the system work though, I installed my Fission crank following the instructions and it spins impressively smooth for an external bearing crank.

bikejack

Joejack, the spacer is in place the problem is that unless the bearing is a sliding fit in the cup it loads the bearing from the side. The cups also have the nylon insert common for tight location in sealed BB's, why Stronglight have used this design when a sliding fit is required is anyones guess.

I tried compressing the bearings together before installing the cranks with no result.

joejack951

Well without being there to check the installation, I can't help much more. I'd double check again that the bearings spin smoothly prior to inserting the axle. I'd also have your bottom bracket shell checked to be sure both faces are perpendicular to the threaded section. Again, I installed my crank per the instructions and it spins perfectly. Either yours is defective or something is wrong with your installation. If you are confident that your frame is correctly machined, I'd suggest returning the crank for another rather than modifying what you have.

Alistaird

Just got a Stronglight Fission Double Activ Link:

https://www.stronglight.com/stronglig...sionDoubleInox

Apart from having to remove the bearing from the RH cup in order to install it (it had obviously been on a display bike) it wasn't too bad to install. Did near a rubber mallet to re-seat the RH bearing and tighten then loosen and tighten the LH crank arm to make sure the RH bearing was fully seated. Now this is done, the bearings feel really smooth (much smoother but a bit stiffer than the old Octalink stuff IMHO but I understand this is normal for an external bearing.)

The instructions aren't very clear but I got there in the end.

Alistair