Lightning crank reliability?

[lanierb]

Only down side I've had is they tend to creak. If I remove the bearings, grease the threads, and reinstall it solves the problem. But the whole operation is incredibly fast. So I like them.

I just had to redo this. It takes liberal grease, not a normal "lube the threads" dab.

This is my one complaint too. However, now that I know what to do it's easy enough to address I guess. My creak comes from the crank spindle bolt (or possibly the splines in there) not the BB threads though. If you guys are getting creaks from the BB threads you could try teflon tape. It will make the coupling a little tighter.

Actually the truth is I've had creaky BB trouble with literally every bike I've owned so I have to wonder if it's not also something about my riding style. On my Trek Madone I used to crack the BB once per year or so -- those things were crap. The FSA BB on my TT bike also has a good creak going right now (and it has only 1000 miles on it and has never seen a wet ride even once).

Edit: forgot to mention for those considering them above that I believe the Vuma Quads have been discontinued so that's no longer an option

[xnavalav8r]

What is the difference between the Lightning crank and the Specialized crank?

[ricerocket]

The Specialized has a larger spindle for BB30, and has more teeth on the Hirth joint in the 2nd gen onwards.

Specialized has been improving their product pretty much yearly as well, the 2011 ones have a new layup that's supposedly noticeably stiffer than previous iterations.

[eric]

The Specialized cranks' spindle is the same 30mm diameter, but it's shorter. It's BB30/pressfit only, while the Lightning will fit into a standard BSA threaded shell or BB30 with adapters. Specialized has better heel clearance. Lighting is poor there. The Spec crank's central fixing bolt head is close to the left crank, not deep inside like the Lightning. Lightning has poor QA and customer service, in my experience.

viewtopic.php?f=3&t=92364&p=794099&hilit=lightning#p794099

[eliflap-scalpel]

What is the difference between the Lightning crank and the Specialized crank?

spindle lenght.

Specy can mount on BB30 frames only . and obviously in the strange named Specy frames.

Lightning can mount in 90% of frames with no issues , BB30 or BSA or PressFit30

( i want to write 100% but i am a road bike rookie )

i installed it on a BB86 Press Fit frame too

[tochnics]

@ eric

and that is exactly why i bought the crank
i still have a classic frame and i this made it possible to run a crank with a 30 mm axle
also when i have a bb30 frame i can get adapters to fit the frame
its not ideal but those adapters wont be making the distance between the pedals wider
because this is fixed

i admit that the bearing adjustment is far from rock solid with a 2.5 mm bolt but it works

[eliflap-scalpel]

i admit that the bearing adjustment is far from rock solid with a 2.5 mm bolt but it works

you have to use a ( not remembering well the number ) 22mm wrench to adjust the preload

and only after , screw the 2,5mm bolt to lock the bug nut

[drchull]

35mm wrench. Be careful side loading the bearings.

[djconnel]

I've used an adjustable wrench for this.

But back to my bike...

While I pedaled, nicely climbing, suddenly there came a creaking,
As of something nearly breaking, creaking at my Lightning Crank.
"'Tis the threads," I muttered, "due to being poorly cut —
Only this and nothing but."

Someone recommended blue Loc-Tite. But I don't have blue Loc-Tite, so need to buy some.

Basically when I put a crank arm @ 3 pm then push down on the crank (or the pedal) there's a loud noise Greasing threads seems to help but doesn't solve it for long. I thought maybe the Ti-Ti interface in the bottom bracket between the crank pieces but I can get the noise with just the drive side in place. Very strange...

[djconnel]

I spoke to Tim @ Lightning and he said that the spindle can wear and develop play against the bearings. They have had success, he says, spraying epoxy paint on the spindle to increase it's radius, although "it can be tricky getting the thickness right", so they will do that if I send my crank arms back. Tempting to try it myself to avoid down-time.

[eric]

Loctite 641 would work better than 242 ("blue") loctite. It's made to fix loose slip fits on cylindrical shafts. 241 is a thread locker, and it won't handle the pressure.

But you may need to use a bit of force to get the cranks out again. I think that unscrewing the fixing bolt about 7mm and tapping the allen socket/key with a hammer would get the left side started. Then a wooden dowel with the center drilled to clear the fixing bolt to get the right out. 641 sticks things together but not permanently, more like a moderate press fit. I have used it on slightly loose FSA ISIS and MegaExo crank splines- they recommend it for the MegaExos. I can get the arms off using the built-in extractor, no problem.

Lighting did the epoxy spray thing to my crank and it did not fix it although it made it better. If you went that way I'd use a couple coats then wet sand with fine paper to get it just to a press fit. Mask it off so you only spray the bearing area. I'd ask Lightning what spray to use. Prep would be important to get it to stick.

[djconnel]

Well this has been a problem since I got the crank, but it's gotten worse. So something, I think, was slightly out of spec. Could be the spindle or could be the bearings. I'd hope it was the bearings: will test spindle diameter w/ calipers tonight. But I suppose spindle is most likely.

[djconnel]

I measured both the bearings and the spindle with calipers and to within measurement error both were approximately 29.92 mm (1.1780 inches). I'll let Lightning know and see what they say.

[eric]

The cranks are somewhere between a locational clearance fit ("snug fit for locating stationary components that need to be freely assembled") or a very light "tap fit" into the bearing.
Locational clearance fit tolerance is 0.0 to 0.0008 inches. Common (i.e. chinese and inexpensive american) digital caliper accuracy is about .001 inches. It'd have to be off by quite a bit before you could reliably detect it with calipers. A good micrometer would work better.

I thought that calipers would not be accurate enough but looked it up anyhow, and it was interesting.

Of course I expect you used calipers because that's what you have.

I doubt that it's the bearings as they are made to tight tolerances. ABEC 3 and above I.D. is supposed to be within +0.0 -0.0002.
High quality bike bearings are usually ABEC 3 or better.

[djconnel]

Thanks! Complication is I am comparing inner and outer radii. So I'm using two different measurements with the same caliper. I doubt my measurements are better than 0.001 inches based on multiple measurements of each dimension. Seems to depend on where I contact the caliper arms.