why is my rotoflex so bent?

[Sam C]

Hi all

I changed one of my rotoflex couplings yesterday and I noticed that both the old one, and now the new one, when in place look like they're being bent in a way they shouldn't. The other side is fine.

It looks as though the two parts of the drive shaft (if that makes sense) - each one of which is either side of the rotoflex - aren't sitting close enough together. As a result when the bolts are tightened which join these parts together, through the rotoflex coupling, the coupling is pulled in two different directions. This gives it a sort of bendy (but symmetrical) appearance - like an 'S' shape all the way round.

It's almost as if the hub-side drive shaft isn't sitting far enough through the hub. But I greased and pushed in as far as it would go and tightened up the nut as much as I could.

Is this something anyone else has seen?

[cook1e]

Riotoflex couplings are normally distorted when fitted, the whole point of them is that they allow logitudinal as well as latteral flexibility. The S shape you describe is normal, what's more concerning is that you say the other side is fine as though this isn't distorted, I'd be more worried about the other side!

[Sam C]

I just thought of something - when I was comparing the two of them the 'fine' one was on the ground taking lots of weight while the 'bendy one' was in the air with the chassis taking all the weight throough axel stands. I didn't compare them once both back wheels were on the ground - I bet they're the same now!  Bit embarassing if that's the case :X

[Richard B]

"Don't worry, they all do that Sir..."  ;)

[Paudman]

Here's one I'm working on at present, off the floor I know but still has the 's' shape clearly visible.

[Sam C]

that's great - really helpful.

Don't know what I'd do without this site!

[Richard B]

I never liked the way the dougnut loads the bearing whilst at rest. Presumably at some point in the suspension arc, a neutral point is achieved where the doughnuts are not distorted.

Go CV  ;)