Hi all.

Just out of curiosity. I´ve seen some discussions around suggesting that the 2 U-joints on the paralever driveshaft should be aligned quite precisely when reassembling. In contrast to this the original workshop manual mention no such thing and when asking a BMW mechanic I was told that on the shafts where this was necessary BMW had made sure it could not be misaligned (fx. by making one spline wider/narrower than the rest). When I disassembled it was not aligned, but out of precautions it is now:D .

Any sugestions to what is correct?

/Bjarne

Hi bjarnek100,

In 2005 there was an article in the UK BMW Club's magazine, reprinted from the USA BMW Owners News, by Paul Glaves, describing the varying joint speeds with multiple universal joints. It was quite complex but I'll transcribe the final conclusions.

In application then, with a BMW Paralever drive-shaft, for simplicity, arrange the universal joints as follows:-

1. Front universal joint driving yoke (attached to the transmission) horizontal.

2. Front universal joint driven yoke will be vertical.

3. Rear universal joint driving yoke - slide splines together so this yoke is vertical.

4. Rear universal joint driven yoke (attached to the final drive) will be horizontal.

Hope this is useful,

Paul.

Hi Paul, and thanks

It´s was very usefull, but I am wondering if it is a theoretical discussion or something that will really affect the lifetime of the driveshaft. Do you perhaps have a link to the articel?



Regards

Bjarne

Hi Bjarne,

Unfortunately I haven't got a link for the article, but I have done a 'mechanical' cut & paste (don't you just love UHU sticks) and I have reduced it to an A4 sheet. I'm not sure about copyright with posting it on the forum, so if you send me a PM with your e-mail address I will forward it to you.

Cheers, Paul.

Article by Anton Largiader on Paralever Suspension

I believe the technique of phasing is more than theoretical. Supposedly, phase the u-joints prevents drive line vibrations that can cause excessive wear in the drivetrain components. Later model R-bikes are using keyed shafts (aka. indexing splines) to ensure u-joints are phased properly. The splines on the earlier K-bikes don't have the means to guarantee phased u-joints; that is a function of the process employed by the mechanic when they service the driveline.

Further discussion about u-joint phasing with reference to Paul Glave's article