Originally Posted by GeorgeSmooth
I raised a concern about this as the 135 vs 335 has less play depth wise when pushing the side shaft in hence the M3 one fitting in 335 depth wise. Someone has raised a concern in this regard that attempted the mod on a 135 and for unknown reason it failed. I cannot say 100% though. Worse case would be to give the M3 shaft a slight shave.
Any more info on this sideshaft failure? I did about 3k miles using that setup and don't recall any issues. I have all the required parts off the car for measurement so will hopefully get a comparison of them when I finish work tonight.
The 86mm vs 102mm is the bolt spacing on the diff flanges which is the reason why the m3 side shafts are required.
Even if there is a small amount of preload on the sideshafts, causing the joint to be pushed in slightly I can see this causing problems especially with aggressive launching.
For an unrelated reason I'm actually going to use the m3 hubs so that the whole of my rear subframe except the lower arms (have Bilstein 335i dampers) will be m3 parts including the BBK.