Wildguzzi.com

General Category => General Discussion => Topic started by: faffi on November 19, 2025, 04:11:56 AM

Title: Why spline lubrication?
Post by: faffi on November 19, 2025, 04:11:56 AM
Especially BMWs seems to require spline lubing of the clutch shaft splines as well as final drive splines. But we never hear this about cars. Well, at least I do not. Anybody know what this is required (more) on bikes than cars?
Title: Re: Why spline lubrication?
Post by: Littlefield on November 19, 2025, 06:01:16 PM
One thing is that automotive driveshaft splines are in an oily environment
Title: Re: Why spline lubrication?
Post by: wirespokes on November 19, 2025, 07:00:39 PM
 The lube is more to inhibit corrosion than to provide lubrication.
Title: Re: Why spline lubrication?
Post by: Pescatore on November 20, 2025, 07:15:50 AM
On a single joint cardan shaft I add a tiny bit of grease at the final drive.
That side slides back and forth when the swingarm... swings.
Title: Re: Why spline lubrication?
Post by: Wayne Orwig on November 20, 2025, 07:31:09 AM
Many car splines (except for the clutch) are 'wet'.
Maybe fewer cylinders mean the power pulses are stronger, as in for two revs:
2 cylinders BOOM------BOOM------
4 cylinders boom-boom-boom-boom
More cylinders have more 'flywheel' weight (crankpins, pistons, rods) to smooth the booms out.
And the clutch splines may be deeper than on a bike.
Or BMW uses that VERY expensive lube as a profit center.
Title: Re: Why spline lubrication?
Post by: Perazzimx14 on November 20, 2025, 10:44:32 AM
Many car splines (except for the clutch) are 'wet'.
Maybe fewer cylinders mean the power pulses are stronger, as in for two revs:
2 cylinders BOOM------BOOM------
4 cylinders boom-boom-boom-boom
More cylinders have more 'flywheel' weight (crankpins, pistons, rods) to smooth the booms out.
And the clutch splines may be deeper than on a bike.
Or BMW uses that VERY expensive lube as a profit center.

Or just use Wurth SIG 3000. A $20 cartridge has enough to lube every BMW driveshaft in your state, twice. You can also use Prestone DOT4 and Mopar 70W-80 at $19 a liter verses BMW's 70W-80 at $56 for a 500ml bottle. No different than buying Honda branded oils/fluids. You can spend more but do you get more. There cost effective alternatives.
Title: Re: Why spline lubrication?
Post by: JHBettsSr on November 23, 2025, 10:40:40 AM
Especially BMWs seems to require spline lubing of the clutch shaft splines as well as final drive splines. But we never hear this about cars. Well, at least I do not. Anybody know what this is required (more) on bikes than cars?
I was a Master ASE automotive tech for about 20 years. And yes, the manual transmission input shaft splines are supposed to be cleaned and lubed when the clutch is replaced. Most clutch kits come with a small amount of specialized grease.