Spline Failure: High percentage or hype percentage?

[DSXMachina]

Hello fellow oil heads. From what I've read in this sub-forum, the dreaded 'spline failure' is the biggie when it comes to stranding riders and costing big bucks to fix. Of course, if it does happen to you it is a tragedy, and it happened to 100% of...your bike!

Naturally a forum focusing on an older model isn't going to mention the anticipation and joy of waiting for the ship carrying your new purchase to arrive in a US port. It's going to mostly involve help requests from members having a problem, and members with advice about repairing problems. It tends to emphasize the 'negatives' in ownership of certain models. I've seen it happen in automotive forums. One would have, for instance, thought that all first edition BMW 335i's were on the side of the road due to the infamous high pressure fuel pump (HPFP) failure. It's all we ever talked about.

So...we talk about spline failure, but to what percent of all oilheads does it happen? I realize I will get responses saying their off warranty bike with only 6K miles stripped the spline/clutch far from home, and others will say their hard driven bike has over 100K with no sign of failure.

What is the real percentage, though? Are we dealing with 1%, 10%, 50%? Obviously unless someone at BMW has aggregated the repair numbers we may not ever know the facts. There must be someone who has a good idea. Anyone?

(It doesn't say so in my blurb below, but I am now also the happy owner of a 2003 R1150R with 11K miles. Piedmont Red. And no, no evidence of impending spline failure.)

 

[pglaves]

If the splines are properly maintained failures are rare. If the splines are neglected or ignored they will fail. Those two statements are true.

Proper maintenance means periodically clean and lubricate the splines. A good target mileage is about 40,000 miles. And a good lubricant is a sticky extreme pressure grease with at least 25% or 30% moly by volume.

The R1150 models are particularly troublesome because the length of the spline engagement is shorter than on the 1100 models. Less length = less area of engagement = greater pressures on what area is engaged = possibility of greater wear. So lubrication is particularly critical on the 1150 models.

 

[jrogers]

I've have been told by my friend who is the dealer owner and a mechanic that it is a very low percentage have problems with the spline Failing.

 

[pglaves]

I've have been told by my friend who is the dealer owner and a mechanic that it is a very low percentage have problems with the spline Failing.

I don't have data to agree or disagree with this, but I do know that dealerships probably do very few failed-spline repairs. They are too expensive at dealer rates. Labor would be somewhere between $2,500 and $3,500 plus parts. So bikes get parted out or owners do the removal and replacement themselves and take or send the transmission off to an independent.

 

[BC1100S]

I've have been told by my friend who is the dealer owner and a mechanic that it is a very low percentage have problems with the spline Failing.

Um, not that rare.


Similar Issue on my 2000 1150GS?

Trying to get back on the road, parts ordered

Hi DJohnson81,

Looks like you might be addressing similar issue that I’m about to dive into. I’m getting some false neutrals shifting from 2nd up to 3rd. Could point to clutch disc / Input shaft splines??
I’m in NorCal and trying to find good independent mechanic not BMW dealer as this will be a big tear down I assume on the level you have pictured here?

Looking for any suggestions, tips etc. Craig Harris videos on YouTube have been super informative on this area. I have a lift table etc. But am still learning to wrench on my bike and not sure if I should dive this deep just yet?

Craig Harris also points out notorious failure of this Clutch disc to Input shaft splines due to design flaw where clutch disc does not sit flush all the back on the splines. Instead only engaging 70% of the splines. He used to have custom disc plates made that would engage the splines fully.

He also speaks about how bikes that have been ridden super hard often have far less wear on the splines, vs those who putter around babying it in Taller gears / lower RPMs. To this point he mentions not going to 6th gear until at least 75mph as 6th is so overgeared it can accelerate the spline strain quickly if using 6th at lower RPMs. Interesting.

Any tips/suggestions/feedback much appreciated. What is the issue you are addressing?
My 2000 1150 GS has been exquisitely maintained, but no spline lube/maintenance performed. Bike has 65k now.

All the best,
Will

 

[pauls1150]

Not especially rare, but proper initial assembly plus periodic maintenance greatly delays it.
i don't think anybody has a record of the percentage of bikes.
And any dealer will deny it's an issue.

Some bikes had little or no grease at the line assembly - like mine, apparently, since it was freakin' Dry when I finally took it apart at 75K miles.
Like Paul G sez, lubricate that interface periodically.

False neutrals are one symptom, rejecting a shift is another, and just "sloppy" or recalcitrant shifting is another. These could also be partly caused by worn shifter linkage.

 

[djohnson81]

Um, not that rare.


Similar Issue on my 2000 1150GS?

Trying to get back on the road, parts ordered

Hi DJohnson81,

Looks like you might be addressing similar issue that I’m about to dive into. I’m getting some false neutrals shifting from 2nd up to 3rd. Could point to clutch disc / Input shaft splines??
I’m in NorCal and trying to find good independent mechanic not BMW dealer as this will be a big tear down I assume on the level you have pictured here?

Looking for any suggestions, tips etc. Craig Harris videos on YouTube have been super informative on this area. I have a lift table etc. But am still learning to wrench on my bike and not sure if I should dive this deep just yet?

Craig Harris also points out notorious failure of this Clutch disc to Input shaft splines due to design flaw where clutch disc does not sit flush all the back on the splines. Instead only engaging 70% of the splines. He used to have custom disc plates made that would engage the splines fully.

He also speaks about how bikes that have been ridden super hard often have far less wear on the splines, vs those who putter around babying it in Taller gears / lower RPMs. To this point he mentions not going to 6th gear until at least 75mph as 6th is so overgeared it can accelerate the spline strain quickly if using 6th at lower RPMs. Interesting.

Any tips/suggestions/feedback much appreciated. What is the issue you are addressing?
My 2000 1150 GS has been exquisitely maintained, but no spline lube/maintenance performed. Bike has 65k now.

All the best,
Will

My issue with the Neutral light was it was bright in neutral and dimly lit in all other gears, the gear indicator was all over the place and would randomly change number whenever it felt like it. I was riding off road through axle deep mud and water and decided to lay it down and have a refreshing swim, that's when it started. When I pulled the gear position sensor (potentiometer) it fell apart in my hand. Hopefully the new one will work a bit better.
I measured the splines on my bike, they seemed to be in good shape, I did however get the new clutch disk with the extended collar just in case.
Just got my new rear main seals today, transmission seals on the way.

Sent from my SM-N981U using Tapatalk

 

[nrpetersen]

Strictly my opinion - but why have I encountered or made aware of so many spline failures - including my own 1975 R90/6 at ~25K miles.

BMW has a mediocre design by having clutch assembly concepts with no pilot bearing for the transmission input shaft into the engine flywheel. My R90 has a machining error in that I can feel the engine-transmission interface "breathing" when ever the assembly bolts are loosened. But it was manufactured in the days before extensive use of numerical machine tools.

But it is the oilhead clutch concept that especially disturbing to this Mech Engr (long retired) in that the clutch housing is not only light weight aluminum, but the engine side flange is interrupted for the starter access hole, in addition to having only those two short small diameter spools for alignment. Yes, if everything is assembled properly in an unstressed condition they could get by with the oilhead design. But anything that compromises the alignment on assembly, such as having a major locked-in load dragging the clutch disc across the flywheel on assembly bolt pull up, will add a nutating radial load to the spline. That nutating radial load happens once per engine revolution even in neutral - of which there are many, and yet has nothing to do with how aggressively the bike is driven.

Yes, the reduced spline engagement doesn't help any, but I don't think it is the golden screw as it doesn't seem to be correlating to failures. Something else is wrong. It could be initial part manufacturing errors but in this day and age of numerical machining equipment, that should have been corrected and stayed corrected after the first years of failure.

So I contend it is very likely an assembly technique error - including at the time of factory assembly.

 

[drost]

I have long thought that spline wear was probably the clutch carrier being out of alignment. It’s a piece of stamped steel. Pictured is my input shaft greased ready for reassembly when I changed my clutch and slave cylinder on my old 1150RT a few years back. I had no issues just thought should probably do preventative maintenance. Clutch had 83,000 miles on it with zero wear on the input shaft. I installed a standard clutch.

 

[nrpetersen]

I have long thought that spline wear was probably the clutch carrier being out of alignment. It’s a piece of stamped steel. Pictured is my input shaft greased ready for reassembly when I changed my clutch and slave cylinder on my old 1150RT a few years back. I had no issues just thought should probably do preventative maintenance. Clutch had 83,000 miles on it with zero wear on the input shaft. I installed a standard clutch.

The clutch carrier has nothing to do with the crank-to-transmission alignment, and that's why it is only stamped steel. The needed alignment is between the engine crank centerline and the transmission centerline. The clutch carrier only gets involved in the assembly process if the clutch disc center happens to be not at the crankshaft centerline. Releasing the clutch disc from the engine before final assembly pull up lets it freely assume the transmission centerline without radially forcing things.

That input spline looks new!

 

[gsaddict]

The clutch carrier has nothing to do with the crank-to-transmission alignment, and that's why it is only stamped steel. The needed alignment is between the engine crank centerline and the transmission centerline. The clutch carrier only gets involved in the assembly process if the clutch disc center happens to be not at the crankshaft centerline. Releasing the clutch disc from the engine before final assembly pull up lets it freely assume the transmission centerline without radially forcing things.

That input spline looks new!

Actually the "carrier" - clutch housing as described on the fiche has a lot to do with the spline wear issue.
The more axial runout between the 3 mounting points, the worse the spline wear.
This I have found having them apart.
It also explains the odd spline tooth wear 2/3 of the way down on the input shaft.
The fact that it is a stamped part and not fully machined likely causes this. IMO the distortion may even get worse over countless heat cycles.

Volvo stern drives had the same issue 20 years ago.

 

[nrpetersen]

I think of axial run out for the clutch carrier attachment would imply something like flywheel wobble. Is that the term you intend to use?

Or do you mean radial run out but that would be released whenever the clutch pack is disengaged (clutch handle pulled in)?

 

[gsaddict]

I think of axial run out for the clutch carrier attachment would imply something like flywheel wobble. Is that the term you intend to use?

Or do you mean radial run out but that would be released whenever the clutch pack is disengaged (clutch handle pulled in)?

Wobble is what I mean.

 

[oldcamper]

The manual transmission cars and trucks i have seen have square cut splines and they never seem to fail.
Does anyone have any idea why BMW chose to use v-shaped splines?

 

[41107]

Strictly my opinion - but why have I encountered or made aware of so many spline failures - including my own 1975 R90/6 at ~25K miles.

BMW has a mediocre design by having clutch assembly concepts with no pilot bearing for the transmission input shaft into the engine flywheel. My R90 has a machining error in that I can feel the engine-transmission interface "breathing" when ever the assembly bolts are loosened. But it was manufactured in the days before extensive use of numerical machine tools.

But it is the oilhead clutch concept that especially disturbing to this Mech Engr (long retired) in that the clutch housing is not only light weight aluminum, but the engine side flange is interrupted for the starter access hole, in addition to having only those two short small diameter spools for alignment. Yes, if everything is assembled properly in an unstressed condition they could get by with the oilhead design. But anything that compromises the alignment on assembly, such as having a major locked-in load dragging the clutch disc across the flywheel on assembly bolt pull up, will add a nutating radial load to the spline. That nutating radial load happens once per engine revolution even in neutral - of which there are many, and yet has nothing to do with how aggressively the bike is driven.

Yes, the reduced spline engagement doesn't help any, but I don't think it is the golden screw as it doesn't seem to be correlating to failures. Something else is wrong. It could be initial part manufacturing errors but in this day and age of numerical machining equipment, that should have been corrected and stayed corrected after the first years of failure.

So I contend it is very likely an assembly technique error - including at the time of factory assembly.

It has nothing to do with NC machining.In the days of no NC we build fixtures that gave the same accuracy's as NC machining.From an old retired Tool&Die Maker.

 

[41107]

The manual transmission cars and trucks i have seen have square cut splines and they never seem to fail.
Does anyone have any idea why BMW chose to use v-shaped splines?

A V-shape tooth simply gives you more surface area making it stronger.

 

[gsaddict]

The manual transmission cars and trucks i have seen have square cut splines and they never seem to fail.
Does anyone have any idea why BMW chose to use v-shaped splines?

Involute (v shaped) splines are stronger.

https://www.google.ca/search?q=invo...GkgEDOC4xmAEAoAEBsAEAyAEIwAEB&sclient=gws-wiz

 

[nrpetersen]

I think the BMW splines are most certainly involute. The shafts look like they are cut with a gear Hobbing machine. This form of spline is like an internal tooth gear, and would inherently have a radius at the root of the teeth which would greatly reduce the tendency to start a crack. It is more difficult to manufacture however. The inside (female) involute spline has to be either done with a Fellows gear shaper or if there is a thru-hole, can be done with a male broach made on a Hobbing machine to get the right profile.

Square edged splines are used in situations which are not so highly loaded because of other design limitations, but where stresses are so low that crack initiation is not of concern. Square edged spline (female) insides have the manufacturing advantage that they can be broached in one push with a special multi-tooth file-like super-tool, and outside (male) square spline could even be done on a milling machine. But in either case, the root of the teeth would have a comparatively sharp corner prone to start a crack.

IOW the involute spline is a stronger spline. They also tend to have more teeth for a given diameter to better share the torque induced loads.

 

[gsaddict]

I think the BMW splines are most certainly involute. The shafts look like they are cut with a gear Hobbing machine. This form of spline is like an internal tooth gear, and would inherently have a radius at the root of the teeth which would greatly reduce the tendency to start a crack. It is more difficult to manufacture however. The inside (female) involute spline has to be either done with a Fellows gear shaper or if there is a thru-hole, can be done with a male broach made on a Hobbing machine to get the right profile.

Square edged splines are used in situations which are not so highly loaded because of other design limitations, but where stresses are so low that crack initiation is not of concern. Square edged spline (female) insides have the manufacturing advantage that they can be broached in one push with a special multi-tooth file-like super-tool, and outside (male) square spline could even be done on a milling machine. But in either case, the root of the teeth would have a comparatively sharp corner prone to start a crack.

IOW the involute spline is a stronger spline. They also tend to have more teeth for a given diameter to better share the torque induced loads.

They are involute

 

[mntngrown]

video of Chris Harris referenced above posts

For a rookie owner of a used 2000 R1100S 6 speed I found this informative. Warning colorful language used.
https://www.youtube.com/watch?v=Jx3e0gqzylY
Beemer boneyard has UK made clutch disc and clutch disc kits with the extended engagement. Could a DIY non-mechanic with a Clymer manual and youtube videos pull this off. Hope this is not a thread derail. OOPS Craig Harris