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Final drive gone south
- Thread starter alke46
- Start date
pglaves
#13338
Voni's '94 R1100RS now has been ridden 416,000 miles. The final drive was inspected at 326,000 miles. The tapered roller bearing was replaced. The "big ball" bearing was fine and left in place. With the new roller bearing the unit was re-shimmed. Now 90,000 miles later all is still well.
Our final drives in Oilheads and K Bikes have the lubricant changed with Castrol Hypoy C (now renamed "Limited-Slip") GL5 80W90 gear oil at 12,000 miles intervals. I have used a MSO2 (moly) additive in our bikes since about 1985 when it was recommended by Oak Okleshen. I originally used Dow Corning Gear Guard but switched to Guard Dog Moly Lubricants additive in the 1990s. Guard Dog is no longer in business since the owner retired but the lubricant is still available from TS Moly and its distributors. Usage instructions vary from 5% to 10% additive in each fill. I use 10% the first time in a bike and 5% on later oil changes.
When it comes to BMW Oilhead final drives the Internet serves as a huge magnifying glass. While BMW has not released definitive statistics it appears that somewhere around 4% or 5% of the units have failed. Almost certainly the failure rate is less than 10%. But several/many units failed more than once. These might have suffered from machining errors during manufacture, but most likely were improperly shimmed and not correctly re-shimmed when reassembled.
A failure rate of 4% or 5% is way beyond an acceptable quality control target. But the assumption that they all fail is a social media driven myth.
Our final drives in Oilheads and K Bikes have the lubricant changed with Castrol Hypoy C (now renamed "Limited-Slip") GL5 80W90 gear oil at 12,000 miles intervals. I have used a MSO2 (moly) additive in our bikes since about 1985 when it was recommended by Oak Okleshen. I originally used Dow Corning Gear Guard but switched to Guard Dog Moly Lubricants additive in the 1990s. Guard Dog is no longer in business since the owner retired but the lubricant is still available from TS Moly and its distributors. Usage instructions vary from 5% to 10% additive in each fill. I use 10% the first time in a bike and 5% on later oil changes.
When it comes to BMW Oilhead final drives the Internet serves as a huge magnifying glass. While BMW has not released definitive statistics it appears that somewhere around 4% or 5% of the units have failed. Almost certainly the failure rate is less than 10%. But several/many units failed more than once. These might have suffered from machining errors during manufacture, but most likely were improperly shimmed and not correctly re-shimmed when reassembled.
A failure rate of 4% or 5% is way beyond an acceptable quality control target. But the assumption that they all fail is a social media driven myth.
Last edited:
saddleman
Enjoy The Ride
The highest mileage final drive I have rebuilt that didn't need rebuilding was just over 300,000 miles. It was from a K1200LT rode mostly in Florida. The lowest mileage failure I have rebuilt was around 8,000 miles.
DEANTRIMBLE
New member
Thanks, good to know a service mileage. I know I've changed the final drive and tranny twice in 10 years but I wasn't to careful what brand of 80-90w I used. Bought this bike with 40k mileage and now it has 66k so I wasn't to far off with the service. It does make you question the german engineering and hope they have improved the next generations. I really like the bike so I'll be keeping it for while at least and hope this never happens again. Not a good feeling.
pglaves
#13338
Lacking of course. Sorely lacking! But the main point I would make is that while Internet chatter supposes that they all or most will or have failed. When in fact way many more than most haven't failed and never will.
It also speaks to the likelihood that some earlier attempts at the use of robotics didn't turn out so well.
DavidEBSmith
New member
My 1997 R1100RT went 150K miles on the original final drive. Then I was going to be riding it in the Iron Butt Rally and got nervous about the FD and had my local shop change the big bearing as a precaution. It's sitting in the garage at 220K so that's 70K on the big bearing and 220K on the rest of the FD.
The previous owner of my 1999 R1100RT had multiple FD issues and finally a failure around 60K that was so major, BMW replaced the entire FD. That one has about 60K on it and is going strong (so far as I know
). It's almost enough FD experience to have statistics.
I use 80/90 because Paul said so.
The previous owner of my 1999 R1100RT had multiple FD issues and finally a failure around 60K that was so major, BMW replaced the entire FD. That one has about 60K on it and is going strong (so far as I know
). It's almost enough FD experience to have statistics.I use 80/90 because Paul said so.
