Safety issue on 2018-2023 GS and RT bikes? (recall under way in Europe)

[Joe Frickin' Friday]

@Bernie brought this to my attention, and I thought everyone here might want to see this:

 

https://ec.europa.eu/safety-gate-alerts/screen/webReport/alertDetail/10008484?lang=en

 

Short version: for RT and GS bikes with a date of production from September 2017 to January 2023, there's a concern that sudden braking at high speeds can break the gearbox input shaft.  BMW has been recalling bikes in Germany and taking unspecified measures in other European countries (I'm guessing that unspecified measure is also also a recall).  

 

The NHTSA (and BMW) doesn't appear to be taking any action here in the US, at least not yet.  That notice was published in April 2023, so if the NHTSA hasn't moved on it yet, then maybe nothing is going to happen here???

 

armchair theories as to what may be happening:

If you're in a tall gear, the engine doesn't have good mechanical advantage over the rear wheel - but the rear wheel has really good mechanical advantage over the engine.  If you stomp on the rear brake while leaving the clutch out with the gearbox in a high gear, and the rear wheel starts to lock up, the tire transitions from static friction to sliding friction, producing a lot less traction force and hence a lot less torque on the rear wheel.  Now the excess braking torque goes to rapidly decelerate the rear wheel, and it also rapidly decelerates the engine.  In the course of rapidly decelerating the engine, it may be possible for the driveline to produce torques across the gearbox input shaft that are a lot higher than what it was designed for.  

 

Alternatively, it may be something about how the ABS behaves that sets up destructive torsional oscillations in the driveline.  Maybe it cycles at a frequency that's unfortunately close to the driveline's natural resonant frequency?  

 

If anyone finds out more, please add to this thread.  Or point to a thread where this issue is already under discussion, and I'll merge my post with it...

 

 

[lkraus]

Sounds like it is the same issue as the previous Safety Recall for the GS/GSA/RTP.  When jumped with poor throttle control, revs may rocket, then landing causes with a large mismatch between wheel speed and actual forward speed, so the input shaft breaks.

 

Solution will likely be a software update.  Patching weak steel with silicon...

 

The GS recall:

https://static.nhtsa.gov/odi/rcl/2023/RCLRPT-23V011-2198.PDF

This safety recall involves the gearbox input shaft. In certain engine operating and riding conditions, i.e., an abrupt difference between the engine speed and the rotational speed of the final drive component, an overload of the gearbox input shaft could occur. This could result in damage to, or breakage of, the gearbox input shaft, and possibly result in a blocked rear wheel.

...

: The engine control unit software will be updated. Owners will be notified by First Class mail and instructed to take their motorcycle to an authorized BMW motorcycle dealer to have the remedy performed for free.

[Bernie]

It could be Larry ( @lkraus) except this notice does not exclude the civilian version of the RT. 

Maybe BMW doesn’t think this could happen in the US, since our speed limits are much lower then in other countries?

[lkraus]

3 minutes ago, Bernie said:

It could be Larry ( @lkraus) except this notice does not exclude the civilian version of the RT. 

Maybe BMW doesn’t think this could happen in the US, since our speed limits are much lower then in other countries?

MY (weak) memory says that when the input shaft issue first arose the initial response from BMW was that the failures were caused by jumps, whether while riding off-road or cops riding off curbs, so the U.S. recall campaign  from January 2023 was restricted to GS/GSA/RTP. I think BMW NA started the recall as a voluntary "service campaign" around January 17, 2023 but it was quickly upgraded to full NHTSA recall with a temporary stop sale on new bikes.  The assumption was that the civilian RT would not experience the same sort of shock loads on the street, so it was not included in the recall. As best I can tell, there is still not a current U.S. recall campaign for the civilian RT (or any other street R model).

 

Mitch's EU recall link is from last April, and does not distinguish between street and authority bikes. It is relatively light on details, so it might just be a general sort of alert. We would probably need to check with someone in the EU to find out if the recall has actually applied to the civilian models. Different jurisdictions have different recall campaigns, so what the EU does may not affect the U.S.  And I'm kind of wondering if anything new is really happening...

 

While we await developments, stay off the brakes in high gear, don't slam your bike into gear if you miss a shift, and keep your RT off those sweet jumps.

 

 

[JCtx]

There's an additional related issue, I think. Just read somewhere (maybe here?) that BMW is now requiring to replace the shaft on all 1200/1250 R bikes every 60K km (or 37K+ miles), and that BMW would cover that. They also recommend lubing the splines every 12K miles, but they don't cover that cost. Therefore, I thought the shafts were the ones breaking, and not the input shafts... but apparently that is not correct. What a mess. I'm honestly not worried about that, and if I owned an RT, I wouldn't either. But GS owners who flog their bikes off-road, probably should. Curious what BMW does here in the US.