Fork Stanchion recall?

[matchlessman]

The angular movement in the top rubber bush is very small, a couple if degrees or so, but good point made earlier if the rubber is less flexible it would strain the joint. There is hardly any vertical force on the joint as the shock takes care of that. The other force is the front to back from braking, which would compress the front of the rubber bush (as the forks would effectively pivot around the lower ball joint) or the weight of bike and rider (not inconsiderable especially when landing after an airbourne moment) which would compress the rear of the rubber bush. Sideways loads would be pretty small. I have highlighted the loads on the bush as the loads on the failing crimp will be almost identical as they are bolted together.
Softer rubber in the bush would allow easier flexing and soften impacts. Unlikely you would feel much difference. The otherk alternative mentioned, a spherical joint would give perfect flex and suspension control, but would transmit a lot of vibration and be very harsh. OK for racing but no good for touring - white finger vibration.

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[fred_jb]

The angular movement in the top rubber bush is very small, a couple if degrees or so, but good point made earlier if the rubber is less flexible it would strain the joint. There is hardly any vertical force on the joint as the shock takes care of that. The other force is the front to back from braking, which would compress the front of the rubber bush (as the forks would effectively pivot around the lower ball joint) or the weight of bike and rider (not inconsiderable especially when landing after an airbourne moment) which would compress the rear of the rubber bush. Sideways loads would be pretty small. I have highlighted the loads on the bush as the loads on the failing crimp will be almost identical as they are bolted together.
Softer rubber in the bush would allow easier flexing and soften impacts. Unlikely you would feel much difference. The otherk alternative mentioned, a spherical joint would give perfect flex and suspension control, but would transmit a lot of vibration and be very harsh. OK for racing but no good for touring - white finger vibration.

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Good analysis. I wondered if load on the bike and heavy braking could be factors in this, but wasn't sure, particularly with the braking, but I think you are right - there must be some tendency to rotate around the joint on the lower arm, though that joint may have a fairly restricted fore and aft range of movement.

I must admit I wasn't sure that normal amounts of flex in the top rubber joint would necessarily be capable of damaging the crimps, even with harder rubber. That is why I raised the possibility that the range of movement might be less than required for all situations, particularly as the part number for this so-called joint link is different for the LC compared with earlier models.

If the compliance in the top bush gets fully used up before the full range of suspension travel, including any bump stops in the strut, then I would expect the top joint to lock and you would then get bigger forces exerted on the crimps. If the maximum possible angle change is only a couple of degrees, then maybe this is not the issue - how did you come up with that figure? It might also be a factor under braking - the stress on the crimps would presumably be worse if the top bush runs out of movement before the ball joint on the lower arm?

In all these scenarios the inner metal bush in the joint link is going to rock and depending on how thin the rubber layer is between it and the outer metal part of the bush (and it looks quite thin), then with a large angular deflection the inner and outer metal parts of the bush will effectively be locked against each other.

 

[matchlessman]

I have to admit the couple of degrees is an estimate based on observation of its behaviour. I'm sure it would be within the limits of the bush to flex. But if it is very hard rubber that would load the crimp.

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[fred_jb]

The other alternative mentioned, a spherical joint would give perfect flex and suspension control, but would transmit a lot of vibration and be very harsh. OK for racing but no good for touring - white finger vibration.
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The spherical joint is an interesting option. I guess the joint would have to be quite tight and have a fairly high resistance to movement so that it didn't move in response to steering input, but would still have to be able to flex readily in response to the presumably rather higher inputs from the suspension movement. I can imagine that spherical joints might give maintenance issues through the joint loosening with wear.

Regarding vibration, I guess it could make jolts from the road marginally more apparent, but I doubt it would make transmission of engine vibration any worse as there is a long pathway for this to go out via the lower arm, and come back up the forks and then through the spherical joints, whereas there is already a much shorter and probably more solid path to the bars through the frame, steering head and top yoke, which is also there with the rubber bush option as I know from experience. I have had numb fingers on my left hand after long rides and have now fitted some Grip Puppies to try to counter that.

 

[roamer]

Interesting ideas on the weakness of the current telelever,
My thoughts are that the fork tubes are thinner wall, and the top plug may be shorter,
Causing a slight flare at the end of the tube,
The advantages of telelever in particular anti dive,
transfers the braking or impact load from the axle point to the wishbone at the lower clamp,
this rigid arrangement transfers a rocking force at the top mounting,
The pressed on bush will prevent the top mounting flaring the tube ,which suggests thicker wall tubes on earlier incarnations without failiure,
My forks were both replaced one side was 0.33 mm and weeping oil, there was 0.96 mm flare at the tube end ,
Totally road use, owned from new,

 

[Dogs & Bikes]

Official DVSA Recall Details for BMW Motorcycles :- R 1200 GS / R 1200 GSA

Follow the Link, to check your VIN number, and see whether you will eventually get a recall letter from BMW Motorrad UK.
With just under 11,000 motorcycles affected. (Don't know if they are UK or Worldwide figures.) It may be sometime if they are just UK! Busy time for the dealers.

http://www.dft.gov.uk/vosa/apps/rec...01589138C88025815A002E9F6B&freeText=Blank&tx=

 

[Neil W]

Follow the Link, to check your VIN number, and see whether you will eventually get a recall letter from BMW Motorrad UK.
With just under 11,000 motorcycles affected. (Don't know if they are UK or Worldwide figures.) It may be sometime if they are just UK! Busy time for the dealers.

http://www.dft.gov.uk/vosa/apps/rec...01589138C88025815A002E9F6B&freeText=Blank&tx=

Mine is within the build dates but does not appear to be within the affected range of VIN numbers shown on the DVSA site , however, it has already been checked and needs the repair carried out so probably safer to take in any bike that is within the build dates and let the dealer decide.

With mine the official party line is one of the fork legs has a measurable gap and BMW recommend that the bike is not ridden until it has been repaired , unfortunately there were no parts available to do it (but the dealers have the tool to do the fix)

As it is going to have other work done I am more than happy to leave it parked up until this and the warranty repairs are carried out .

 

[Andi_archer]

Same with my 2015 GS which is WB10A0109XXXXXX not in the 202 TO 207 range

 

[alp]

The build dates are shown as 22/08/13 to 19/06/17 which just about covers most LC GSs bought except for the early birds in 2013. I'm not entirely sure how the VIN numbering system works since my Rallye falls in the build date range but has VIN WB10A 5109 HZ XXXXXX but the VIN range quoted is WB10A 0202 FZ 16184 to WB10A 0207 HZ 923445. I.e. 3 variables...... 0202 etc, FZ etc and the last numbers 16184 etc. Anyone cracked this code?

 

[kurienp]

The build dates are shown as 22/08/13 to 19/06/17 which just about covers most LC GSs bought except for the early birds in 2013. I'm not entirely sure how the VIN numbering system works since my Rallye falls in the build date range but has VIN WB10A 5109 HZ XXXXXX but the VIN range quoted is WB10A 0202 FZ 16184 to WB10A 0207 HZ 923445. I.e. 3 variables...... 0202 etc, FZ etc and the last numbers 16184 etc. Anyone cracked this code?

There's a sticky on decoding Vin numbers here http://www.ukgser.com/forums/showthread.php?t=390040

 

[Deleted account 181015003]

Interesting ideas on the weakness of the current telelever,
My thoughts are that the fork tubes are thinner wall, and the top plug may be shorter,
Causing a slight flare at the end of the tube,
The advantages of telelever in particular anti dive,
transfers the braking or impact load from the axle point to the wishbone at the lower clamp,
this rigid arrangement transfers a rocking force at the top mounting,
The pressed on bush will prevent the top mounting flaring the tube ,which suggests thicker wall tubes on earlier incarnations without failiure,
My forks were both replaced one side was 0.33 mm and weeping oil, there was 0.96 mm flare at the tube end ,
Totally road use, owned from new,

I agree with you thinner tubes and the braking forces could be the true issue

When braking the front wheel is forced backwards as the bike weight moves forwards. The ball joint on the wishbone acts as a hinge transferring the forces to the top fork mount resulting in a force that is trying to push the fork tubes forward this constant on off force every time the front brake is applied could after time weaken the top of the tube or mount if it is not up to the job.

The force from the brakes is at the same point and direction as hitting a pot hole or off road riding and the official cause of the failures

The failure of the fork top mount is very common in accident damaged bikes where they have had a frontal impact, early generation bikes often had broken yokes later LC bikes the forks tend to part at the mount as it is weaker than the yoke casting.

 

[alp]

Engineer, I feel it's ok to show the principle of the movement but more detail would show that the suspension angle does increase with compression UNTIL the blue link goes past the 90 degrees relative to the stanchion tube as compression increases at which point it reverses and decreases the suspension angle. I don't have actual numbers for this but it certainly looks that way on the bike that the 90 degrees link position is max suspension angle but not yet at max compression.

I think that I should apologise since I've had a closer look at the 'blue' link on my bike in better light and I don't think it has any chance of going past the 90 degree relative to the stanchion tube for the available stroke if it ever reaches 90 degrees.

 

[tanneman]

Service and MOT done. 3 year old GSA, no gap. Ride if like a pussy and you'll be fine.

Nutty takes crap photos

 

[westride]

This is a serious design fault, no one should underestimate this. I can't stand people just complaining for the sake of it! I have owned 7 new GS bikes from 2003, have covered a lot of miles in many parts of the world! I clearly think very highly of BMW and in particular the GS. However with a strong engineering background and one that understands stress! I do understand why people on this site are concerned! I have never ever felt concerned riding any of the GS bikes I have owned. I now have my first concern! You will never get me to engage in any type of slang against any individual. I have strong principles in life about remaining happy at all times! Let's all pull together, remain happy and most of all, let's hope BMW correct this design fault properly!!

 

[Nutty]

Nutty takes crap photos

That saves me having to do a ride report from last weeks trip to Italy & the RDGA.

 

[tanneman]

Ok, you noticed. I'll change the tapatalk signature

Nutty takes crap photos

Edit: The missus and I will be off to the RDGA, Gorges du Verdon and Vercors soon. Lots to do and see. You been to the Dolomites or just kept to the north west of Italy?

 

[Wierpig]

That saves me having to do a ride report from last weeks trip to Italy & the RDGA.

Good.No more pictures of the same fucking mountains with snow on the top, the same forests and gses with loads of stickers on the panniers.

 

[Wokkaman]

Ok, so had my service done at beginning of July, no gap on the forks... however an email send to me now says as soon as they have the parts it will be booked in for the recall

 

[Nutty]

Good.No more pictures of the same fucking mountains with snow on the top, the same forests and gses with loads of stickers on the panniers.

I was on the KTM. And I don't do panniers or stickers.

 

[mcinlb]

24K service done yesterday, stanchion gap checked - 0.1mm which is borderline, ok to ride but will be replaced when they get new bushes.