This need's reporting to BMW!!!

[Psyko]

If the bolts are loose, the fork legs are not gripped tightly by the fork brace (yoke).

This can result in the forg legs rotating in the brace, resulting in the loss of alignment of the front wheel i.e. the front wheel can wobble sideways as it isn't rigidly gripped due to the foks legs being loose.

Riding with a front wheel wobbling from side to side = likely crash.

Take the front wheel of a bicycle and hold the two spindle ends allowing your straight arms to be the forks. Get someone to spin the wheel and then turn your arms as though they were forks. You'll feel the forces of precession (I think that is what it's called - one of Newton's Laws - the turning force of your arms is translated by the gyroscopic effect of the spinning wheel and manifests iteself through a turn at an angle of 90 degrees beyond your arms. This is why a bike countersteers.). If you imagine these forces happening on a much heavier motorcycle tyre at much higher speeds, you can appreciate why the forks need to be well braced. Actually feeling these forces makes the concept easier to fathom.

Someone please correct me if I'm talking out of my proverbial - I'm not an expert: someone showed it to me once on an advanced riding course to demonstrate countersteering, but I always felt it showed how important a strong set of forks is too. Or maybe I just have weedy arms!

Cheers,

Psyko

 

[Pukmeister]

Anyway, the chances are that the bracket/bolts will settle down after a couple of checks.

Sorry Shep, I strongly disagree with the above statement. I have retorqued mine twice previously, with I guess about 2000 miles between intervals and on this third occasion have resorted to using Loctite and paint marks to keep tabs on things. My bike has done 19,300 miles in total.

My bike has (thankfully) never suffered from any unusual handling traits in the time I have owned it despite the bolts being slightly loose, and last weekends rideout across Salisbury plain (cheers Steptoe ) gave things a damn sight more shaking than any road trip on tarmac could and all is still well.

My mate bought a low mileage used R12GS about 3 months ago and his fork brace bolts were also loose. I think this is a definite cause for concern.

 

[Dave Price]

Take the front wheel of a bicycle and hold the two spindle ends allowing your straight arms to be the forks. Get someone to spin the wheel and then turn your arms as though they were forks. You'll feel the forces of precession (I think that is what it's called - one of Newton's Laws - the turning force of your arms is translated by the gyroscopic effect of the spinning wheel and manifests iteself through a turn at an angle of 90 degrees beyond your arms. This is why a bike countersteers.). If you imagine these forces happening on a much heavier motorcycle tyre at much higher speeds, you can appreciate why the forks need to be well braced. Actually feeling these forces makes the concept easier to fathom.

Someone please correct me if I'm talking out of my proverbial - I'm not an expert: someone showed it to me once on an advanced riding course to demonstrate countersteering, but I always felt it showed how important a strong set of forks is too. Or maybe I just have weedy arms!

Cheers,

Psyko

You're slightly mixed up there I'm afraid:
In simple terms, the revolving wheel creates forces that resist movement ie. resist steering input. The effect is like a childs spinning top or giroscope.In effect, when the motorcycle is on the move, the wheels create an inherrent stability, which is only affected by other forces acting on it. That's why you often see a riderless motorcycle remain upright on a race track, untill its speed drops off.

Counter steering is a completely different process, and is the term that describes the input a rider puts in at the handle bars, to make the motorcycle lean and therefore negotiate a curve.

Over simplified but hope I've made sense.

 

[riverking]

Miriam,

I feel that you may prefer a more straightforward explanation;

If you do not sufficiently tighten the wheel nuts on your bike, the wheels will fall off, and so will you. HTH.

 

[Lord Snooty]

This appears to be a frequent and serious issue, there is another rider on this site who has had a crash due to this problem.

Are we being a bit presumptious here?
Without knowing the full circumstances and seeing an experts report, how can you make statements like this.
In my relatively long experience, I've rarely heard of riders taking responsibility for their own mistakes, and I've rarely, if ever, seen a collision that can be directly attributable to a mechanical defect.
I'm not suggesting that this isn't a problem, but lets see some hard evidence before getting too hysterical.

Collecting hard evidence is exactly the reason for me suggesting the website to gather data. There is already evidence of this problem, you only have to read through the numerous threads and postings on the issue and there is one guy on this site who has been thrown off his bike after experiencing loss of control brought on by front wheel wobble induced by loosening of his fork brace.

 

[(RIP) sherpa]

Me confused too!!!

If the bolts are loose, the fork legs are not gripped tightly by the fork brace (yoke).

This can result in the forg legs rotating in the brace, resulting in the loss of alignment of the front wheel i.e. the front wheel can wobble sideways as it isn't rigidly gripped due to the foks legs being loose.

Riding with a front wheel wobbling from side to side = likely crash.

Don't any of these bikes have a front axle?

My 1150 GS has a metal tube of about 1" diameter holding the front wheel through the bottom of the fork legs.
If I undo ALL of the fork brace bolts, surely, the only thing that will happen is the fork tubes will work their way UP the braces.
I can't understand how the forks can twist if they have a metal bar through them in a machined hole!

I wait to be enlightened

Sherpa

 

[Psyko]

You're slightly mixed up there I'm afraid:
In simple terms, the revolving wheel creates forces that resist movement ie. resist steering input. The effect is like a childs spinning top or giroscope.In effect, when the motorcycle is on the move, the wheels create an inherrent stability, which is only affected by other forces acting on it. That's why you often see a riderless motorcycle remain upright on a race track, untill its speed drops off.

Counter steering is a completely different process, and is the term that describes the input a rider puts in at the handle bars, to make the motorcycle lean and therefore negotiate a curve.

Over simplified but hope I've made sense.

I think you are right - and so am I! When you impose a lateral force on a spinning wheel (by pushing the bar), the turning effect manifests itself 90 degrees further round. Hence you push on the left bar and the turning force is translated by the forces of precession into a left hand turn - not to the right, as happens at walking pace. Try it with a bicycle wheel. If there is no turning force exerted, the gyroscopic forces keep it going straight as you describe. When I did this (with the wheel spinning quite fast) it tried to pull itself out of my grip. Hence my thought that these forces could stress the forks if they were not securely held.

Cheers,

Psyko

 

[loosenuts]

If this "story" gets into the MCN just think what it will do the the value of YOUR 1200GS.

There's Ricky decided that he wouldn't buy a 1200 because of what he has read on this site.

Take the matter up with your dealer and BMW before going to the "press"

WHATS YOUR BIKE WORTH AFTER IT HAS SLID DOWN A MOTORWAY AT 80 MPH

 

[loosenuts]

Please pardon my lack of knowledge on this subject, but exactly how does not having the right torque on these bolts cause an accident? I'm not a technical person and it would help me to get a clear picture on how this problem is so dangerous.

Thank you!

DEAR MARIAM i dont know what on earth your riding in the picture but you look good, if you take your hands off the thingy and your feet off the thingy you would probably fall off rather like a bolt that is not tightened properly, forgive me if i sound like im being a smart arse ,its has been a long 3 months, but you do look good

 

[nadeem]

DEAR MARIAM i dont know what on earth your riding in the picture but you look good, if you take your hands off the thingy and your feet off the thingy you would probably fall off rather like a bolt that is not tightened properly, forgive me if i sound like im being a smart arse ,its has been a long 3 months, but you do look good

Now that wasn't patronising, eh Miriam....?

 

[Shep]

Sorry Shep, I strongly disagree with the above statement. I have retorqued mine twice previously, with I guess about 2000 miles between intervals and on this third occasion have resorted to using Loctite and paint marks to keep tabs on things. My bike has done 19,300 miles in total.

My bike has (thankfully) never suffered from any unusual handling traits in the time I have owned it despite the bolts being slightly loose, and last weekends rideout across Salisbury plain (cheers Steptoe ) gave things a damn sight more shaking than any road trip on tarmac could and all is still well.

My mate bought a low mileage used R12GS about 3 months ago and his fork brace bolts were also loose. I think this is a definite cause for concern.

Hi Pukmeister,

Thats OK, everybody will have to make the decision to loctite or not, you've made yours, how will you check the security of the fork yolk/bridge if the bolts are glued in?

The bridge could move on its own and your bolts still torque up ok, the only way to check now will be to remove the bolts,clean them, then retighten to the correct torque, ever thought of the excess loctite getting in the joint between the fork and the bridge?

My last 1200 had done 18,000+ miles, the current 1200 has only 400mls, my daily ride includes 1/2 to 3/4 of a mile of off road, also the old bike as with the new one, was used for gentle green laneing (fitted with 020's), and apart from the odd quarter turn of a fixing, the only items to come loose have been the pannier fixing bolts.


Regards Shep

 

[Whele]

To glue or not to glue??

Surely an investigation to determine the reason these clamp bolts are becoming loose needs to be conducted, before owners all over the UK glue them in place.

1. Over time are the fork tubes compressing in the bottom clamps therefore causing the clamp bolt to become loose?
2. With age/use/vibration/stress is the alloy of the bottom fork brace effectively stretching and therefore causing the clamp bolts to become loose?
3. With age/use/vibration/stress are the bolts stretching (are they high tensile?) therefore reducing the tightness of the bolt?
4. Is the clamp bolt vibrating loose during use?

Only in the case of 4 will Loctite help, in cases 1,2,and 3 it will just compound the problem by making the clamp bolt appear to be tight and possibly at the correct torque when in fact the clamp itself maybe loose. It’s also worth noting that marking the bolt (with paint as an indicator of it loosening) will only be effective against scenario 4 also.

Do Harris do a triple clamp for these bikes?

 

[Pukmeister]

Very good points there Whele, and duly noted. I had already wondered myself about those points you mention.

I consider that Loctite is the best short-term solution I can personally use until anything better can be found. I hope that BWM do some research on this matter and issue a product recall in due course to reassure all us (and future) owners of their products.

In the meantime I will still check the bolts periodically and retorque/ reapply threadlock as and when necessary if I suspect things are not as they should be. Like anything, prevention is better than cure, especially when we are talking about having an accident at speed.

 

[jp-speed-triple]

afternoon.

Can someone please enlighten me as to what the correct torque setting is so I can run out and check mine?

I searched and found this thread as it would appear my top yoke (for want of a better term) is loose on the bike and wondered what the fix was. There appears to be play in the bearing as the centre bolt is still tight.

Now having read this I want to also check the clamp bolts lower bracket.

thanks in advance.

JP

 

[Andy B]

THIS might be useful.

 

[SpudBoy]

It was - thanks for posting the link.

 

[john1215]

Hi,

I bought a GSA in November 2010 from Allan Jefferies and everything seemed okay. I put a tank bag on it after the first week and the bag stayed on until I noticed that the front tyre wasn't keeping its pressure. At the beginning of December I had the tyre checked by Rainbow at Rotherham who found that the front tyre was defective and that air was escaping from the area around the tyre bead. The tyre was replaced under warranty. The tank bag was still on my bike when I brought it out of the repairing dealer and I discovered that a buckle on the bag was broken. I removed the bag and was riding along scrubbing the front tyre in when I lookwed down to find the top yoke appeared out of alignment with the rest of the bike. If I rode with the bars/yoke in line with the rest of the bike I would have ridden into the left hand kerb. The alignment was perfect when I picked the bike up in November but now the alignment is not right. Would this have been caused by the wheel being removed to repair the tyre or is it likely that this has happened over the course of the first 1000 miles and I've not noticed it due to having the tank bag on (which hides the top yoke incidentally). I'm not trying to blame either Allan Jefferies or Rainbow for this but wondered how this might have occured and is it something I should get done asap before riding much further.

Thanks

John

 

[Wapping]

If I rode with the bars/yoke in line with the rest of the bike I would have ridden into the left hand kerb.

is it something I should get done asap before riding much further.

Nah.

You know you will run into the nearside curb, so it will come as no surprise. Leave it.

Or, apply regular right hand push counter steer and all will be well.



PS Quite what do you think the answer to your question might be? Or, are you looking for confirmation that your bike is normal? If the latter, approach dealer for reconfirmation.

PPS Not many bikes hit the nearside curb as a matter of course, other than through rider error. If you think it normal, be happy.

 

[john1215]

Nah.

You know you will run into the nearside curb, so it will come as no surprise. Leave it.

Or, apply regular right hand push counter steer and all will be well.



PS Quite what do you think the answer to your question might be? Or, are you looking for confirmation that your bike is normal? If the latter, approach dealer for reconfirmation.

PPS Not many bikes hit the nearside curb as a matter of course, other than through rider error. If you think it normal, be happy.

Wapping,

Not everyone has a fountain of mechanical knowledge at their fingertips and I certainly don't. I came into biking only 3 years ago and have very little such knowledge to draw on which is why I put posts such as these on this forum as I know that (most of the time) I will get an informed and constructive reply. On the other hand I was contributing to a forum post, others may have had similar problems but because of clever dicks like you they may be reluctant to make any posts. Thanks anyway for your reply and no I don't think my bike is normal as you put it but I'm well aware that there could be any number of reasons why this sort of misalignment could happen and I wanted to be as informed as possible before I approached the dealer.

john1215

 

[ghiribizzo]

John, I'm struggling to figure out how you are so absolutely sure that the bar/yoke was perfectly aligned with the rest of the bike in November.
I take it when you write that they are not now, you mean that in a situation where the bars are apparently in a 'riding straight ahead' position - the wheel points left?
Does the bike track straight if you release the bars?
But I take it that you feel that when you're going in a straight line, the bars are apparently pointing 'right'?

Basically if they are that bad - go straight to the dealer and point it out to them. You bought it recently and they had the wheel out.
Not as if your mate did it.

I'm presuming here that it's a simple misalignment and not that they dropped the bike whilst in their care and are doing a big bit of?

But they should sort it without issue.