Bar trembling 60-70Km/Hr.....R1200GS (09)

Dr.KC

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I would like to have your opinion on the following issue.

When riding my R1200GS (09) with one hand or no hands I feel (and see also) a very slight trembling of the bar around 60-65Km/H not while acceleration but only when leaving the throttle and rpms go down on their own.

Actually I don’t know if the term “trembling” is the correct one. It feels like a very fine oscillation that becomes obvious first on the mirror and after on the bar ends. Imagine that it does not affect the stability of the bike or the braking ability and you cannot say even that is annoying…..but….its something that I want to solve….or learn to live with

I feel nothing on speeds less that 55Km/H and nothing also from 70Km/H up to 170Km/H.

A very close friend of mine owns a motorbike tyre shop and we spend the whole afternoon on last Friday (shop closed) to check out almost everything. My friend performed both static and dynamic balancing on both spoked alloys, he checked all the spokes, the spoke mounting centres, frond shaft, and both bearings and found no problems at all….actually there was no need of any extra weight addition on the wheels since tires was changed from the previous owner 450Km before and balancing was found just perfect. Also the neck bearings found OK with no play at all.

He said to me to live with it or get read of the 46 Givi Top Case I mounted on the GS (I did that because the original BMW case is very small and my helmet does not feet in their). He said also that this is very common to most on-off bikes due to the change of their geometry, and that he heard in the past some other GS owners complaining about the same issue.

I have not checked yet the behaviour of the bike without the top case (actually I ride the bike almost 1 week)……so I will give it a try.

Your opinion or experience will be highly appreciated people!!!
:comfort
 
Top cases can sometimes cause the type of weave you describe but also tyre pressures, suspension settings and actually the type of tyres as well.

Check them all.
 
I would put money on it being the top box. I had this exact same problem on a previous (non-BMW) bike. At motorway speeds the top box acts like a sail, loading the rear of the bike and causing the suspension to go light at the front which is where the weaving comes from. I cannot explain why it only occurs in a specific speed range but that was my experience as well - probably something to do with harmonics around that particular speed and some suspension components.

The easiest way to know for sure would be to take the top box off and go for a ride, see if the problem has gone away.
 
If you take your hands off the bars at the speeds you describe most bikes bars will start to oscillate..... There's a reason for it, but I can't remember.

I wouldn't worry about it.

:rob
 
I would like to thank you all for your reply.

Today I placed 30Km without the top case…..the light oscillation reduced to 90% (I don’t say 100% because some very little…really little oscillation was just their because I did not have time to uninstall the Givi universal mount and the extra BMW case support…both weight 4Kgr).

So it seems that it was all about the case size and position on the GS.

To be honest, the case seats on the very end of the bike, something like 1.5m from the CoG of the bike…so I guess the solution is to change the suspension setting or just live with it.

I shall keep you all informed upon any progress.

Thanks once again for your replies.
 
I would like to thank you all for your reply.

Today I placed 30Km without the top case…..the light oscillation reduced to 90% (I don’t say 100% because some very little…really little oscillation was just their because I did not have time to uninstall the Givi universal mount and the extra BMW case support…both weight 4Kgr).

So it seems that it was all about the case size and position on the GS.

Update.....trembling was there again...no matter if the GIVI was there or not...so I had to do something.

I asked a friend of mine owning a tyre shop to change for a test my EXP Tourance tyres with any used he had from customers leaving back their old tyres. We managed to find a set with 14.000Km in very good condition and we installed them to see if the trembling issue was still there....

Test report:

My front tyre had the problem from the very beginning.....but never thought to perform the test any earlier.....:blast The used set saw no evidence of trembling at any speed range no matter if the GIVI was installed or not.

So, I kept my rear tyre and I my friend provided me for free the used one for the next 1500Km until I replace them with Dunlop Trailmax TR91.

http://www.dunlop.eu/dunlop_euen/mc/tyres/on_off_road/Trailmax_TR91.jsp

:beerjug:
 
I have Metzeler tourance EXP tyres on my 2010 1200gs, and i think that when the tyre is new, the block tread does tend to give a small amount of feedback to the bars. However i have now done about 1500 miles on them and they have settled down now.It may be worth putting them back on and putting some miles on them
 
It may be worth putting them back on and putting some miles on them

I am sorry :Dfor not mentioning that, but I have placed on my EXP set, almost 11.000Km. Initially the trembling was around 60km/h and the last 4.000km moved between 60-85Km/h.

It is not a general issue of all EXPs, it just happened on my set. Overall, the EXP performance is very good on both wet or dry tarmac. I shall move to the Trailmax because I ride 90% on and 10% off road. :Motomartin

Anyway, in Greece the tarmac is of very pure quality so I shall change them on the next 1500Km no matter what.
 
I just replaced a set of very worn Tourances with Conti Trail Attack and the bar shake has gone.

:beerjug:
 


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