2010 GS weave

[mikef]

I took delivery of a 2010 model GS about a month ago. Up until the running in service at about 600 miles, the bike felt solid at 80-90mph motorway speeds. After the service, I noticed that the bars were occasionally weaving slowly from side to side at the same kind of speeds, particularly in 'dirty' air behind large vehicles like trucks and coaches. I didn't have time to take it back to the dealer and I sort of hoped it would go away but 1000 miles later it hasn't. I've played with the ESA settings and tried going faster but it doesn't make any difference. It's not dangerous, just slightly disconcerting. Before the GS, I had 3 RTs in a row and those were really stable at any speed; I expected the GS to feel a bit lighter at the front but not this.
My GS has the Adventure screen/winglets and Trail Attack tyres but I don't think these factors are relevant. The fact is that the bike was fine before the service and exhibited this weave after the service so it seems to me that the cause is something that happened during the service. I have spoken to the dealer who of course denies that anything they did could have caused this although, to be fair, they have offered to look at the bike. So, my question to the forum is what could they have done to cause this, if anything?

 

[Slowdown]

IME, tyre pressure, amount carried and suspension settings all affect the amount I (used to) weave.

I run tyres at the tyre manufacturers(not BMW's) recommended pressures now - almost universally 36 F and 42 R.

I found the front shock was set way too high - dropping the front shock preload down made things better, but setting the suspension up as per Ohlins's recommended settings(on their website) worked wonders. The same for the rear - I found I needed more preload than BMW thought I would. But I have fully adjustable WP Shocks, as I couldn't get on with the OEM ones.


With the front shock 'set' I found changing rear preload was easy as I just make sure the dipped beam comes to the same point - then I know the bike's 'level'

 

[Kahuna]

I took delivery of a 2010 model GS about a month ago. Up until the running in service at about 600 miles, the bike felt solid at 80-90mph motorway speeds. After the service, I noticed that the bars were occasionally weaving slowly from side to side at the same kind of speeds, particularly in 'dirty' air behind large vehicles like trucks and coaches. I didn't have time to take it back to the dealer and I sort of hoped it would go away but 1000 miles later it hasn't. I've played with the ESA settings and tried going faster but it doesn't make any difference. It's not dangerous, just slightly disconcerting. Before the GS, I had 3 RTs in a row and those were really stable at any speed; I expected the GS to feel a bit lighter at the front but not this.
My GS has the Adventure screen/winglets and Trail Attack tyres but I don't think these factors are relevant. The fact is that the bike was fine before the service and exhibited this weave after the service so it seems to me that the cause is something that happened during the service. I have spoken to the dealer who of course denies that anything they did could have caused this although, to be fair, they have offered to look at the bike. So, my question to the forum is what could they have done to cause this, if anything?

MikeF

I have heard on this forum that the GSA has a more vague and less planted feel to the front end at higher speeds, and I guess that could be due to different ride heights and geometry but may also be because of the screen and winglets. Therefore it's possible its your GSA screen mod that's caused it. Only test is to put the original back on and take it for a run. My 08 GS has the winglets and no problems.

Other possibility is that they changed the tyre pressures to the book setting (I found they set mine to the level necessary for pillion + luggage when I took into a dealer in Spain), so perhaps a little fine tuning there might iron out your weave either!

Some times we're not so observant of the way the bike reacts during running in (is the book OK with 90 during running in??? LOL).

Best of luck with it. Be good to hear how this is finally resolved.

 

[Mr K]

Could the "dirty air" be hitting your shoulders or arms and causing you to input the weave into the handlbars?

Just asking.

 

[Nice 'n' Fat]

80-90mph ....................... you could always try slowing down

 

[MrC]

I have a similar weave behind big vans/trucks etc in this so called "dirty air". Are you fairly tall? As Mr K says, is it just your arms being blasted by turbulent wind doing this, because as soon as I move out of this turbulent air into say, the outside lane, it goes and all is good again. I'm fairly tall, and seem to take quite a lot of air onto the tops of my shoulders and arms.

When i've been blasting along above and below these speeds with "clean air" hitting the bike/me, i have never felt a wobble or weaving sensation.
My 2p worth...

 

[MorayGSer]

I have a similar weave behind big vans/trucks etc in this so called "dirty air". Are you fairly tall? As Mr K says, is it just your arms being blasted by turbulent wind doing this, because as soon as I move out of this turbulent air into say, the outside lane, it goes and all is good again. I'm fairly tall, and seem to take quite a lot of air onto the tops of my shoulders and arms.

When i've been blasting along above and below these speeds with "clean air" hitting the bike/me, i have never felt a wobble or weaving sensation.
My 2p worth...

Agree with MrC this type of weave is fairly common in dirty air. Is it only happening in this area ie behind Trucks/Vans? If so easiest way to test is to slowly increase distance between you and Large vehicle if weaving stops then dirty air is cause. However if it only happens in these circumstances then I thik its clear that dirty air is cause only an opinion mind.

 

[mikef]

Thanks for all replies. Sorry to be pedantic but I make the point again that the bike was fine before the service. In fact I rode it about 60 miles up the A1 to Balderston in Peterborough at 80-90mph speeds to get the service done and rode it back down the A1 2 hours later after the service at similar speed. Before the service, no weave, after the service, weave. No difference in screen, weight or riding style. Kahuna might have a point though. What I did notice (from the typre pressure monitor on the dashboard) was that Balderston had upped the pressures from the recommended 1 up setting of 2.2/2.5 bar to which I had set the tyres to a 2.4/2.9 bar setting. I will try reducing the pressures to see if it makes a difference but Balderston say that it wont.
Btw, 85-90 equates to about 5500rpm which is the max running in rpm. To Nice 'n Fat, if I wanted to ride slow, I'd buy a Harley

 

[Tuono1961]

Have you checked the steering head bearings. Pop it on the centre stand to check there's no binding. It might be part of the 1st service adjustments and they might have over done it

 

[Edventure]

Suffering exactly the same on an '10 GSA.

 

[mr badger]

Btw, 85-90 equates to about 5500rpm which is the max running in rpm. To Nice 'n Fat, if I wanted to ride slow, I'd buy a Harley

It is, but not for long periods. If you've done much at this speed/revs in the first 6k ten you've not done your new engine a favour.

Only things at service that could induce weave are tyre pressures or a shot rear bearing.

Otherwise, check out what others have said: tyre pressures, air conditions, luggage, your posture on the bike etc.

 

[elefantman]

dump the screen and have a quick blast you'll find the front feels a lot more planted

 

[Mav]

My 06 GSA is def not as stable in dirty air at high speeds - I always just assumed it is the turbulence hitting the handguards and mirrors...

 

[SilverFish]

My 06 GSA is def not as stable in dirty air at high speeds - I always just assumed it is the turbulence hitting the handguards and mirrors...

I agree, same thing on my 1150GS and 1200GSA - I just stayed away from the backs of lorries..?

 

[elevensies]

I took delivery of a 2010 model GS about a month ago. Up until the running in service at about 600 miles, the bike felt solid at 80-90mph motorway speeds.

i thought motorway speeds were 70mph in this country? you must have been abroad recently. germany perhaps?