Gentle wobbble at 90Mph

  • Thread starter Thread starter cmyers_uk
  • Start date Start date
A heavy topbox has induced weaves on my GSs. I now tour with a virtually empty topbox as a result. You could mount your topbox in the pillion position as I've done in the past.

Aftermarket screens can also be a problem.
 
Have you actually CHECKED the tyre pressures with a guage?? The TPS thingies could be wrong :nenau

Also, if it only does it at 90, and not 85 or 95, then don't ride at 90 :nenau :nenau

Never had a problem with my 1200, with luggage or without luggage, Pillion or not.

But then, I am anal about tyre pressures.
 
You can't get bt21's in the right size for the front so my BMW main dealer recommended the combo, this was also brigestones recommendation and see link below it won a mag award. I do take your point about mixing types and brands but in this instance it was well researched and a recommended combo. A search of this site only gave good results .

September 2008 Bike Magazine R1200GS Tyre Test - road tyre test winner: Bridgestone Battlax BT020/BT021 combination.
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Point taken about not driving at 90 but what happened was I wanted to squirt passed a car doing say 88 as I got to 90 the weave started brain said Danger, Danger and closed the throttle.

Reading all the replys it seems it's a) common and most likely a combo of tyre pressures, weight in topbox and also I had

jacket open. I had set pressures the week
before to 2.2 and 2.5 as per manual but gave
the readings when it happened.

So for tommorrows journey , no top box, tyre pressures as mentioned here and I will report back

cheers
chris
 
i had the same in the past, asked here just as you have done and someone mentioned the top box... mine was full and heavily loaded. i reduced the weight in the top box and all was well.

also worth checking your pressures with a seperate guage and not what the on bike computer says.
 
Digger06 said:
i havnt got a 12 but isnt the comfort setting for lower speeds???
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Never heard that before, pretty sure it's not in the Handbook.

I've been 2 up with Pans & TB on Comfort setting at a 100+ many times, with no weave.
 
Quick Update :-

Many thanks to all who replied. I set the tyre pressures to 32 - 36 as per manual and removed the top box. I had the same load in side panniers.

This did the trick totally stable as fast as I wanted to ride. So next week its bring the top box back with just light i.e coats etc and see how that works.

It is amazing the difference the top box with weight in made.

Thanks again
Chris
 
cmyers_uk said:
Quick Update :-

Many thanks to all who replied. I set the tyre pressures to 32 - 36 as per manual and removed the top box. I had the same load in side panniers.

This did the trick totally stable as fast as I wanted to ride. So next week its bring the top box back with just light i.e coats etc and see how that works.

It is amazing the difference the top box with weight in made.

Thanks again
Chris
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Glad it's sorted :) However your tyre pressures are still too low; ignore the handbook and go with what Bridgestone reccomend which, as has already been stated, is 36/42.

You should then be able to ride with the top box (loaded) and still be stable.

Andres
 
Will up the pressures as you say apologise went with what I had documented. Many thanks chris
 
Chris, forget about using the top box above 90mph. It acts like a spoiler on the back of a car: the air pressure on the box generates an opposite force on the front wheel which begins to feel light and starts to wobble.

In my experience, with fully loaded panniers and the Tourances running at 2.3/2.6 F/R the bike is rock steady at 110mph. No top box... I wouldn't want to go much faster with the panniers for aerodynamic reasons.

Achim
 
Achim, Thanks for the explanation. I had never thought of it like that. To be honest 90 is my top cruising with a squirt between 90 - 100 as required to scoot past something . I must say without it, it was solid even on COMF which I still prefer for motorway work. I will sort the tyre pressures out tomorrow. Unfortunately I got caught by a camera today so maybe it wont be a requirement soon unless Im careful :-)

Thanks again.

Very interesting.
Chris
 
Used to happen with my 1150 when using a large Givi 52L top box 1 up. It's fine 2 up but I think it's just the aerodynamics the bike with a of the top box 1 up.
 
cmyers_uk said:
Thank you for the advice. I'll try top box and tyre pressures. Can anybody else confirm if comfort setting is only for low speeds. Thanks again for everybodies comments

thanks
chris
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You can use comfort at any speed it just smooths things out, I often use it on motorways then switch to normal / sport mode when taking slipways and roundabouts etc.

Obviously the faster you go on twisty / bumpy roads you might not want to use it so much
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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