My bike is channelling my forum name!

ShakeyGS

ShakeyGS

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Last night, I noticed that if I relaxed my grip on the bars totally, the bars shimmy. Not enough to get into a tank slipper or such like but it’s something I haven’t noticed before.

The shimmy frequency seems to be related to road speed and disappears above 50.

Front tyre is correctly inflated top 36, is about 2 week’s old on the bike and was manufactured late last year. I can see where the front tread pattern of the Tourance next might cause a shimmy but itbwould have to be a harmonic or fraction of the apparentbtyrevtread frequency.

I refitted the wheel myself so this morning I’ll go and recheck all the bolts etc.

Anything else I should check? Anyone else get this?

With normal grip on the controls I can’t feel a thing.
 
Get the front wheel rebalanced before you go any further

I've had the same on my Conti Trail Attacks. As they wear they can start a shimmy through the bars. Most noticeable at slower speeds
 
Can't say I have noticed anything like this on my 2018 GS Rallye TE. I have Tourance nexts too.

What are your suspension/ride mode settings? Luggage or not?
 
Top box most of the time, Road mode.

I did try cycling through Normal, Soft, Hard rebound but it made no difference.
 
1st question, is there any evidence that the wheel was balanced (weights?)
2nd question, is the tyre seated equally all round the rim?, jack the front up and spin it, any out of true will be noticeable.

You can then deduce your next course of action:-
either balance, reseat and balance, look further afield
 
It's a boxer. The engine drive being in line with the wheels makes such shimmies more likely and especially when riding over longitudinal road features. Check the balance, avoid heavy weights in the top box and enjoy the bike.
 
And if all else fails, make sure the tyre does not have a sidewall defect, I had this before on a Harley they changed the tyre and all good.
 
ShakeyBMW said:
That’s with the wheel on the bike?

I’ll look to see if I’ve thrown a wheel weight.
Click to expand...

With the wheel rotating - it shouldn't make a difference if it is on the bike or not.

You said you had a tyre fitted 2 weeks ago - did they balance the wheel and tyre then? Static or dynamic?
 
Static. And it looks like it may have thrown a section of one of the weights so the wheel is now in the boot of my car and it’s off to my fitter we go.

I’ll report back..........
 
ShakeyBMW said:
Static. And it looks like it may have thrown a section of one of the weights so the wheel is now in the boot of my car and it’s off to my fitter we go.

I’ll report back..........
Click to expand...

Sometimes static isn't good enough. I had a 1cm bar oscillation until I got the fron dynamically balanced. Don't listen to anyone who says static is good enough
 
fredaroony said:
Sometimes static isn't good enough. I had a 1cm bar oscillation until I got the fron dynamically balanced. Don't listen to anyone who says static is good enough
Click to expand...
I can see how that might be true of the back wheel but there is no difference in rotating mass on the front wheel if it’s in the bike or out ? (Not questioning what you say; just trying to understand).

Anyhoo, the wheel was in balance but for the sake of thoroughness, he added a 5g weight in one spot. Test ride this afternoon.
 
fredaroony said:
Sometimes static isn't good enough. I had a 1cm bar oscillation until I got the fron dynamically balanced. Don't listen to anyone who says static is good enough
Click to expand...

This is correct. Whilst I balance my wheels static, the best way is dynamic as I learnt from the many years fitting tyres as part of my job.


Sent from my iPhone using Tapatalk
 
ShakeyBMW said:
I can see how that might be true of the back wheel but there is no difference in rotating mass on the front wheel if it’s in the bike or out ? (Not questioning what you say; just trying to understand).

Anyhoo, the wheel was in balance but for the sake of thoroughness, he added a 5g weight in one spot. Test ride this afternoon.
Click to expand...

Imagine sticking a 50g weight on the left side of the front rim and another 50g weight 180 degrees opposite on the right side of the rim. For static balance it would be perfect but, dynamically, it would shimmy madly!
 
Greg Masters said:
Imagine sticking a 50g weight on the left side of the front rim and another 50g weight 180 degrees opposite on the right side of the rim. For static balance it would be perfect but, dynamically, it would shimmy madly!
Click to expand...
That makes sense. The fitter used a typical powered rotating machine so I’m assuming that’s a dynamic balance.

I’m also assuming that a static balance is one done on a simple stand type device?
 
ShakeyBMW said:
That makes sense. The fitter used a typical powered rotating machine so I’m assuming that’s a dynamic balance.

I’m also assuming that a static balance is one done on a simple stand type device?
Click to expand...

Yes you are correct


Sent from my iPhone using Tapatalk
 
Tourance Next..there was only one tyre worse than the next.....Tourance EXP
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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