tires not subject to road "giggles"

[georgesgiralt]

Hello !
My '82 R65 has a Metz Lasertec in front and a Metz ME77 rear.
When the tires where absolutely new, she was perfect.
Now, the front has around 2000 km and every time I pass a painting mark or a defect in the road, the bike makes a giggle.
When I was younger I was accustomed to this behavior. But since I rode a Triumph Legend and an Honda CBF600SA6, I am more concerned about this. Add to this that the roads in my town are getting worse and worse...
I've tried to inflate the tires more, check the steering, fork oil, rear shocks, but to no avail.
So could you tell me what tires I should get with a short answer : tire brand xx model yy is (not) subject to this... in order not to start another "what tires" thread...
I'm looking at Michelin, Bridgestone, Heidenau and Mitas. I would prefer to avoid Pirelli, Avon and Dunlop as I had bad experience in a previous life with these brands...  
Many thanks in advance !

[Bob_Roller]

I've had Metzeler ME33/ME99, now the Lazertec series on my "81 R65 since 1987 .

The only time I had problems, was when my pressure gauge went bad and I was under servicing the tires .

They exhibited the same road feel, rain grooves etc. would cause wandering problems, unsettling at the least !!!!!!

[nhmaf]

The Bridgestone BT45 that I have on my R65LS are not too bad at resisting rain groove/scarified pavement/bridge decking wiggles.   They were better when new, but as the wear down I think all tires become more susceptible.   Certainly, tires which have a tread pattern with many grooves and/or tread blocks that are in-line or parallele with the centerline of the tire will tend to squirm more and try to follow grooves in the roadway.   The older style "classic" tires from the 60s-80s were notorious for this, as are the "retro" or classic style new tires that mimic those themes.  

The Metlzers (ME33) which I had on before I switched to Bridgestones did have an urge to follow the raingrooves and bridge decking in my area quite strongly, though they were good tires in the rain.  

Tire pressure, as Bob R posts, is also very important.
I run my front tire pressure at 36PSI.  

[Barry]

Against immediate logic I found it was the worn rear tire that caused mine to wriggle. A new front tire did nothing but a new rear Pirelli City Demon fixed it and it's still fixed after 5000miles.

[georgesgiralt]

Humm,
I thought, like you, that the culprit could be my ME77.
but, it is not worn out, far from it. (at 90% new)
So I thought that the rear shock could be at fault. Alas, I live near the manufacturer (Fournales) and they checked them to find them perfect !
So I'm puzzled...

[Matt Chapter]

So I thought that the rear shock could be at fault. Alas, I live near the manufacturer (Fournales) and they checked them to find them perfect !
So I'm puzzled...

Time to move on to the next culprit then.. after market fairings / bags? are you carrying any loads?

Maybe if you'd keep the front tire on the ground more, your wife wouldn't move around so much?

Could also be low fork oil, steering bearing, loose rear wheel (ask me how I know!).

Does it seem to start in the front or rear?  If you stiffen your arms does it reduce the effect?

I guess I should add I'm running a lazertec right now, have run them before to the wear bars and find them to be pretty nice tires.  I do get a head shake at certain speeds due to my fairing.  Rarely happens when I have my hands on the bars though.

[georgesgiralt]

Well,
This bike has had a lot of work done since last may when i put her back into service.
First I removed the RT fairing to ease her up a little (she has around 170 000 km on the clock).
Then I renewed front brakes (new seals, new Goodridge lines, new pads) then I renewed the front fork and removed the fish which where in there... and put 5W oil in it. Then the steering bearing where dismantled and cleaned (grease was as hard as a rock) and put back into service with a new pack of grease. Seeing the status of grease on the steering, I opened the wheel bearings, cleaned them, greased them and checked play. I also did the same to the swing arm bearings...
So IMHO the set up if quite fine now. As per the  load, the bike has a set of Krauser panniers, one was quite loose, so I put rubber on it to make it fit snugly back again.
So I've checked all of what I can think of...
She always was tricky to ride on bad roads. Even running on the road's markings was adrenaline prone...
Now I think that the tires may cause this...  Don't know better...
Please do not tell me to dismantle her again... I spent too many hours in the garage already ! And I risk my wife ask for divorce  

[Bob_Roller]

The standard fork oil for airhead bikes, is 7.5 wt, I don't know if a 5 wt oil would make any real world difference or not .

Have you checked the accuracy of your  tire pressue gauge/indicator ?

Are the tires/wheels in balance ?

I had the front balance weights come off at about 80 mph, I thought I was going to loose control, due to the shaking .

[Barry]

I'm using Castrol synthetic 5W fork oil without problems but as we know unless oil is the same brand and product line then comparisons are something of a lottery to the point of 5W vs 7.5W being meaningless. At the operating temperature my 5W is thicker than Castrols own dino 10W which seems crazy.

[Barry]

I wouldn't dismantle anything again but you did ensure the swinging arm and steering bearings had some pre-load ?

I'm using Castrol synthetic 5W fork oil without problems but as we know unless oil is the same brand and product line then comparisons are something of a lottery to the point of 5W vs 7.5W being meaningless. At the operating temperature my 5W is thicker than Castrols own dino 10W which seems crazy but it's true.

[georgesgiralt]

Hello !
The wheels are in balance as the bike handle perfectly if the road does not have any flaw in the direction of the ride.
It is when riding on a mid lane marking or a ridge on the tar that I experience shaking...
I had 3 tire gauges. The one on the compressor, one gift built into a Michelin Bibendum (a key fob) and the original BMW stick in the tool box.
The Michelin has died due to moisture during a ride, and the other two quite agree.
The steering bearings and swing arm bearings have been checked. The steering when I renewed the grease which was hard and stiff like a brick  and the swing arm pivots have been checked when I replaced my clutch. Assembly was one by the book. So I expect the bearings to have the proper adjustment.
As I own a Honda which use 10 weight oil, I've some left. I will change the oil in the fork and see what this gives. I'll try to change one thing at a time and see where it goes... I agree about the difference from brand to brand.. Once I thought I had misplaced the cap because the 2 oils looked the same viscosity, one was a 20 and the other a 10 ...
BTW, this bike, when new, had a RT fairing. (it was an option to help sell them in France). When I decided to remove the fairing, a dealer told me to remove the two spacers above the springs in the fork.
It is unclear on the fiche if these spacers are fitted on stock bikes or only on fairing fitted one ? (they are steel, massive, about 1 inch thick, look like a washer on steroids ...)
So any advice would be appreciated !

[Bob_Roller]

If the OEM springs were replaced with a 'progressive' type aftermarket springs, the spacer is required, as the springs are shorter than the OEM springs .

[Barry]

If the springs were stock then they would have had a dab of paint on them which I think was brown. If they do turn out to be stock and spacers had been fitted to provide some additional pre-load to take the extra weight of the fairing I would take them out. The real test would be to measure static and rider sag to see if the forks are providing the correct ride height.

[georgesgiralt]

"to see if the forks are providing the correct ride height."
Which I do not know.
As far as I know the original dealer, nothing has been changed from the stock bike. He just added at extra cost the fairing and increased it's margin as far as he can by not providing/fitting accessories he had to fit...
(for example the stock bike was with crash bars, but they had to be changed/modified to cope with the fairing. so he removed them, without refund... And I was unable to get them, then ! all I was able to get was a pair of aftermarket crash bars which where ugly and cheap)

So, as far as I know, the springs are stock and 30 years old...

[steven m]

Most likely culprit is incorrect installation of wheel bearings, which my brother went through from previous owner with his R65.  Checked everything you have all discussed and issue persisted until he had the bearings reinstalled properly.  That is what is allowing the lateral movement that makes the bike feel like it wants to swap ends on a grooved road.  I have the same tires as he does on my R65 and experienced none of it while riding on the same roads, so forget about tire design problems, incorrect fork springs, etc.  If the steering head bearings and swing arm bearings are good, and the shocks are good, your wheels are balanced and not bent, your tires aren't damaged, what does that leave?  The wheel bearings.  Took my brother a long time to finally figure it out, and it came down to the rear wheel bearings allowing lateral movement- just a little, and not obvious when being checked while stationary.  Pull both wheels, check the factory manual, and repack and reinstall the bearings correctly.  Or have a good BMW shop do it, but make sure they have experience with our bikes as apparently it is an easy mistake.