What causes a speed wobble (high speed weave)

[MT account]

So, moral of this story is DONT FIT Bridgestone BT-023 to your MT09, unless you never go over 100mph!
I will be posting a new thread, to see what sport touring tyres work with the MT09[/QUOTE]
jeeze you had me worried there! has anyone ever rode @100mph in a pisspot, t shirt and speedos?
......its not recommended. ill stick to sub 150kph then.....

 

[marthy]

Get some Pirelli Angle GT! After a track day in the wet (rain right before the track evening started and the track never completely dried out) I put the bike to the test hitting the speed limiter every laps about 1/2 down the straightway and holding it until the end... rock solid!

 

[razz]

Thanks for the info Steve , this morning was my first change to try mine on a closed runway , no weave at all with the new adjusters fitted last week tyre pressures 36/36

 

[relz]

Teckie guy from Bridgestone rang me today.
He went into lots of technical detail about tyre force, resonance, harmony etc and lots of stuff I didnt get.
The long and short of it is the S20 is approved for use on the MT09, the BT023 and T30 havent been tested, or on their list of approved tyres for the MT09. He is aware of the fact certain tyres dont suit certain bikes, as appears to be the case with the BT023 and the MT09.
He suggested i try the T30's (at my own expense) and see if thats any better. I obviously replied I didnt fancy forking out £250 to be their geuini pig and testing their tyres for them, I would use a brand from another manufacturer.
So, moral of this story is DONT FIT Bridgestone BT-023 to your MT09, unless you never go over 100mph!
I will be posting a new thread, to see what sport touring tyres work with the MT09

Bloody Hell!
I just got me a new Brdigestone T30 front tire, yesterday, and I'm experiencing the same wobbles. Mine start at around 180kmh (tested on my private airstrip of course).
I tried that speed at three different times during my ride, and it's consistent. Above that speed it wobbles, below that it doesn't.

My previous worn out OEM Dunlop 214 tire, had no such problem. It was perfectly steady, unless driven fast in harsh conditions (e.g. bumpy road, with head on wind). It worked fine on the exact same route (on the same private airstrip).

I'm really pissed off.
I'm going to call the tire dealer to see what he has to say...

 

[relz]

T30 gives you the opportunity yo input your bikes details and will tell you (in this case) that the T30 is not for the MT-09

I don't really buy it, I see that as a website gimmick (though I may be wrong).
They probably group the motorcycles in large categories of sport/touring/off-road etc. and suggest each group their premium tyre of that category... In the past I never noticed any adverse handling difference between using a Sport tire, vs. a Sport-Touring tire other than increased wear or stickiness.

They also write just below that:

Disclaimer - These results are provided for guidance only. Please always seek the advice of your local Bridgestone Tyre Dealer before purchasing and fitting tyres. Tyres should ALWAYS be fitted by a trained professional. If you have any questions, please contact Bridgestone in Your Country or your local tyre specialist.

And I did install it at an official Bridges tone Tyre Dealer, who said they should be just fine. I'm going back to him, to have the tire fitting and balance re-checked. I hope it improves...

 

[stevecbr]

Let us know how you get on relz, but I think Bridgestone sport touring tyres dont work on the MT, even though you would expect them do.
In future I will do my own research as makfai suggests, as £220 is a lot to spend to turn your new bike into a high speed death trap

 

[MT account]

Let us know how you get on relz, but I think Bridgestone sport touring tyres dont work on the MT, even though you would expect them do.
In future I will do my own research as makfai suggests, as £220 is a lot to spend to turn your new bike into a high speed death trap

ill give you the definitive report on S20's later in the year when i thrash them round a few big hills in the north. i dont have problems with them at present but the dunlops scare the crap out of me over 100

 

[sporti]

I'm just going to leave this here...

Motorcycle Tires, Motorcycle Parts, Discount Motorcycle Tires, Motorcycle Gear, & Motorcycle Accessories

 

[relz]

ill give you the definitive report on S20's later in the year when i thrash them round a few big hills in the north. i dont have problems with them at present but the dunlops scare the crap out of me over 100

Strange, how these things are. My Dunlops were fine up to the limiter.

I went back to have my tire re-balanced, and there is an improvement. Now its almost always fine up to about 200 kph, only the odd wobble rarely.

I wonder if its possible that the new tire turns in easier/quicker than the previous one, which just emphasizes an underlying wobble that was always there?

 

[MT account]

Strange, how these things are. My Dunlops were fine up to the limiter.

I went back to have my tire re-balanced, and there is an improvement. Now its almost always fine up to about 200 kph, only the odd wobble rarely.

I wonder if its possible that the new tire turns in easier/quicker than the previous one, which just emphasizes an underlying wobble that was always there?

its mostly down to the lightness of the bike coupled with being sat upright like a giant sail.........and crap damping in the forks

 

[relz]

I realize that. But why one tyre and not the other?
Neither the bike weight not my riding position has changed.

 

[relz]

Let us know how you get on relz, but I think Bridgestone sport touring tyres dont work on the MT, even though you would expect them do.
In future I will do my own research as makfai suggests, as £220 is a lot to spend to turn your new bike into a high speed death trap

So....
I've had my bike looked at, steering bearings etc. No problems there.

I've had my front T30 tyre re-balanced twice more, once at the tyre dealer and once at my regular Yamaha garage... And the wobble still exists at high speeds.

So far the current assumption is that apparently, as stevecbr said earlier, the Bridgestone support touring tyres don't work well with the MT09. It's supposedly due to the tie rigidness vs. the bikes light weight.

What I find strange is that the Ron Haslam racing school use the T30 on their cbr600rr bikes, which according to spec are lighter than this bike. Also, one of the members in this forum mentioned that his MT09 in the UK came stock with the T30's (stumbled across the post when searching for Bridge stone related posts).

My Bridgestone tyre dealer has agreed to take back the slightly used (aprox. 1000km) T30 front tyre, and fit a new S20 instead charging me only the difference in cost, I.e. free fitting and balancing, yet again. I hope that the S20 will not suffer from the same problem. I also hope that the hypersport tyre won't wear down too quickly compared to the Sport Touring mileage I was aiming at.

The only other thing I can think of is the fact that I'm running a PR3 on my rear, and perhaps the Michelin and Bridgestone don't play together nicely... as opposed to the Michelin and Dunlop which did. If this is the case I'm better off changing the rear to a T30 too, which might solve the whole problem.
Its a bit of a gamble choosing which route to take, since no one is guaranteeing success either way [emoji20]

 

[stevecbr]

If you want to stick with Bridgestone the only tyre gauranteed to work is the S20's as a set. They work well but only last 3000 miles.
Why not run a PR3 on the front, these tyres are recommended, work well and last for ages? This way at least you will have a matching set
UK bikes either come with Dunlops or Bridgestone S20's as standard, NOT the T30's

 

[relz]

Found the poster with the OEM T30's

My MT 09 (UK) spec has T30's fitter as OEM. They are fantastic I had 020's then 021's on my old FJR 1300 but these are the brilliant. I ride on shit eastern european roads for those members who have ridden / raced round Donnington park before it eventually got resurfaced. the tarmac is the same as that, rounded off polished stones in the rock hard tarmac but the T30 grip and grip. I did try pilots on one of my other bikes, but had to bin them as they were terrible I guess they would last for years and years. Other riders resort to putting qualifiers on yep qualifiers for road riding !!! so T30's recommend them

If the tyre shop I went to had PR3 in stock, it all would have been simpler, but there were reasons I decided to go with Bridgestone this time . You can read about it in the OP of the link above.

 

[ShaunSuperBike]

Had new tyres fitted tuesday, BT023's to my MT09.
Rode fine tuesday, did about 70 miles scrubbing in tyres, didnt go that quick.
Took it out wednesday, rode about 50 miles, but couldnt get much over 100 as bike started to weave.
It was very windy, so not sure if that could be the cause on a naked bike.
Wasnt able to tell today, due to pouring with rain.
Just wondered if anyone experienced similar with naked bikes, or do I need take a trip back to tyre fitters
Nothing else changed on bike, tyres are correct pressures, everything looks tightened up, new balance weights were fitted and are still stuck on, bike is only 6 months old so not likely to be worn bearings.

Hi Steve it's Shaun here at SuperBike Magazine, thanks for the email the other day.
As I said in the reply I've not had a chance to use the T30 on the MT-09 yet but I've used them on the Ron Haslam school and they were superb. I also saw Jason O'Halloran and Ryuichi Kiyonari come past me going down Craner Curves like I was stood still, absolutely on the limit and both using the T30 shod 600RR, so the grip isn't in question. Whether they work on the MT-09 or not I can't say until I try them.

I've currently got a pair of Michelin Pilot Road 4's on the MT and they are absolutely superb, not a single fault with them at all. Grippy from cold, stable, great in the wet and lasting forever.
Can't recommend them enough

 

[Triple Trouble]

I've currently got a pair of Michelin Pilot Road 4's on the MT and they are absolutely superb, not a single fault with them at all. Grippy from cold, stable, great in the wet and lasting forever.
Can't recommend them enough

Hi Shaun. I'm on my 2nd PR4 rear at the moment. The first lasted just over 4000 miles. It started to square off a tad but had loads of tread left. I completely agree with ur above quote.....excellent tyre IMO

 

[Yamahayzr500]

Mines the same except at over 110 - 120 I have to shut off sometimes I thought it might be the yamaha top box or uneven road ???

 

[relz]

So....
I've had my bike looked at, steering bearings etc. No problems there.

I've had my front T30 tyre re-balanced twice more, once at the tyre dealer and once at my regular Yamaha garage... And the wobble still exists at high speeds.

So far the current assumption is that apparently, as stevecbr said earlier, the Bridgestone support touring tyres don't work well with the MT09. It's supposedly due to the tie rigidness vs. the bikes light weight.

What I find strange is that the Ron Haslam racing school use the T30 on their cbr600rr bikes, which according to spec are lighter than this bike. Also, one of the members in this forum mentioned that his MT09 in the UK came stock with the T30's (stumbled across the post when searching for Bridge stone related posts).

My Bridgestone tyre dealer has agreed to take back the slightly used (aprox. 1000km) T30 front tyre, and fit a new S20 instead charging me only the difference in cost, I.e. free fitting and balancing, yet again. I hope that the S20 will not suffer from the same problem. I also hope that the hypersport tyre won't wear down too quickly compared to the Sport Touring mileage I was aiming at.

The only other thing I can think of is the fact that I'm running a PR3 on my rear, and perhaps the Michelin and Bridgestone don't play together nicely... as opposed to the Michelin and Dunlop which did. If this is the case I'm better off changing the rear to a T30 too, which might solve the whole problem.
Its a bit of a gamble choosing which route to take, since no one is guaranteeing success either way [emoji20]

So.... the saga continues.
Today I went in to the tyre dealer and swapped my slightly used (~1000km) T30 to a brand new Michelin Pilot Road 4 (which he just got in stock the other day). This way I'm using a tyre which is known to work well on this bike, and I'm using the same brand as my rear tyre.

That should solve all my issues, right?
Wrong!

I'm now running the PR3 on the rear and the PR4 on the front. Both are pretty new and in great condition, the front was also Dynamically Balanced upon installation. Air pressure set to manufacturers recommendation 42/36.
I still have the bl**dy high speed wobbles.

I'm certain I didn't have the wobbles, prior to changing my front tyre to the T30 a few weeks ago.

What else can I do?
Balance the rear tyre?
Experiment with tyre pressures?

Any other ideas, other than instructing my mechanic to tear apart the bike looking for all possible causes?

 

[marthy]

Throw your owner manual in the trash and drop those presssure to 30/30 before you hurt yourself. Those are the pressure I would use on a 500 lbs bike riding 2 up... and still.

 

[Triple Trouble]

Throw your owner manual in the trash and drop those presssure to 30/30 before you hurt yourself. Those are the pressure I would use on a 500 lbs bike riding 2 up... and still.

Out of pure interest marthy, why so low?