Front wheel vibration

[Slipperyeel]

Ok. This is a story I need to first layout the history. Then see what you think of my ideas...

A year and half ago I had a pair of CTA 3s fitted by ProTyre here in North London. I'll be coming back to this detail later.

About a week later I jumped onto the steed for it's regular outing down to Italy. Immediately on the M20 down to Eurotunnel I was aware (hard to miss!!!) vibration from the front at around the 130kmh mark - it faded away at 140+kmh, but crept back in, less pronounced, after around 155kmh.

So I did a return trip with this flippin vibration.
On returning to London I took the wheel to a bike shop near me. They added 10g at about the 9 o'clock position - a first for a weight to be added not opposite the valve... It mostly worked, but not completely.

Fast forward to this last week. I decided, while in Italy to replace the front tyre. Get rid of what I decided was a duff tyre from the start. CRA fitted this time.

Onto the auto strada to discover the vibration is back, much like it was originally . FFS.

The vibration is not continuous, it fades in and out at roughly 1.5Hz. it's not massive, but can clearly feel it in the bars and I can see the mirrors and dash vibrating on and off as it gently pulsates.

My thoughts:
Wheel bearings knackered? (They feel smooth)
Spokes loose? (Need to check them)


It's definitely associated with the front wheel as this change of tyre demonstrated.
Additionally, this story only appeared straight after that tyre change a year and a half ago.

The last point referd to Protyre who fitted the CTAs. In the days after fitting, I found two bent spokes on the rear wheel - I replaced them.
But did something else happen to the front wheel? But what could have?
I called ProTyre to complain about the bent spokes and was told that around the same time he did my tyres, there was a bust up, the fitter left the business and took all his tools (or walked off with tools belonging to the business!).

I'm really not sure what else would cause the vibration, that is clearly associated with the front wheel. Wondered about the gearbox and if a tooth was missing, but there is zero vibration in my feet or backside, which I would expect if that was responsible?

Any wild thoughts out there?

Bit of a story. Apologies!

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[botus]

simple steps

take the top box and luggage off the bike - go for a test ride - top boxes are renowned to give weird issues
if you have a silly screen - take it off go for a ride
remove the fender extender from the front mudguard - go for a ride
remove any other garbage in the wind-stream that's not standard - AKA accessory trash bags, gizmos, junk, nav screens, spot lights etc.

refit one by one and see if it comes back

if that's inconclusive - borrow a different wheel and tyre and try it

I wouldn't think much of the list could ever do it but then my KTM1290 became a death trap one day to the next all of a sudden - never found the cause - yet it had ONLY two changes on the bike, the fender extender and a vehicle electronics recall - which ever since the active suspension was utterly mad - the vibrations from that at 120mph where horrific, 2" back and forth insanity of the wheel spindle making you think the forks will literally snap off - I did get a slight change when the fender extender came off - but multiple dealer visits and 5 further software interventions and two new rear shocks never helped at all


Wheel vibration from imbalance comes in two speed ranges places
static - which is all they bother with on front wheels around 59 to 65mph - usually 62mph (heavy bit falls to the bottom)
dynamic - side to side wobble of wide tyres, this comes in around 82 to 85 mph (Dunlop tell me I'm an idiot for believing rear wheels definitely need this on modern bikes - insisting they don't even need this for moto GP)

outside these ranges balance is just not a good idea rather than noticeably problematic for the rider
new tyres have a yellow spot on the sidewall - this indicates the the bit that is supposed to be fitted beside the tyre valve

 

[glenn2926]

When I had my S10 I replaced the worn tyres with Tourance just as I had on my GS. It had a very pronounced head shake at around 160kph. The tyre fitter replaced the tyre for me but it was just the same. I then put Avon trail rider tyres on it and never had the problem again. Maybe some bikes just don’t suit some tyres.

 

[Santa-2512]

When I had my S10 I replaced the worn tyres with Tourance just as I had on my GS. It had a very pronounced head shake at around 160kph. The tyre fitter replaced the tyre for me but it was just the same. I then put Avon trail rider tyres on it and never had the problem again. Maybe some bikes just don’t suit some tyres.

On the Hexhead & TC i've had / got

Karoo 3 gotta love the NOISE!!!!

Trailriders, some noise, but stick like the proverbial, very good in the dry & wet

Tourance take some time to bed in, but just like the Trailriders

As glenn says, some bikes dont like certain tyres

 

[MWH]

Is the wheel true? Maybe worth checking.

 

[Bin Ridin]

Have you checked the torque on the fork clamp pinch bolts?

 

[theoneandonly]

have the wheel dynamically balanced , not statically , a good machine will have a "fine" button it shows exactly , to the last gram . i have cut weights in half to get 000 left and 000 right = perfection . if bearings have ANY faults , the machine will growl at you. it tells no lies. while it is spinning , any runout or ovallity is obvious.
i once had a ktm , go CHUNCK CHUNCK ( repeated per rev)

don't see how you would damage spokes on a machine .

 

[Slipperyeel]

Gents. Thanks for the feedback and ideas. We are all mostly on the same page.

Botus - thanks. Your thinking is logical and remains an option. But see below.

Santa/Glenn -yea, not all tyres work, but this is/was the 3rd set of CTAs, because they did work

MWH - is the wheel true? A question I still need to check, along with spoke tension...

Bin Ridin - I'm with you, but everything has been torqued carefully - being me, I loosened everything after fitting, checked rotation, the torqued it all myself...again

oneandonly - this could be the real answer - I mean if it's balanced as perfectly as able, then it's something else - if it's still there!

At the weekend I will check for run out and spoke tension. They are the last bits that I can check here at home. It's a little maddening, but thankfully it's only something that reveals itself once up to a constant motorway speed.

Will feedback!

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[Slipperyeel]

I've finally got back into this.

I put the wheel onto the balancer rig and in seconds it was clear the wheel is buckled (laterally). I think outside the specs tolerance too, though really I need to get the tyre off to check the amount for certain. Initial measurements are at around 2.8-3mm.

Contemplating sorting it myself - yes, know they are a challenge - or finding someone to true it for me.

Fairly convinced this is the cause of the vibration as it's not a gentle wave of a buckle, it swerves a fair bit at one area only. I think it explains why it only comes in at high speeds. Either way it needs sorting.

Radial run out appears ok. But again, tyre needs to come off to properly check and get some numbers.

If anyone has a current recommendation for someone that knows these wheels and can true them would be great. I've heard some names in the past of people who 'used to do them' or are no longer do them. So looking for up to date recommendations.

Thanks



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[botus]

cast or spoked

if spoked do you have a broken spoke ? when truing up a wheel often better to take stain off the other side than try winding on tension

 

[Pukmeister]

Rodin, good luck finding anybody willing to touch spoked BMW rims.

Tale of woe here:

BMW GS Wheel Building. - Stotfold Engineering Company Limited

At Stotfoldengineering a large part of our work comes in from other restorers who do not have the machinery or skills to do the job, this work includes aluminium welding , reboring, grinding, and wheel building, to name a few. We have always prided ourselves in having the machinery to do all...

www.stotfoldengineers.co.uk

 

[Slipperyeel]

cast or spoked

if spoked do you have a broken spoke ? when truing up a wheel often better to take stain off the other side than try winding on tension

It's spoked. None bent or broken. Maybe I hit a pot hole at some point but forgot, yet it did something

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[Slipperyeel]

Rodin, good luck finding anybody willing to touch spoked BMW rims.

Tale of woe here:

BMW GS Wheel Building. - Stotfold Engineering Company Limited

At Stotfoldengineering a large part of our work comes in from other restorers who do not have the machinery or skills to do the job, this work includes aluminium welding , reboring, grinding, and wheel building, to name a few. We have always prided ourselves in having the machinery to do all...

www.stotfoldengineers.co.uk

I fear you are probably right...

Needless to say, I've now filled my YouTube feed with spoked wheel videos . But, if I am to believe what I'm seeing, my wheel is well inside a recovery envelope, it's nowhere near as bad as some in seeing.

I'm going look at your link, but sitting down with a glass of wine, to soften the blow

ps. Just looked at the BMW fiche/shop. They £1200 per wheel . This is definitely going to be a repair job!

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[Slipperyeel]

Thanks for the read Puckmeister. Interesting amount of detail.

I have two options: find some fool to do it for me or get into it myself.

Unless the price is right, I think the latter is going to be where I go. I can print parts to fit into my balancer to help with alignment/centralisation (it's the front wheel, so central, no off-set)...I have the space too, so I can throw the tools across the room on the third, fourth or fith day

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[JohnnyBoxer]

Rodin, good luck finding anybody willing to touch spoked BMW rims.

Tale of woe here:

BMW GS Wheel Building. - Stotfold Engineering Company Limited

At Stotfoldengineering a large part of our work comes in from other restorers who do not have the machinery or skills to do the job, this work includes aluminium welding , reboring, grinding, and wheel building, to name a few. We have always prided ourselves in having the machinery to do all...

www.stotfoldengineers.co.uk

Cheaper to buy new wheels reading that sorry tale
I picked up a new silver 1150/1100 GS rear wheel at a dealer retirement clearance for £120 which in hindsight is a bargain
I use it to run a half worn tyre out locally, if I fit a new pair to go on a trip

 

[Pukmeister]

If it were mine, I think I would fabricate a jig or find a way to mount it between centres in a lathe, then clock its radial and axial runout with a DTI. As you say, luckily its central so no offset woes.

From the little I have read about BMW rims, making adjustments can really throw out the rims in both directions unexpectedly. I guess its a case of a little tweak of a spoke tensioner followed by a whack with a rubber/plastic hammer then clock the rim to see how much it has moved.

What about using softwood and a hammer to see if you can deflect the rim in the right direction without changing the spoke tension beforehand ? I've done this with my mountain bike rims before now with success.

How much runout are we talking here ??

 

[botus]

Maybe I hit a pot hole at some point but forgot,

are you suggesting you have found a road surface to ride on in the UK ?

I only have potholes and gravel - "not seen a road" for at least 25 years in the parts of the UK I drive on

 

[Pukmeister]

Reading your story again and trying to "join the dots", if the wobble issue started after the sacked Protyre fitter changed your tyre(s) I wonder if he got very heavy-handed with your wheel whilst the tyre was removed or somehow really hung off his bead breaker or tyre lever thus causing a localised deflection in your wheel rim ?

If this is the case, perhaps applying sufficient force/leverage in the opposite direction with the wheel held in a jig would tease it back into an acceptable runout ?

As for potholes, we've all seen the damage they can cause. I had to weld-repair an 1100GS gearbox years ago due to the rear frame mounting lug snapping in half as the rider hit a pothole in the dark on an Austrian road.

 

[Richie N]

I've finally got back into this.

I put the wheel onto the balancer rig and in seconds it was clear the wheel is buckled (laterally). I think outside the specs tolerance too, though really I need to get the tyre off to check the amount for certain. Initial measurements are at around 2.8-3mm.

Contemplating sorting it myself - yes, know they are a challenge - or finding someone to true it for me.

Fairly convinced this is the cause of the vibration as it's not a gentle wave of a buckle, it swerves a fair bit at one area only. I think it explains why it only comes in at high speeds. Either way it needs sorting.

Radial run out appears ok. But again, tyre needs to come off to properly check and get some numbers.

If anyone has a current recommendation for someone that knows these wheels and can true them would be great. I've heard some names in the past of people who 'used to do them' or are no longer do them. So looking for up to date recommendations.

Thanks



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Reading the thread that was going to be my suggestion. I had a similar issue on my old gsa. I bought a couple of alloys for the winter and never refitted the spokes.

 

[Pukmeister]

I believe the spec is 1mm of total runout at the rim.

If that figure I quoted is correct, having 2.8-3.0 mm must have it shaking like a shitting dog ??