Z3M shaking at 70 mph

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bertiejaffa
Joined: Fri 26 Jul, 2013 09:28
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  M roadster S50
Location: Manchester

Z3M shaking at 70 mph

Post by bertiejaffa »

Hi All, I am hoping that this is something simple like a wheel balance has come off or something but just in case I thought I better canvass the opinion of the professionals.

As some of you know, my M has just had quite a bit of work done including a new clutch, inspection2 service and all the brakes fully striped down and refurbished. Today I have driven around 200 miles, mainly on motorways and the car feels fine apart from as soon as I get to 70mph or above when the car shakes quite badly... the minute I get back down to below 70 the shake is gone.

With the brakes having just been done Im pretty sure its not a sticky caliper - none of the wheels were overly warm and the steering wheel doesnt shake from side to side it is literally just like the whole car is shaking. The best way to describe it is like putting your hand on the washer when it is on the spin cycle...

The shaking happens in any gear when 70 mph is reached, so I am sure its not an issue with 5th gear, and when my M is doing 70 in 5th the revs are usually around 3,500. I have taken it up to 4-5,000 is all the other gears and it doesn't shake so I am ruling out the new clutch and gearbox work....

I am planning on taking it to a tyre place to have the wheels balanced in the morning... but in the meantime if you have any thoughts? Bushes? Tyres? (although no tramlining or anything like that).

EDIT** I have just spoken to my mechanic about something else and while he was on I have mentioned the problem and he reckons the bushes looked fine when he was giving it the service so I am hoping it has just lost a balancing weight
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Joycey
Joined: Mon 11 Jul, 2011 22:15
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  M roadster S52
Location: Basingstoke

Re: Z3M shaking at 70 mph

Post by Joycey »

Alright Bertie,

Twice I have had a similar problem on my M,

1) The prop shaft bearing/housing past its due date causing it to spin off centre

2) Running non M wheels, missing spigot ring.

Hopefully its nothing too serious just food for thought.

Lee
peter2b
Joined: Sat 01 Nov, 2014 18:47
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Re: Z3M shaking at 70 mph

Post by peter2b »

its Mr plod after you if you are going over 70
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bertiejaffa
Joined: Fri 26 Jul, 2013 09:28
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  M roadster S50
Location: Manchester

Re: Z3M shaking at 70 mph

Post by bertiejaffa »

Joycey wrote:Alright Bertie,

Twice I have had a similar problem on my M,

1) The prop shaft bearing/housing past its due date causing it to spin off centre

2) Running non M wheels, missing spigot ring.

Hopefully its nothing too serious just food for thought.

Lee
Cheers pal - the wheels are non standard but they are the same wheels that I have had on the car since I got it 15 months ago so I am hopeful that its not a missing spigot ring - the prop shaft bearing issue sounds more drastic?
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bertiejaffa
Joined: Fri 26 Jul, 2013 09:28
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

peter2b wrote:its Mr plod after you if you are going over 70
peter2b
hopefully he does notice that it was 71 mph :lol:
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Del
Joined: Sat 19 Nov, 2011 18:35
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Re: Z3M shaking at 70 mph

Post by Del »

I've only ever experienced this in respect of either a sticking brake calliper or wheel out of balance - and as you say the wheel will get very hot with the former :)
bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

Del wrote:I've only ever experienced this in respect of either a sticking brake calliper or wheel out of balance - and as you say the wheel will get very hot with the former :)
cheers del - hears hoping! the one thing I forgot to do is take it up to speed and then let it freewheel to see if the issue is there, if it is then it is definitely the wheels (or that area) and would rule out the drivetrain etc....
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andy18n
Joined: Tue 05 Feb, 2013 20:56
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Re: Z3M shaking at 70 mph

Post by andy18n »

Sounds like rear wheel balance to me....good luck
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pingu
Joined: Fri 30 Apr, 2004 16:01
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Re: Z3M shaking at 70 mph

Post by pingu »

Does your mechanic know to pre-stress the propshaft centre bearing?

Did the propshaft go back in the same position?

Is the balance weight still on the propshaft?
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bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

pingu wrote:Does your mechanic know to pre-stress the propshaft centre bearing?

Did the propshaft go back in the same position?

Is the balance weight still on the propshaft?
I am assuming yes to all the above but would have to ask him directly - would any of these result in the issue - specifically at higher speeds? And is there any easy way I can check?
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Del
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Re: Z3M shaking at 70 mph

Post by Del »

They don't always clean the spot with solvent where they stick the little flat alloy wheel balancing weight and so they could just fall off. I was checking my daughter's little C1 recently and noticed that the tyre fitter had crimped new balancing weights to the outside of the front steel wheel rim which were so loose they were virtually spinning around the rim as the wheels went around :)
bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

Del wrote:They don't always clean the spot with solvent where they stick the little flat alloy wheel balancing weight and so they could just fall off. I was checking my daughter's little C1 recently and noticed that the tyre fitter had crimped new balancing weights to the outside of the front steel wheel rim which were so loose they were virtually spinning around the rim as the wheels went around :)
ok, the wheels have just been referred and the mechanic did say that the weights had been stuck on rather than crimped so this could be the problem... Im hoping so, it sounds easier than pingu suggestions :?
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pingu
Joined: Fri 30 Apr, 2004 16:01
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Re: Z3M shaking at 70 mph

Post by pingu »

bertiejaffa wrote:
pingu wrote:Does your mechanic know to pre-stress the propshaft centre bearing?

Did the propshaft go back in the same position?

Is the balance weight still on the propshaft?
I am assuming yes to all the above but would have to ask him directly - would any of these result in the issue - specifically at higher speeds? And is there any easy way I can check?
You can only ask him the questions. Everything is above the heat shield and the exhaust.
Pingu
bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

pingu wrote:
bertiejaffa wrote:
pingu wrote:Does your mechanic know to pre-stress the propshaft centre bearing?

Did the propshaft go back in the same position?

Is the balance weight still on the propshaft?
I am assuming yes to all the above but would have to ask him directly - would any of these result in the issue - specifically at higher speeds? And is there any easy way I can check?
You can only ask him the questions. Everything is above the heat shield and the exhaust.
Cheers Gary
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bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

hmmmm dropped the car off today and checked the back tyres... turns out they are week 49 2009.... I still suspect a lost weight but I am probably looking at new tyres - shame as these have the typical 5 mm of tread :head:
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petecossie
Joined: Wed 11 Apr, 2007 13:13
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Re: Z3M shaking at 70 mph

Post by petecossie »

bertiejaffa wrote:hmmmm dropped the car off today and checked the back tyres... turns out they are week 49 2009.... I still suspect a lost weight but I am probably looking at new tyres - shame as these have the typical 5 mm of tread :head:
Couldn't they just check the wheels first to see if out of balance. Cheaper than changing tyres straight away. If the tyre walls aren't showing signs of cracking/deterioration and there are no obvious defects keep them going a little bit longer. Their was a discussion recently on the Z3 M Coupe forum on this very subject, see link below. That might ease your mind on whether to straightaway replace or use for a bit longer.

http://www.z3mcoupe.com/forum/showthrea ... ight=tyres
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pingu
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Re: Z3M shaking at 70 mph

Post by pingu »

I should get out of bed earlier. Petecossie beat me to the same answer by three hours :D .

You may want to check the tyres for ovality. This will be obvious on the balancing machine, but an unscrupulous balancer will just sling loads of weights on to compensate.
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Southernboy
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Re: Z3M shaking at 70 mph

Post by Southernboy »

After some contemplation, it occurred to me that the shaking isn't anything to do with the car....... :lol: :lol: :lol:
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bertiejaffa
Joined: Fri 26 Jul, 2013 09:28
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Location: Manchester

Re: Z3M shaking at 70 mph

Post by bertiejaffa »

pingu wrote:I should get out of bed earlier. Petecossie beat me to the same answer by three hours :D .

You may want to check the tyres for ovality. This will be obvious on the balancing machine, but an unscrupulous balancer will just sling loads of weights on to compensate.
Ok so the upshot is that the rear wheels had thrown their balancing weights, the passenger front wheel was slighty out of track and the rear wheels and tyres are not perfectly round. I have had the tracking sorted and the weights replaced - I did a very quick test at lunchtime and it feels better and I will be doing a trip down the motorway tomorrow so will be able to judge the results more.

@petecossie: Thanks for the link, aside from the slight misshaping, the tyres themselves are in good condition so depending on the testing tomorrow I will probably keep them for now and maybe keep my eye out for some replacement wheels later in the year.

**EDIT** the wheels on my 2.0l are fine so I am considering putting them on just to see how it runs on those just to confirm that a change of wheels/tyres will resolve the issue
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bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

Ok so I took the car out tonight and the judder is all but gone so it looks like it was the thrown weights more than anything else. The only judder that remains is the very slight one that has always been there since I have owned the car and having now spoken to the garage I can only assume this is due to the slightly misshapen wheels. I can live with it for now but will take them to a local wheel specialist over the summer and get them looked at and a quote for making the perfectly round again. Thanks for all your input guys... amazing just how much judder there was just through a couple of lost weights.
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beerbelly
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Re: Z3M shaking at 70 mph

Post by beerbelly »

are the wheels a snug fit on the hubs ? they need to fit exactly even a tiny amount of movement between hub and wheel with no bolts in can cause this .we bought a set of aftermarket alloys for our z3 and they had a 73.2 centre bore felt as though they were a good fit but had the Hattie Jacques at about 70 mph we rang the company who we bought the wheels of and they sent us a set of spigot rings that were fag paper thickness fitted them and it totally cured the problem.
peter2b
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Re: Z3M shaking at 70 mph

Post by peter2b »

Some times the tyre can go egg shaped ifyou jack up the car and spin the wheel you can see if it is round, had that on a mini years ago took ages to find out what was wrong(i was a boy racer use to spin the tyres)
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Southernboy
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Re: Z3M shaking at 70 mph

Post by Southernboy »

Hi Lee
If your rims are "oval" you best get them sorted sooner vs later... it'll only mess up good tyres if you don't.
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Del
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Re: Z3M shaking at 70 mph

Post by Del »

ABS/wheel speed sensors are so sensitive these days - I would have guessed that they would have caused a warning light to light-up if there was any significant tyre mis-shape.
bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

beerbelly wrote:are the wheels a snug fit on the hubs ? they need to fit exactly even a tiny amount of movement between hub and wheel with no bolts in can cause this .we bought a set of aftermarket alloys for our z3 and they had a 73.2 centre bore felt as though they were a good fit but had the Hattie Jacques at about 70 mph we rang the company who we bought the wheels of and they sent us a set of spigot rings that were fag paper thickness fitted them and it totally cured the problem.
hmm good suggestion, the wheels are aftermarket (they came with the car) and I did get some spacers for them after after a while to fill the wings out. The spacers are the ones that bolt to the hub and then the wheel bolts to the spacers so they should be very firm, however I am not sure that they are the full width of the inner wheel - I dont have any spigot rings so I might invest in some.

Just for clarity though, I am not sure that any wheel I have ever had on any car has always been a snug fit over the hub - primarily I am thinking about when I have to change the tyre etc and I am putting the wheel back on - I feel like I have always had to juggle the "up and down" as well as the "round" to get the bolts to line up with the hole. Or have I just never noticed?
peter2b wrote:Some times the tyre can go egg shaped ifyou jack up the car and spin the wheel you can see if it is round, had that on a mini years ago took ages to find out what was wrong(i was a boy racer use to spin the tyres)
peter2b
Good point, I will jack it up slightly this weekend and spin the wheels and see if it hits the floor at any point in the revolution
Southernboy wrote:Hi Lee If your rims are "oval" you best get them sorted sooner vs later... it'll only mess up good tyres if you don't.
Yeah you're right, however I seems to be hemorrhaging money on cars at the moment :bawl:
Del wrote:ABS/wheel speed sensors are so sensitive these days - I would have guessed that they would have caused a warning light to light-up if there was any significant tyre mis-shape.
Hi Del, good point, there has never been any ABS lights on the M since I've had it. Guessing any mis-shape isnt bad enough? The garage did say it was only minimal
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bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

Ok so today's update...

1) Jacked all 4 wheels up slightly and inserted a 2' piece of cardboard under the wheels until the cardboard and wheels just audibly touched and then spun them. The fronts never stopped "touching" through a full revolution but both rears "grabbed the cardboard. However. they only grabbed it slightly... there was still some cardboard under the wheels through the rotations so the grabbing was only sufficient to slightly move the cardboard at the wheels most "oval" point / the cardboard highest point. On the basis of this I assume that the fronts are ok and the rears are only minimally out of shape.

2) I measured the car-side hub centres. All 4 centres are 72.5mm wide, including the spacers that are on the rear wheels.

3) I measured the inner diameter of the wheels. Rears are 74mm and the fronts are 73mm. I find it difficult to believe that such small margins might be contributing to a slightly uneven ride at high speeds but then again when you consider the forces involved etc maybe it does?

So, I am going to order some spigot rings tomorrow and some new bolts (all mine are looking tired and one of my locking ones has been replaced with a non locking 18mm head one :?: :head: )
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bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

beerbelly wrote:are the wheels a snug fit on the hubs ? they need to fit exactly even a tiny amount of movement between hub and wheel with no bolts in can cause this .we bought a set of aftermarket alloys for our z3 and they had a 73.2 centre bore felt as though they were a good fit but had the Hattie Jacques at about 70 mph we rang the company who we bought the wheels of and they sent us a set of spigot rings that were fag paper thickness fitted them and it totally cured the problem.
Ordered some spigot rings... can I just ask for some advise?

The rears are a standard size (72.5 hub / 74.1 wheel) however the fronts are slightly smaller (72.5 hub, 73.1 wheel). Everywhere I look they don't do rings this size, however I can get a ring that is 73.1 to 74.1. My thoughts are to get the rings and then cut a 1mm slither out of the circumference so that they fit the wheel snugly and have a 0.5mm gap around the hub.

Assuming I can force them on despite the additional 0.5mm thickness will this work?
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Captain
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Re: Z3M shaking at 70 mph

Post by Captain »

I'm sure those will work, which did you get the metal or plastic rings. Once the wheel is bolted up it tends to squash the rings slightly giving a nice tight fit on the hub, that's what I found when using spigot rings a while back.
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bertiejaffa
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Re: Z3M shaking at 70 mph

Post by bertiejaffa »

Captain wrote:I'm sure those will work, which did you get the metal or plastic rings. Once the wheel is bolted up it tends to squash the rings slightly giving a nice tight fit on the hub, that's what I found when using spigot rings a while back.
Cheers captain, I have got the plastic ones - they were much cheaper than the metal ones. I will update when I have them on the car.

B
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