20" wheel balancing problems - Page 2 - Porsche General - PistonHeads UK

Has anyone had any problems with balancing 20" Porsche wheels? Specifically 981/991? I did my first tyre change recently (from factory pitted Pirellis) and despite being an awful tyre the car was as smooth as silk. I had Goodyear Asymmetric 2 N rated fitted and the wheel wobble on the motorway as awful, the garage was apologetic, they re calibrated their machine and tried again but no luck. I tried another garage who were better but again the steering wheel was shaking annoyingly at 60mph. In the end I drove to the other side of the country to use a friends tyre balancing machine which he has in his garage at home. We examined each wheel and tyre for damage or runout etc., and everything seemed perfect. We calibrated his machine and re-balanced the wheels as accurately as we could, it's an improvement by 99% but the car isn't as smooth as it was. I can live with it but it got me wondering if anyone else has had a similar problem? The only thing I can think of is the tyres have a minor defect that the wheel balance machine isn't picking up? I could either try a newer more accurate wheel balancer or try road force balancing (they balance the tyre and wheel separately).

I'm really fussy about wheel inbalance myself. I think a front wheel slight inbalance tends to be more noticeable on rear wheel drive cars and it doesn't take much to notice this through the steering wheel. Assuming the balancing machine is correctly calibrated, it still requires the fitter to place the weights exactly in the correct position and also on the wider wheels to balance the wheel with weights (usually) placed on the inner and outer parts of the wheel.. I suspect you may have this in conjunction with a badly inbalanced tyre itself and the wheel balance process is not able to fully overcome the issue in the same way that you can't balance out a slightly buckled alloy. Personally I'd go to a Porsche specialist or even an OPC and get them to take the time to get them spot on, (obviously after explaining the issue with them). I've had wheels in the past that felt fine in warm weather and yet had a slight inbalance on really cold days, so it doesn't always appear to be an exact science. I'd also clean the inside of the wheel and remove and thicker carbon deposits etc and get the tyre pressure where you want it before you start the processs. Also try out a few different road surfaces because this can also have a bearing on steering feel.

My 2 cents... I have no idea how meticulous your tyre fitters are, and without wanting to do them a disservice without knowing what they have done I would just recommend you go to some fitters that have all the correct equipment, training and have good attention to detail. I use one of the Pirelli Performance centres that came in the top dozen of the annual performance audits. A quick google search will get you a list of them. The one closest to me that I am happy with is Micheldever in Hampshire. The #1 rated place is near Birmingham I think. If there is an out of specification defect with the tyre you should just be able to insist on a replacement.

As above, and/or try a specialist wheel alignment place, like Wheels In Motion in Chesham, Herts.

I have OCD about this stuff and have spent far too long over the years worrying about it... About ten years ago, I found a tyre shop that gets it right, and I make an eighty mile round trip to get all my tyres fitted there. I get through about half a dozen sets a year across three cars due to all the road mileage/ track days etc., so it was worth finding the right guys. In summary, I think I'd say: all tyres are not created equal, and there is a huge variation in the capability of tyre fitting equipment and the willingness/ ability of tyre shops to use it. I found this useful article which explains a lot of the background here: http://www.tirereview.com/when-is-it-overkill/

While I appreciate not all tyre garages are equal I doubt they will be able to better balance the wheels than what they are now, unless they have significantly superior equipment (and training). I am going to leave them how they are but it would be nice to know if other people have had similar experiences. It would not be the first time that I have bought a set of Goodyear Asymmetric tyres that have been defective/questionable build quality.

SkinnyPete said: While I appreciate not all tyre garages are equal I doubt they will be able to better balance the wheels than what they are now, unless they have significantly superior equipment (and training). Significantly better equipment is exactly where hunter road force balancing comes in.

Sorry of these sound like noddy questions but... At the start of subsequent balance sessions were the wheels checked to see if they were out of balance or were the weights just stripped off and a fresh start was made? And I'm guessing/hoping that when the last weight was put on the wheels were checked once more and it was confirmed that the last weight put in place resulted in a fully balance wheel? Does the problem get worse over time? And unlikely if the tyres haven't been removed since first installed but have they moved on the rims? Have you tried contacting Goodyear?

AW10 said: Sorry of these sound like noddy questions but... At the start of subsequent balance sessions were the wheels checked to see if they were out of balance or were the weights just stripped off and a fresh start was made? And I'm guessing/hoping that when the last weight was put on the wheels were checked once more and it was confirmed that the last weight put in place resulted in a fully balance wheel? Does the problem get worse over time? And unlikely if the tyres haven't been removed since first installed but have they moved on the rims? Have you tried contacting Goodyear? When I balanced the wheels myself I checked the existing balance, they were out significantly (e.g. 100g a wheel), I then removed the weights and checked again, 3 of the wheels balanced better with no weights at all. After I had added the weights I checked them once again and always got the remaining weight down to 1-5g. I have not refitted the tyres and they haven't moved on the rim either, I know this because the coloured dot markings are aligned with the valve stem. I don't think the problem gets worse over time although the problem is so subtle that its unnoticeable on certain surfaces. I haven't contacted goodyear.

I think you have a wonky tyre. Call Goodyear.

Well you might not be wrong, but if I call Goodyear they are going to want me to buy 4 new tyres, send the old ones back and maybe get back to me in a few months with their "findings". The warranty/returns process for tyres is a joke.

Then pressure the dealer you bought them from and if you bought them via credit card consider getting the card company involved as well.

find a company near you that has a Hunter GSP9700. It is the only machine I use. It will measure the run out of the alloys and more importantly check the high and low spot of a tyre, I have had a tyres before where the road force created causes vibrations. The key is though the machine shows this so its very easy to get a replacement from the manufacturer or retailer. I tend to have alloys 19" or upwards and I am very very fussy about vibraitons and balancing

http://www.hunter.com/wheel-balancers/road-force-e...

Thanks! Shame their website doesn't allow you to search for locations in UK though.

SkinnyPete said: Thanks! Shame their website doesn't allow you to search for locations in UK though. Their website is not ideal, I beleive they do have a search page for UK dealers. As far as i am aware quite a few Porsche garages do use them, all of bentley of them and some independant garages too. Ill see if I can find the UK search page even though its not a comprehensive list!

SkinnyPete said: Shame their website doesn't allow you to search for locations in UK though. Yes it does - http://www.balancemycar.co.uk/

Jakg said: SkinnyPete said: Shame their website doesn't allow you to search for locations in UK though. Yes it does - http://www.balancemycar.co.uk/ There we go, someone beat me to it. I was just about to link that website.

Cheers guys. So would you say the Hunter machine is a fail safe way to get the balance spot on? Closest place to me wants £30 a wheel which seems reasonable given the annoyance it will solve, in future I will just pay the extra!

SkinnyPete said: Cheers guys. So would you say the Hunter machine is a fail safe way to get the balance spot on? Closest place to me wants £30 a wheel which seems reasonable given the annoyance it will solve, in future I will just pay the extra! I would say so. Generally if you have a vibration from the wheels it can only point to two things: the alloy or the tyres. If the alloy is damaged and out of round the machine will pick up on this as there is a measuring tool which should be used first to measure if the alloy is within tollerance and of course the user of the machine should also do a visual check. If the tyre has a fault in it then the machine will 100% pick this up and will say there is too much excess ft lb of force generated. The machine at that point will try to match up the high spot of the alloy with the low spot of the tyre and try and balance this out and will spin again to see the rate. Either it will go in the amber/green area of the graph meaning its fine now or go into the red: it will state EXCESSIVE ROAD FORCE. If its just tipped into this section then you should be fine as if the tyres are generally new then it will fix itself within the first 100 miles if its significantly into the red then its a case of getting it swapped from the manufacturer or retailer. I stopped wasting my time going to any other garage or using any other balancing machine, I have been to BMW, mercedes, other independants, new blackcircle garages and if their machine says balanced then they have no clue what so ever on how to resolve the issue. 30 pounds a wheels seems about right, its best to get it done right first time. Ps If I remember correctly normal wheels balancing machines only spin up to a rate of 30mph. The Hunter is tested at a much higher speed, 50 or 70mph coupled with the road force measuring tool. Its as good as its going to get. Edited by XMT on Wednesday 20th September 16:23

+1 for Road Force but make you ask for re-indexing (dismount and rematch tyre to rim) plus balance. Best money you will spend. And if one tyre is duff then report can be used to get a replacement. I know do this routinely - only way to ensure factory fresh smooth ride in my opinion (I am fussy).

Time to revisit this thread, as this issue has been frustrating me for eight years, and I m still no closer to a proper resolution! Here s a breakdown of my tyre saga so far: 1st set (Factory-fitted PZero): Perfectly balanced, no issues. 2nd set (Goodyears): Started having the imbalance I originally posted about. Got it about 95% sorted by balancing them myself, but still had a slight vibration. 3rd set (PS4S, Road Force balanced by a Porsche specialist): I was told one tyre was faulty (they produced a reading of about 70nm iirc). The imbalance never fully went away, but I lived with it. 4th set (PS4S, again Road Force balanced by the same specialist): Balanced fine, no complaints. 5th set (PS4S, same specialist): This time, they claimed both front wheels were buckled and couldn t be balanced correctly - despite the fact that the outgoing tyres were running silky smooth. The new set had a terrible imbalance. I then took the car to a different garage with a Road Force machine, and after three attempts, they managed to get a perfect balance. Now, ahead of fitting my 6th set (see my recent thread), I decided to get the front wheels checked - assuming the "buckled" diagnosis was accurate. I took them to one wheel repair shop: they said both wheels were straight and true. For peace of mind, I took them to another shop - same result. So here I am, still frustrated and asking myself: why is it so hard to get a smooth ride? At this point, I m leaning toward one of two conclusions: 1. The build quality of the Michelin PS4S is inconsistent 2. Or this highly-rated (and pricier-than-OPC) Porsche specialist doesn't actually know what they're doing. Edit to add, I'm going to try the SportContact7 and see if I have more luck. Edited by SkinnyPete on Friday 4th July 16:25

How about trying the Zeros again to see if that resolves it or perhaps this is a suspension issue and that could be checked over including the springs?

SV_WDC said: How about trying the Zeros again to see if that resolves it or perhaps this is a suspension issue and that could be checked over including the springs? The suspension is in excellent working order, and the fact that the imbalance appears and disappears immediately after fitting new tyres or carrying out rectification work leaves me in no doubt that the issue lies with the tyres. Edited by SkinnyPete on Friday 4th July 20:22

I have always found MPS4S great balance wise. Rim matched and Road Force on my 17 year old 997 and they often only need 5-10g a wheel. Indeed both back wheels currently have no weights (first time ever in 30 years in 911s). Ride is like a new car. Maybe I am lucky, or my local garage (Litchfield) know what they are doing.... PS the rears are 305s so not easiest tyre to balance.

I had similar issues on a 996 Turbo ( 20 years ago - Christ, time flies) and it turned out to be slightly warped front brake discs. Had them replaced ( under warranty) and problem went away !

AW10 said: I think you have a wonky tyre. Call Goodyear. I had two tyres fitted that were not round, they got replaced and the problem went away.

I had a new set of tyres fitted recently and think I may have finally solved the issue. One wheel came back with a road force runout of about 30nm, which is probably close to the limit of what you’d want on a car with low-profile tyres and sporty suspension. The other was showing 80nm - definitely something you’d feel. The Hunter balancer also picked up a bit of runout on the rim, which the tech kindly marked for me. On the drive home, the car felt pretty smooth under 65mph, but the faster I went, the more vibration I got through the front axle. I ended up taking the wheel to another refurb place. They told me it was minor and not really worth touching, but since I’d mentioned the vibration, they agreed to try. They did make me sign a disclaimer in case the wheel cracked, which was about the point I called Porsche for a price on a new one… £2411 including VAT - ouch. Anyway, they reduced the runout, refitted and rebalanced the tyre, and the difference at 80mph is noticeable. Haven’t had the chance yet to test it on a really smooth stretch of road at higher speeds to see if it’s 100% sorted, or if it’d benefit from being road-forced again, but it was definitely worth doing. I’ve gone down a bit of a rabbit hole on wheel balance over the past couple of weeks, but my main takeaway is this: the bigger the wheel and the lower the profile, the more precise everything has to be. On a 16-inch rim with 55-profile tires and soft suspension, you can get away with quite a lot. But on something performance-focused like a Porsche on 20s, there is far less tolerance for imperfection.

£2400 for 1 alloy wheel!!!

Glad I have 18”s !