The car is a Prestigio 150 Auto and came with Bridgestone Potenzas 225/45 R18.which tramlined quite badly and were replaced at about 20,000. I thus tried Avon ZZ3s bought on the internet via Tyre Shopper for £116. Between 12-16K miles they started humming at the rear and eventually the tread parted from the sidewall. Avon were very good and replaced FOC. However the new ones have now reached the same mileage and the humming has just started although the tyres look perfect and are half worn. One possible explanation is the speed humps at the bottom of the road which just manage to catch the inside edge of the tyres possibly 20 times per working day.

kennethgordon said:

The car is a Prestigio 150 Auto and came with Bridgestone Potenzas 225/45 R18.which tramlined quite badly and were replaced at about 20,000. I thus tried Avon ZZ3s bought on the internet via Tyre Shopper for £116. Between 12-16K miles they started humming at the rear and eventually the tread parted from the sidewall. Avon were very good and replaced FOC. However the new ones have now reached the same mileage and the humming has just started although the tyres look perfect and are half worn. One possible explanation is the speed humps at the bottom of the road which just manage to catch the inside edge of the tyres possibly 20 times per working day.

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The humming is more likely due to the way the tyres wore due to the large amounts of camber at the back end. I had a set of Goodyears that did the same.

BTW it's not good to drive over speed humps in that manner. It splays the wheels and prematurely wears the suspension bushes.

Radlet6 said:

BTW it's not good to drive over speed humps in that manner. It splays the wheels and prematurely wears the suspension bushes.

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I've seen roads where they've put two of these square humps across the width of the road - one per carriageway. You have to drive in the middle of the road to drive over them properly. I'm always worried about ripping the sump off by driving with a wheel on each side of one hump.

I'm guessing that the original intention was that there should be three across the width of the road, so cars drive square over two of them but ambulances can drive straight down the middle of the road and completely miss them, straddling the centre one with their wider axles and higher ground clearance.

Perhaps councils aren't reading the instructions on them any more.

kennethgordon said:

The car is a Prestigio 150 Auto and came with Bridgestone Potenzas 225/45 R18.which tramlined quite badly and were replaced at about 20,000. I thus tried Avon ZZ3s bought on the internet via Tyre Shopper for £116. Between 12-16K miles they started humming at the rear and eventually the tread parted from the sidewall. Avon were very good and replaced FOC. However the new ones have now reached the same mileage and the humming has just started although the tyres look perfect and are half worn. One possible explanation is the speed humps at the bottom of the road which just manage to catch the inside edge of the tyres possibly 20 times per working day.

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Thinking about it some more, I reckon you can be almost certain that the speed bumps are what's wrecking your tyres. If you're driving along the sloped sides of them then that must put the inside sidewalls under huge compression. As the opposite side of the tyre is in the air, the air inside the tyre won't be compressed, so each of the inside edges will be crushed under the weight of the car.

This would do all sorts of nastiness to the sidewalls and the corner between the tread and sidewall.

As I said earlier, I think the councils are fitting these bumps in the wrong place. I usually try and drive one side alongside the bump (on the flat road surface), with the other side going up and over the centre of the bump.

I can imagine the council meeting where some "bright spark" did a Powerpoint presentation, showing that by using 2 instead of 3 they could save £x per installation.

I'm lead to believe, a couple of years ago, the residents of a local school street on which numerous /----\ speed bumps were installed experienced suspension bush damage after a year or so of regular traversal and put claims into the councils for the repairs.

The speed bump still exist and I generally (not always) put either the N/S or O/S wheels directly up and over the middle of the bumps. I slow right down to walking pace over the bumps but then find, depsite the 20mph zone cars overtake well in excess of the 20mph limit and just fast driving over the bumps. Company cars and vans are the worst offenders.

I would like to see the Swedish? water speed control ramps installed in the UK. These are long tubes filled with water with air space for water displacement. If you drive slowly over these then the water just gently displaces to the sides. Hit them at speed and it is like driving up a kerb head on at that speed. You only do this once or twice!

I agree about the Swedish humps, but like all good things they cost money. So why have something that can do the job right when you just stick two cheap lumps of suspension breaking tarmac in the road?

Up where I live these are quite common. I wonder though if it's any coincidence that the Head of Highways is a biker? :rumour:

Interesting. Mine came with Potenzas 225/45R18 which tramlined. so I changed to Avon ZZ3s at about 20,000. At 12-13k they started droning and eventually at about 15k the garage spotted that the tread was lifting on the inner edges. Avon very sportingly renewed FOC., but now after another 12k they are droning again. Is there a cure for the suspension as this is very expensive. I have seen another thread for vectra rear suspension that talks about a recall for adjustment Is this the same thing or do I grin and bear it
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I'm not sure why soem tyres "feather" on the Croma / Vauxhals and other do not.

The Croma rear suspension is rubbish. Do not expect much more than 30K miles out of a set of rear tyres. I've had four "all four wheel" geometry checks and three alignments.

I'm not sure what Fiat have done to the rear setup but I'm beginning to think that the rear ride height is too low. Lowering increase negative camber. At the same time this affects toe-in/out. All evidence I have todate shows that you can not set a nagative camber of much less than two degrees without inducing toe-out. Negative camber wears inside edges. Toe-out wears inside edges so YOU CAN'T WIN.

If the rear ride height was raised then the camber would naturally go postive and you would then be able to set a better toe.

I am having ongoing problems with the rear tyres on my Croma (225/45R18). The second set of Avons have now lifted their tread at about 13k so I obviously need to change manufacturer. Has anyone managed 20k on Barnums or Hankooks as these are available locally at half the price of Bridgestones, Pirellis etc

kennethgordon said:

I am having ongoing problems with the rear tyres on my Croma (225/45R18) ...

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Take care considering mid-range tyres - as some may meet Croma spec … but not for 225/45R18 tyres.

For example – Barum Bravaris2, Falken ZE912, Kumho (?).

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55 1.9/16v 150 Prestigio
Front: Conti SC3 225/45R18 95W, Rear: Falken FK452 225/45R18 95Y

The £55 Forceum cheapos are still working - nothing has exploded and nobody has died. They've done a few thousand miles now.

They're on the back, and I took about 5 tons of rubble to the tip in the Croma last week (about 300kg at a time), at 30-50mph for about 300 miles in total (lots of trips). So they've been load-tested now.

The only very slight downside is that they do make a bit more roar than the previous Hankook V12 EVOs. The Forceums are audible at 60-70mph, silent otherwise. I think the Hankooks were unusually quiet though, and I don't have any other comparison. The Forceums do have a fairly chunky tread, which is probably the reason for it.

Overall, I'm very happy with them. I'd rather have them and £50 change per tyre instead of the Hankooks.

After only 35000 miles I am looking to fit my third set of tyres,previous ones have been 215/55/R16 W Pirrelli.Read all your comments but still not sure what to buy,only use the car for towing the caravan. Should I fit budget tyres or not?

Well, I've been very impressed by my first "budget" tyres. Such a disparaging term really, suggesting crappiness. I suspect the reality is more about profit margin and european inefficiency/labour costs than product quality.

These tyres are worth googling for:

www.eptyres.com

They are the parent company for Accelera and Forceum.

any one run toyo t1r's on a croma?

My Prestigio 150 comes with 225 45 R18 tyres which I hate. They are very expensive, do not wear very well and give a very poor ride around town. I would like to change them for the other sizes quoted for the Croma namely the 215 50 R17 or indeed the 205 55 R16. Will I notice the required improvement in ride and will I notice a serious deteriation in road holding if I went all the way to the 16" wheels I do not drive particularly fast around corners(it's a Croma remember) but I do do a lot of town work.

I got a set of 17's from a new 159, for £300, the Michelins would have been over £600. Brera wheels fit.

I use 205 55 16 Bridgestone Blizak LM 25 on 16" Vectra C steelies in the winter and factory 17" alloys with Goodyear NCT 5 in the summer. Both sets are serving me well and no big difference in the feel. I guess the winter set is a bit less heavy and minimally higher in the sidewall, and winter tires are softer so overall slightly less bumpy in the winter.

The ultra-cheap Forceum tyres are still doing fine on the back (almost like new, after 15k miles), but I needed replacements for the front.

I did try the Forceum ones on the front, but they did roar a lot. They do have an unusually chunky tread pattern, so it's understandable.

I got the next cheapest instead, which are Accelera PHI 225/45 ZR18 95Y XL. These were an amazing £66 each online, including delivery. Fitting was £5 per tyre at Halfords.

They're also made by Erlang Perdang in Indonesia, the same company as the Forceum ones. They're completely different in every way though - different sidewall shape, logos, tread, markings etc.

So far, they're perfect. As quiet as any other tyre I've had, nice and smooth and grip fine.

One difference I noticed is that the Accelera's have "RR 27" on the sidewall, whereas the Forceum's state "RR 47". I wonder if this is the Rolling Resistance? Google doesn't know - I don't think it's an industry standard marking. If it is then that's another reason why the new ones are better.

Doofer said:

... the Accelera's have "RR 27" on the sidewall, whereas the Forceum's state "RR 47". I wonder if this is the Rolling Resistance? ...

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I don’t think “RR27” & “RR47” fit with `rolling resistance’ – more likely a batch code from their Bogor plant (?)

The RR boundaries are …

Green label: ≤ 9.0
Yellow label: ≤ 12.0
Red label: > 12.0

An (Indonesia) example would be the GT Radial Champiro HPX with a (Green) RR of 8.7 – a (Green) wet-grip index of 140, & a (Green) 71dB of noise.

Source: http://www.kiesdenieuweband.nl/bandenlijst.php?season=1

Thank you very much - that's what I was attempting to find out about!

I can't remember what colour the labels are. Is the small painted spot (about 10mm) on the sidewall the same?

The Acceleras have a yellow spot. The Forceums no longer have a spot after a year of use.

Google translation of your web page:

http://translate.google.co.uk/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=nl&tl=en&u=http%3A%2F%2Fwww.kiesdenieuweband.nl%2Fbandenlijst.php%3Fseason%3D1&act=url