As you know by now have now an XJ . I pointed out that car could do with alignment and ride was a bit jittery to garage who are reputable and are members of various standards and bodies etc etc It's all good as it's going back in Monday anyway. Today I got a tpms warning. It seemed to sort itself. I decided to have a look a tyres all of which have great thread and like new. On checking the load index I noticed that the rear tyre stated 98 whilst the front was 93. I referred to handbook and apparently minimum on rear should be 104 and front should be 102 I believe it's an honest mistake but given tyres do not support vehicles weight a blowout or worse could potentially kill. Quite shocked but glad I checked.i take it insurance company wouldn't be happy either with current tyres..... Expensive mistake for the garage. Present :2008 TDV8 HSE
Gone Audi A5 2.7TDI
Gone Discovery 3 HSE
Gone Mercedes CLK
Gone Range Rover 2.5 DSE

Last edited by Googsy on 8th Nov 2014 9:19pm. Edited 1 time in total

I've been researching tyres for the FFRR recently and upon checking found my current ones were only 106W - all 4 of them (Pirellis).

I've now ordered 4 replacements with a load index of 114V.

It's kind of funny - once you know it makes you worry!!

Yes going up is fine but down is a no no most people wouldn't even notice. I believe the tyre fitter should be held accountable . Present :2008 TDV8 HSE
Gone Audi A5 2.7TDI
Gone Discovery 3 HSE
Gone Mercedes CLK
Gone Range Rover 2.5 DSE

+1 for fitting stations being held accountable

Alternatively, if one had let go, I reserve the right to try out a new vice on the fitters testicles

109 on 20" for the ffrr and 112 on 19"

I pretty much always spec over rated tyres swmbos skoda has 97 rated tyres 730kg per corner, coz we used to tow wth it.

http://www.tyresave.co.uk/tyreload.html

For reference the above linky has a load index table, 106 rated tyres are technically rated for 950kg per corner, whch is 3800kg, so over half a tonne over the mgw of the ffrr.......but yet we need 109 minimum tyres.......which are rated at 1030 per corner, 4120kg or over 750kg over the mgw.

Hey ho better safe than sorry. There is nothing that can't be fixed with a hammer😜😜
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Why do you need to overspec so much? thats already taken into account with the standard weight spec on most vehicles.

IE the 109 ratings mean that the vehicle could take 4120kg in weight across its wheels. Now the FF is only rated to 3500 MRO including the 150 you would have on the nose if towing.

Now taking into account the split from front to back, the front is going to be no more than 1500kg in standard guise for any engine and could rarely increase any more than that unless you whack a winch on or sumpguard but even that lot would only add another 150...
Taking into account braking, and weight transfer you'll add a bit more onto that but then the rear still does do some braking.

Then there is the back... If your sticking over 1000kg in the back of the FF then your plain dumb. The chasis is well past its safety margin at that point and while the tyres and brakes could possibly cope with it the folded up back seats are not going to stop that weight if you had to slam on...

The 255/60/18 standard spec is 112 from my handbook so even more over spec!

As long as the tyres have good tread and are the right size and dont look cracked i think in most insurance cases you wouldn't need to worry about them... Unless of course you were doing 120mph fully loaded and one went pop!

Also dont forget, cheaper tyres might stick a good weight rating on them but do we really think they are upto that job when needed.... FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

northernmonkeyjones wrote:

For reference the above linky has a load index table, 106 rated tyres are technically rated for 950kg per corner, whch is 3800kg, so over half a tonne over the mgw of the ffrr.......but yet we need 109 minimum tyres.......which are rated at 1030 per corner, 4120kg or over 750kg over the mgw.

Hey ho better safe than sorry.

I guess there could be a good argument for "over-rated" tyres on a 4x4 though.

Take using 109's for example. Once you go cross-axled you will be taking the majority of the vehicles weight on just two wheels with a third taking a wee bit and this will probably be on stoney ground which is already doing its best to nip the sidewalls. At that point, even if your car is at mminimum curb weight you've overloaded the tyres and again those rocks will be doing all they can to destroy your sidewalls.

We then, using the same tyres, hop on the motorway with a car full and hammer along for hours on end without giving a thought to the rubber other than how much tread there is - never a worry about internal damage to the carcase.

I'd rather play safe and go up one plus in my size the load index went from 106 to 114 with little choice in-between.

Now for the funny / stupid bit - my car came with OF 22" rims fitted with Pirelli 106 rated tyres. Around these parts, accessing farm land or going to meet friends for rides with the horse trailer, we regularly go off-road and 285/35R22 106W tyres look like they're about to get ripped to shreds

So, after following threads on here, I've ordered a set of 305/40R22 114V XL tyres and have hot air gun ready to make the necessary mods to the rear OS arch liner I hope these will look a wee bit better.

Once all is done I'll post a pic or two so you get the idea and have the opportunity to have a good laugh

^thats a fair point about off road driving.

305..... Thems some wide tyres!

Will, I tend to overspec the mrs car for safety's sake, and being a pretty fast car the higher rated also tend to have stiffer side walls so area slightly better drive. But yes you are correct standard spec would be fine. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
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"305..... Thems some wide tyres!"

I know I can still hear the supplier laughing after I asked him to source me some winter tyres in that size

kingpleb wrote:

Taking into account braking, and weight transfer you'll add a bit more onto that but then the rear still does do some braking.

You make light of this phenomenon. Just exactly how much weight do you class as "a bit" ?? All those on here with any kind of Engineering Degree will tall you it's quite a bit more than "a bit".

Towing a trailer, downhill with some ballast in the car (wife, kids luggage etc) I'll tell you that you'll be weighing a lot (LOT) more than 650KG per front corner then. Jam the brakes on and at least a couple of tonnes moves it's point of moment forwards to the front wheels.

Then run over a bump in the road under those conditions. How much energy does that transfer to the tyre? Put your fingers in and find out (No, really, Don't)

Oh yeah, you definitely need over a tonne per tyre at that point.

I don't understand why weight rating is so little looked at or published. I always check the weight rating on tyres before I buy, but the information for many cars is hard to find.

By the way, these are the official figures, from the handbook.

Quote:

7.5J x 18 255/60 R18 112 H or V- All
8J x 18 235/65 R18 110 H - Winter
8J x 18 235/65 R18 110 H N Y
8J x 18 255/60 R18 112 H or V N Y
8J x 19 255/55 R19 111 H or V- All
8.5J x 20 255/50 R20 109 V- All

Personally, I think the manufacturer's standards should be fine unless the car was being used in a very nonstandard way. However, overspecing can't hurt and, if it makes you more comfortable, .
When it come to cross-axelling, this would occur at EXTREMELY low speeds (or no speed ) so you would be into static rather than dynamic loads, wouldn't you? My experience of offroading tyres is to choose the biggest and toughest sidewalks.