The load rating is the on the sidewall next to the speed rating. For example, '98W'. The 98 is the load rating and W is the speed rating.

Here's some reading

http://www.tirerack.com/tires/tirete....jsp?techid=35



Cheers
DD

 

Hi Brian,

I second xjay8's recommendation of the Yokohama Advan series - I've been running them on our '93 for years (third set now) and they'll be at the top of my list when the terrible Pirelli Scorpions the PO installed on our '04 wear out. The Yokos offer great wet and dry traction, excellent steering response and cornering, and a smooth and quiet ride.

I would respectfully disagree with Doug that the speed rating is not important. It doesn't matter if you never intend to drive 149 mph or faster, but it does matter that the Jaguar engineers designed the ride quality, handling, steering, and most importantly, the BRAKING, based on the sidewall and internal construction of speed-rated tires.

Higher speed ratings often correlate with higher load ratings, but not always. Tires for a dump truck might be rated for exceptional load handling, but the engineers may have given little consideration to ride quality or durability at 70 mph. Tire design is an exercise in compromise: wet, dry, mud and snow traction, temperature range, tread life, handling, steering responsiveness, ride quality/compliance, noise, rolling resistance/fuel economy, etc. Increasing performance in one area tends to decrease performance in another, so tire designers attempt to optimize the qualities of a given tire for the specific type of vehicle on which it will be used.

The Pirelli Scorpions the PO installed on our '04 were designed for Crossovers and SUVs, with an emphasis on low rolling resistance to improve fuel economy. They have a load range of XL, or "Extra Load," but their speed rating is just H, or up to 130mph, which seems like it should be fine. However, even in normal driving I can feel the sidewalls roll over while cornering, the steering is not as precise as it should be, and the wet traction (cornering or braking) is not as good as I am accustomed to with Yokohamas. Do not put Pirelli Scorpions on your Jaguar!

Please consider the Yokohama Advans and other quality tires with both the speed- and load-ratings specified by Jaguar for your model, even though you intend to always drive at or below the speed limit. The reasons for doing so go well beyond speed.

My two cents.....

Cheers,

Don

 

I recently got a set of BFGoodrich g-Force Sport COMP-2, they are very quiet and comfortable to ride. Sears had a very good price for them at the time.

Previously I had Goodyear Eagle F1 Asymmetric All Season - and these were noisy - very noisy.

 

I respectfully disagree with your disagreement

I do agree that the engineers consider tire design/construction when designing suspension, brakes, etc. They choose a tire, or work with a tire company to produce a tire, that compliments their design intent.

That being the case you can go with the exact same tire as the car was originally equipped with and thus keep the exact same balance of characteristics.

However.....

Tire designs vary quite a bit. Even within the *same* load rating or speed rating you'll typically find numerous brands and designs----different materials, different construction, different tread design, different rubber compounds, etc. Naturally they'll all have different driving characteristics. Obviously, then, any change from the exact OEM tire eliminates the balance of characteristics that the car designers intended.

I'm inclined to think that, with the possible exception of some exotic sports cars, car builders anticipate this and don't design suspension and brakes that are SO sensitive to tire design that a safety concern is raised.

For example, and some here might remember this, and number of years ago Jaguar was shipping base-level XJ8s to the USA with a V or W rated tire (can't remember the brand off hand). The particular tire, despite being high priced, delivered very poor treadlife. Owners were furious about spending $1200 for new tires after only 12k miles or so. In response, Jaguar simply began fitting USA market cars with a different type of tire, H-rated, and set the speed limiters to 129 mph...or something like that. I very seriously doubt the suspensions and brakes were re-engineered for this change.

What I'm driving at, ha ha, is that I don't see a lower speed rating necessarily compromising steering/braking performance to the extent of being a safety issue nor to any greater degree than we'd experience by switching brands, sizes, or tread dsign....which is something all of us do on a regular basis.

(For that matter, look how often we routinely use non-OEM brake pads. Very clearly we're tampering with the original design intent and characteristics but we know that we'd have to go very badly wrong to end up with something actually unsafe)

Obviously if you pick a lower speed rating you'd be well advised to keep your speed below the rating

I do recommend that loads ratings not be casually ignored becuase, if nothing else, you want to make sure the tires have ample capability to keep the car off the ground. That's pretty much the primary intent of tires

Cheers
DD

 

I get the impression that insurance companies in the US are less interested in tyre specs than they are elsewhere.

Certainly here in the UK fitting tyres of a lower speed rating than the vehicle manufacturer specifies is a 'no-no' as far as insurance is concerned; definitely if the vehicle is capable of a higher speed than the tyres (and irrespective of any lower national speed limits).

I'm not sure about the annual MOT (roadworthiness test).

I add this 'just in case', as this forum has quite a few subscribers outside the US.

 

Graham (GGG) reported on another tire thread that installing tires with a lower speed rating than specified by the manufacturer is an MOT failure in the U.K.

Don

 

I selected the Bridgestone serenity and I have no sound, they are quiet and ride well. The prior tires were very noisy and sounded like a drone.

 

Probably with good justification as only about .5 % of auto accidents in the USA are tire related, according to the NHTSA.

Tire condition and, very specifically, under-inflation were determined to be the primary cause of tire-failure-related accidents, with actual defective tires (that is, faulty manufacture, making up the difference) . In my brief research of the stats I found no mention of tire type or specification, although, if measured, it might be included in 'condition'.

Incidentally, light trucks and passenger vans are statistically more prone to tire-related accidents than passenger cars. I can't remember the percentage difference but it was significant. Traffic *deaths* related to tire failure is about 1.2%...compare this to the .5% overall accident rate mentioned above. I wonder if this could be attributed to the larger number of passengers typically carried in vans....carpool vans and the like?

Anyhow, there probably just isn't enough reason for USA insurance companies to 'go there' with regard to tires in general or speed ratings in particular.

Heck, they pay up when drivers do really, really dumb and illegal things.....so it would be sorta hard for them to deny a claim for an accident that occured at 60 mph because the car was rolling on tire that had a speed rating of 'only' 118 mph.

Cheers
DD

 

Presumably....or perhaps I should say hopefully.....they'd deny a claim only if the accident was tire related, right?

I mean, if you were backing out of your driveway and clipped your neighbor's rear bumper, the insurance company wouldn't deny the claim becuase of tire specification. Would they?


Cheers
DD

 

The sales receipt for the Pirelli Scorpions that the PO had installed on our '04 XJR states something to the effect of, "The tires selected by customer do not meet the speed rating requirement of the vehicle manufacturer and customer has been informed of this matter and accepts full responsibility."

That would seem to indicate that even if American insurance companies haven't given notice to tire specifications, American lawyers have.... :-)

Cheers,

Don

 

Yeah, that's the American Tire Association lawyers talking :-).

The vast majority of Jags I see on the road are being driven as though they were made out of glass or the driver had a bowl of goldfish on the passenger seat so I maintain that, in the real world scheme of automotive safety, tire speed ratings are an insignificant factor....unless you really DO plan on cruising down the highway at 120-140-160 mph !

Cheers
DD



Cheers
DD

 

There we go...please tell me more about them. I know the bouncing ball around the baby commercial make them look very inciting for quiet and comfort. I am kind of leaning toward them because of that.

I put a set of Michelins on my Cadillac and they were noisier than I remember.

 

Hi Doug...what load rating am I looking for? As you can tell I am not a tire guy. Generally speaking, I usually just go in and take what they recommend but at today's high prices I wanted to know my options.

Thanks,
Brian

 

Ah yes...."The Land of Litigation" ;o]

 

Australian insurrance companies take a very dim view of incorrect spec tyres per vehicle.
Jaguar specified tyres for our X308's at 98W.
Pirelli was the manufacturer selected to provide the nauseating P4000e
Mediocre performance and poor tyre life.
These were fitted on my car when I bought it seven years ago and I couldn't wait to get rid of them and replaced with Yokohama's AVS dbDecibel V550 which has just been replaced here in Aust. with their
Advan series.
The characteristics of these tyres suit the X308 to a 'T' (sic) ;o))

 

Brian,
The spec for X308's is 98W and you have several good choices with this speed and load rating.
If you driving style is moderate then Khomos, Sumitomos, Hancooks
will suit at avery competitive price.
From their you head upwards in pricing and performance.
But really, Pirelli and Michelin do not cut it today.

 

Hahahaa...I agree to a certain extent Doug.
Taking into account that tyre rating are designated for a tyre that is loaded to a certin level and the speed rating is calculated for a tyre to maintain it's designed sped rating for a minimum of 1 hour.
On these cars you can acceptably use 'V' rated tyres safely.
Taking into account the weight of these cars unlaiden is 1780KG (3960lbs)....add a bit luggage and a couple of passengers....you out on the highway running at 75mph in 85deg.F temps for a couple of straight hours, it's amazing how much heat builds in the tyre....and heat is the big killer of tyres.
Also depends on the road surface....is it concrete, smooth macadam or course bitumen?
Our roads here are notoriously harsh on tyres and because of our much drier conditions, we go for harder compounds and this is where the noise factor sharply increases, especially in cars that are not well insulated from road noise.
This where modern tyre types like the Yokohamas and others with 'directional' tread patterns come into play to quell noise levels.

 

Max,

I had two sets of those AVS db and loved them, coming from very expensive Michelins. The AVS db was quiet and excellent in all the other right ways, including appearance. The Advan S.4. that we're currently running on our '93 is a very nice tire, too, and it's what I'll consider first when the sub-par Pirellis on our '04 wear out (I'm doing my best to accelerate the process).

Someone mentioned the General Altimax on this thread or another, and that's what I'm currently running on our BMW 325i. It's been a surprisingly great tire for the money, has a cool, aggressive tread pattern, and flat-spots less than the Michelins or Kumhos that preceded it (they're fairly low-profile tires, so they all flat-spot to some degree). If it's available in sizes that will fit an XJ, and you lean toward a more sporting tire, it would be worth considering.

:-)

Don

 

I gather that Michelins are falling out of favor?

I've bought 'em in the past and have been happy; they always seemed worth the cost. But maybe not so much nowadays?

Cheers
DD

 

I have had real good luck Michelin Pilot Sports on my XK8 (about 30K miles on them now and with Pirelli on other cars.

Much improved handling, ride and much lower noise from the Conti-Pro's that were on it when i bought it.