Load Indices for Tyres

[Guest]

I am looking to replace my tyres and am looking at prices on mytyres.co.uk. I am looking at Continental Sport Contact. I had thought 'all' I needed to worry about was the size, speed rating, manufacturer and type, but it would seem that to further confuse the issue the load index also has a bearing on the price. So the questions are:

1. Is a load rating of 89 OK for the front wheels of a standard 1990 944 S2 (I think that the answer to this one is 'yes', but thought that I ought to check)
2. Does anyone know the practical difference between the Sport Contact, Sport Contact 2 and Sport Contact 3?
3. What speed rating should I be going for, is Z-rated OK?
4. What, for that matter is the difference between ZR rated and V rated?

So much ignorance from one person!!
Cheers,

Graham

 

[sawood12]

I think you have to be careful with speed and load ratings on the tyres for insurance purposes. A work collegue of mine recently asked his insurance company if he could downgrade the speed rating on his Volvo to the one below as it was perfectly adequate given the top speed capability of the car but they insisted the replacement tyre had to be the same speed and load rating as OEM recommendations for his insurance to be valid. It should specify in your handbook what the OEM recommendations are.

 

[ross255]

I think if your insurance company is going to get that picky, then you are probably going to come unstuck anyway. All they have to check is if the tyres are N rated or not, in which case regardless of the rating, they can still say that they are not OEM recommended.

I would be interested if anyone has had an insurance company bother to check this?

 

[burrow01]

Hi,

I think we have been here before [] - no current tyres are N rated for 944's

They started the process at the end of 944 production

Pete

 

[sawood12]

Also N rating is nothing to do with the safety capability of the tyre (which speed and load ratings are) - it's simply about optimising the performance of the tyre specifically for the car. The only thing the insurance company is bothered about if you were were unfortunate enough to be involved in an accident that might bring into question the tyres involvement are 1. were they legal in terms of tread depth and condition and 2. are the speed rating and load rating of the tyre correct for the car. Obviously all insurance companies are different and some might not bother as long as the tyre ratings cover the capabilities of the car but it's something you should check out yourself to satisfy you are complying with the insurance company.

 

[Hilux]

What speed rating should I be going for, is Z-rated OK?

Note: the speed rating is for a tyre in optimum condition at the correct pressures at the stated speed for only 10 minutes so downgrading is not advisable.

 

[dlknight]

ORIGINAL: burrow01

Hi,

I think we have been here before [] - no current tyres are N rated for 944's

They started the process at the end of 944 production

Pete

Hi Pete, I am not saying you should use N rated tyres (I myself have non-N rated tyres on the front of my car). N rating started before the end of 944 production as can be seen if you read the official Porsche 944 Workshop manuals.

Cheers

Dave K.

 

[burrow01]

ORIGINAL: dlknight

ORIGINAL: burrow01

Hi,

I think we have been here before [] - no current tyres are N rated for 944's

They started the process at the end of 944 production

Pete

Hi Pete, I am not saying you should use N rated tyres (I myself have non-N rated tyres on the front of my car). N rating started before the end of 944 production as can be seen if you read the official Porsche 944 Workshop manuals.

Cheers

Dave K.

Hi - I agree (which is why I said at the end of production - I cannot remember which year N rating started, and 944 production stopped, but I thought there was a small overlap?) but my point is that I don't think that any current tyres are N rated for a 944 - each tyre is N rated for specific models only, not all Porsches

Pete

 

[Guest]

ORIGINAL: Hilux

Note: the speed rating is for a tyre in optimum condition at the correct pressures at the stated speed for only 10 minutes so downgrading is not advisable.

Can I take it from what you say that Z rated is not the correct speed rating? If so, what is the correct rating?

 

[mik_ok]

See HERE for speed rating info.

I use W (Toyo T1R) but Z is fine, and came about when no-one seemed to think higher than 150mph would be needed.

W and Y came later.

Weirdly you'll see tyres listed as ZR-W and other weirdisms due to the above. (A "ZR-W" is W-rated but also passes the "Z" criteria) [&:]

 

[Hilux]

[blockquote]

[blockquote]quote:

ORIGINAL: Hilux

Note: the speed rating is for a tyre in optimum condition at the correct pressures at the stated speed for only 10 minutes so downgrading is not advisable.
[/blockquote]
Can I take it from what you say that Z rated is not the correct speed rating? If so, what is the correct rating?

[/blockquote]

Z is absolutely fine []

For how long do you intend to do 150mph []

 

[944s2]

N spec started way back in 1988! I researched this a year or so back for an article I submitted to the PP and was also put on Titanic forum and Continental do an N spec for the 944 S2

 

[sawood12]

Maybe so but I bet you'd be hard pressed to find anywhere that stocks them assuming Continental still manufacture them. The N rating is accompanied by a number e.g. N3 and say if N1 was suitable for the S2 I bet you can only get say N2 or above now.

 

[944s2]

Believe it or not off the shelf ! Quick look in mytyres.co.uk & blackcircles both have them in N1 spec My local specialist always has both front and rear in stock in N1

 

[Justin85]

They must be Sport Contact's then - which are positively ancient and regardless of being N-Rated or not have been superceded by at least two new tyres in their own range, let alone all the other tyres which are now available - not always in the correct size for an S2, maybe...
There's no way I'd choose a N-Rated tyre designed 10 years ago against a newly designed tyre, which wasn't N-rated - IMHO, the Eagle F1 GSD3's on my S2 are superior in all ways to the MXX3 N2's which were on it previously - and were probably aproved by Porsche for a 964 with completely different characteristics to the 944.

Justin.