Tyre load ratings

Started by heylinb4nz, July 08, 2022, 06:27:34 PM

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heylinb4nz

Had some new Contisportcontact5 fitted to the A8L(D4) and upon getting home reaslied they were

a) V rated (240kmh)
b) 100 load ratings

Im not too worried about the speed rating, its Stage 2 V6T and pushing 430HP but its a family car and rarely gets over 140 kmh during overtakes.

On the tire load 100 rating = 800kg and the car is supposed to have 104 / 900kg from factory

I did some calculations with 4 adult passengers, 50kg luggage, full tank, spare tyre which comes in at 610kg per wheel...leaving about 30% safety margin before maximum load.

Should I take them back ? or will I survive :)

Gordo

You will survive, just remember to increase the tyre pressures when loaded.
However, as the vehicle manufacturer has specified a "104" tyre you may have problems with the WoF, if they notice you have "100" tyres, as you're supposed to have at least that rating for your tyres.
These are my thoughts and opinions - sometimes I'm wrong, but not often ;-)

the phantom

VTNZ wouldn't notice something like that!
Land Transport New Zealand, taking the fun out of driving since August 2008

schattenblau

Insurance company might if you have an accident.

:police:

Mike1410

This NZTA article re WOF regulations and reasons for failure doesn't mention tyre load ratings in any detail, other than in Point 4 - that they basically need to be the same on all tyres on any axle. As for speed rating, Point 7 would surely apply, since even a 'V' rated tyre is rated (at 240km/h), well in excess of the NZ speed limit. The WOF inspection seems to focus more on tread and general condition of the tyres above everything else.

My A8 runs on Michelin Primacy 4 rated at 99 W (and also marked as Extra Load on the casing).

https://vehicleinspection.nzta.govt.nz/virms/in-service-wof-and-cof/general/tyres,-wheels-and-hubs/tyres-and-wheels#tab1

johnp

You will probably find it very difficult if not impossible to find a 19 inch car tyre with a 104 load rating in New Zealand.
Been through this myself recently with 235/50/18 inch tyres for my T5 van. These are a spec for the van if it has the factory alloys, but a minimum 104 load rating.
I would have needed to go to van 8 ply tyres to get this rating, meaning a change of the alloy wheels on the van.
I found no car tyres in NZ of the size required with a 104 or higher load rating.
Highest was a 102.
Also the lower the profile the lower the tyre rating seem to be.