Tyres with 2 load ratings?

[ChemicalChaos]

Hi all, I'm looking at some new tyres. They are marked as 101/104S and this has me very confused. How can it simultaneously have an 800 and 900kg rating? It's a concern as the lower one means that 4 of them won't be sufficient for the MGW rating of the vehicle

[blank]

Sure someone will confirm but I think it's to do with when they're being used on a dual axle. I.e. 2 tyres on one side. Usually for bigger vans etc.

[ChemicalChaos]

Ah I see.

Which way round does it work? Ie which figure for which layout?

[blank]

This should explain it:
http://www.motinfo.gov.uk/htdocs/m4x0d000001.htm

Assuming it is a normal 2 axle, 4 wheel, sounds like you need higher ratings if it's over 1,650kg per axle.

[TooMany2cvs]

ChemicalChaos said:

Which way round does it work? Ie which figure for which layout?

The higher load is in single-wheel use, the slightly lower is dualled. I think the logic goes that the inner sidewall's heat dissipation is reduced in a dual-wheel setup.

[ChemicalChaos]

Thanks. I've managed to ask for a closer picture of the ratings, it looks 900kg single? I dont understand the C PR6 code as I've never seen that before.




Either way, it may be panic over nothing as it turns out. I was working on the assumption of a 3500kg MGW for the vehicle as it's a pretty hefty thing, but I was surprised to dip into the handbook and see:

Maximum gross vehicle weight:
- Diesel engine vehicles (self levelling suspension) 2880 kg (6349 lb)

which is a lot lot lower that I thought!

In fact, I really really do not get why it then goes on state the standard tyre fitment as 105 to 109! No wonder the ride is so crap....

Edited by ChemicalChaos on Thursday 27th February 15:45

[TooMany2cvs]

ChemicalChaos said:

I dont understand the C PR6 code as I've never seen that before.

Commercial vehicle tyre, 6 ply radial.