tyre load ratings

[curly head]

after a bit of research i had some new tyres fitted yesterday but I now think i have cocked up as the load ratings are as follows:

81 front - 462kg
84 rear - 500kg

the van is a westy but the previous owner stripped the interior out so now only has a full width bed :evil:

we are off to france soon with our kiddlies and would hate for it to be unsafe. i know there are people who say only fit commercial tyres etc but have any of the smart car tyre brigade had any issues? whats the reality of fitting smaller tyres?

comments most welcome :lol:

 

[Eeza]

Looking at a Campmobile (Westy) the maximum vehicle load was 4773 lbs *453.59237/1000 so give or take, a total vehicle weight of 2164 kgs divide that by the front to back weight distribution ( Approx. 46/54%) and that will give you a load on the rear wheels of approx. 1169 Kgs and a load on the front of 996 kg (Allowing for roundings etc..)

Divide both by two and you will have approx. individual weights for the wheels

So Minimum for a fully loaded Westy on the rear is 584 kgs and the front 497 kgs

Now I think I have worked that out right and I do stand corrected if its cocked up as I am at work, but I think you may be getting towards the tyres comfort zone.

I guess tyres have changed a great deal in the 40 years since these vehicles were new and so they will have a much better construction but I think you will feel the weight, I guess your gonna have to suck it and see, my westy came with tyres from the states and it was like driving with Blancmange tyres :mrgreen:

I used the stats at the back of the vw owners manual for 1970 for reference Your van may be considerably lighter than the figures i have used as you have removed the kit.

Tyres are like Oil and women, everyone has their own opinion, (I think Carol Vorderman's looking Seriously Hot in that ISME Advert, but is it just me :mrgreen: )

 

[KateLovesPurple]

Putting aside views about what tyre is best etc. etc., as has been mentioned, people have their own views on tyres, the fact of the matter is those tyres you have fitted are only rated to a load quite a bit lighter than your van "could" be loaded to. Therefore, in my opinion, I would not be happy to run them. In addition, should you have an accident, it is always feasible that the insurers may not pay out due to unsuitably rated tyers being fitted.

 

[Tristan71]

I had standard car tyres on mine but i never really felt comfortable with them but commercial tyres are tricky to find in specific sizes I'm still looking for some for mine I've got the back sorted with 195/70/15s but the fronts are narrower and really tricky to find also tyre sizes affect gear ratios

 

[Nugsy]

I did some working out for this a while back

Service book has the following

Gross Axle weight front....1010kg
Gross Axle weight rear.....1270kg

Load index rating is 85 for 515kg and 93 for 650kg per wheel

However this is the gross weight so loaded to its maximum. The unladen weight of the vehicle is 60% of gross. The difference in actual weight is 870kg - 2250kg verses 1380kg. I ended up with this:

unladen is 60% of gross 60% 100%
606kg is 60% 1010kg LR67 LR85
762kg is 60% 1270kg LR75 LR93

So figure if the rating is at the higher end of the range its safe as it will never be 100% of the axle weights...

I understand tyre technology has moved on etc but surely the standard has stayed teh same and an LR85 tyre has the same sidewall strentgh it ever did. Does the law state the tyre has to be capable of the gross weight. 870kg is a big weight to be carrying as a payload?

 

[aspro]

Does the law state the tyre has to be capable of the gross weight. 870kg is a big weight to be carrying as a payload?

I have often wondered about this. Did a little research a while back and from my interpretation I would say no, the tyres don't need to carry the vehicles gross permissable weight. However, this is my interpretation so don't quote me on it. Have a read here. http://www.etyres.co.uk/uk-tyre-law" onclick="window.open(this.href);return false;

All it says in regards to tyre suitability is, All tyres must have a service description i.e. load and speed index. If the vehicle was to operate outside the service description indicated on the sidewall, for instance at a higher speed or carrying more weight than the limit then the tyres would be deemed to be unsuitable for the use, and a prosecution would follow.

So I guess if you can prove the vehicles weight is suitable for the tyres ratings then you would be ok. Again, this is my interpretation of the law.

 

[curly head]

Does the law state the tyre has to be capable of the gross weight. 870kg is a big weight to be carrying as a payload?

I have often wondered about this. Did a little research a while back and from my interpretation I would say no, the tyres don't need to carry the vehicles gross permissable weight. However, this is my interpretation so don't quote me on it. Have a read here. http://www.etyres.co.uk/uk-tyre-law" onclick="window.open(this.href);return false;

All it says in regards to tyre suitability is, All tyres must have a service description i.e. load and speed index. If the vehicle was to operate outside the service description indicated on the sidewall, for instance at a higher speed or carrying more weight than the limit then the tyres would be deemed to be unsuitable for the use, and a prosecution would follow.

So I guess if you can prove the vehicles weight is suitable for the tyres ratings then you would be ok. Again, this is my interpretation of the law.

this sounds more like it :lol:

my van must be one of the lightest around as it has nothing in it apart from a bed, if the 60% of gross applies i am well within the weight limit.

wierdly enough the tyres i took off where of a higher rating but drove like shit compared to the new jobbies.

 

[KateLovesPurple]

Does the law state the tyre has to be capable of the gross weight. 870kg is a big weight to be carrying as a payload?

I have often wondered about this. Did a little research a while back and from my interpretation I would say no, the tyres don't need to carry the vehicles gross permissable weight. However, this is my interpretation so don't quote me on it. Have a read here. http://www.etyres.co.uk/uk-tyre-law" onclick="window.open(this.href);return false;

All it says in regards to tyre suitability is, All tyres must have a service description i.e. load and speed index. If the vehicle was to operate outside the service description indicated on the sidewall, for instance at a higher speed or carrying more weight than the limit then the tyres would be deemed to be unsuitable for the use, and a prosecution would follow.

So I guess if you can prove the vehicles weight is suitable for the tyres ratings then you would be ok. Again, this is my interpretation of the law.

Probably spot on, but if you were to one day decide to build up a full interior and take a load of luggage on a long holiday, or decide to use the large space to take a load of crap to the rubbish tip then there is a risk of being overweight for the tyres. Maybe better to change up before this happens? Just a thought to prevent any possible problems with the law should you have an accident or get pulled for looking overloaded, which does happen!

For comparison, I am running 195/65 15 95T's on the front and 205/65 15 102/100T's on the back. They are not C rated tyres, no need for that so long as the load and speed index is sufficient. I find that combination absolutely fine to drive, they don't feel in anyway skittish or wallowy on corners and no tramlining either.