Tyre load index - what have you got?

[AxlFoley]

I was just having a look at tyre load index, assuming that a bus is arround the 1425kg weight, this would require a tyre load index of 121, I was just wondering if any of you actualy run a tyre with this index?

my 195x50s have a load index of 86 or 530kg!!

Also any one know what effect the increased load has on the tyre??

 

[uber cool]

Oh, here's a hot topic. :shock:

Implications of incorrect tyres taken to the letter are that you are not insured! Its a van and hence must have commerically rated tyres.

86 are car tyres, so apart form being not insured they will have increased body roll on corning as the side walls are not reinforced.

Its not just the static load to consider, it cornering forces etc. That's why I cringe when folk use smart car tyres on a van.

Having said that I used to run these on my old van. However now how low profile 185.65.15 extra reinforced, which arent commerical but better than car tyres. So I would guess even i'm not covered if an insurance company did not want to pay out.

 

[AxlFoley]

yeah hot topic indeed.

The 86 rated tyres I found were actualy reinforced.

http://ssl.delti.com/cgi-bin/rshop.pl?details=Ordern&cart_id=71445129.110.10358&typ=R-154131&ranzahl=4&Breite=195&Quer=50&Felge=15&Speed=H&weiter=0&kategorie=6&Ang_pro_Seite=15&rf=1&Transport=P&dsco=110&sowigan=So" onclick="window.open(this.href);return false;

 

[bobley]

The early bay handbooks state a 7x14 tyre capable of taking 1520 lbs. If you cross reference that on the standard table of load ratings you come with 94 rating. The "metric" equivalent of 7" = 185R14 (load rating 90) and the XL/Rf version is 4 units higher than the stock tyre so you get a 94 rated 185R14Rf.

On late bays the manual specifies either 185R14 Rf (94 rating) or 185R14C 6 ply. 6 ply is hard to find but my technical manual tells me they would be 99 Rated.

You can use car tyres, you just need to seek professional advice, but the key point is that the design spec is 94 minimum load rating. VW will have done this so they can use a common tyre and the rating is designed to cope with the 1300kg limit on the back axle. 1300kg / 2 tyres = 650kg each = 94 load rating.

The bone of contention comes when you argue that the front axle is only designed to take 1010kg so thats 505kg per tyre = 85 rating. Then you argue that you'll never load your bus to the max anyway so you end up getting an 80 rating and then you say that modern tyres have huge design margins on and this is the point where you find yourself in the shed levering the front tyre of your kids budgie bike.

 

[AxlFoley]

so based on that argument a load rating of 86 is fine on the front axle!

thats good enough for me

 

[Loxy]

I was just having a look at tyre load index, assuming that a bus is arround the 1425kg weight, this would require a tyre load index of 121, I was just wondering if any of you actualy run a tyre with this index?

my 195x50s have a load index of 86 or 530kg!!

Also any one know what effect the increased load has on the tyre??

thats 530kg per axle though not total - you need to check the plates for the max axle weights.

 

[AxlFoley]

what do you mean by plates?

 

[Justin & Muttley]

All a big fuss over nothing IMHO - my van weighs a lot less than my Subaru; would I use the same type of tyre on the van? - hell yes!!

 

[Loxy]

what do you mean by plates?

There should be a plate behind one of your seats stating the max axle loadings.

 

[AxlFoley]

ok nice one i'll have a look

 

[mk2matt]

this has got me worried now as my bus has a lower rating than 94 mine is 88 will this be ok???

bus aint going nowhere at moment as i blew engine up friday on way to plymfest

 

[bobley]

88 is a bit on the low side for the rear axle. Can you not get some Rf / XL stamped tyres next time? That'd be roughly 92 then and it'd be pretty much there.

Meanwhile - ref Imprezas - you need to check the handbook. The one I had back in 2006 grossed at 1850kg I think and still had 91 rated tyres. A bay has a much higher gross weight and therefore needs higher rated tyres? Its not what the vehicle weighs empty which is important. Its the maximum potential weight it could be.

 

[Justin & Muttley]

...Meanwhile - ref Imprezas - you need to check the handbook. The one I had back in 2006 grossed at 1850kg I think and still had 91 rated tyres. A bay has a much higher gross weight and therefore needs higher rated tyres? Its not what the vehicle weighs empty which is important. Its the maximum potential weight it could be.

I understand all this - but I just think it's a big fuss over nothing!

I wouldn't put tyres on any of my vehicles that were too big, too tall, too low profile etc - but at the same time I don't believe that a 'car tyre' would automatically fail on my van, I'll stick to fitting good quality tyres of the right size for me, but I certainly won't be insisting on commercial tyres as I don't think it's necessary!

 

[bobley]

Gotcha.

Yep - you do not need to fit commercial tyres on a bay. You can if you want, it wont do any harm and VW give you the option on late bays but we dont talk about the dark side on this forum

If you think about it, bays are similar to modern people carriers, they run on high performance car tyres and carry loads at least as much as a bay.

 

[AxlFoley]

ok so how do the different loads effect the different tyres? is it heat build up, or increased wear? or just down to strength in the wall?

so many questions lol

 

[mk2matt]

thanks for getting me worried


when i got new tyres last time the tyre place game me 86 rating and said they will be fine, but this time as i got larger wheels i got 88 rating as that all they had at the time

so if i need 90+ i will have to cough up the extra dosh but if there is no major worry will stay with what i have until something goes wrong

 

[bobley]

I wouldn't worry about it too much. Its not like we use our buses as trucks carrying full payloads. For light duty work (camping basically) then I'm sure anything in the high 80s will be fine. There was a bloke on VZI who was running smart car tyres (73 rating IIRC) and he'd had a couple just implode. He wasn't too bothered, it was just a chance he took.

 

[uber cool]

yeah hot topic indeed.

The 86 rated tyres I found were actualy reinforced.

http://ssl.delti.com/cgi-bin/rshop.pl?details=Ordern&cart_id=71445129.110.10358&typ=R-154131&ranzahl=4&Breite=195&Quer=50&Felge=15&Speed=H&weiter=0&kategorie=6&Ang_pro_Seite=15&rf=1&Transport=P&dsco=110&sowigan=So" onclick="window.open(this.href);return false;

Sorry got that wrong 82 are car three....... Think mine might be 86 or 92

 

[AxlFoley]

Yeah i dont think i'll run smart car tyres!

I want my vanto be as safe as possible form my kids to travel in. well as safe as a 70s bus can be!!

 

[AxlFoley]

if you search here for your desired size, you can select brands that are reinforced.

http://www.mytyres.co.uk/" onclick="window.open(this.href);return false;