tyre load index

bongoing-mad-simon · Post by **bongoing-mad-simon** » Tue May 15, 2007 2:38 pm

hi all
just found this load index thought it might be useful

The load index is a numerical code, which corresponds to the maximum load a tyre can carry at the speed indicated by its speed symbol, under specific service conditions. For specific load index details see below

brorabongo · Post by **brorabongo** » Tue May 15, 2007 9:05 pm

At a risk of sounding stupid, and being lazy what rating should we be aiming for?

bongoing-mad-simon · Post by **bongoing-mad-simon** » Tue May 15, 2007 9:14 pm

hi borabongo,
the load rating on my bongo are 91, not having an owners manual i do not know what the bongo weighs that is why i was looking on what 91 means. if anyone would be kind enough to have a look and post the weight we should be able to work out what rating we need.

___________________

simon

I'm bongoing mad R U?

trevd01 · Post by **trevd01** » Tue May 15, 2007 9:16 pm

There is a fact sheet in the members area.

The generally accepted minimum is 96

bongoing-mad-simon · Post by **bongoing-mad-simon** » Tue May 15, 2007 9:30 pm

hi trev01
just looked on http://www.valuetyres.co.uk for my sized tyres in a 96 and they don't supply them the highest rating is 95 but most of them are 91, i'm running 245/40/17 rear 225/45/17 front

_______________

simon

I'm bongoing mad R U?

trevd01 · Post by **trevd01** » Tue May 15, 2007 9:55 pm

Sorry about that Simon. Van rated tyres tend to be higher profile, which means 15 inch or 16 inch. We have stuck to 15 inch for comfort, and have a choice of a lot of van rated tyres.

I'm sure there are higher rated 17 inchers around though - big heavy mercs, beemers etc must need 'em. No doubt Michelin or Conti's though.

Looking at good old http://www.miata.net/garage/tirecalc.html your tyres are also about 5% smaller than standard.

Others are running 17s - someone will come forward with a recommendation I expect.

madmile · Post by **madmile** » Tue May 15, 2007 10:07 pm

Unfortunately as the tyre info is displayed on the inside of the drivers door - 92 front and 96 rear - any less and you will be very lucky if your insurance company pays out in an accident. As its something people usually pay little attention to (and very easy for an assessor to check), its an item that will almost certainly be clocked by your insurance company just at the wrong time.
You can get larger tyres in a decent load rating and they dont need to be full van rated tyres that look like they are on an old tractor

I have a van with 215/55/17's 98 load rating and £60 each. They did require a small adjustment so the speedo did not under-read.
Its only my personal view, but I think the slightly larger tyre fills the arch a bit better without going down the route of lowering the suspension.

trevd01 · Post by **trevd01** » Tue May 15, 2007 10:25 pm

madmile wrote:<snip> they dont need to be full van rated tyres that look like they are on an old tractor

These are 100 rated, not too tractor like!

(but only 2115/65 15)

madmile wrote:Its only my personal view, but I think the slightly larger tyre fills the arch a bit better without going down the route of lowering the suspension.

Of course it's only the width that you are changing, as the diameter of the new wheel/tyre combo is the same, so the distance between the top of the tyre and the wheel arch lip is actually the same, from the side... More wheel, but less sidewall

madmile · Post by **madmile** » Tue May 15, 2007 10:41 pm

On my vw transporter I have 215/65/15's they are continental van co's and they are very commercial in appearance, as opposed to vanco xl's which have a nice tread pattern similar to that of yours trevor.

With regard to the wider tyres, the profile (i.e 55) is a percentage relativity to the width. I am not sure of the calculation (someone has done a link somewhere), but in simple terms a 215/55/17 will be taller than a 215/45/17.
The calculator gives an exact diameter etc so you can tell how much your speedo will over or underread with different size tyres.

bongoing-mad-simon · Post by **bongoing-mad-simon** » Tue May 15, 2007 10:44 pm

hi trev
can i go down a width to 235 rear and 215 front
as i can get a better choice of weight ratings

___________

simon

I'm bongoing mad R U?

trevd01 · Post by **trevd01** » Tue May 15, 2007 10:57 pm

in simple terms a 215/55/17 will be taller than a 215/45/17.

You are right, Mike.

Point I was making is that without changing the gearing or speedo, the diameter of the new wheel/tyre combo should be the same. More wheel. less tyre, as I said. http://www.miata.net/garage/tirecalc.html

(I learned all about diameter /aspect ratios /gearing from years of offroading Landies by the way.)

265/75 16s! - which are the same diameter as 7.50 x 16s or 235/85 16s on a Landie

madmile · Post by **madmile** » Tue May 15, 2007 11:08 pm

Ahh - now if you had said about not changing the gearing.....

Thanks for re linking the calculator - I never remember how to do that sort of thing, but it is very useful when you are phoning round for tyres and trying to get sufficient load rating. If you depart from the 15 inch wheels there is usually a compromise to get the right tyre / price, but its important to not get too far away from original sizes.

I remember a fellow bongo owner calling round for some advice and some parts that I had spare - we were dicussing speed /revs and he commented on the fact that he could do 85 mph at 3000rpm - his tyres were something like 195/55/15's. The worrying thing was that his dealer put them on new for him as part of the deal

trevd01 · Post by **trevd01** » Wed May 16, 2007 8:15 pm

bongoing-mad-simon · Post by **bongoing-mad-simon** » Thu May 17, 2007 8:46 pm

hi trevd01
i've just found tyres that are near perfect to standard the sizes are
235/45/17 97 for the rear and 215/50/17 95 for the front (used your checker to find out the sizes) just like to say thankyou for your advice.

________________

simon

I'm bongoing mad R U?

trevd01 · Post by **trevd01** » Thu May 17, 2007 9:07 pm

Glad to be of help! (I'm a bit of a tyre-size geek, I'm afraid)