Tyre size on 15 inch BRM rims

When I got the van it had technically ok car tyres but when I went back to stock and a load rating over 100 8 ply tyres it made so much difference to the road holding.

 

Both axles individually.
Plus total weight

 

Do you remember what the rear axel GVW was?
All the info I can find say 1300kg which is above a 92. 92 = 630kg X 2 1260kg.
But theory and written word is no substitute for an actual weight.

 

It doesn't matter what your van weighs, the tyres must be capable carrying the maximum plated weight of the heaviest axle which is 1400kg

 

https://r.tapatalk.com/shareLink/to...7&share_fid=5720&share_type=t&link_source=app

 

I've got cheapie 'Empi 5' type 15" wheels on mine, probably 6J? Can't remember the offset but possibly the same as the BRMs? Recomissioning the van after it's 8 year lay up I had to buy new rubber all round and after a bit of research I went for Toyo Proxes CF2's in 195/65/15 95H XL. Being XLs and 95 rated they're good for 690kg @ max 50psi which equates to 1390kg per axle. Got a very good deal from Demon Tweaks eBay store when they became eligable for a snap discount and got a set of 4 for just £135 delivered!

 

From the linked above thread commercial tyre weight debate.

2013: I'm posting this in case it is ever useful for those involved with the great commercial tyre & weight debate.

In a previous thread Zed kindly pointed out that my incorrect rated tyres, may be one of the reasons I was blowing about in the wind at high speeds.

They are Conti 185 65 R15 88T (Max load per wheel 560kg).

To cut a long story a bit shorter, I spent ages trying to source some Commercial rated tyres of the same size.

I couldn't find anything that much better, despite conversations with the Technical Services Mgr for Conti & with Stapletons (National tyre wholesaler).

If i could go wider then I may have more options, but that would mean ditching my fuchs (connected with 25mm wheel adaptors).

So I started considering changing my brake set up to porsche pattern 5 x 130, so i could ditch the adaptors & fit wider tyres with a slightly better rating.

This was going to cost a bloody fortune, but when speaking to our very own Mr Weeding he suggested I visit a weigh bridge.

Gross weight 1580kg (including me@80kg, EDIT weight taken at 1pm, kids dropped off at pool at 8am- see post below!)
Front axle 720kg (including me)
Rear axle 820kg (I was still in van but only rear axle on weigh bridge)

After that I visited an old colleague who is a tyre expert (working in fast fits and on commercial vehicles). He said the best tyres he could source in my size were Yoko 185 65 R15 92T reinforced. Result, these should be better than my car tyres & will handle up to 630kg per wheel e.g a rear axle of 1260kg!

OK the vehicle wasn't fully laden, but it weighed quite a lot less than I had been expecting.

This is what went on the weighbridge:
Late bay, devon pop top, bunks, bench seat, buddy seat, fixed table. It doesn't have a fitted sink or cooker.
Vehicle contained: Under buddy seat: tools, spares, jump leads, 2 x gas burners. Rear: 1/4 tank petrol, duvet, pillows, 2 camping chairs, table, boules, bow & arrow, badminton kit, kettle, pans etc

Estimated fully laden (Unlikely I'll ever put this much in)
Front 720kg + Another large adult 80kg, food & booze 50kg, clothes 2okg. Total = 870kg max?
Rear 820kg + 4 x large adults on rear seat 320kg, More fuel, 40kg, awning 20kg, more camping chairs 10kg. Total = 1210kg max?

I will go back to the weigh bridge when im fully laden with camping gear,

2015 NEW INFO: I went back to Weigh bridge fully laden and I mean fully laden.
Gross weight 1900kg
Front Axle 940kg
Rear Axle 1040kg

Front: me and my partner, 40l fridge packed with booze
Middle: Massive tent/awning, 2 person tent, food, camping stuff for four people, clothes etc
Rear: 6ft/80kg mate, his 7 year old son. Full tank of fuel. Under rear seat: cadac bbq, gas bottle, 2 tables, 2 chairs, wind break

Summary my new 185/65/R15 92T reinforced tyres are legal and more than adequate! 630kg per tyre load rating!

New info ends!

So I think if i get reinforced tyres with a slightly high load rating (92) then I will be good to go!

Some of you (if anyone actually reads this far) will think i should just change back to 14" wheels. I'm not doing that because when i was growing up i always wanted a set of fuchs, plus if i changed back it would balls up the gear ratios and i've just fitted a new box that matches up well with the engine ratio wise. So do one!

For the uber geeks and anyone else still alive after reading this:
Original bay window van tyres were either 185 R14 C 6PR, or 185 SR14 Reinforced (stengthend passenger car). Diameter was approx 652MM. (based on 185 80 14, rather than 82% profile)

Current tyres & 15" wheels have a diameter of 621mm ish (based on 185 65 15) & i'm happy with this gearing.

Weights from Original Vehicle manuals: EDIT Different vans/years may be different
Van weight (Camper)
Unladen 1495kg
Capacity/Payload 755kg
Gross Vehicle weight 2250kg
Gross axle front 1010kg
Gross axle rear 1270kg

Conclusion:
I've been typing far too long, i need a yellow snow, my friend is cooking me tea and i'm running late! Plus I've spent far too long trying to research & find the correct tyres. Before i joined this forum i'd happily been driving around with the wrong tyres for 10 years!

I hope this benefits somebody, somewhere at some point.......................or you can all just rip the yellow snow out of me............i haven't even bought the tyres yet!

 

The max playted/gross axle rear when I looked for my bus was 1270kg.

I'm an early late bay

 

See above

 

Thanks that tyre is worth further investigation, XL didn't exist when these things were built, not as far as I know.

 

They can be up to 1400kg for late bays. But the tyres still legally need to match or exceed the plated axle weight on you VIN plate.

 

Toyo Proxes CF2 195 65 15 95H XL, set of 4 still cheap at £142... https://www.ebay.co.uk/itm/4-x-Toyo-Proxes-CF2-High-Performance-Road-Tyres-195-65-R15-195-65-15-95H-TL-XL/143372599768?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Those tyres put me 110kg over the plated max rear axle load.

 

Hi Paul,
Were there any issues when running the 88 tyres?
I’m not sure the kerb weight of an aircooled T2 Danbury but guess 60% is at the rear so could this be a safety issue with tyre loading?

 

Actual kerb weight is irrelevant. The tyres need to be appropriate to the manufacturers max axle rating which is stated in the handbook.

for my westy it needs 85 front and 93 rear.

the “xl” rating is related to tyre pressure (up to 50psi iirc).

 

There's more plys on XL too, as I understand it.

 

Apart from the poor handling and risk of failure of the overloaded tyre the issue would be your insurance. Or lack of, the bus isn’t roadworthy using tyres with insufficient load rating and if you read the small print on your policy it will state that the vehicle must be maintained in roadworthy condition.

 

It's really quite simple, the load rating of tyres fitted mustn't be less than half the maximum permitted axle weight as given in the handbook or on the vehicle plate if it's still present. So first find out the max axle load for your van, mine's 1280kg as above but it seems there's quite some variation - so check yours. Half the max axle weight to give the required minimum tyre load capacity (so mine's 1280/2 = 640kg). Then reference the tyre rating as shown below...

So again, refereing to my own case the minimum suitable rating is 93 at 650kg, hopefully giving my 95 rated tyres a reasonable safety margin .

 

That's rear, right?

 

no, it’s rear both sides

 

That’s very helpful thanks. My van is an ‘04 Brazilian and came with limited info and nothing on axle load.Danbury aren’t the best for providing info. It’s interesting they don’t all leave the same axle load ratings.