What tyres on your van

[Overdrive]

Hi Alan

 

I would prefer rear wheel drive any day - but I guess that's another thread on it's own!

Already started looking at older transit based Motorhomes.

 

I think the stability comes from Radial tyres with wider treads. My classic car has rear wheel drive and originally had narrower cross plies. But placed on non-standard alloy rims with radial tyres with a wider tread but similar profile so speedo reads correctly feels so sure footed in comparison.

 

David

[Basil]

Hi Snowie, I would recommend Avon Vanmaster M+S see

 

http://www.avon-tyres.co.uk/van/vanmaster-ms

 

the only snag is they only make them in certain sizes and not sure which size you require. The extra grip on wet grass and in mud is astonishing and the ride, in our case is much improved and quieter with better stopping and handling in all weathers.

If they are available in your size they are well worth fitting and they are not overly expensive costing the same as our Goodyear Cargo G26's that we had before, which were a very good tyre.

 

Bas

[Guest pelmetman]

snowie - 2012-03-04 1:10 PM

 

Hi Overdrive;

 

I'll take Advanced Motorists advice.

 

It's years since I had a rearwheel slide, of any significance at any rate.

 

Yep me to :D.................my last was during bus driver training in 85, driving a crash gearbox double decker bus downhill in the snow......... when it went 8-)........................got to the bottom of the hill................................. and a round of applause :D

[snowie]

pelmetman - 2012-03-04 6:37 PM

 

 

It's years since I had a rearwheel slide, of any significance at any rate.

 

Yep me to :D.................my last was during bus driver training in 85, driving a crash gearbox double decker bus downhill in the snow......... when it went 8-)........................got to the bottom of the hill................................. and a round of applause :D

 

I'm not proud of it; except that I caught it ........just......... It was 1973 or 4, rushing to the Humber ferry at New Holland, in a Austin Healey 100-6, thankfully nobody else was involved. I definately slowed me down!!

 

alan b

[snowie]

Hi Bas,

 

Ducato is on 215/70s.

 

Having a look at pressures now, might be worth experimenting a bit. Had van weighed last year, and weighed almost everything that went in it, so should be able to establish all-up weight,

 

regards,

alan b

[josie gibblebucket]

We replaced all 4 with Firestone Vanhawk last year. No probs at all, ours is a SWB Boxer and tyres came in at under £300. Same rating as originals too.

[Robinhood]

For 215/70 (15in) you should be able to get even premium quality tyres (Continental, etc.) fitted for not much more than £100 per corner.

 

If you think the ride is hard at the moment, then I would not (as has already been posted) switch to "Camping" tyres, as they tend to have less-pliant sidewalls (and thus potentially a harsher ride).

 

It is certainly worthwhile checking pressures, and adjusting correctly for the axle loadings (which you really need to determine via a weighbridge, rather than simpy working on the all-up weight), especially if you're running at high pressures already.

 

What pressures are you running at at the moment?

[snowie]

Hi Robin,

 

My axle weights are;

 

Front; 1.520, Rear; 1.440, with fuel, water and gas at prescribed levels, + toolkit, bikerack and chemicals etc.

 

with everything except clothes, food and bikes BBQ, hob etc. All have been weighed, individually, but axle weights not adjusted.

 

I've been running at 4.1 front and rear,

 

regards

alan b

[Robinhood]

I do not claim to be an expert, so on your head be it, but Continental would recommend somewhere around 3.1 front and 3.0 rear for these (empty) weights on 215/70R15 Vancos (109/107R). This from their technical data handbook.

 

The Tyresafe motorhome leaflet unfortunately does not have this size to be able to cross-check.

 

4.1bar on the Conti chart would equate roughly to an axle load of 1900kg.

 

I suspect you have a bit of leeway to drop the pressures, but a fully loaded axle weighing would be best.

 

 

[snowie]

Tricky one this;

the Ducato handbook says 4.1 front and 4.5 rear, as does sticker in door jamb.

 

I've emailed Bridgestone as I couldn't find a load-tyre pressure chart on their website.

 

alan b

[Robinhood]

snowie - 2012-03-05 7:33 PM

 

Tricky one this;

the Ducato handbook says 4.1 front and 4.5 rear, as does sticker in door jamb.

 

I've emailed Bridgestone as I couldn't find a load-tyre pressure chart on their website.

 

alan b

 

 

.....which is entirely the correct thing to do.

 

Unfortunately, when only one pressure is quoted, it (usually) has to be the one that is sufficient to support the 'van being used at (or over) it's maximum weight.

 

When questioned with real axle weights, especially those well below this, tyre manufacturers will often recommend lower (sometimes significantly lower) pressures.

 

I realise that your vehicle was originally shipped as a standard van; my current vehicle, however, is the only motorcaravan I've ever had where the door jamb pressures actually coincide with the tyre manufacturer's data (and even then only for the max axle weights). Michelin have three times quoted me significantly lower presures for "camping" tyres than the base vehicle manufacturer recommendation (even when the maximum design axle weights were quoted!).

 

Good luck with your query.

[snowie]

Thanks; I can't imagine that the pvc window installer worried about it or generally had much weight onboard ( I know glass is veary but..)

I shall persue it

alan

[Guest 1footinthegrave]

snowie - 2012-03-05 7:33 PM

 

Tricky one this;

the Ducato handbook says 4.1 front and 4.5 rear, as does sticker in door jamb.

 

I've emailed Bridgestone as I couldn't find a load-tyre pressure chart on their website.

 

alan b

 

Whats that in old money, I put 55 psi and 60 in the rears, mind you assuming you can ever find an accurate gauge anywhere

[colin]

snowie - 2012-03-05 7:33 PM

 

Tricky one this;

the Ducato handbook says 4.1 front and 4.5 rear, as does sticker in door jamb.

 

I've emailed Bridgestone as I couldn't find a load-tyre pressure chart on their website.

 

alan b

 

The pressures relate to load, tyre size and tyre rating, there is a page somewhere on tyresafe which gives recommendations for this and using it I reduced tyre pressures accordingly, unfortunaly the tyresafe website is playing havoc with my computer so cannot direct you to page.

[Keithl]

Colin,

 

My link to tyresafe didn't work either but I've managed to find the download, Link.

 

If that doesn't work the link came from this page Link.

 

Keith.

[Robinhood]

.....but, as I said above, the leaflet doesn't give the ratings for a 215/70 (non Camping) tyre. :-S

 

(I keep a downloaded copy on my PC).

[Brambles]

Owners often make the mistake of looking at the label on door pillar and assuming they are the tyre pressures to use. The label is a legal requirement by vehicle manufactures to state the MAXIMUM pressures for the tyres at max tyre loading, for the tyres fitted when manufactured.

Some vehicle manufactures will also add a label or additional information to show the correction factors for diffrent axle or tyre loads from the maximum.

 

[colin]

Robinhood - 2012-03-05 10:02 PM

 

.....but, as I said above, the leaflet doesn't give the ratings for a 215/70 (non Camping) tyre. :-S

 

(I keep a downloaded copy on my PC).

 

May not make any differance, cargo and camping tyres can have the same load rating, check out 195/75-16 and 225/65-16.

p.s. I have a hard copy in the van, but thats at 'new house' and I'm at 'old house', but luckely that page loaded and I now have copy on this computer.

[Robinhood]

.... Though I have noted this before (and actually have an eMail from Michelin saying they would quote the same pressures for camping an non-camping tyres - they seem to have become somewhat more cagey with their advice since they sent me that, though :-S), I think without a definitive statement for the particular tyre profile and load index, the emphasis should remain on the "may".

 

I have little doubt that, given previous correspondence and experience and referring to the data tables I have, I would (subject to understanding the fully loaded axle weights) personally be inclined to reduce the pressures somewhat (and I'd be reasonably happy to extrapolate from my Continental data tables for similar profile, load index, etc. tyres from other major manufacturers.

 

The OP however, is going about things the correct way; I'm simply trying to add to the weight of evidence that it is probably going to be worthwhile pursuing this route for a less harsh ride.

 

Without definitive info to rely on, however, any change will be entirely at his risk. It would thus have been nice to quote specifics from the tyresafe leaflet, but we can't. :-S

[snowie]

4.1 approx= 60psi, 4.5 approx= 65psi

 

So dropping 5psi front and rear could be beneficial

 

Bearing in mind Ducato front max load = 1850Kg, current load 1520Kg and rear max load =2000Kg, current load = 1440Kg, there would appear to be scope for a proportional reduction to front and rear.

 

I'll keep researching.

regards

alan b

[Guest 1footinthegrave]

If anyone could point the way to a decent tyre gauge that would be good, bought so many, but they all turn out to be Chinese rubbish, even a so called branded RAC one, total crap. Not much point to knowing the pressures without being able to confirm them, and garage forecourt gauges seem no better.

[Keithl]

1footinthegrave - 2012-03-05 11:11 PM

even a so called branded RAC one.

 

That'll be Ring Automotive Components then!

 

Like me I bet you thought it was from the good old Royal Automobile Club!

 

Keith.

[Robinhood]

snowie - 2012-03-05 11:05 PM

 

4.1 approx= 60psi, 4.5 approx= 65psi

 

So dropping 5psi front and rear could be beneficial

 

Bearing in mind Ducato front max load = 1850Kg, current load 1520Kg and rear max load =2000Kg, current load = 1440Kg, there would appear to be scope for a proportional reduction to front and rear.

 

I'll keep researching.

regards

alan b

 

The max axle weights you quote give recommended pressures from Continental very close to your door jamb figures.

 

I suspect posting the following extract is going to make the forum go "wide", for which I apologise, but it needs the full page width copying to be intelligible, and shrinking it makes it illegible (I turned it on it's side, but I then found it difficult to read!)

 

Assuming your tyres are 205/70R15 8PR with 109 load index, they will be similar to the Vanco 8s of the same spec at the bottom of this extract.

 

The table to the right gives an idea of the potential pressure gradient by axle loading, which will give you some ideas if you wish (at your own risk) to experiment.

 

The best solution is still advice from the manufacturer.

 

HTH

 

edit:

 

......well, it didn't make things go wide, but you will have to click to download, and then maximise the resulting window to make it readable.

 

 

 

[colin]

snowie - 2012-03-05 11:05 PM

 

4.1 approx= 60psi, 4.5 approx= 65psi

 

So dropping 5psi front and rear could be beneficial

 

Bearing in mind Ducato front max load = 1850Kg, current load 1520Kg and rear max load =2000Kg, current load = 1440Kg, there would appear to be scope for a proportional reduction to front and rear.

 

I'll keep researching.

regards

alan b

 

To use the table above or the tyre safe table you first need to know the load index of your tyres and the actual/expected maximum load, neither of which you have disclosed (unless you wish to use the book figure for max load), so at this time nobody can know.

[Derek Uzzell]

For their 'ordinary' light-commercial vehicle 215/70 R15C 109/107R Agilis 81 tyre Michelin provides the following axle-load/inflation-pressure data:

 

Axle-load Inflation-pressure

 

2060kg ......... 65psi

1660kg ......... 51psi

1460kg ......... 43psi

 

These data (as one would expect) near-enough match the Continental data provided by Robin Hood.

 

These are 'static load' pressure recommendations and Michelin have advised in the past that the front-axle static-load inflation pressure may be increased by 10% to deal better with cornering and braking weight transference. For example, for a measured FRONT-AXLE load of 1660kg, Michelin would suggest around 56psi (51psi + 10%).

 

Playing about with tyre pressures must be based on accurate AXLE-LOAD measurements. There's little point weighing the complete vehicle then guessing at its axle-loadings. It's also worth pointing out that tyre manufacturers' pressure recommendations are based on a relatively warm ambient temperature (I've been told that 20°C is the norm) - so it's a waste of time with motorhomes to seek accuracy down to a single-figure psi.

 

It's also worth emphasising that some vehicles do have a harder ride than others even when their tyres are identical and run at identical pressures. If it turns out that, when tyre-pressures are matched to measured axle-loads, the vehicle still has a harsh ride, then that's just tough luck. What should never be done is to reduce tyre pressures below their axle-load recommendation in the hope that this will soften a harsh ride. Tyres being run at unsuitably low pressures are potentially lethal, while a harsh ride is just uncomfortable.