Tyre Pressure increase

[Robtel]

Hi All,
Looking for some feedback /thoughts on the following just out of interest.
When I purchased my current caravan at the end of last year I enquired about having the mtplm increased. I asked this not because I wanted to load more and more gear into it but because the caravan has a four wheel drive mover fitted which effectively reduces the payload by 75kg. By weighing all the accessories I normally load into the van plus an allownace for clothes I reckon I would still have met the original mtplm but only just. So to allow myself a little leeway should I ever be stopped by a VOSA roadcheck I opted for the weight increase. This lifted the mtplm from 1756kg to 1800kg, only 44kg, not a massive amount, but enough to keep me legal in the event of a road check. Now the bit about the tyres - the original recommended pressure was 42psi, the new info sticker from the caravan manufacturer states 50psi. That's an increase of 8psi for each of the 4 tyres but the potential weight increase is only a maximum of 44kg, seems a little disproportionate. I would not have been surprised to read of an increase of 2 or 4psi but 8 seems a lot ( 50psi is the maximum according to the tyre wall info)
Any thoughts on this?
Robert

 

[Lutz]

I would tend to agree with you, but the only source that will be able to give a satisfactory answer is the manufacturer himself. Does the tyre pressure information relate to the same tyre size and load rating? Maybe the 44kg extra requires tyres of the next higher load rating. Such tyres may not be available from the same tyre manufacturer and corresponding adjustments to tyre pressure were needed to suit those from a different source.

 

[colin-yorkshire1]

hi Rob, I wouldn't bother mate, the reason being nothing has changed as you say you had the mtplm increased just to keep you legal in case of a road side check so presumedly you don't intend filling the van with the extra 44kg.
so its going to be the same weight as it was before the tyre pressures were ok before so no change,
colin

 

[Robtel]

Lutz, yes applies to the same tyres.
Colin, exactly what I was thinking. On Saturday my van had a sticker on the side reading max weight 1756kg, tyre pressure 42psi, on Sunday the new sticker reads max weight 1800kg tyre pressure 50psi. Absolutely no other change made to the van other than I can potentially load another 44kg.
Thanks to you both for your input.
Robert

 

[JonnyG]

I too find it strange to have such a large increase in PSI for just 44kg, but as you were concerned with VOSA, and they would indeed go by the info available to them, if the manufacturers states 50 PSI, then running her at 42 PSI would put you on a sticky wicket,unless you can find out why they feel the need for such a large increase in PSI for such a small additional payload

 

[Robtel]

Hi JonnyG,
Take your point about running with the tyre pressures lower than the recommended but would VOSA be troubled about that as the pressures are "recommended" whereas the weights as I understand it are enforceble with no give or take. Don't know the definitive answer to that myself.

 

[colin-yorkshire1]

hi Rob,
surly the tyre pressures are only a recomendation for the maximum weight?? if not then then some of us are in a spot of bother what??,
the sticker on the side of my bailey clearly states 33psi but that was for the standard tyres 165/80x13 but I changed them for 185/80x13C 8ply steel radials the max pressure written on the side wall is 65psi but the towsafe tyre chart says 42psi for the weight of the van, but I run them @45psi. as it is better when using the motor mover.
if jonny is right then the vospa men would be unhappy that the tyres are 45psi and not 33psi as written on the van

 

[Lutz]

I think we all agree that the information printed on the sticker is not what one would expect and none of us can come up with a a good reason for such a big increase in the recommended tyre pressure. Rather than conjecture an explanation I would recommend getting in touch with the caravan manufacturer, pointing out your reservations about the details on the sticker being correct. Unknown to us there may be good reasons, but it isn't completely out of the question that a mistake was made.

 

[colin-yorkshire1]

yes Lutz I agree and in Rob case a clarification from the makers could be helpful bearing in mind the the big difference for only 44kg,
however it does seem sometimes that as new information comes to light (almost on a daily basis) that there is allways a new bit of legistlation or procedure that us caravanners have to follow and check before the van comes out.
what newbies make of it all must be very worrying, it's bad enough for those of us that thought we knew it all???.

colin

 

[xtrailman]

With out knowing your tyre size and load rating , how can your question be answered ?
Refer to this chart to get the pressure required, or close to it.

http://www.tyresafe.org/caravantyres/load/

My Valencia can have an increase to 1600kg, the axle rating.
An increase of 35kg, i believe Bailey increase the psi from 62 to the maximum 65psi.
But that is for a 195/70/15 light commercial tyre with a load rating of 104. And a 1620kg max rec' load

 

[Willi-Wonti]

Up till my vans service in April, I had inflated the tyres to the makers hand book recommendations of 65lbs.
During the service the mobile engineer pointed out the max pressure on the sidewall of 62lbs, so may be that is a starting point for you check the max psi on the tyre

 

[Robtel]

Willi-Wonti - one of the first things I did was to check the the tyre's maximum pressure, as stated in original post maximum is 50psi.

I have emailed manufacturer, no response as yet. I'm heading off to warmer climes (hopefully) at the end of this week so will post any reply I get if one arrives before I go.

 

[Robtel]

yes Lutz I agree and in Rob case a clarification from the makers could be helpful bearing in mind the the big difference for only 44kg,

I have received a reply from the caravan manufacturer:
"Our tyre supplier always advises that the maximum tyre pressure be used when the weight is upgraded."

Would seem to be a blanket increase to max pressure no matter how much or how little the weight increase is.
Thanks to all who have replied.
(I'm off to finish loading up my van before heading south

)