Tire pressures when towing

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Nov 11, 2009
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Clive. I think you are the first person I know who uses kpa. I grew up with psi and bar . What does everyone else use?
As one who had a combination of Imperial and SI through university then at work most times it would be Imperial units. But I never dropped SI totally so when doing calcs I’d tend to use SI then convert at the end to imperial so others could understand the outcome.

Between solo and full load my rear tyres go up 10 kpa……. 1.45psi Only Subarus persnickety approach would put such a small difference on the label. But what do you expect of a company that requires all four tyres to be within 1 mm tread depth 😂
 
Mar 14, 2005
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If the manual was clear, I would.

Unfortunately like many a user manual, including caravans, it's sadly lacking in clarity.
Totally agree... On a number of different issues we see car manufacturers using slightly different protocols when managing variables. I am confident the manufacturers understand the dynamics of their products better than anyone else so it is not only sensible to follow their instructions, it could be that using different manufacturers or your own methodology could actually rather than manage a situation, it could make its worse.

Otherwise what is the point of manufacturers giving the specific information.

If any instructions do not make sense or need clarification consult the dealer or manufacture.
 

Sam Vimes

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Sep 7, 2020
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I suspect that if I had the inclination, which I don't, to contact the manufacturer or dealer all I would get is RTFM.

I think what's needed is a quick start guide to 'Your Car'. This could include things like what and where to put consumables and also things like tire pressures and load/tow carrying capability. Instead we get a confusing number of facts in a manual that's supposed to cover different versions with different optional extras.

My current car's plates include MAM, GTW and Loading on Front and Rear Axles. To the average user I suspect these dont't mean much. Nowhere can I find the Kerb Weight from which I could work out what payload I could carry.

The tire pressure plate just shows figures for 1-3 persons plus some luggage and 4-5 persons and more luggage but doesn't state if these are light traveling Hobbits or fully kitted our NZ Rugby Players.

Writing user manuals is not seen as a priority in selling cars. Most punters are interested in things like how many cup holders it has and what colour can I get it in.
 
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Nov 11, 2009
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I suspect that if I had the inclination, which I don't, to contact the manufacturer or dealer all I would get is RTFM.

I think what's needed is a quick start guide to 'Your Car'. This could include things like what and where to put consumables and also things like tire pressures and load/tow carrying capability. Instead we get a confusing number of facts in a manual that's supposed to cover different versions with different optional extras.

My current car's plates include MAM, GTW and Loading on Front and Rear Axles. To the average user I suspect these dont't mean much. Nowhere can I find the Kerb Weight from which I could work out what payload I could carry.

The tire pressure plate just shows figures for 1-3 persons plus some luggage and 4-5 persons and more luggage but doesn't state if these are light traveling Hobbits or fully kitted our NZ Rugby Players.

Writing user manuals is not seen as a priority in selling cars. Most punters are interested in things like how many cup holders it has and what colour can I get it in.
The weight per passenger is often defined as 75 kg. Don’t know which century that was defined?
 
Jun 20, 2005
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The weight per passenger is often defined as 75 kg. Don’t know which century that was defined?
11st 11lbs. They’d be stars at Fat Club. 😋😋
I don't think the aviation world use that figure in their take off calculations🤪
 
Nov 11, 2009
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11st 11lbs. They’d be stars at Fat Club. 😋😋
I don't think the aviation world use that figure in their take off calculations🤪
You’re right the UK male average is 83 kg, and female is 71 kg but spanning 18-90+ years it can mean anything to anyone. I’d be very happy to see 83 kg but I think at 6 ft 4 I might be viewed as underweight.
 
Jun 20, 2005
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You’re right the UK male average is 83 kg, and female is 71 kg but spanning 18-90+ years it can mean anything to anyone. I’d be very happy to see 83 kg but I think at 6 ft 4 I might be viewed as underweight.
That’s the current aviation norm since the DC8 fatal crash full with American Marines. Shame there’s no consistency
 
Jul 18, 2017
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I knew psi many years ago and then we went decimal and started using bar in the sixties. Emigrating here was taking a step back in time going back to imperial. :ROFLMAO:
 
Nov 16, 2015
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We had to carry 4 American riggies offshore, in Nigeria, in a small helicopter, we had to off load one as each chap weighed in at over 115 kg. Then on the trip out with the 4th we brought one of the first 4, back with a heart attack. To many stairs on the rig.
 
Jul 18, 2017
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We had to carry 4 American riggies offshore, in Nigeria, in a small helicopter, we had to off load one as each chap weighed in at over 115 kg. Then on the trip out with the 4th we brought one of the first 4, back with a heart attack. To many stairs on the rig.
We used to be taken into the field in the Alouette helicopter and you prayed for a good pilot. As each person jumped out with all their kit, the helicopter became lighter by about 100kg causing it to rise.
If your pilot did not compensate in time for the weight loss the helicopter could be several or more feet off the ground as five people bailed out in rapid succession. Result a gammy knee to this day!
 

Sam Vimes

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A few years back we flew from Invercargill, at southern tip of New Zealand, to Stewart Island. The plane was an old Britten Norman Islander.

At check in the guy behind the desk, who looked about 12 and turned out to be the pilot, asked us to put our feet on the footprint marks in front of the desk. When we asked why it was so they could weigh us. We didn't get the results.
 
Sep 26, 2018
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I guess most manufacturers will be following the Volvo lead- no paper manual! It's built into the info system and also available on line. It's not a bad idea, because it's easier to search than a 2 foot thick chunk of tree that covers every feature in every variant of your car!
 
Nov 11, 2009
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I guess most manufacturers will be following the Volvo lead- no paper manual! It's built into the info system and also available on line. It's not a bad idea, because it's easier to search than a 2 foot thick chunk of tree that covers every feature in every variant of your car!
Plus 80% of the print consists of warnings, extraneous info etc. Finding text that is useful is a challenge.
 
May 7, 2012
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PSI because I understand it. With the others I am just assuming figures I am given are correct but with PSI I should be able to spot a seriously wrong figure.
 

Parksy

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Nov 12, 2009
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What are these 'tires' of which the OP speaks?

Are thet the same as 'tyres' as fitted to all the cars which I have owned or driven ? :LOL::giggle:
We never make comments about spelling or grammar on this forum, although I understand that your comment is light hearted.
We have no way of knowing about the educational standard of any individual, they may be dyslexic or simply unable to spell.
As long as a forum post can be understood by the majority of those who read it, we leave it alone. 😊
 
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Nov 16, 2015
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Nov 6, 2005
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I have always used Psi, and on my motor bike I carry what we call the Worms, for emergency repairs. Works well on all tyres Cars as well.


I use Co2 cylinders to inflate the tyres
Also known as "tyre strings" - I have a set ready to try as it would avoid the faff of inflating and fitting the space-saver spare.

These days I use Bar rather than PSI, as the TPMS sensors on my car seem designed to work directly with Bar and only convert to PSI arithmetically.
 

Sam Vimes

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Sep 7, 2020
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The new car arrived yesterday and it did come with a short guide which, as usual, included a lot of 'where fitted' stuff which I don't have.

Between that and the full user manual there is no information on payload, towing and tire pressures. One is advised to look at the placards on the actual car, which are not exactly easy to interpret.

The only piece of information relevant to this issues that I found was that the 'nose weight' maximum is now 100kg whereas on the old model it was 75kg.

The manuals I found on line do have some information but its now obvious that these are for different geographic regions and it seems odd that supposedly the same car in different countries can have different information in this respect.

Then again talking yesterday to the company that's going to fit the towbar, they told me that they sometimes get the same vehicles type come in but made in different regions and have different specs
 
Jan 3, 2012
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We check our handbook for towing pressures and also the door pillar but now things have change they have to be reset at the VW dealer
 
Nov 11, 2009
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We check our handbook for towing pressures and also the door pillar but now things have change they have to be reset at the VW dealer
What do you mean “ reset” at VW dealer? I really cannot understand why a dealership have to be involved in tyre pressures.
 

Sam Vimes

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Sep 7, 2020
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There may well be a whole host of reasons, both personal and technical, why someone has to get the garage to do somethings on a vehicle. Sometimes it helps to understand that everyone is different from ourselves.

I once had to take my brand new Toyota of just a few days old back to the garage because I couldn't find the jack. It took them just 30 seconds to point it out under one of the seats.

As Beachball is fond of saying 'To each his own'.
 
Nov 16, 2015
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What do you mean “ reset” at VW dealer? I really cannot understand why a dealership have to be involved in tyre pressures.
There are several Youtube videos showing how to reset the TPMS on the Tiguan, and other cars.
 
Jul 18, 2017
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What do you mean “ reset” at VW dealer? I really cannot understand why a dealership have to be involved in tyre pressures.
Fitter does not allocate sensors to correct tyre i.e. sensor from front offside is put on rear nearside?
 

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