Tyre Pressures

Discussion in 'Tech/Mech General' started by OddSocks, May 12, 2014.

  1. OddSocks

    OddSocks Read Only Funster

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    Forgive me starting a new thread for this, but thought it important.

    I just checked my tyre pressures! On advice from another thread about performance.

    I have 215 R14 C tyres on. According to the plate attached to the drivers seat they should be inflated to 40psi front and 47psi at the rear

    I found them to be inflated to 75 and 62 at the front and 75 and 78 at the rear.

    The pressure on stamped on the side of the tyres which I think is the maximum pressure rating is 65psi. So I am worried about my tyres now. They all have very deep treads on them, which appear to be even across the tyre. I have only done a few hundred miles on them since purchasing the van. But who would have pumped them up so high, and why?

    So should I be worried about the tyres? I have let them all down to the pressures indicated on the drivers seat now, and they do look a little like they need pumping up!

    What to do?
     
  2. veevee

    veevee Funster

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    Are these the correct original size for the vehicle and the rim?
     
  3. JeanLuc

    JeanLuc Funster

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    The pressures you found in the tyres seem remarkably high. 65psi as marked on the tyrewall is the maximum allowable pressure. Also note that above 65psi (4.5 bar) you need high pressure valves, not the standard rubber car tyre valve.

    Specific Camping Tyres run at higher pressure than standard van commercial tyres - yours are the latter so higher pressures do not apply. Camper tyres are marked CP (Camping Pneu) standard van tyres are marked C. Many of us run on C tyres and a they are often standard equipment when the motorhome leaves the manufacturer.

    To check your correct pressures, you really need to know the actual loaded weight on the axles, but for practical purposes, if you go off the weight plate maxima and then apply the factors contained in the tyre guide (available in the Fun downloads section) you will not go far wrong. Here is a link to the download:-
    http://www.motorhomefun.co.uk/downloads/useful-tools/7/motorhome-tyre-data-74/
     
    Last edited: May 12, 2014
  4. OddSocks

    OddSocks Read Only Funster

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    Have no idea, only had it a few weeks. I guess there is a good chance they are original. The plate attached to the drivers seat mount specifically names the 215 R14 C tyres, and that is what is on the van now.
     
  5. sb8263

    sb8263 Funster

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    Did you check them when not driven on them ? what i mean is cold,,,,i am a tyre fitter and if you drive around then check preassures they will show a lot higher,,,,,,always check tyre preassures when the tyre is cold,,,,before you drive anywhere,,,:thumb:
     
  6. OddSocks

    OddSocks Read Only Funster

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    Yes, stone cold. I have not driven at all today.


    Will look in the book that came with the van. There is a tyre pressure chart. My tyres are not on the one you linked to.

    Thanks for all the help btw. I will check the pressures again using a different gage. I am using a digital one I got in Halfords, so it is possible it does not function correctly? I'll find another one to use.
     
  7. NickNic

    NickNic Funster Life Member

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    Just a thought...

    Are you sure your pressure gauge is reading correctly? May be worth checking them with a different one.
     
  8. JeanLuc

    JeanLuc Funster

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    Whoops - sorry, I did not check the list of sizes in the guide before putting in the link. If you check / know the axle loadings (when loaded) the tyre manufacturers will normally tell you what pressures to run at if you give them a call.
     
  9. OddSocks

    OddSocks Read Only Funster

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    Bloody made in China junk waste of money crap!

    The tyre pressure gage I purchased was way out of calibration.

    Borrowed one from dad. His read 32.5, my new one from Halfords read 40
    Dads read 38.5 at the back, my new one from Halfords read 50

    Can I pump the buggers up? Nope. The 10amp rated 12v extension lead from guess where will not carry enough power for the 10amp compressor to run. It craps out at about 44psi - I need 47psi at the rear.

    What a bloody stupid day I have had! :Angry:

    Not sure I will ever buy anything from Halfords again. Although having said that the new windscreen wipers I have on my van and also my car are totally brilliant!

    So looks like I will be feeding 50p pieces into the pump at the shell station to get my rear tires back up to pressure. Bugger! I hate paying for air. :Angry:

    Avoid Halfords digital air pressure gauge. Crapola!
     
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  10. TheCaller

    TheCaller Funster

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    It's worth pointing out, for anyone who genuinely does need higher pressures, that many garage forecourt air supplies only go up to 4 bar (approx 60psi). At least my local garage only charges 20p, but you only get one tyre up to 4 bar for that if it needs very much putting in.

    Fiat's door panel quotes 5.5 bar on my Ducatto Maxi. For their 225/75 R 16 CP that are fitted, Continental quote 3 bar front & 4 bar rear for the actual weighbridge verified loaded axle weights (which is pretty close to the 3.5T max). It rides & drives very much better at Continental's recommended pressures than it does at Fiat's. :thumb:
     
  11. scotjimland

    scotjimland Funster Life Member

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    Buy a good12v compressor and no more "stupid days" .. :Smile:

    Like this Ring RAC900

    I believe Halfords also sell them..:Wink:

    If you don't want to spend that much then a double barreled foot pump will do the job.. and as a bonus.. build up you're leg muscles.. :Laughing:
     
  12. tonyidle

    tonyidle Funster

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    Good info in that link. I was rather amused however by the "Popular Axle Configurations". Apparently everything that's popular, other than a straightforward four-wheeler, is RWD.
     
  13. Phill D

    Phill D

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    a few pointers having corresponded with my tyre manufacturer on this subject ( Vanco Camper tyres ).

    1. the max pressure printed on the wall of the tyre is for US use only, is not relevant to EU. mine also says 65psi .

    2. you need to weigh the axles separately and then email the tyre manufacturers customer services who will give you the correct pressures.

    eg; my tyres say max 65psi on walls. FIAT say 5.5bar all round full loaded ( 80PSI ), having weighed the axles Continetal Vanco emailed me back and gave me... the following:-

    Fully loaded; Front 62 psi .. rear 80psi ( thats 1500kgs front and 2000kgs rear )
     
  14. Puddleduck

    Puddleduck Funster

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    Great timing! We just got the van weighed (and it is 3120 kg, including us, full fuel tank, full fresh water tank and with basics aboard :BigGrin:) so can now check out the tyre pressures.
     
  15. Masman

    Masman Funster

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    Maplins do a high pressure pump
    :thumb:
     
  16. OddSocks

    OddSocks Read Only Funster

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    Thanks guys.

    My compressor works fine so long as I don't plug it in to the 12v extension cable. So I can pump the front two tyres, and by taking it out via the hab door I can do the rear passenger side tire. Just can't reach the rear drivers side without the extension. So that tire can only be inflated to about 44psi until I get a higher rated extension.

    Where can I get my axles weighed?

    For the moment I will inflate according to the axle weight on the info plate by the drivers door. There is a chart in the owners manual with the pressures.

    Cheers dudes!

    And remember Avoid this useless product
     
  17. Sidney

    Sidney Funster

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    I used to run Vanco. This MH came with Michelin and I just got an email back from them...


    The Michelin Agilis Camping tyre is designed especially for motorhomesand would be the preferred fitment on a motorhome.

    The Agilis Camping tyre boasts a long life by using the same technology as the Michelin Agilis van tyre range. It has a reinforced construction to enable the use of higher pressures, has 8 kerbing protectors built in to each sidewall to increase resistance of sidewall scuffing and is M+S (mud and snow) marked to give sufficient grip when occasionally travelling in difficult conditions such as unsurfaced roads, mud and snow.

    The suggested tyre pressure for the rear of a motorhome running on the Agilis Camping is 80psi. This is due to the construction of the tyre with 2 casing plies enabling the use of higher pressures. Its construction and the use of higher pressures is designed to cope with continual heavy loads sometimes found on Motorhomes and can help with wear pattern issues if lower pressures are used particularly on the rear axle.

    The front pressures however can be adjusted according to accurately weighed axle loads for a more comfortable ride and optimum performance.



    So no matter what the weighbridge figure are put 80 PSI into Michelin Agilis on the rear axle. Hmmm :RollEyes:
     
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