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Tyre Pressure advice and members comments

Discussion in ''How To' & 'Handy Hints'' started by cammokombi, Jan 25, 2007.

  1. mish13

    mish13 Well-Known Member

    Messages:
    3,493
    Location:
    Gold Coast "Parkwood"
    mish13

    Hi Doc I couldnt agree with you more, I have a 74 camper and cant believe how affected it is by the wind and trucks. I dont know how people handle them with a bigger motor in them I for one would not want to go any faster. They say you get used to it I hope so as its soon to be my daily driver when my other car sells.
     
  2. Schmoburger

    Schmoburger Active Member

    Messages:
    4,381
    Location:
    Nowra/Jervis Bay area, NSW.
    You do get used to it. It's kinda like getting into a non-heated pool... at the moment you are still at the stage of freezing ya nuts off, but soon you will not wanna get out! :D

    But anyway... the effects of crosswind can be made a fair bit worse by any slack in the steering caused by a slack steering box, worn ball joints or tie rod ends, or worn center-pin... a lot of Kombis I drive do seem to haver a lot more play in the steering than they should... mine included at the moment, and it makes things rather hairy in strong winds.

    Having "Light Truck" (I use the term generically so don't go there those who normally go there... :D) tyres, which have multi-ply reinforced sidewalls does seem to help handling a lot in windy conditions... not so many spontaneous lane changes and such! :eek:

    Cheers!
     
  3. chopper

    chopper New Member

    Messages:
    248
    Location:
    south of goldy
    After reading the thread yesterday I decided to change the tyre pressure as suggested (32@front and 40@back); I had the tyre pressure at 36 allround prior to that, as suggested by a mechanic. I use my Kombi as my daily(Banora to Helensvale-110km roundtrip) and the difference was quite amazing. It didn't seem to be affected by windgusts as much anymore and the drive was much smoother. Thanks heaps to start this one Cammokombi!!
    chopper
     
  4. Kombi Dad

    Kombi Dad Well-Known Member

    Messages:
    2,408
    Location:
    Bungendore, NSW
    Looks like after 50,000ks on the Coopers I should have been running a little less as the centre of the tyres have slight more wear then the outer edges. I have decreased the pressure slightly to give it a try. The 40 was recommended by the tyre company.
     
  5. syncro

    syncro Well-Known Member

    Messages:
    9,033
    Location:
    Southern Highlands
    Conflict of interest here. :)
     
  6. Kombi Genes

    Kombi Genes New Member

    Messages:
    11
    Location:
    Redcliffe
    around the 40 mark is what i have been told to inflate tyres to at work (apprentice mechanic) and inflating to around that mark will help to prevent your tyre wearing all in the one place and so you will get longer life out of your tyre... (should help to prevent tyre wear :p)
     
    Last edited: Apr 12, 2008
  7. jon ward

    jon ward Active Member

    Messages:
    5,759
    Location:
    Travelling Australia
    i work in a tyre shop and if u have normal passenger tyres eg; 185/65/14 then u should put about 34psi all round.
    if u have light truck tyres eg; 185R14 then u should have 38psi all round.
    Basic rule of thumb is;
    if u have 14inch wheels then 34psi
    15,16inch wheels then 36psi
    17,18 and above then u are nuts and should be driving a commodore.
     
  8. DonYan

    DonYan New Member

    VERY true !!! I learned to drive in a Renault Dauphine, next automobile was a '63 VW beetle, and mostly I like rear engine cars. With swing-axles, Mercedes Benz had a spring betwen the half-axles that augmented or diminished rear wheel camber, and the articulation point was LOWER than the diferential, not like VW's had articulation point at the midle of diferential.

    VW in 1967 reduced the diameter of the rear torsion bars, aded the "Z" bar that actually works on corners., or to suport more load. (the camber compensator) What it does, is transfer loads to the front axle. The stabilizing bar of front axle became stiffer, also.

    On all these autos I learned that for stability, and NO SIDEWIND SENSITIVITY, tyre diferential is BASIC. I also fidled with my cars, finding out what happens if I adjust this, or that, like rear wheel convergence. Factory VW setting say a litle divergence, and with convergence really you forget about side winds (not on hurricanes, though: there is a limit) and never noticed wear increasing on the tyres. The VW sedan half axles can be converged, they have slanted mounting holes for three bolts on the plate that holds them to the torsion bar. It makes a huge handling difference.- Now, I am talking of MINIMAL adjustments, 1/8 of an inch diference measured on one mark on both rear tyres, oriented to the front, then half rotating 180° to measure the same points again but oriented to the rear now. Rear measure should be 1/8 of an inch wider, betwen both rear tyres. Up front they should have convergence always.
    10-08-08_1440.jpg 10-08-08_1447.jpg 10-08-08_1442.jpg
    T-2 (bay windowsXP-SP3) Combis have CV joins, no swing axles. They have the same adjustment points for convergence-divergence adjustment. The automatic had, from VW factory setings, lower ground clearance on rear axle (slightly lower, the seem to be accelerating) and CONVERGENCE. Same adjustments that I made on my other non-automatic Combis...I use 48 psi when loaded, 44psi with my labrador & tools (1/3 full payload) Up front I use 33 psi to 35 psi
    23-06-08_1117.jpg 10-08-08_1449.jpg
    I also found it BASIC on the out back, to carry two spare tyres. One is up front the other on it's original spot. Both spares have 48 psi. The plywood top I made to cover the tool equipment, is because the "no see" technique avoids roberys...México is going through dire straights at this moment...the big cities have this problem, not on the back-country: the people are marvelous, the food is superb, the beer is cold!
     
    Last edited: Aug 11, 2008
  9. Mickldo

    Mickldo New Member

    Messages:
    106
    Location:
    Maryborough, Qld
    The idea of having different tyre pressures front to rear is to compensate for the different axle weights front to rear. Ideally the size of the tyres contact patch area should be the same on all four tyres. Obviously if the rear is heavier (like in a Kombi) then the rears should have a higher pressure than the front.

    A trick some 4wders use for getting the tyre pressures right is to measure the contact patch length. The easiest way is to get two sticks, screwdrivers, whatever and put one at the front of the tyre and one at the back. Slide them in under the tyre until the touch the tyre. Measure the distance between the two. It should be the same front and rear.

    Different driving conditions require different pressures/contact patch lengths. Whether you are driving on bitumen, gravel, sand or whatever there is an optimum pressure. Generally the rougher the conditions the longer the contact patch that is needed.

    As the vehicle load increases the pressure will need to go up to maintain the contact patch length. So once you figure out what length works well when driving around town unladen the same contact patch length can be used (with the corresponding higher pressure) when you are loaded up for a big trip.

    Once you have figured out the correct contact patch lengths keep a note of the pressures cause the pressures are a lot easier to adjust and remember while on the road.

    I hope you can all understand my description. If it doesn't make sense I will try to organise some photos of how to do it.
     
  10. Mickldo

    Mickldo New Member

    Messages:
    106
    Location:
    Maryborough, Qld
    Oh, I forgot to add that it pays to check the sidewall of the tyre for its max tyre pressure. Most passenger car tyres are only rated up to 35psi which might not be a high enough pressure for the load you are carrying. If you go over on this pressure you run the risk of blowing the tyre out. LT tyres have a higher load rating and higher max pressure and may be better in some circumstances.
     

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