Commercial Tyres & Weight Debate - my experience so far.

Discussion in 'Mech Tech' started by paulcalf, Sep 25, 2013.

  1. I'm posting this in case it is ever useful for those involved with the great commercial tyre & weight debate.

    In a previous thread Zed kindly pointed out that my incorrect rated tyres, may be one of the reasons I was blowing about in the wind at high speeds.

    They are Conti 185 65 R15 88T (Max load per wheel 560kg).

    To cut a long story a bit shorter, I spent ages trying to source some Commercial rated tyres of the same size.

    I couldn't find anything that much better, despite conversations with the Technical Services Mgr for Conti & with Stapletons (National tyre wholesaler).

    If i could go wider then I may have more options, but that would mean ditching my fuchs (connected with 25mm wheel adaptors).

    So I started considering changing my brake set up to porsche pattern 5 x 130, so i could ditch the adaptors & fit wider tyres with a slightly better rating.

    This was going to cost a bloody fortune, but when speaking to our very own Mr Weeding he suggested I visit a weigh bridge.

    Gross weight 1580kg (including me@80kg, EDIT weight taken at 1pm, kids dropped off at pool at 8am- see post below!)
    Front axle 720kg (including me)
    Rear axle 820kg (I was still in van but only rear axle on weigh bridge)

    After that I visited an old colleague who is a tyre expert (working in fast fits and on commercial vehicles). He said the best tyres he could source in my size were Yoko 185 65 R15 92T reinforced. Result, these should be better than my car tyres & will handle up to 630kg per wheel e.g a rear axle of 1260kg!

    OK the vehicle wasn't fully laden, but it weighed quite a lot less than I had been expecting.

    This is what went on the weighbridge:
    Late bay, devon pop top, bunks, bench seat, buddy seat, fixed table. It doesn't have a fitted sink or cooker.
    Vehicle contained: Under buddy seat: tools, spares, jump leads, 2 x gas burners. Rear: 1/4 tank petrol, duvet, pillows, 2 camping chairs, table, boules, bow & arrow, badminton kit, kettle, pans etc

    Estimated fully laden (Unlikely I'll ever put this much in)
    Front 720kg + Another large adult 80kg, food & booze 50kg, clothes 2okg. Total = 870kg max?
    Rear 820kg + 4 x large adults on rear seat 320kg, More fuel, 40kg, awning 20kg, more camping chairs 10kg. Total = 1210kg max?

    I will go back to the weigh bridge when im fully laden with camping gear,

    NEW INFO: I went back to Weigh bridge fully laden
    and I mean fully laden.
    Gross weight 1900kg
    Front Axle 940kg
    Rear Axle 1040kg


    Front: me and my partner, 40l fridge packed with booze
    Middle: Massive tent/awning, 2 person tent, food, camping stuff for four people, clothes etc
    Rear: 6ft/80kg mate, his 7 year old son. Full tank of fuel. Under rear seat: cadac bbq, gas bottle, 2 tables, 2 chairs, wind break

    Summary my new 185/65/R15 92T reinforced tyres are legal and more than adequate! 630kg per tyre load rating!

    New info ends!

    So I think if i get reinforced tyres with a slightly high load rating (92) then I will be good to go!

    Some of you (if anyone actually reads this far) will think i should just change back to 14" wheels. I'm not doing that because when i was growing up i always wanted a set of fuchs, plus if i changed back it would balls up the gear ratios and i've just fitted a new box that matches up well with the engine ratio wise. So do one!

    For the uber geeks and anyone else still alive after reading this:
    Original bay window van tyres were either 185 R14 C 6PR, or 185 SR14 Reinforced (stengthend passenger car). Diameter was approx 652MM. (based on 185 80 14, rather than 82% profile)

    Current tyres & 15" wheels have a diameter of 621mm ish (based on 185 65 15) & i'm happy with this gearing.

    Weights from Original Vehicle manuals:
    Van weight (Camper)
    Unladen 1495kg
    Capacity/Payload 755kg
    Gross Vehicle weight 2250kg
    Gross axle front 1010kg
    Gross axle rear 1270kg

    Conclusion:
    I've been typing far too long, i need a *******, my friend is cooking me tea and i'm running late! Plus I've spent far too long trying to research & find the correct tyres. Before i joined this forum i'd happily been driving around with the wrong tyres for 10 years!

    I hope this benefits somebody, somewhere at some point.......................or you can all just rip the ******* out of me............i haven't even bought the tyres yet!
     
    Last edited: Sep 9, 2015
    Ben72, Kruger, Sick Boy and 11 others like this.
  2. Poptop2

    Poptop2 Administrator

    I was safely assured by my hgv tyre fitting company 600lb rated tyres are ok but officially 900lb?
     
    paulcalf likes this.
  3. Kruger

    Kruger Sponsor

    Good write up, keep it updated with how the reinforced tyres go.

    Cant say I ever have to go have a tug after typing for ages, but if needs must -& if thats your thing, crack on...:)
     
    konaboy6284, dog, MK-Bay and 3 others like this.
  4. Also remember that roadholding is a factor too, not just weight. I found my van didn't wander anywhere near as much after I went back to C rated tyres.
     
    brothernumberone and paulcalf like this.
  5. Thankyou for taking the time to post a most informative thread regarding this subject BB. Out of interest how much do you think you will weigh after your dump?
     
    paulcalf likes this.
  6. Seriously though...a large cooked breakfast can make all the difference when it comes to buffeting and cross-wind situations;)
     
    paulcalf likes this.
  7. 77 Westy

    77 Westy Supporter

    If you want to be legally correct the actual weights are immaterial, it is the specified weights that the tyres must be suitable for. Anything less and your insurance could be invalid just when you need it most – in the event of an accident.

    With a declared maximum rear axle loading of 1270kgs each tyre must have a load rating of 93 (650kgs) or higher, regardless of the actual weight.

    600lbs is about 272kgs, 900lbs about 408kgs, neither are even close to being safe.
     
  8. I'll keep you updated when I fit them

    I should have entitled the thread guess the swear word that has been blanked out!
    tug is only 3 letters, you should have gone for t u g :D
     
    Last edited by a moderator: Mar 18, 2014
    Poptop2 likes this.
  9. Glad is was useful

    I think I could deduct about 5kg after a dump!
    I'll go and update the original post and add in how long it was since i took one though as that could have a huge impact on the overall weight i'm basing my entire calculations on!

    After a w e e w e e it would only be be about 500g i'd be deducting though
     
    Last edited by a moderator: Mar 18, 2014
  10. Good point but as they aren't available in my tyre size, in the event of an accident, I think i could argue that i had sourced suitable replacements based on the actual weight of the van.
     
  11. Interesting Info
     
    paulcalf likes this.
  12. Poptop2

    Poptop2 Administrator

    I think the bit we need to concentrate on is the sidewall and ply rating - prefix P = 3-5 ply which is not strong enough for vans prefix C = commercial 8 ply plus. this is what you need on your van- C prefix.

    Any thing less is chancing it!
     
    paulcalf likes this.
  13. In the size i need i can only get the Yoko 185 65 R15 92T, I'm told these are reinforced 6 ply tyres used on commercial vehicles, so sidewalls will be stronger than my current car tyres. They are not 102 C tyres, if any one ever finds 185 65 R15 102C then please let me know!
     
  14. It says "R" on the side of mine, then a space , then "ULD"...not exactly sure what it stands for? maybe some of the other letters have been scrubbed off due to kerbing;)
     
    paulcalf and Poptop2 like this.
  15. I've sourced some Continental Vanco Contact2 185/65/R15 92 T Reinforced tyres, to replace the 'car' tyres that I had on.

    I'll update the thread when I've done a few miles in them, to let people know if they have made any difference to the vans handling.

    Fingers crossed it stops the van trying to 'wander' at high speeds in high winds.
     
    Poptop2 likes this.
  16. By high speeds,
    Do you mean double figures?
     
    Richard W12 likes this.
  17. yep I once got it up to 11mph!
     
    minirob and konaboy6284 like this.
  18. The wandering in high winds could be play in the steering. Ours did (even with C rated tyres on).
    I had the idler pin replaced, and they also recommended replacing the drag link, and one of the track rods - which has tightened things up quite a bit. The steering box is next on the hit list as it's leaking anyway.
     
  19. Marc
    I also think the wandering in the wind could be caused by something else (Swing lever?).

    I started a thread on it ages ago, but was advised tyres were first thing to change, so i'll see if that makes any difference first then start looking at Steering related bits!

    http://thelatebay.com/index.php?thr...ds-in-strong-winds-swing-lever-problem.26426/

     
    MarcT512 likes this.
  20. Michelin agilis 195/70/15? 654mm rolling radius....
     
    Last edited: Mar 18, 2014
    paulcalf likes this.

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