Off-Road Tyre Guidance, Tire ideas

Off-Road Tyre Guidance, Tire ideas

This video clip is all about tyres and how to read the codes on the sidewall.

one:02 Common Knowledge Dimensions Codes
three:23 Load Rating
six:43 Load Rating Deflated Tyres
7:50 Velocity Rating
8:fifty six Very best Prior to
ten:37 PLY Rating
eleven:26 Mud & Snow Tyres
twelve:thirteen Tread Depth Gauge
thirteen:21 Yellow DOT
fourteen:22 Over INFLATION AND Less than INFLATION

For Mud terrain vs All terrain see this video clip:

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48 thoughts on “Off-Road Tyre Guidance, Tire ideas

  1. the yellow dot is meant to be at the valve but sometimes as a tyer fitter you have to spin the tyer on the rim to lower the weight you have put on a tyer as all rims are not round
    again this all depends on the rim manufacturer cheap Steal rims are more likely to be more out of round than a higher end rim

  2. 1:40, I'm thinking the R stands for Radial. Practically a forgone conclusion at this point, but when radial tires were first starting out, there were predominantly B bias ply tires
    7:47, Almost. Load ratings are for the given pressure at the rated speed. You can exceed the rated load without a problem, but if you do, you cannot approach the rated speed. Likewise, if you lower your pressure, the weight rating at the rated speed is reduced, you can just go slower than the rated speed. This is handy info bc usually when you run reduced pressure, you're off road and not going highway speeds anyway.

  3. In Europe the information needs amending, the maximum speed rating of the tyre must exceed the maximum speed of the vehicle to be legal. I have to have an S rated tyre as the S rated tyre is 1 MPH higher then my vehicles maximum speed.

  4. Great information as always Ronny! Question. If a tire is load rated at 1700 @max pressure of 80psi, then what is the load rating at the "actual" tire pressure that is in the tire? Nobody puts 80psi in a mud terrain, correct?  The vehicle  manufacture specs dictate the psi (usually found on the drivers door jam in US and Canada), so by using that psi, we are never at the tire manufactures max load rating. Is there a formula then to figure out what the load rating then is for a 1700@80psi three when the tire is ran at 40psi? Would it be 850 because only 50% of max pressure is used?

  5. I've been researching tires for at least a year now, actually learnt something new. Didn't know how to read the man date, and I didnt know about the yellow dot…good vid once again Ronny! Cheers!

  6. New to all of this, never paid attention to my tire specs, you are very informed, this was an excellent video and a great help. Thanks for sharing your knowledge!

  7. Hey Ronny, you videos are so dense in terms of information, I just wanted to thank you for providing us such a nice 4WD show! Its a pleasure to watch every single video you make. Keep up the great work, Cheers from Northern Germany!

  8. I was under the impression that there was a point in which the first number on the metric measured tires stopped indicating the width and began indicating the height of a tire. Perhaps I learned this incorrectly many years ago.

  9. For good technical information about tyres (tires in USA) download the pdf document, DOT HS 810 561 (following link), distributed by US Department Of Transport.

    Chapter 5 “Tire Load Capacity” was written by Stephen M. Padula, an engineer with Michelin North America.
    A tyre placard attached to a vehicle provides the correct tyre inflation pressure for the stated load and tyre size. The tyre manufacturer states the maximum load at maximum inflation pressure on the sidewall of LT tyres. What both the vehicle and tyre manufacturers are primarily concerned with is the correct, or optimum vertical deflection of the loaded tyre, because tyre footprint and heat created at speed are directly linked to tyre size and vertical deflection, and thus to load and inflation pressure.

    When either of, tyre size or load, are changed the inflation pressure must also change to obtain the correct, vertical deflection.
    For a tyre, same as for any spring, Vertical Stiffness = Vertical Load divided by Vertical Deflection

    Now, Vertical Stiffness is a function of, tyre size (effective volume of air), inflation pressure, and inherent stiffness of the tyre carcase, which is usually ignored being relatively small.
    Vertical Stiffness Kz = 0.00028 * P * square root[ W x OD ] + 3.45 (from Michelin North America) where:
    Kz is Vertical Stiffness in kg/mm
    P is inflation pressure in kPa W is tyre tread width in mm
    OD is tyre outside diameter in mm
    The TRA (Tire and Rim Association) publish load vs inflation pressure data for LT tyres based on the formula: Load = Max Load * (Inflation Pressure/Max Pressure)^0.7

    When you don't have the TRA load vs inflation pressure data, but you know:
    the vertical load on the tyre, the maximum load and maximum inflation pressure from the tyre sidewall, the TRA formula can be used to calculate the inflation pressure for LT tyres:
    Inflation Pressure = Max Pressure * (Load/Max Load) ^1.4286
    note: (1/0.7) = 1.4286
    units for pressure and load are same as given on tyre sidewall

    Alternatively, for a conservative (higher) Inflation Pressure, close to what Michelin North America recommend, use the following formula:

    Inflation Pressure = Max Pressure * (Load/Max Load)

    The maximum load rating for an LT tyre increases if any of the following increase:
    tyre sidewall height (increases effective volume of air)
    tread width (increases effective volume of air)
    maximum inflation pressure (i.e. ply rating/load range increase)

  10. As always a great video Ronny. Thanks for uploading this, was most enlightening and it never hurts to refresh knowledge hey I'll be sharing this as I do most of your videos to Geraldton 4×4 FB Group.

  11. 1) To brush over Speed Rating is slack. It's really important from a legality point.

    For insurability purposes you must not have tyres which have a speed rating lower than that on the tyre card stated by the manufacturer of the vehicle.

    Every year many crashes occur and insurance companies refuse to pay out because the 4wd owner fitted a lower speed rated tyre and hence made the vehicle unroadworthy and uninsured. Eg fitting Symex jungle tyres to a 2016 Landcruiser 200 Wagon – it's not legal.

    It's an inconvenient truth and a bitter pill to swallow. There is literally 1000's of uninsured 4wd's out there with owners who unwittingly  fitted under-speed-rated tyres.

    2) Ply "Rating" is as stated here but it is for weight carrying purposes and not puncture resistance. Also, the various belts and cords do not "Add Up" as is stated here. That's just wrong. The 10 ply rating is separate from the individual actual plies.

    The ten ply RATED tyre in this video has the LOAD carrying capacity of an original bench-mark standard plied tyre with ten actual plies. Modern materials and manufacturing methods have achieved this. A tree root or sharp object doesn't care about technology.

    A 10 ply cross ply tyre with 10 actual belts / cords is many times stronger against puncture and stakes.

    The more plies a modern radial tyre has is not necessarily commensurate with greater puncture or stake resistance. This must be remembered when tyre shopping.

  12. Load rating is defiantly the best thing to look up. Some people at tire shops don’t understand and could sell you the same brand, model and size you want but a load rating suited for an SUV and not for the 1 ton truck it’s going on. I just bought tires and the guy at the shop had no idea what it was good for but I verified they were suitable, was load rating “E”

  13. Could you post images of how much the tire should bulge? It probably comes down to experience but I swapped out the grandtreks on my Cruiser for cooper AT3s and they buldge way more at the same pressures. Currently going off door jam recommendations of 200kpa. Sometimes I add 10-20 if it feels too squishy.

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