2

I'm fixing up my box trailer (a Lynton Loadtrekker), which is now 9 years old.

I want to replace the rusted wheels and aging tyres, as I was advised in this answer.

Now I'm trying to work out what replacement part to order. I don't have a manual for the trailer. I've been working out the details by looking at the original wheels and tyres. A local supplier has pointed me at two apparently suitable replacements, but they aren't quite the same as the originals.

Originals:

5.00-10
4 stud holes with 4" PCD
Zero offset
8 ply rating
Tyres marked: Max load 500 kg at 71 PSI
Trailer plate marked: Gross laden weight 750 kg, Tyre pressure 60 PSI

Replacement candidate 1 TWT 1011:

6 ply
Max load per tyre 437 kg
Max pressure 45 PSI

Replacement candidate 2 TWT 1012:

8 ply
Max load per tyre 475 kg
Max pressure 65 PSI
£13 more expensive than candidate 1 per tyre

If I understand this correctly, both candidates are OK with respect to max load: I need at least 375 kg per tyre (trailer gross laden weight 750 kg / 2).

Also, because candidate 2 has a higher ply rating, I expect it might last a bit longer.

But I'm confused about the tyre pressure.

The supplier says with candidate 1, I'd need to inflate the tyres to their max pressure of 45 PSI.

They haven't given me a clear answer about candidate 2. I assume I shouldn't inflate them to max, similar to the originals, where max marked on the tyre is 71 PSI, but the trailer plate says to use 60 PSI.

So the simpler (and cheaper!) choice seems to be candidate 1. But is this safe, given the replacements use a lower ply rating than the original?


The original tyre:

original tyre

5.00-10
84N
8 P.R.
LOAD RANGE D
MAX LOAD 500 KGS 1105 LBS AT 5.0 BAR 71 P.S.I. PRESS
TUBELESS
E4 0013825
4907
RIM:3
KINGS TYRE
MOULD FROM U.S.A
DOT 1NB1

Here's the trailer, to give an idea:

the trailer

2

The ply rating is a roundabout way to indicate the max. load. There aren't that many plies in the tire (just one or two, normally). You'll want some margin on the max. load, because without a scale it's difficult to estimate how much weight you put in the trailer, and you could overload it or put the load in asymmetrically.

There are other parts of the tire specification that indicate the max. load:

  • the load index (84N): 84 is a load of 500 kg, and speed index N = 87 mph
  • load range (D) = 8 ply

Candidate 2 is the closest to the original specs. Ignore the tire pressure indicated on the trailer, just use 65 psi for this tire.

BTW, Lynton is still in business, you could ring them for advice.

1

The main thing to consider is that you use a Trailer Tire and not an automotive tire. Next, make sure your load rating gives you an adequate safety factor on what you will be hauling with your trailer. Third, be sure to inflate your tires according to the pressure rating on the tire, not the trailer or somebody's suggestion. The load rating of the tire is based upon the printed pressure indicated on the tire. Other than that, you have many options to suit your needs and trailer.

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