Tyres - Ply Rating

Submitted: Wednesday, Jan 09, 2008 at 20:37
ThreadID: 53286 Views:7412 Replies:4 FollowUps:14
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Good evening,

I will be purchasing new tyres at some point during the next 4 months in preparation for a trip to the Simpson this year and then a trip through the centre and then onto the Kimberley in 2009. The vehicle does not do many km's around town, maybe 10k per year max. I have researched tyre brands and styles and will look to fit A/T's but will also consider M/T's. It seems to me that all brands have pros and cons and I have read posts about all the major brands having issues at various times, so it seems to me that the most expensive brands may not necessarily offer better overall value. I also understand that driving style, pressures and general care can often make more difference than tyre choice. I think I will head in the direction of Maxxis or Hercules as they seem to offer good value, I would have considered BFG's but it seems that they are possibly not the tyre they used to be and are expensive also. Having read numerous opinions I have come to the conclusion that going back to split rims is probably not needed these days but that also rules out purchasing MRF's which I know are very strong.

So, my question relates to ply rating. I currently have 15" rims and I have noticed that most of the tyres available seem to be 6ply construction but there are 8 and 10 ply construction available in 16" sizes. Hercules Terra Trac is and example of this (unless I have researched wrong). I understand that ply rating may not necessarily make a tyre strong anyway as there would be other factors such as design and quality. Are 6 ply construction tyres generally considered sturdy enough for heavy duty work or would you recommend selecting a heavier ply rating. To go to an 8 ply construction I would need to obtain 16" rims which shouldn't be too hard given the vehicle is a 60 series cruiser.

Sorry for the long winded question, I am just aiming to make the best choice of tyre to cover me for both trips if possible. Thanks in anticipation.

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Reply By:- Wednesday, Jan 09, 2008 at 21:09

Wednesday, Jan 09, 2008 at 21:09
G'Day Dave

I run the A/T Terra Trac in 10 ply.

The 10 ply is a few kg heavier than the 8 ply according to the website.

AFAIK the extra weight must come from somewhere, presumably extra rubber, so should offer more puncture resistance than the 8 ply. How much is unknown.

I found I had to run the 10 ply on about 13PSI over Big Red, whereas mate with Cooper ST had no trouble on 20PSI.

Hope this helps

AnswerID: 280676

Follow Up By: Davo_60 - Wednesday, Jan 09, 2008 at 21:35

Wednesday, Jan 09, 2008 at 21:35
Thanks for the info Rolande. Have you had a good run out of the Terra Tracs?
FollowupID: 544974

Follow Up By:- Thursday, Jan 10, 2008 at 21:36

Thursday, Jan 10, 2008 at 21:36
G'Day Dave,

Technical info can be here


My 10ply do have a higher load rating than the 8ply of the same make/size, and as mentioned, also weigh more.

Two tyres currently have close to 50K on them, the other two almost 40K. I am confident that they would last for 70K.

I will change them well before this as we have another outback run this year and I like to have a fresh set at the start of each trip.

Just a report from our local supplier, he said he has never had a return for warranty in the three years he has been selling them, and they have been fitted to lots of logging contractor vehicles, earthmoving contractors, etc. Around town I would guess at 1 in 4 vehicles has them fitted, (medium country town)

The 10ply generally come in around $50 - $80 cheaper per tyre than BFG or Cooper.

I'm happy so far


FollowupID: 545187

Follow Up By: Davo_60 - Thursday, Jan 10, 2008 at 22:01

Thursday, Jan 10, 2008 at 22:01
Thanks Rolande, great info. Hopefully someone supplies them in Canberra.

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Reply By: Member - Axle - Wednesday, Jan 09, 2008 at 21:39

Wednesday, Jan 09, 2008 at 21:39
Hi Davo, just to chuck a spanner in your works! ,i was told by a well known tyre company, that ply rating is not the issue its LOAD rating that should be looked at. Dunno! bought crap brand at the time, they have done 40000 k about half worn out and have carried a fair amount of weight around for the last two years. Its pot luck half the time i reckon.

Cheers Axle.
AnswerID: 280688

Follow Up By: Davo_60 - Wednesday, Jan 09, 2008 at 21:51

Wednesday, Jan 09, 2008 at 21:51
Thanks Axle, I hadn't really taken much notice of the load rating. I might go back and compare them also. I think you may be right that luck has something to do with it with most brands. I don't mind spending extra for a better product but don't like throwing money away for the same result.

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Follow Up By: splits - Wednesday, Jan 09, 2008 at 22:25

Wednesday, Jan 09, 2008 at 22:25
I have heard the same thing Dave. Plys can vary in thickness and the material they are made out of but a load rating is a load rating and that is it. I have noticed while looking at some tyre company sites that the same type and size of tyre often comes in different ratings.

You may find it benificial to ring the technical inquiry number of the manufacturer of the tyres you select and discuss, pressures, load ratings, different types of driving etc. I did this recently with Goodyear and had a long talk with them. The information I was given would start a few arguements on this site but I followed it to the letter on a recent major trip and everything worked perfectly.

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Follow Up By: Davo_60 - Wednesday, Jan 09, 2008 at 22:38

Wednesday, Jan 09, 2008 at 22:38
Thanks Brian. There really is so much info and choice out there and even spending more does not seem to necessarily guarantee better results. I will try obtaining technical advice from the manufacturers as suggested. I'm guessing your advice related to pressures etc. and I have read every possible opinion on that subject through this site and others, don't need to get into that argument!

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Reply By: Member - Scoof (SA) - Wednesday, Jan 09, 2008 at 21:56

Wednesday, Jan 09, 2008 at 21:56
Hi Davo,

I was in the same position before Xmas as you.
This time I bought on price, so far I'm happy with the choice, the tyres are called Trailcutter made in USA.
When I was looking for tyres I didn't have a huge choice I have 17" X 265 it limits the choice some what.
Over $100 cheaper per tyre over BFG.Hope I don't regret it later but time will tell.
I purchased Michelin last time never again that's why this time I went on price,rather than a well known brand.
You will have a good choice with 15" and 16" happy hunting.

Scoof .. :-)
AnswerID: 280691

Follow Up By: Davo_60 - Wednesday, Jan 09, 2008 at 22:07

Wednesday, Jan 09, 2008 at 22:07
Thanks Scoof
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Reply By: mattie - Wednesday, Jan 09, 2008 at 21:56

Wednesday, Jan 09, 2008 at 21:56
Hi Davo
the ply rating is exactly that, it is not how many ply layers there are, which would relate to the load rating as mentioned above.
We have 10 ply rated coopers and have had a great run out of these but i would say that the 10 ply rating does make the ride rougher and i only ever run them at 35psi even when loaded and the kk hooked up, the stiffer tyre i would have to agree with the above post about having to let the tyres down further to travel on very soft sand.

AnswerID: 280692

Follow Up By: Davo_60 - Wednesday, Jan 09, 2008 at 22:11

Wednesday, Jan 09, 2008 at 22:11
Thanks Mattie, now that you mention it I do recall something about ply rating being just that, at rating. Given that others are using 10ply I am leaning toward getting hold of some 16" rims and going for something with a 10ply rating, not too concerned about the ride - it's already rough!

FollowupID: 544986

Follow Up By: Member - Oldplodder (QLD) - Thursday, Jan 10, 2008 at 08:54

Thursday, Jan 10, 2008 at 08:54
My understand of ply rating, is that it is used to be the actual number of plies in the tyres, when they were canvas and rubber. So more plies (and more rubber) gave you a heavier load rating. May still be the case with cross ply truck tyres.

Looking at my radial 10 plies, the sidewall states 2 plies nylon plus one ply of steel, and 2 plies in the walls, same as 6 and 8 ply tyres. Maybe they just use heavier plies instead of more? Load rating is 112/120 however, a lot more than a 6 ply tyre. And it is a heavy (in weight) compared to a 6 ply, so it must be more rubber.

8 and 10 ply tyres do give a harder ride.
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Follow Up By: Davo_60 - Thursday, Jan 10, 2008 at 13:25

Thursday, Jan 10, 2008 at 13:25
Thanks Oldplodder, I think I will look for a set of the factory 16" (not splits) and fit some heavy duty 16" tyres in an 8 or 10 ply rating and use them for the trips.

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Follow Up By: jeepthing - Thursday, Jan 10, 2008 at 14:20

Thursday, Jan 10, 2008 at 14:20
mattie, If you have a look on the sidewall of your ST's, I assume that's what they are? you'll note that the tread is rated 2 ply steel and 2 ply polyester, the sidewalls are 2 ply polyester.

I asked the local Cooper dealer about this and I was advised Coopers use a thicker cord than a majority of manufacturers so they multiply by 2.5. This means tread is 10ply and sidewalls 5ply.

If you get the opportunity get hold of a case and with your fingers on both sides see how thick the sidewalls are particularly on the roll from the edge of the tread to the sidewall....you will get a shock.

You will find that all radial tyres are like this hence easy staking and stone penetration in this area. I have seen a stick no thicker than a matchstick puncture this area.

I have been advised that because the tyres are a radial tyre they need to be like this.

I was informed that the only tyre that has a thicker area in this vicinity is a cross ply which is fitted on a split rim and in reality these types of tyres are the only really bullet-proof ones in their construction.

The load rating is extremely important when loaded and probably more so when towing and loaded. A light truck tyre has a greater load rating than a passenger constructed tyre.

As an example, a Pirelli Scorpion AT in LT245/70R16 has a load rating of 113S 1150kg @180k; a Dunlop Grantrek in the same size and they don't appear to make this size in LT is 107S, 975kg @ 180k and a Cooper ST LT245/75R16 is 120N, 1400kg @ 140k.

Cooper don't seem to make a LT in 245/70R16, but as you can see it would be a stronger tyre due to the load rating but that load rating expires at 140k.

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Follow Up By: Davo_60 - Thursday, Jan 10, 2008 at 15:01

Thursday, Jan 10, 2008 at 15:01
G'day Jeepthing,

I have taken on board the advice generally from this thread in relation to load ratings etc. The main issue I have found is that the load ratings on the 15" tyres from most manufacturers are lower that for the 16" tyres. Most have 8 and 10 ply ratings (and higher load ratings KG) for the 16" but not 15". I currently have 15" rims with Pirelli Scorpions but I think it may be worth getting 16" rims with something like 10 ply Maxxis to use for touring. They originally came out with 16's anyway.

FollowupID: 545085

Follow Up By: jeepthing - Friday, Jan 11, 2008 at 08:20

Friday, Jan 11, 2008 at 08:20
Hi Davo,

How do you find those Scorpions. Are they the ATRs or ATs. The tyre size for my vehicle is 245/65 R17 and unfortunately the brands that have that size are limited. Coopers don't make the ST in that size and I have been having problems with the ATRs with puncturing. Coopers tell me that the compound is too soft for gravel/stone country. They don't make them in LT for my size.

It's got to the stage where I really don't trust them anymore as I do some fairly isolated travelling. I've been doing some extensive research and came across some testing that Australian 4WD Monthly did on tyres some years ago and the Pirellies came up trumps. I like the tread pattern on the ATs
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Follow Up By: Davo_60 - Friday, Jan 11, 2008 at 20:41

Friday, Jan 11, 2008 at 20:41
Hello Jeepthing,

The Scorpions were on the vehicle when I bought it and I would estimate they have travelled about 25k. They still have good tread depth so I would estimate 50 - 60k should be no problem. I have mainly driven on road with some dirt but no off road. They are the Scorpion A/T's. I have not had any issues with them but as mentioned I have not given them a hard time either. On road they are fantastic and tend to mask the 60's ride and handling deficiencies, good on dirt. I previously owned an FJ62 with BFG's and the Pirellies are light years ahead on road. I have researched them and have found good and bad reports similar to almost every other tyre brand.

I have enough tread on the four on the vehicle to complete this years trip and I have considered the option of buying 1 new scorpion spare and just sticking with what I have. The only issue is that I would still need to buy tyres next year anyway. I am still leaning toward keeping the scorpions for on road use and getting a set of 16's for bush work.

FollowupID: 545393

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