D4 19inch COOPER Zeon LTZ 255 55 19

Hi Jon.

Excellent write up I think you have covered it all. I asked for science and you delivered an excellent synopsis of they factores in a form that is easily digested.

My conclusion being the only variable I can really afford to change in the travel I do is the tyre and by tyre I am actually referring to its load rating it needs to be more capable at these loads and I don't think there is anything in 19 inch that goes over a load index of 112 whereas 18s go to 114 for a NSW legal and up to 122 if you are in some of the other states not much more at 114 but it may be enough.

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Originally Posted by PaulGOz

18s go to 114 for a NSW legal and up to 122 if you are in some of the other states not much more at 114 but it may be enough.

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That tyre has more going for it than just its slightly higher load index as it is LT construction rather than passenger.

I am currently completing a loop of Aus towing a near 3.5t caravan. We have done about 17k kms on the trip. While we haven't done a lot of dirt roads we have done about 800kms of corrugated and rocky roads around Litchfield and from Alice to Kings Canyon as well as numerous dirt roads into camping sites.

I run Hancook Dynapro ATMs 255/55/19 (these are a light truck construction) with a TPMS to keep an eye on things. Front tyre pressure is 36 and rear 46 cold and at about 20c. The front tyres never go up more than 5psi and get to a temp around 45. The rears go up to 52 Psi and a temp 52c. This is when driving at 100kmh on tar on a 35c day.

So far not a single tyre issue (a big touch wood here as there is certainly a degree of luck involved).

Some factors to consider. The Hankooks are a LT construction and are noticeably heavier that the Pirelli ATRs i had previously. I think they are just stronger.

I also went to a weigh bridge before heading off on the trip. I found that the back axle on the car was about 200kg over its rated limited and i was not heavily loaded in the car. The caravan ball weight was 300kg so well under the 350kg limit. It doesn't take much to overload these cars. I went and removed as much weight as i could to get close to the rated axle load limit. I don't have any heavy accessories such as bullbar, long range tank or rear wheel carrier. I do have a second battery system and a front runner roof rack with two push bikes on it.

I believe a lot of tyre problems may be related to excessive loads being placed on passenger tyres. I would be interested to know if others have ever measured their axles loads?

Peter
CORRECTION: the Hankook DynaPro ATM are not a Light Truck tyre as indicated above. I dont know if the load rating is any better than the Cooper Zeon tyre.

I have never checked my weights. Given your experience though I doubt I would be any better placed in terms of load. There are 4 of us in car although we add up to less than 200kg due to young kids, likewise I have no real accessories other than rhino platform rack and second battery in 3rd row footwell. I also carried straps, tools and an engel 60 L freezer in car. The rest of car was stuffedcwith some clothing and other lighterweight items. My towball weight I estimate at about 250kg. I tried to manage this carefully as well by only using rear wster tank and loading jerry cans in rear most positions and using them from front most positions first. When I incurred both punctures I was actually on my lighter side as I was running low on fuel and water.

Another query do you use std hitch and tongue? The mchitch and a longer tongue will place the leverage point further rearwards therefore lifting more weight off front on to rear axle. I am not sur how much this would work out to but another 200mm must have an effect and some simple maths could probably approximate thus. I use std hitch.

I had considered hankook but found them difficult to find they dont seem to have a good dealer network or agents in Sydney.

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Originally Posted by RoverLander

I run Hancook Dynapro ATMs 255/55/19 (these are a light truck construction) with a TPMS to keep an eye on things. Front tyre pressure is 36 and rear 46 cold and at about 20c. The front tyres never go up more than 5psi and get to a temp around 45. The rears go up to 52 Psi and a temp 52c. This is when driving at 100kmh on tar on a 35c day.

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Sounds like they are working well. Can I suggest you try dropping the front 1 or 2psi? You might find it makes the front end a little less "skatey" - improve turn-in and give you a better ride.

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Originally Posted by RoverLander

Some factors to consider. The Hankooks are a LT construction and are noticeably heavier that the Pirelli ATRs i had previously. I think they are just stronger.

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At 111H, the Hankooks have the same load and speed rating as the LTZs and the ATRs. I don't think they would be LT in that size.

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Originally Posted by RoverLander

I believe a lot of tyre problems may be related to excessive loads being placed on passenger tyres. I would be interested to know if others have ever measured their axles loads?

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Agreed.

Cheers,
Jon

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Originally Posted by jon3950

Sounds like they are working well. Can I suggest you try dropping the front 1 or 2psi? You might find it makes the front end a little less "skatey" - improve turn-in and give you a better ride.



At 111H, the Hankooks have the same load and speed rating as the LTZs and the ATRs. I don't think they would be LT in that size.



Agreed.

Cheers,
Jon

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Jon, I checked the tyres this morning and you are correct, they are not LT and there is no indication they are. My appologies, i should not listen to tyre salespeople next time ;) i will try to edit my original post.

They do have a statement that they are heavy load rated whatever that means. I do know that the tyres are heavier than the Pirelli ATR but i cant compare them to the Cooper Zeon.

I will try to reduce the front tyre pressures a little and see how it feels but it seems to ride and steer fine at the moment.

Peter

Wow 1 or 2 psi. I am surprised Jon did not give you a temp with that. I do agree though I have recently taken a few psi out of fronts. I find it gives a bit more compliance on patchy roads and gives more confidence. On the super smooth freeways in the dry you wouldn't notice the difference but head to a more interesting b road and it is better. I would drive the mrs nuts if I stopped to air down 2psi at a time.

On the LT thing I had found some specs on tyre weights and from memory the dynapro where a few lbs heavier with the UK duratracs a few lbs heavier again. Does this mean a stronger tyre all things being equal? There is also XL I think this just gives a plus 2 load rating so 109 without this and 111 with it.

I have a theory that we may never see higher load ratings in 255 55 19 tyres as there is just not enough sidewall for the higher load ratings we would all feel like we were driving around on solid rubber tyres.

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Originally Posted by PaulGOz

Wow 1 or 2 psi. I am surprised Jon did not give you a temp with that. I do agree though I have recently taken a few psi out of fronts. I find it gives a bit more compliance on patchy roads and gives more confidence. On the super smooth freeways in the dry you wouldn't notice the difference but head to a more interesting b road and it is better. I would drive the mrs nuts if I stopped to air down 2psi at a time.

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Laugh if you want. I find a noticeable difference between 35 and 34psi (by my gauge) on the front. Given the facts Peter had given us, I was just trying to offer a suggestion based on my experiences that I thought might help. It may not. If it doesn't then ignore it, but what you are saying above is the same thing (except about your mrs, it doesn't worry mine :D).

Cheers,
Jon

One or two psi can make a real difference in how a car handles and reacts to bumps etc. Most people can't be bothered to experiment so drive for tens of thousands of kilometres not happy how their vehicle handles but they just get used to it. So they know no better.

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Originally Posted by jon3950

Laugh if you want. I find a noticeable difference between 35 and 34psi (by my gauge) on the front. Given the facts Peter had given us, I was just trying to offer a suggestion based on my experiences that I thought might help. It may not. If it doesn't then ignore it, but what you are saying above is the same thing (except about your mrs, it doesn't worry mine :D).

Cheers,
Jon

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I agree to Jon, maybe that racing background gives you a bit more on what the car is doing, I ran 32psi in the D4 pre-bullbar and winch, now run 36psi, just trying different pressure each trip to get the best result, the difference without and now with the bar and winch is very little, although the difference wasn't much anyway, just 4psi made it better again.

The missus can't tell either;)

Baz.