Scalloped Cooper STMAXX front tyres

[Matty_P]

Ive got some really bad scalloping on the front set of my 265/65/17 ST MAXX with 40,000kms on them. Jus did a rotate today but reading thru some threads i saw a comment from someone that tows a trailer most weekends and said this causes some scalloping.....makes sense as i just did 1500kms with a Jayco Swan outback and full load. It did have a sag in the arse but its only 80,000kms since the the Bilsteins / Lovells got installed.I cant imagine the shocks would be stuffed in that short time given limited off road work and min van towing.
Anyone noticed towing vans or heavy trailers has caused scalloping on front tyres?

[old Jack]

All agressive tread tyres scallop on the front wheels, rotations front to rear every 5,000 or 7,500 kms minimises the scalloping but once the tyre is scalloped it takes a long time to wear down even if it is fitted to the rear diagonal position. Reduction in tyre pressure can assist in correcting scalloping when fitted on the rear axle.

OJ.

[zoom]

Scalloping on the front = struts are shot

PS do you have a bull bar and bash plates ?

[Matty_P]

Yes have a factory alloy bulbar and bashplates...i will make sure i get the rotation done more frequently.

Thanks Zoom and OJ..

[Matty_P]

All agressive tread tyres scallop on the front wheels, rotations front to rear every 5,000 or 7,500 kms minimises the scalloping but once the tyre is scalloped it takes a long time to wear down even if it is fitted to the rear diagonal position. Reduction in tyre pressure can assist in correcting scalloping when fitted on the rear axle.

OJ.

Thanks OJ on the point of pressure, I have run the Coopers at 40PSI front and rear but some weeks ago dropped them to about 37PSI as i heard feedback from a Coopers rep saying that most customers run too high pressures. They claim that the stength in the Coopers sidewalls means they can be run at lower pressure without detriment.

[old Jack]

Thanks OJ on the point of pressure, I have run the Coopers at 40PSI front and rear but some weeks ago dropped them to abou 37PSI as i heard feedback from a Coopers rep saying that most customers run too high pressures. They claim that the stength in the Coopers sidewalls means they can be run at lower pressure without detriment.

With my Challenger that has roughly 1200kg loads front and rear axles I run 34 psi all tyres around the city and when I load up the rear to GVM to GVM+150kg I go up to 36psi. My tyres are LT245/75R-16, they wear evenly across the tread face and I get 70,000-75,000kms on a 4 & 1/2 tyre rotation.

OJ.

[Kingbrown]

Maybe it's my style of driving but after 83000km I have no sign of scalloping on my ST Maxx (265/70/17) that are fitted to my Challenger.
Wear is very even on all tyres and wheels haven't been balanced or aligned since the tyres were new.
50% of the km's have been on the dirt, generally in desert areas.
No towing for me but generally loaded heavy to GVM+.
Pressure 35-40psi. Rotated corner to corner every 10000km (spare is not included in the rotation).
I expect to get another 10000 out of them.

[old Jack]

Kingbrown, you cannot complain about your tyre wear or life. I suspect it is the cornering in the city and suburbs that causes excessive scalloping on the front tyres.

On tyre pressures, I looked up my tyre inflation load tables and here are the figures of what load each size tyre will take at 35 psi, this supports that too many people run too higher pressures in their tyres.

LT245/75R-16 773kg per tyre.
LT265/70R-16 827kg per tyre.
LT265/75R-16 868kg per tyre.
LT265/65R-17 802kg per tyre.
LT265/70R-17 859kg per tyre.

OJ.

[insect_eater]

Kingbrown, you cannot complain about your tyre wear or life. I suspect it is the cornering in the city and suburbs that causes excessive scalloping on the front tyres.

On tyre pressures, I looked up my tyre inflation load tables and here are the figures of what load each size tyre will take at 35 psi, this supports that too many people run too higher pressures in their tyres.

LT245/75R-16 773kg per tyre.
LT265/70R-16 827kg per tyre.
LT265/75R-16 868kg per tyre.
LT265/65R-17 802kg per tyre.
LT265/70R-17 859kg per tyre.

OJ.

Just a couple of clarifications - Are these specifically for the STMaxx, or a particular load rating? And are these static or dynamic loads? -i.e. does one need to account for weight transfer during braking etc?

[old Jack]

Just a couple of clarifications - Are these specifically for the STMaxx, or a particular load rating? And are these static or dynamic loads? -i.e. does one need to account for weight transfer during braking etc?

The figures are from the Toyo Load Inflation Tables USA. All pressures are cold and are correct for all LT tyres be they 8ply or 10ply, 8ply pressures stop at 65psi and 10ply stop at 80psi. The reason for the post was it show people that they do not need to run 40+ PSI in their LT tyres, some may choose to do so for better fuel economy, or for sharper on bitumen steering response but the negatives are a harsher ride and more load on your shockers.

OJ.

[Ent]

To help in the understanding it is the air in the tyre that carries the load, not the side wall. The higher the volume and pressure the greater the load that can be carried. LT tyres are designed for higher pressures so they can carry more.

As OJ writes higher than 36 PSI are not needed on the Challenger for say the 265x75x16 as the Challenger hits GVM. On a truck then that tyre would be at much higher pressure as much higher GVM.

We use to under inflate our tyres but nowadays I think many over inflate. 40 PSI is something I see no need to exceed on the Challenger.

No doubt you get sharper handling at higher pressures but at some point the trade-off with ride and impact absorption works in favour of a lower pressure.

[Kingbrown]

Kingbrown, you cannot complain about your tyre wear or life. I suspect it is the cornering in the city and suburbs that causes excessive scalloping on the front tyres.

No doubt about it OJ. My chariot doesn't see much of the city and suburbs.
Going easy on the brakes could be another factor. There's not much hilly stuff or traffic where I tend to go. Manual box helps in that respect as well.

[sharkcaver]

Going easy on the brakes could be another factor.

I believe this is the main factor for scalloping. Diving under brakes. Does the same thing on dirt bikes too.

[insect_eater]

The figures are from the Toyo Load Inflation Tables USA. All pressures are cold and are correct for all LT tyres be they 8ply or 10ply, 8ply pressures stop at 65psi and 10ply stop at 80psi. The reason for the post was it show people that they do not need to run 40+ PSI in their LT tyres, some may choose to do so for better fuel economy, or for sharper on bitumen steering response but the negatives are a harsher ride and more load on your shockers.

OJ.

Thanks OJ - as it is an important point, I wanted to confirm for me and others that the info applied generally to LT tyres

[pauld]

http://www.bridgestonetire.com/tread-and-trend/drivers-ed/tire-tread-wear-causes