I was inspired to revisit this subject by a “late night” conversation with friends who had just fitted cross-ply tyres to their vehicles without realizing it. Many 4×4 owners still go for this option either for tradition, cost or just blind faith in the information given by the tyre dealer. In reality they are a false economy and they are not as safe as radial tyres.
Radial Tyres and Road Safety
If we look at the history of tyres we find that all tyres were of cross-ply manufacturing process until Michelin invented the radial tyre process in the early 1970s; and if you remember the advert campaigns, they were deemed, by an ex police chief with a funny voice, as a “major contribution to road safety.”. He has subsequently been proven to be absolutely spot on with his statement. Understanding why this point is correct, is fundamental in understanding why we should refrain from fitting cross-ply tyres to our vehicles when they are going to be used for general and even fairly extreme off-road driving.
Differences Between Radial and Cross-Ply Tyres
The way that radial tyres are manufactured give them a flexible side wall whilst still retaining strength. This flexible sidewall allowed greater control over the direction of the tyre on the road and hence the vehicle went where you steered it without any hesitancy! Also, and of extreme importance, it allowed the tyre to retain its contact patch on corners rather than lean on a corner and lose contact.
The cross-ply tyre has opposite qualities because it has a rigid sidewall. This rigid sidewall and the general design of the tyre don’t allow heat to dissipate as effectively and the tyre wears out faster. Also, they don’t have a very high speed rating. Generally about 80 – 100 KPH. What this means is, if you drive in excess of this speed for over 4 hours you risk a blow out. This is why most vehicle manufacturers don’t recommend fitting cross-ply tyres onto their vehicles.
How to Tell a Cross-ply Tyre from a Radial Tyre
Then the question of how to recognize whether the tyre is one or the other arose. This is very straight forward. A common size of tyre for a 4×4 is 750 16. If it is written on the tyre 750R16 it means it is one of the good guys. The R standing for radial. If it doesn’t have the R, i.e. 750-16, then it’s one of the cheaper type. If it’s a profiled tyre such as 235/85R16 then it will be a radial.
Never Mix The Tyre Types
The two types of tyre should never be mixed on a 4×4 (or on any other vehicle for that matter). If you think about it, if you do you have one type of tyre that has a mind of its own and tends to want to wander and the other that you have control over working against each other then this could lead to a dangerous loss of control. I have seen some folks carrying a cross-ply as a spare. If you are one of these then I would suggest changing it to suit the other four or if you have to use it then make sure you drive carefully until you can get the damaged one repaired.
Are there Any Uses for Cross-Ply Tyres?
Saying that, cross-ply tyres still have their place and generally can be fitted to vehicles that work in extremely harsh environments where there are no roads and the tyre risks getting side wall punctures from tree stumps or sharp rocks.
As a side note, whatever tyre you decide to fit ensure that you follow the vehicle manufacturers’ recommendations for tyre pressures for that size and manufacturing process of tyre. Under inflated tyres are dangerous and can take off at least 20% off a tyres life. Obviously wildly over inflated tyres are just as dangerous with the same effect on life span.