My favourite hobbyhorse....  Get a tape measure, and with help, measure the width across the van between the centre of the tread at the front and rear of each axle. Always use the same point on the tyre, eg the centre of the tread, or the shoulder etc. The difference is toe-in or toe-out. On my Jayco 16 ft poptop, I had about 10 m toe-out, and wore out 2 tyres in 18000 km. Jayco denied any responsibility, and blamed it on AL-KO (the axle manufacturer). AL-KO tried to straighten the axle and got the toe-out to be about 8 mm toe-in, but after 3 sets of tyres worn out, I finally spat the dummy and asked ALKO what the toe-in should be. To their credit, AL-KO finished up sending me another axle, which I fitted in my driveway (I certainly could not do that now). This axle still had 5 mm toe-in at the centre of the tyre tread, but it was better. I have about 40000 km on this axle, and the left tyre is wearing down now, but that is 5 times better than it was.

 

I think the problem is the way the axles are made. They are a square section solid axle, with a round stub axle welded onto on face of the axle. Presumably they have a jig to hold the stub axle whilst they weld it, and they then tack it is place and then go along and fill up the gap between the circular face of the stub axle against the flat face of the main beam axle. This is a massive weld, and as the weld cools, it would shrink that side. Welding the other side should theoretically bring the axle back into alignment as that weld shrinks, but it will never come back totally to the original (true) position. Thus, you are left with a stub axle what is not truly parallel to the main beam axle. The head honcho at AL-KO told me that some toe-in was necessary for stable towing, but I don't believe that. I certainly have proved that 5 mm is the maximum toe-in before the tyre starts scrubbing.

 

Interestingly, the caravan I had before this Jayco also had an axle with tow-out, but that was 11 mm, and the tyres lasted 10000 km only, so by the time I buy my sixth caravan, maybe I might get one with a proper alignment? My pet hobbyhorse. I walk around caravan parks looking at tyres on vans. Probably 5% of them have worn tyres on the inner edges and the owners don't know about it (unless you get down on your knees and look under the van you will never see it). Most caravans only do a few thousand km per year and faults like this will certainly not show up during the warranty period

 

 

I have just had my 12 month old van tyres balanced and alignment checked. I took it to a truck outlet specialising in this type of work as most tyre outlets cannot balance and align caravan tyres. Already there was some wear on the tyres and, of course, they needed adjustment. The mechanic said that the manufacturers do not do them before delivery and that most vans were out. The cost was $270.00. I was told later that our local Jayco dealer could also have done the work.