"Super single" tyres - pros and cons?

[ChemicalChaos]

Ive seen a lot of trucks recently with a single extra-wide tyre on a wide rim, where there would normally be a pair of normal back-to-backs - such as the drive axles.

I'm assuming this is an economy measure as one big tyre is less cost and less maintenance than 2 tyres (and can't get debris wedged in them). If so, why are they only just beginning to appear? Obviously I appreciate that it means a) 2 different sizes of spare needed and b)a blowout immobilises the truck rather than reducing it to just limping.

Are there any other pros and cons? I'm interested in the debate

[scanner102]

I've never known anyone to put super singles on the drive axle because I don't think they have the load capacity. I do know of them being put on the steering axle or the lift axle because they do have a higher load capacity to the standard single tyre. Typically hiab units have them on the steering axle because of having higher front axle loads.

[s p a c e m a n]

I too don't think you've been seeing what you think you've been seeing, can't think of a reason to run a super single on a drive axle. They're pigs on steering axles too, tramlines like a bh which means you actually have to drive rather than just occasionally pay attention

[Nickyboy]

They're common to be fitted to steer axles but not drive axles.

IIRC the early Renault Magnums had large single tyres on the drive axles but i don't think it ever took off as being viable

Found a pic

Edited by Nickyboy on Monday 4th August 15:50

[ChemicalChaos]

^^ that's exactly what I have been seeing. Seen a few both rear axles of American trucks too so they presumably do have the capacity for a drive axle

[Nickyboy]

There was a tyre manufacturer who developed a huge drive axle tyre, i remember reading about it a few years ago in one of the transport publications, never seen one on the road however so i'm guessing it wasn't viable, not sure whether Euro regulations on axles etc have anything to do with it.



Thats the typical US single set up

[Harvey Mushman00]

Ferrymaster ran 5 of these in the 1980s and Shell oil ran dozens of ERF 6x4s and Foden 6x4s with supersingles on the drive axles, to say they were a disaster is an understatement, they overturned far too easily.

[Magictrousers]

Mercedes have been offering super wide single drive axle tyres for a couple of years, depending on chassis type. They're not type approved for UK vehicles, something makes me think they shouldn't be seen on visiting foreign lorries either.

[GC8]

Surely EU approval trumps all of our rules/restrictions/laws?