Big Tyres: Pros and cons

"...all tyres lengthen their footprint when they air down, and they all bag in the sidewall. Previous comments suggesting that wide tyres get wider and skinny tyres get longer is absolutely incorrect and patch testing has shown this to be the case." I'd like to see the evidence of that Slunnie...

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Originally Posted by Slunnie

I disagree.

Personally, I think 7.50s do absolutely nothing well in comparison to a modern tyre except that they have a thicker stronger carcass. They don't grip the road well, they don't grip trails well, they dont grip rock well, they don't air down and retain stability when cross sloped and I don't think they particularly do mud well. They do cut through everything well though, because they're skinny.

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The 750r16 I quoted was just an example of a skinny but high profile tyre that Land Rover's have used and we can relate to. Nothing more should be read into that, I've only experienced them on a perentie off road and that did not include any real deep mud or sand.

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There is a lot perpetuated on here, and it doesn't mean it's correct.

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Yep, you said it. Which is why I included links to some external articles so people can make up their own mind. It would be good if you could provide some links to support your argument against skinny tyres other than just personal experience.

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Originally Posted by Rick122

The 750r16 I quoted was just an example of a skinny but high profile tyre that Land Rover's have used and we can relate to. Nothing more should be read into that, I've only experienced them on a perentie off road and that did not include any real deep mud or sand.


Yep, you said it. Which is why I included links to some external articles so people can make up their own mind. It would be good if you could provide some links to support your argument against skinny tyres other than just personal experience.

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Likewise I have spent time in Perenties also and my opinion isn't particularly good. This is in part due to the tyres they have, the pressures they run and the load carrying spring rates which they are made with. The vehicle itself however is very good.

If websites are what justify experience, as opposed to the opposite, then my website is at www.slunnie.com - Aussie Built Rovers

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Originally Posted by MrLandy

"...all tyres lengthen their footprint when they air down, and they all bag in the sidewall. Previous comments suggesting that wide tyres get wider and skinny tyres get longer is absolutely incorrect and patch testing has shown this to be the case." I'd like to see the evidence of that Slunnie...

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An example:

Beadell Tours - Tyre Footprints by Mick Hutton

• Goodyear Wrangler RT/S ? 265/75R16LT ? 10 Ply (original fitment on F250s)
• MRF M77 ? 7.50-16 ? 14 Ply

https://www.aulro.com/afvb/images/im...015/06/915.jpg

So in that picture the 750r16 (aprox 190mm width) has almost the same footprint width and length when aired down to 20psi and not much less length at 10psi as the much larger, 40% wider 265/75r16. That's interesting. I would have thought a bigger difference. The tread blocks are a lot chunkier and spaced out on the old 750/16 though.

A good read, thanks for all the info input guys.

Of course this just means I'm even more confused as to what to get next :(

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Originally Posted by Rick122

So in that picture the 750r16 (aprox 190mm width) has almost the same footprint width and length when aired down to 20psi and not much less length at 10psi as the much larger, 40% wider 265/75r16. That's interesting. I would have thought a bigger difference. The tread blocks are a lot chunkier and spaced out on the old 750/16 though.

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Treadfaces on those particular tyres are similar, the next carcass width down (235/245 etc) would be about the same. The variation in length is due to the rigid construction of the MRF. The MRF at 10psi is similar to the GY at 20psi, but pressures for a given footprint will vary due to load, tyre construction etc so despite it being a pressure based comparison, it probably should be in practice a footprint length comparison - but thats not as interesting. :lol2:

Thanks Slunnie, interesting that footprints appear similar, however there is clearly less bagging widthwise in the 7.50R16... Meaning less frontal resistance especially in sand...

...than 265/76R16. These sidewalls would push far more sand than the tall ones of the 7.50R16.

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Originally Posted by Slunnie

Treadfaces on those particular tyres are similar, the next carcass width down (235/245 etc) would be about the same. The variation in length is due to the rigid construction of the MRF. The MRF at 10psi is similar to the GY at 20psi, but pressures for a given footprint will vary due to load, tyre construction etc so despite it being a pressure based comparison, it probably should be in practice a footprint length comparison - but thats not as interesting. :lol2:

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Which supports the theory that if there is little difference between skinny and wide tyres when aired down, then there is little reason to go to a bigger tyre when there are so many more compromises to be made. Each to their own.