Tyres again, 255/65/16

[Ausie Kev]

Tyres, again.
On my Disco 1998 300 Tdi auto, I am running 245/70/16 in Michelin LTX M&S.
In Australia I can't get this size and pattern any more.

I'm thinking about dropping back to standard height, as the extra get up and go would be nice. But I like the wider tyre for sand work. This asks a good question, is a wide tyre better than a tall tyre when let down in sand?

Has anybody tried 255/65/16 on a 300Tdi auto? I can get this pattern in a Toyo Opat.

Will I still be able to let them down to make them more effective. Any rubbing?

I notice some other Landies are running these as standard.

My Disco is stock.

Ausie Kev

[Disco]

Hi Kev! A wider tyre has an advantage over a skinny one especially in sand. If it is deflated, then so much the better, because in sand, the larger the balloning effect, the better the floatation. You can certainly fit the 255x65x16 with confidence as they are 1/2 inch smaller in diameter to what you are already running, however, they won't make such a big difference in the get up and department.

[aussie disco97]

Hi Kev,
I have a 300tdi and have had them since 1994 never been boged in sand and have always run standard 205 x 16. The way it was explained to me was that when you let your tyres down it is the extra lengh of footprint that matters,the wider the tyre the bigger the pile of sand in front of the tyre that the car has to climb onto. Bulldozers and tanks don't have wide tracks they have long tracks, makes sense really.

[Disco]

I haven't seen too many Sand Racers fitted with skinny tires, nor do they look like half-tracks. How much extra length of foot print do you get from a 205x?x16, as apposed to a 255x65x16? Not much! That is assuming they are 205x85's. The reason bulldozers and tanks have longer tracks rather than wider ones is because engineering wise, it's more practical. Who wants a 12 foot wide bulldozer anyway.

[texasrover]

A 255 vs. 245 is not enough increase in width to argue over. Either one will be fine. It is not like you are talking about floatation tires verse tractor tires.

[Ausie Kev]

Thanks to all for input.
It does ask a few good questions.
Long Vs wide foot print in sand.

If I get the best answer I will tell all.
Ausie Kev

[Black Magic]

I have 265/70/R16 and don't see any tyre rub - but I haven't been anywhere and aired down yet. I did go off road a couple of weekends ago without problems.

[130CC]

Just my two cents but...
In regard to length vs width the physics of it remains the same in regards to weight on area. If you increace a tyre patten forwards lengthening the tred by 10% then the load per square foot is decrerased if you get my meening. The same applies when you go in width. Here in Canberra your rego is based on the weight and class of your vehicle. A 980kg suzuki swift costs about $500 for the year while the 130 costs me $980. What they don't take in to account is that the 980kg's is spread over 1/3 the size of the road surface area/contact in comparision to the tyre on road contact area of the 130 you do the maths pounds of preasure per square inch of contact is the same(roughly) I am just equivalent to 3 suzuki swifts. If they ever figured this out I would be paying more for rego, thank god they haven't worked it out or maybe they have their just being nice(government run so I doubt it). Sorry bit of the topic but helps in explaining.
When in sand you have now take in to account the forward roll of the vehicle when changing gears the wider the tyre is the faster the car will slow down on gear change because more forward contact (front face size) of the tyre building up as you slow down. Then you have to take into account the cut of the tyre the widder the tyre the more it tends to not dig in to the sand as you drive because of this wider face, the longer the tyre the more it tends cut in to the sand increasing the size of the face of the tyre. You might start to get where I am going both tyres whether the increase forward in length or increase in width the performance is about the same some people will swear by fatties and some about skinnies but it is all about increasing the footprint of the vehicle to place the vehicles weight over a larger area therefor increasing flotation of the vehicle on the sand.
I have both fatties and skinnies and prefer the fatties as the surface area at low preasure apears to be bigger than that of my skinnies.
Adam

[rmuller]

255/65/16 is what came stock on my DiscoII