I would like to have 255 50 R20 tyres on my car, so I have just bought 2 new Pirelli Scorpion Zero's for the fronts ( PNCS - just looks like a bit of damping stuck on the inside of the tyre)

But my rear tyres are 255 55 R20's ( 10% more profile) , they still have over 5mm of tread on them, and are just too good to throw away, so can 50 profile on the front and 55 on the rear work OK ??


Read a bit on google about why low profile might be a good option !
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There are several reasons why 4WD makers are taking the low profile tyre path: more precise steering; better on-road handling; more powerful braking; quicker water dispersal and more torque capacity.

Low profile tyres improve steering response because there is a reduced amount of flexible sidewall between the wheel and the tyre tread. If you fitted a video camera to the front mudguard of a 4WD and steered it around a series of hard turns you’d see how sidewall flex slows down the steering action that’s imparted to the wheel. In the case of a higher-profile tyre the wheel can be seen moving momentarily before the tyre follows it.

With a low profile tyre there’s no perceptible tyre sidewall flex and the wheel and tyre carcase move as one in response to steering inputs.

A low profile tyre can improve on-road handling, because the stiffer sidewall doesn’t roll towards the inside of the corner and so the tread area remains more stable, in contact with the road.

The torque load on the tyre is at its greatest at lift-off and under heavy braking, and the torque capacity of a tyre is generally increased if its sidewalls aren’t very tall. A stiffer sidewall is better able to resist the tendency for the wheel to rotate inside the tyre – look at slow-mo footage of a dragster taking off for an illustration of tyre sidewalls distorted by engine torque.

255/50R20 is the original size for a 2011 car, and you will have crisper steering and handling with them. LR recommend changing all four tyres at once and warn that having different types around the car can result in instability. I'd certainly not consider running different sizes on the front and rear axles, the supposed "saving" is just not worth it in the context of your and your passengers' safety, construction & use regulations and possible harm to the car. Only Range Rovers since 1988

Yes I am fully aware that would be or very well maybe the LR stance on this, I was hoping for a more practical response, they are still 20" wheels all round, with 10 inches of tyre width ( 255mm) and if I had 200kg in the boot, and my tyre pressures were a little lower than normal, then in all possibilty I would be running 10% lower ride height on the rears, which I am sure LR would have considered way back in 2002 with the original L322 design and its continued appeal to farmers and other countryside linked businesses, but thank you all the same for your considered response.

Last edited by pcourtney on 11th Jan 2024 1:54pm. Edited 1 time in total

On a permanent 4x4 driveline I would say that the rolling radius of the tyres need to be identical to stop any transmission wind up hence the reason not to even use new and used tyres together because of the different tread depth.

I cannot believe I am even reading this - different diameter tyre sizes on a permanent drive 4x4.

Never mind mechanical sympathy, if you lose control of you vehicle as a result have you no thought for the safety of yourself, passengers & other road users - and also invalidating your insurance - common sense would stop most people from doing it. 2021 L405 Vogue SE 4.4 V8 DIESEL ~ #17

255/50 R20 are not 'low profile' - you would need 21" or 22" wheels to acheive this in the modern 'SUV' style.
The L322 is never going to compte with a modern SUV in handing and most opt for taller tyres ( i.e the ones you have on the rear) to maximise where the L322 does beat modern SUV's - ride comfort. 2012 TDV8 Vogue (L322)

Can someone please explain the principle behind transmission wind up? All road vehicle transmission systems are fitted with differentials, these exist precisely to take account of differences (hence the name) between the actual revolutions of each wheel on an axle (eg, when cornering) and between axles in multi axle set ups, whilst maintaining drive to all driven wheels. So, what exactly is this transmission wind up? Drives:
2010 FFRR TdV8 Vogue - Stornoway Grey
2010 FFRR TdV8 Vogue SE - Zermatt Silver
1998 BMW E36 M3 GTII

The diff is not designed to run continuously. 2012 TDV8 Vogue (L322)

Given the state of our roads, I.e. the number and depth of potholes we all see every day, it’s 255 all round for me and the improvement over 250’s is very noticeable.
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

rvbush wrote:

Can someone please explain the principle behind transmission wind up? All road vehicle transmission systems are fitted with differentials, these exist precisely to take account of differences (hence the name) between the actual revolutions of each wheel on an axle (eg, when cornering) and between axles in multi axle set ups, whilst maintaining drive to all driven wheels. So, what exactly is this transmission wind up?

@OP:

Some good and knowledgeable advice above, I think.

My view, (and probs a lot of others) is that any FFRR is not a “performance” vehicle in terms of handling at any stretch of the imagination, and any small gain in handling will be at the detriment of comfort, and therefore pointless, so most of us opt for comfort, but it’s purely a personal preference.

If I wanted an SUV with “handling” I’d junk the FFRR, and buy a Cayenne

Meanwhile, you can drastically improve the handling of your fullfat for free!

Slow down a bit  “If it ain’t broke, don’t fix it” -where’s the fun in that?

Handling can also be drasticaly improved IME by replacing worn suspension components and a good 4 wheel alignment. Any marginal gains from stiffer sidewalls will be negated if the whole wheel geometry is being altered under load due to worn bushes. 2012 TDV8 Vogue (L322)

Baltic Blue wrote:

Given the state of our roads, I.e. the number and depth of potholes we all see every day, it’s 255 all round for me and the improvement over 250’s is very noticeable.
Mike.

I assume Baltic Blue means 55 profile over 50 and not the width (255 vs 250). 2012 TDV8 Vogue (L322)

Hi,

Depends what you plan on doing with your car.

Anything less than a 55 profile you should consider as on road use. Although 50s and lower will work offroad there are some disadvantages that are great on the road / track but not really practical once you get off the blacktop.

Tyrewall felx is a definate advantage in rocky road conditions, lower tyre pressures combined with a high profile sidewall will allow the tyre to "grab" the rocks. Low profile and stiff sidewall cannot do that.

Similarly lowering tyre pressures in lower profile tyres will bring your rims that much closer to the ground so even small rocks are just going to chew your rims to bits.

For sand it's preferable to have a lower tyre pressure to allow the tyre to "balloon" and be able to grab the surface.

Running lower profile tyres running low pressures are at much higher risk of being pulled off the bead in rough going if you put any stress on the tyres.

Horses for courses, but I'd say of your using your RR on loose surfaces stick with 55 or higher, if your Chelsea High Street then go with whatever your like, but your never going to overcome the physics of heavy weights in motion.

Andy Fuji White 2012 4.4 TDV8 Westmiinster