As I find the ride on the standard 275/40/20 tyres very hard, for the last couple of month I have done some research on available options to improve the experience. Here I would like to share my observations.

With the Brembo brakes the options are limited to 19", 20" and 22" alloys.
*Note: According to Compomtive sales team the 18" Bowler rims can not be fitted to RRS without turning the Brembo brake calipers.

As I found the ride on 20"s to hard 22"s was not an option for me. So have set to test the two other alternatives that I found reasonable. These were the standard 255/50/19 and the slightly oversized 275/45/20.

The side wall on 275/45/20 is 0.6" larger than on the stock 275/40/20 and it is only 0.1" smaller then on the 255/50/19.

I first started with the stock 255/50/19 - the ride has considerably improved. You could feel it most on two occasions. First the car stopped following the washed spurs on the roads. And second when driving over any uneven surfaces. Above all the fuel economy has improved significantly. The down side of this option however is the looks. The car just does not look so nice with the 19" wheels.

So I then switched to 275/45/20 - the ride is comparative to 255/50/19. Though the car feels lot heavier to drive. The steering is harder, turning circle is increased and the gearing is also affected.

Thus in summary if you want a nicer looking RRS stick to the standard 275/40/20 though if you rather prefer the "Range Rover" ride quality downsize to 255/50/19.

C10KO

A good report!

On the economy side, did you use the onboard computer/adometer and if so was it re-calibrated for thedifferent sizes? Now - MY11 RRS Autobiography TDV6, Orkney gray, tints, steps, daylight running lamps and allllll the toys!!!
Ex- RRS HSE TDV6 07 Java Black, bi xenon, corner lights, side steps, tints, cool box, smoke side repeats, chrome "sport" boot sill
Ex - Audi A4 Cab 3.0TDi Quattro
Ex - Freelander2 SE TD4
Ex - CRV Auto

Thanks mate...

For the economy comparison I went down the simple route and calculated it with the help of travelled distance to the number of litters consumed over a same route. To make the comparison more accurate I have selected the very same route - 450 miles of motorways, A roads, B roads and towns.

The fuel consumption with 255/50/19 was the best at 10.1 litters per 100 km; with 275/40/20 it came to 10.5 litters and with 275/45/20 I averaged 10.6 litters.

I have forgotten to mention in my earlier post that with the standard 275/40/20 the car feels that it handles better. Though it is only a feeling as you can drive identical speeds in the corners with the 255/50/19 tyres. This is however not the case with the 275/45/20 which raise the point of gravity by 0.6" what result in significantly reduced handling.

I actually like the ride of my 275/45r20 tyres... wouldn't the fuel consumption be better over distance because the rpm's are lower for the same mph, no?

Specification Sidewall Radius Diameter Circumference Revolutions Speedometer Odometer Difference
255/50-19 5.0" 14.5" 29.0" 91.2" 695/mi 60MPH 10000mi N/A
275/45-20 4.9" 14.9" 29.7" 93.4" 678/mi 59MPH 9763mi 2.4%
275/40-20 4.3" 14.3" 28.7" 90.0" 704/mi 61MPH 10132mi -1.3%

Alex, in theory you are absolutely right but from the observation the car tends to run on higher rpm - better said the car shifts a lot latter and stays in gear longer. As an example there is a light incline where I know that a certain speed that the car shifts to third gear in both 255/50/19 and 275/40/20 but it stays in second with 275/45/20. This is what I believe causes the increase in consumption.

Forgot about that bit Thanks for the info...

Did not mean to upset anyone.... I might have come across as a bit blunt...

Alex

Alex, you have not upset anyone... This is a forum and to me more opinion (positive or negative) gives all of us a better chance to understand issues related to our beloved cars

C10KO wrote:

This is a forum and to me more opinion (positive or negative) gives all of us a better chance to understand issues related to our beloved cars

and to take the p ss out of each other enjoy the forum without fear purple people eater

There are no good days, just some days that are not as bad as others!


Gone RR 4.0 P38 Autobiography MY99 Red ( money pit)
Gone RRS MY06 2.7TDV6 HSE Rimini Red
Gone RRS MY10 3.0TDV6 HSE Bali Blue with lots of bits (never grew to love it)
Here Now - 3.6 TDV8 FFRR OVERFINCH Stornoway Grey - loving it x
My work car Ford Mondeo 2.0 TDci Zetec auto Estate in Silver

Just to throw another one in the ring so to speak, I find the ride quality on the Goodyear Wrangler MT/R in 255/55/R19" very good although noisy.
fuel consumption is a little worse by about 3mpg Sons of dogs come hither and get flesh
Clan Cameron