nicke60gre

My research has to do with 19" Tyres.
Here is the results of my measurements:

For a 245/40 R19 RFT the net weight is 13 Kg.





One 245/35 R19 RFT (does not exist) should weigh a little less. Let's say 12.5 Kg.

My previous 225/50 R17 RFTs with around 40% tread remaining are 13,5 Kg each, so they are much heavier than 245/40 R19 because of the wider sidewall (wider steel reinforcing material) A new 225/50 R17 RFT should weigh more or less 14,5 - 15 Kg.




My previous standard summer tires (Vredestein Ultrac 235/35/ R19 with 70% remaining tread), weigh 10,5 Kg, therefore, a new one should weigh around 11 Kg.







A standard 245/35/19 tyre should weigh a little more. Let's say 11,5 Kg.


So, the difference is that: RFT is 1 Kg heavier than a standard 245/35/19 tyre so, 4 Kg. in Total.

BUT,

A spare tire kit with jack etc, weigh 17 Kg,







so, the gain is: 13 Kg. lighter car with RFT's and no spare.
My gain is a little less because of my little larger tyres, but I'm OK even with my 11 Kg. lighter car with RFTs, than with normal tyres.


Here is my new Summer Dunlop Potenza RE50A 94W RFTs for my 167s.
I've bought 245/40 for the fronts and 275/35 R19-96W for the rear wheels.
I know that size is not recommended by BMW but that's not a problem.











There are many reasons that I had to go with RFT's and this size:

1. First reason is that I want to higher the car from the ground by 1 cm, because my front bumper is hitting the ground at every big road unevenness, when downhills, at jerky crossroads, etc.
2. Another reason is that I want to fill a little more the gap between the wheels and the fenders.
3. Another reason is that I will have then, a more accurate speedo and not 5%-8% faster as is on all E60s (mine is 8% faster, measured by GPS)
4. Another reason is that I think that the lower profile RFTs seems to be softer ...(at least, I've tested the 225/50/17 compared to 245/40/19 and I found that, by my hands, It was much easier to press/stretch the 19" sidewall, than the 17".
5. Another reason is that, when I will install my 3.0L engine, my 2.2 differential will be too "short" for the engine and even more, when I will supercharge it and get 335 HP of it.
6. Another reason is that with the RFTs I will drop the 10 Kg. less car's weight, from the trunk (spare kit absence) to the lower possible point below the car (wheels)
7. Cornering with RFT's is sharper.

Now, about cons, I will keep you posted

baadaaboo

you don't need to go to work today? you really have time to do all these?! amazing!!

0700700

HOW cool is this... i hadnt seen one of those ancient scales, since we stopped using them in bulgaria in 1989

whentmets

Not really convinced about the weight theory. In principle you assume that the weight would be proportional to the size of the tire. However, it can easily be possible that it is not. Different size tires are constructed differently and the sidewall steel and compound layers can destroy the weight proportions. Same probably holds true for different brands of tires of the same size.

Although, your analysis has a lot of logic, I believe it can only be applied to specific brand tires and sizes. Don't you think?

Yoko

LOL...LOL...

my530i

You guy don't know Nicko enough. He's self-employed and specialized in sign.

EBMCS03

Hahahha its not only 13kg that you saved... its ROLLING weight that you saved... which is A LOT!

firewalker

Speaking about the 'cons'... enough of the scale pictures, we trust you!
Instead, lets see more pics of the babe in your sig.

nicke60gre

You are "the future" GO AHAID
That's what I've found in my dirty garage. If difference was minimal, then, I would use a more accurate one.

KAF

Quite, the issue is the amount of UNSPRUNG weight, not the weight of the car.

You did not need to do all this work, the weights of specific tyres can often be found on the manufacturers websites.