Falken 452's
- Thread starter conaero
- Start date
...?
Emtee
New Member
- Messages
- 8,446
In trying to figure out what to go for it's evident that because of the tyre sizes available, some difference in RR is unavoidable.
I used a couple of tyre calculators to look at the options for the back of my 4200.
Standard.
265/35/18 - Overall tyre diameter of 643mm. Circumference of 2019mm. 797 revolutions per mile.
Options.
275/30/18 - Overall tyre diameter of 622mm (a difference of -21mm or -3.27% against standard). Circumference of 1955mm. 823 revolutions per mile.
275/35/18 - Overall tyre diameter of 650mm (a difference of +7mm or +1.09% against standard). Circumference of 2041mm. 788 revolutions per mile.
285/30/18 - Overall tyre diameter of 628mm (a difference of -15mm or -2.33% against standard). Circumference of 1973mm. 815 revolutions per mile.
285/35/18 - Overall tyre diameter of 657mm (a difference of +14mm or +2.18% against standard). Circumference of 2063mm. 780 revolutions per mile.
Sod it, I've done the back so I may as well do the front.
Standard.
235/40/18 - Overall tyre diameter of 645mm. Circumference of 2027mm. 794 revolutions per mile.
Options.
245/35/18 - Overall tyre diameter of 629mm (a difference of -16mm or -2.48% against standard). Circumference of 1975mm. 815 revolutions per mile.
245/40/18 - Overall tyre diameter of 653mm (a difference of +8mm or +1.24% against standard). Circumference of 2052mm. 784 revolutions per mile.
255/35/18 - Overall tyre diameter of 636mm (a difference of -9mm or -1.4% against standard). Circumference of 1997mm. 806 revolutions per mile.
255/40/18 - Overall tyre diameter of 661mm (a difference of +16mm or +2.48% against standard). Circumference of 2077mm. 775 revolutions per mile.
One of the calculators I used advised no more than +/-2.5% variance in diameter.
So to add a little bit more rubber to protect your rims, wider by 10mm with no change to the sidewall ratio is best whether front or back. If you want to add 20mm, then again leaving the ratio unchanged is probably the most consistent between front and back, but your speed and mileage readings will be further off.
Hope this helps.
I used a couple of tyre calculators to look at the options for the back of my 4200.
Standard.
265/35/18 - Overall tyre diameter of 643mm. Circumference of 2019mm. 797 revolutions per mile.
Options.
275/30/18 - Overall tyre diameter of 622mm (a difference of -21mm or -3.27% against standard). Circumference of 1955mm. 823 revolutions per mile.
275/35/18 - Overall tyre diameter of 650mm (a difference of +7mm or +1.09% against standard). Circumference of 2041mm. 788 revolutions per mile.
285/30/18 - Overall tyre diameter of 628mm (a difference of -15mm or -2.33% against standard). Circumference of 1973mm. 815 revolutions per mile.
285/35/18 - Overall tyre diameter of 657mm (a difference of +14mm or +2.18% against standard). Circumference of 2063mm. 780 revolutions per mile.
Sod it, I've done the back so I may as well do the front.
Standard.
235/40/18 - Overall tyre diameter of 645mm. Circumference of 2027mm. 794 revolutions per mile.
Options.
245/35/18 - Overall tyre diameter of 629mm (a difference of -16mm or -2.48% against standard). Circumference of 1975mm. 815 revolutions per mile.
245/40/18 - Overall tyre diameter of 653mm (a difference of +8mm or +1.24% against standard). Circumference of 2052mm. 784 revolutions per mile.
255/35/18 - Overall tyre diameter of 636mm (a difference of -9mm or -1.4% against standard). Circumference of 1997mm. 806 revolutions per mile.
255/40/18 - Overall tyre diameter of 661mm (a difference of +16mm or +2.48% against standard). Circumference of 2077mm. 775 revolutions per mile.
One of the calculators I used advised no more than +/-2.5% variance in diameter.
So to add a little bit more rubber to protect your rims, wider by 10mm with no change to the sidewall ratio is best whether front or back. If you want to add 20mm, then again leaving the ratio unchanged is probably the most consistent between front and back, but your speed and mileage readings will be further off.
Hope this helps.