Post by George MX-5 (Admin) on Jul 7, 2015 10:04:42 GMT 2
Hello MX-5ers
I take it we all live in sunny South Africa where we hardly have snow, ice and super wet roads (all year round or ever)
So what are you looking for in your ride then ?
Softness and Comfort
If you just want comfort, softness and don't mind losing speed, torque and stiffness (handling) and losing a little fuel milage then you can go with a wider tyre and taller side wall.Remember that bigger tyres = heavier as well (it's all about rotational inertia, the equation which is MR^2 for a hoop (ring) or 1/2MR^2 for a disk. a car wheel is somewhere between these two. M is mass, R is radius (how far the mass is from the rotational axis - the axle for a car). so, as you can see, the added mass makes a huge difference as most of it is probably in the rim , which has the largest distance from the rotational axis.)
Stock tyres are Potenza 205/45/17 on MX-5 ,a good few choices are listed below.
Michelin Pilot Super Sport - 225/45/17 (Hard and noisy)
Goodyear Eagle F1 asymmetric 2 - 225/45/17
Continental Extreme Contact DW - 225/45/17
225 Tyres fit on the stock rims perfectly
Sporty Handling Tyres
Keep in mind that generally as you soften the sidewall and/or provide it with more flex for a softer ride you will likely lose some turn in responsiveness. Still grippy, but not so much head-snapping throw you out the window sharp turn in...
Michelin Pilot Sport AS PLUS in 215/45/17 (Kwonw to wear out quickly though)
Michelin Pilot Sport AS3 215/45/17 (Better tyre)
BF Goodrich G-Force Sport Comp 2 214/45/17 Very Good Tyre
Kumho Ecsta 215/50/R16 or 17
Understanding Tyres
Tires are measured and marked in W/A/D. Tread Width/Aspect ratio/Wheel Diameter. Width multiplied by aspect gives you your actual sidewall height in mm. You double the two products to get both sides of the tire. With a 50 aspect you just use the width number as it is even math but for all others, you have to multiply first then add.
With all the info now found at tire sites they usually give good diameter/circumference numbers without having to do the math anymore but I had an ASE master mechanic argue with me that the 3 digit number was the sidewall height and the 2 digit was the width. He was quite wrong and it appears many people share his confusion.
As an example, a 205/50/16 wheel and tire will be 611mm in diameter. 406 for the wheel, 205 (102.5 X2) for the sidewalls.
A 215/40/16 would be 578mm in diameter. 406 for wheel 86X2 for sidewalls. The 215 is actually smaller in diameter and circumference since only 40% of the width is represented in the sidewall.
The the diameter and circumference are affected only by the aspect ratio between widths. Yes a 215/50 is taller than a 205/50 but only a little (1cm of diameter 3.14 cm circumference). The aspect ratio is most important factor when you are saying a "taller" tire.
If the aspect ratio is the same then yes, each tire would also get taller with any width addition but to just say "taller" when speaking of the width number is a potential misnomer and takes away the buyers option of going to a lower aspect ratio tire to still get width without adding circumference
I take it we all live in sunny South Africa where we hardly have snow, ice and super wet roads (all year round or ever)
So what are you looking for in your ride then ?
Softness and Comfort
If you just want comfort, softness and don't mind losing speed, torque and stiffness (handling) and losing a little fuel milage then you can go with a wider tyre and taller side wall.Remember that bigger tyres = heavier as well (it's all about rotational inertia, the equation which is MR^2 for a hoop (ring) or 1/2MR^2 for a disk. a car wheel is somewhere between these two. M is mass, R is radius (how far the mass is from the rotational axis - the axle for a car). so, as you can see, the added mass makes a huge difference as most of it is probably in the rim , which has the largest distance from the rotational axis.)
Stock tyres are Potenza 205/45/17 on MX-5 ,a good few choices are listed below.
Michelin Pilot Super Sport - 225/45/17 (Hard and noisy)
Goodyear Eagle F1 asymmetric 2 - 225/45/17
Continental Extreme Contact DW - 225/45/17
225 Tyres fit on the stock rims perfectly
Sporty Handling Tyres
Keep in mind that generally as you soften the sidewall and/or provide it with more flex for a softer ride you will likely lose some turn in responsiveness. Still grippy, but not so much head-snapping throw you out the window sharp turn in...
Michelin Pilot Sport AS PLUS in 215/45/17 (Kwonw to wear out quickly though)
Michelin Pilot Sport AS3 215/45/17 (Better tyre)
BF Goodrich G-Force Sport Comp 2 214/45/17 Very Good Tyre
Kumho Ecsta 215/50/R16 or 17
Understanding Tyres
Tires are measured and marked in W/A/D. Tread Width/Aspect ratio/Wheel Diameter. Width multiplied by aspect gives you your actual sidewall height in mm. You double the two products to get both sides of the tire. With a 50 aspect you just use the width number as it is even math but for all others, you have to multiply first then add.
With all the info now found at tire sites they usually give good diameter/circumference numbers without having to do the math anymore but I had an ASE master mechanic argue with me that the 3 digit number was the sidewall height and the 2 digit was the width. He was quite wrong and it appears many people share his confusion.
As an example, a 205/50/16 wheel and tire will be 611mm in diameter. 406 for the wheel, 205 (102.5 X2) for the sidewalls.
A 215/40/16 would be 578mm in diameter. 406 for wheel 86X2 for sidewalls. The 215 is actually smaller in diameter and circumference since only 40% of the width is represented in the sidewall.
The the diameter and circumference are affected only by the aspect ratio between widths. Yes a 215/50 is taller than a 205/50 but only a little (1cm of diameter 3.14 cm circumference). The aspect ratio is most important factor when you are saying a "taller" tire.
If the aspect ratio is the same then yes, each tire would also get taller with any width addition but to just say "taller" when speaking of the width number is a potential misnomer and takes away the buyers option of going to a lower aspect ratio tire to still get width without adding circumference
) I have hired the Rock Race way this Saturday 24 June, if you would like to come onto the track and use the strip you are welcomed to will be R300 per person.