[iceman]

Has anyone change or upgraded t0 20" wheels? I was wondering what is the disadvantage if I will change my tyres size from 245/40 into 255/50 R20. Will it matter or not? Need advise please.

 

[bigiainw]

Going to a bigger tyre size will push your speedo to record a lower speed than you are actually doing, although the captiva generally reads 3-4 mph less than it is actually doing, so provided you don't have a huge difference in size, there shouldn't be too much of a problem

 

[iceman]

Thanks for your advise Bigianw. I was just thinking that the 40 series is too low and will not protect my alloys in case of deep road holes. Anyway, if their is not big difference with the speedo, I think I will go for it. Cheers.

 

[bigiainw]

You need to be careful though, becuase the aspect ratio is just that, so if you use the tyres suggested, then not only are the sidewals 10% higher, they are also highere by 10% of the increase in tread width, that is, thew 245/40 gives a rim to road depth of 98 mm, and the 255/50 gives a depth of 127.5mm, which changes the circumferance of the wheel and tyre combo.

Using a tyre size calculator http://www.alloywheels.com/tyrecalc.asp, it reckons that at a true 70mph on the speedo, you will be doing 75.87mph.

 

[Arshad]

Thanks for your advise Bigianw. I was just thinking that the 40 series is too low and will not protect my alloys in case of deep road holes. Anyway, if their is not big difference with the speedo, I think I will go for it. Cheers.

The 40 profile is 40% off 245 so still gives you a decent sized tyre wall.

You'd have to drive through 10cm pothole for it to get to the wheel.

The ride is considerably harder once you get the 20's on but the handling is also vastly improved.