Thinking whether i should go 17" or 18"

[JayD]

Hi guys

currently on 18" wheels Im not sure if i want to go down or not

Can anyone with 17" wheels show me pics?

Also how do you find speed humps etc?

Thanks

[wolfie1]

speed humps no bother at all doesnt scrape if you go over them right
17" wheels-

[JayD]

Thanks buddy... Mine pretty low and I\'ve been caught out in London on some short humps.

[m1tch]

The question you need to be asking is: how big are my brake calipers?

15"-16" = optimal for performance with regards to acceleration (smaller rim helps with acceleration and keeps the weight down) - why do you think Mazda chose to run a fairly wide 16" on the FD?
17" = Compromise between looking good and grip performance
18"+ = show only (unless you have massive brakes fitted and need the extra clearance)

[wolfie1]

fd also came with 17"
if you changed the aspect ratios of the different sized tyres you would be able to have the same rolling circumference!
for example a 205/60 16 would have the same rolling circumference as a 235/35 18, if you go onto michelins website there is a guide there to the exact figures

[m1tch]

fd also came with 17"
if you changed the aspect ratios of the different sized tyres you would be able to have the same rolling circumference!
for example a 205/60 16 would have the same rolling circumference as a 235/35 18, if you go onto michelins website there is a guide there to the exact figures

Wasn\'t that due to them running larger disks on some models though?

[wolfie1]

dont know, could have been, makes sense

[JayD]

fd also came with 17"
if you changed the aspect ratios of the different sized tyres you would be able to have the same rolling circumference!
for example a 205/60 16 would have the same rolling circumference as a 235/35 18, if you go onto michelins website there is a guide there to the exact figures

That\'s very interesting ummm...

What size tires do you run on your 17"?

[wolfie1]

225/45 17 on the front and 255/40 17 on the rear

[JayD]

Umm tempting... i would like to run 9.5" or 10" on the rear

[RotRex]

225/45 17 on the front and 255/40 17 on the rear

Why the lower profile at the rear? Should it not be the other way for high speed stability or have you compensated with adjustable suspension?

[m1tch]

Why the lower profile at the rear? Should it not be the other way for high speed stability or have you compensated with adjustable suspension?

The \'lower profile\' is due to the wider tyre, the profile of the tyre is the % of the tyre width so having a wider tyre will mean a lower profile as its done as a % to match the same circumference so both tyres are basically the same:

225/45/17 vs 255/40/17 = 6mm difference in circumference
225/45/17 vs 255/45/17 = 88mm difference in circumference

http://www.alloywheels.com/Tyre_Calculator

[RotRex]

The \'lower profile\' is due to the wider tyre, the profile of the tyre is the % of the tyre width so having a wider tyre will mean a lower profile as its done as a % to match the same circumference so both tyres are basically the same:

225/45/17 vs 255/40/17 = 6mm difference in circumference
225/45/17 vs 255/45/17 = 88mm difference in circumference

http://www.alloywheels.com/Tyre_Calculator

Interesting. It potentially opens up a range of tyre choices. I will have to use the calculators next time I get tyres. Or ask you for advice.

[wolfie1]

just realised a typo i made, i am running 235/45 17 on the front

[kummbho]

fd also came with 17"
if you modified the element percentages of the different scaled car tyres you would be able to have the same moving circumference!
for example a 205/60 16 would have the same moving area as a 235/35 18, if you go onto michelins web page there is a information there to the actual figures