Tyre Sizes

[Lotus1]

Hi folks,

I'm looking to replace my wheels and tyres in next few weeks and have noticed that my existing rear tyres don't seem to be the right size...

According to the User Manual, a 3.0i with 18" wheels should have 225/40s on the front and 255/35s on the rear - mine has 225/40s all round. Strangely, the Manual also says that with 17" wheels you can use 225/45s all round...so I'm thinking it's not that critical to have wider tyres on the rear...?

Does anyone else have 225/40s all round?

Steve

 

[Zeefour]

Hi folks,
According to the User Manual, a 3.0i with 18" wheels should have 225/40s on the front and 255/35s on the rear - mine has 225/40s all round. Strangely, the Manual also says that with 17" wheels you can use 225/45s all round...so I'm thinking it's not that critical to have wider tyres on the rear...?

Does anyone else have 225/40s all round?

Steve

The 18" wheels are part of the sport package which are staggered (which i have). I believe the 17" may use the same width tires front and rear. Nothing wrong with same size all around most cars have that configuration. Wider wheels in the back give you a wider foot print for more traction

 

[Lotus1]

Hi folks,
According to the User Manual, a 3.0i with 18" wheels should have 225/40s on the front and 255/35s on the rear - mine has 225/40s all round. Strangely, the Manual also says that with 17" wheels you can use 225/45s all round...so I'm thinking it's not that critical to have wider tyres on the rear...?

Does anyone else have 225/40s all round?

Steve

The 18" wheels are part of the sport package which are staggered (which i have). I believe the 17" may use the same width tires front and rear. Nothing wrong with same size all around most cars have that configuration. Wider wheels in the back give you a wider foot print for more traction

...but it's more fun with a 'loose' rear end

Steve

 

[Zeefour]

quote]

...but it's more fun with a 'loose' rear end

Steve[/quote]

Not sure i want to interpet that remark , but assuming we are still talking cars, turn of the traction/stability control (DSC) and you can drift with the best of them

 

[Wondermike]

Lotus1, which wheels do you have? If they're original BMW wheels, the backs are wider and should definitely have wider tyres on them.

 

[Lotus1]

Lotus1, which wheels do you have? If they're original BMW wheels, the backs are wider and should definitely have wider tyres on them.

Mike,

They are original Starspoke 108s... I don't think there would be any reason why you can't have a 225 (9") tyre on an 8 1/2" rim - it's going to affect the handling but the tyre isn't a mis-match for the rim.

Steve

 

[Wondermike]

No I suppose no reason why not - at least with a 255 tyre you'll get a bit more protection from kerbs etc, something that the RFTs are pretty good for. You gonna replace the rears with 225 or 255?

 

[Lotus1]

No I suppose no reason why not - at least with a 255 tyre you'll get a bit more protection from kerbs etc, something that the RFTs are pretty good for. You gonna replace the rears with 225 or 255?

I think it will have to be 255s - it must be the better option if that's what BMW specify

Steve

 

[plowy]

I ran 225/40's on the rear of mine for about a month in the summer as i got them cheap for two track days, after the first i left them on till the second and did a few miles in between, to be perfectly honest I could not tell any differance when i put the 255's back on, the car was faultless on track and as you can imagine it took some stick on both occasions.

 

[Lotus1]

I ran 225/40's on the rear of mine for about a month in the summer as i got them cheap for two track days, after the first i left them on till the second and did a few miles in between, to be perfectly honest I could not tell any differance when i put the 255's back on, the car was faultless on track and as you can imagine it took some stick on both occasions.

That's good to know - thanks

Steve

 

[Zeefour]

?[/quote]

I think it will have to be 255s - it must be the better option if that's what BMW specify

Steve[/quote]

Wider back tires are more useful at the drag strip than road racing around corners. Most NASCAR cars use even sizes all around, and they only use 15x9.5 wheels on the cars. But cars do look nice and aggressive when they sit low with staggered wheels

 

[Lotus1]

Wider back tires are more useful at the drag strip than road racing around corners. Most NASCAR cars use even sizes all around, and they only use 15x9.5 wheels on the cars. But cars do look nice and aggressive when they sit low with staggered wheels

Thinking about it, some of the reports I read before buying suggested that the Z4 tends towards understeer...so I suppose using the same size tyres all round would compensate for this :wink:

Steve

 

[plowy]

Wider back tires are more useful at the drag strip than road racing around corners. Most NASCAR cars use even sizes all around, and they only use 15x9.5 wheels on the cars. But cars do look nice and aggressive when they sit low with staggered wheels

Thinking about it, some of the reports I read before buying suggested that the Z4 tends towards understeer...so I suppose using the same size tyres all round would compensate for this :wink:

Steve

Good theory Steve but it don't work I promise.