Which size wheel for 'full size spare'

[kevster184]

Hi

I am considering either buying another alloy if I find one or a steel wheel for a full size spare.

I have the Dynamic 17" FR alloys which are 7.5J H2 ET51 fitment with 225/45 tyre

But I am stuck as to which steel wheel tyre combination I would need, ie 6 or 6.5 J with 205 tyre?

The thinking behind it is I've had several punctures recently and with work commitments it would be great to have a proper wheel to throw on and continue using the car while I sort the issue out.

I do have a space saver but as we know they are naff at 50 mph!

I am keeping an eye out for another alloy but any help on a steel wheel would be great too.

 

[DEAN0]

225/45R17 tyres are the same rolling diameter as a 205/55R16

Typically a 205 should be on a 5.5" or 6" rim to maintain the correct shape.

 

[kevster184]

225/45R17 tyres are the same rolling diameter as a 205/55R16

Typically a 205 should be on a 5.5" or 6" rim to maintain the correct shape.

Great thanks. Does the ET51 offset have to remain the same or I assume it's different to suit a thinner wheel?

 

[DEAN0]

Great thanks. Does the ET51 offset have to remain the same or I assume it's different to suit a thinner wheel?

I would guess it needs to be the same to clear the brakes.

You could go with a bigger ET to push the thinner wheel out but then the load on the bearings will change ( IE the middle of the tyre will no longer be where it was designed to be )

 

[kevster184]

I would guess it needs to be the same to clear the brakes.

You could go with a bigger ET to push the thinner wheel out but then the load on the bearings will change ( IE the middle of the tyre will no longer be where it was designed to be )

Dont think they sell a wringly offset wheel?

Looks like the S trim model still has steel wheels but 15"

If they were 16 it may fit

Clear the brakes is the important bit but an ET for a 205 wheels tyre will be different than for a 225 wheeled tyre surely

 

[DEAN0]

Clear the brakes is the important bit but an ET for a 205 wheels tyre will be different than for a 225 wheeled tyre surely

Why ?

The ET is the position of the centre of the tyre width in relation to the mounting face of the wheel.

It is designed so that the load of the wheel is applied correctly to the hub and the geometry of the suspension / steering is as intended.

205 tyre with an ET51 will have the middle of the tyre width in the same place as a 225 with an ET51.

The only reason to deviate from the factory ET is if you have clearance issues with suspension / bodywork / brakes

 

[g_berserk]

Has anyone ever figured a way to keep a 5th wheel identical to the other 4 in the spare bucket?
I'm tempted to buy another wheel for my Cupra since I don't feel comfortable at all with a space saver wheel, but the space under the carpet looks restricted.

 

[DEAN0]

Has anyone ever figured a way to keep a 5th wheel identical to the other 4 in the spare bucket?
I'm tempted to buy another wheel for my Cupra since I don't feel comfortable at all with a space saver wheel, but the space under the carpet looks restricted.

Yes - put one of your current wheels in the spare holder and measure how far above the boot floor the top of it sits ( for example lets say 50mm )

Buy a sheet of 50mm thick polystyrene and make two blocks the same shape as the boot floor around the wheel for the tray to sit on.

You loose some boot space but will have a full sized spare.

 

[ben4012]

Has anyone ever figured a way to keep a 5th wheel identical to the other 4 in the spare bucket?
I'm tempted to buy another wheel for my Cupra since I don't feel comfortable at all with a space saver wheel, but the space under the carpet looks restricted.

I couldn't get a 205 55 16 in the well at all. I was going to carry a winter as (near to) full size spare.

 

[ben4012]

Dp.

 

[ben4012]

Clear the brakes is the important bit but an ET for a 205 wheels tyre will be different than for a 225 wheeled tyre surely

The same et on a different rim width will make a difference. There is a wheel and tyre guide in another current thread.

 

[kevster184]

The same et on a different rim width will make a difference. There is a wheel and tyre guide in another current thread.

I'll hunt that out. Trying to establish if the ET is specific to a wheel and tyre combo, the car or both!