Wheel offset vs spacesaver spare.

[Trenchard]

I'm having a spot of bother with my wheels and could use some expert advice.

I fitted Brembos with bigger discs from a Renault Megane Cup onto my Astra convertible. To clear the calipers, I got hold of a set of 8J x 17 wheels with an ET of 35. To get a better ride quality, I replaced the original 215/40 x 17 tyres with 225/45 x 17. These gave me the expected improvement in ride quality and also gave better rim protection but the combination was just kissing the rear arches and munching slightly on the plastic liners at the front.

After quite a lot of research, I found that my original 7.1/2J x 17 wheels (ET 47) clear the calipers perfectly
when fitted using 10mm spacers. Accurate measuring shows that when I have the 225/45s put on the graunching will be gone.

What's foxing me is the standard spacesaver spare wheel. This steely is 5 x 110. I don't know what the ET is but there is no way it can clear the calipers - it'd need spacing by far more than 10mm.

OK, firstly, with the spacers on my original wheels, is the ET now 57 or is it 37? I've tried the sporty Renault forums with no joy re. a spare so it seems the only option at the moment is another standard wheel to use as a spare - I could go to 7J.

Any wheel gurus anbout at all?

[Scrump]

A 10mm spacer behind a wheel with an offset of ET47 will give an offset equivalent to a wheel with an offset of ET 37.

[mmm-five]

Assuming it's a square set-up and your big brakes are on the front only, can you not simply use the spacesaver on the rear
and move a rear wheel to the front if you have a front puncture.

[Trenchard]

mmm-five said:

Assuming it's a square set-up and your big brakes are on the front only, can you not simply use the spacesaver on the rear
and move a rear wheel to the front if you have a front puncture.

Thank you, gentlemen, much appreciated.
Yes, the Bimbos (Brembos) are up front, where they're doing an excellent job...



The use the spacesaver and swap front to rear has been floated before. It's an excellent idea so I'll go with it. Strikes me as better than carrying a gum-and-aerosol-can kit, which I understand is a tyre killer.

Thanks again, David

Edited by Trenchard on Saturday 12th March 22:44