Board logo

Stupid Sunday afternoon question
Snuggs - 8/4/12 at 02:03 PM

Are space saver wheels/tyres the same diameter as the standard wheel/tyre ?

They always seem to look a lot smaller



And before anyone asks, YES I have been to the pub

[Edited on 8/4/12 by Snuggs]

Slimy38 - 8/4/12 at 02:20 PM

They have to be. Not only would it make the car unstable to have different tyre sizes on the same axle, it would also make things like traction control and ABS have a hissy fit if they were different.

The wheel is usually a lot smaller (11 or 12 inch wheels are common) but the tyre has a HUUUGE profile as well as being about half the diameter of a normal wheel.

bi22le - 8/4/12 at 02:43 PM

Considerably thinner as well.

The diameter difference is probably an optical illusion, you have been down the pub!!

jacko - 8/4/12 at 02:45 PM

There not in a new Astra but you only fit them on the rear of the car [ swap rear wheel to front and fit spare on rear etc
and you can only do 50 mph on them
Jacko

madteg - 8/4/12 at 03:18 PM

Had saab 9000, fitted space saver and drove 60miles at 50mph on M1 It killed my diff, when i looked into in my space saver was about 2" smaller in height. So my planet gears in diff would have been working all the time, i think this boiled the oil.

morcus - 9/4/12 at 02:07 AM

Same for all cars, your only meant to use them on the rear. I assume it's because the car wouldn't steer propperly with the narrower wheels. Can you put them on Driven wheels though?

Do you actually need a spare wheel? All the advise from the DVLA or whoever seems to suggest that you'r not really meant to use it unless you've got a safe place to swap it over and you know exactly what your doing and everythings perfect.

Slimy38 - 9/4/12 at 08:31 AM

I've heard that from all sorts of sources, I'm 99% sure my insurance T & C's and my breakdown recovery T & C's both say don't change your wheel unless you're absolutely 100% sure and safe etc.

Mind you, the number of times I've seen people change a drivers side wheel on the side of a motorway, with their back side sticking out into the left hand lane, I think more manufacturers should just not give them a spare wheel!

rusty nuts - 9/4/12 at 11:49 AM

quote:
Originally posted by Slimy38
I think more manufacturers should just not give them a spare wheel!


Like the newFord Fiesta!

MikeRJ - 9/4/12 at 12:14 PM

quote:
Originally posted by Slimy38
They have to be. Not only would it make the car unstable to have different tyre sizes on the same axle, it would also make things like traction control and ABS have a hissy fit if they were different.

The wheel is usually a lot smaller (11 or 12 inch wheels are common) but the tyre has a HUUUGE profile as well as being about half the diameter of a normal wheel.


They can have a smaller rolling radius in some cases. My ZS180 comes with a 125/80R15 space saver, but the standard tyre size is 205/45R17. This gives a difference of about 6% in wheel speeds.

It only fits on the rear of the car though, as it won't fit over the brakes on the front.

[Edited on 9/4/12 by MikeRJ]

MikeRJ - 9/4/12 at 12:23 PM

quote:
Originally posted by morcus
Same for all cars, your only meant to use them on the rear. I assume it's because the car wouldn't steer propperly with the narrower wheels. Can you put them on Driven wheels though?


Have a look at this video of Chris Harris driving an AMG Mercedes on 4 space savers

Peteff - 9/4/12 at 06:42 PM

quote:
Originally posted by jacko
There not in a new Astra but you only fit them on the rear of the car [ swap rear wheel to front and fit spare on rear etc
and you can only do 50 mph on them
Jacko


You can do 80mph on them in a Polo, the bloke who passed me on the M1 did anyway with a spacesaver on the front nearside and his wife and a baby in with him as well ( I assume they were his ).

morcus - 10/4/12 at 01:14 AM

That video is great, though not as good as when he took the BMW to Wank mountain.

907 - 10/4/12 at 07:55 AM

Since occasionally I tow a car trailer I wouldn't want anything other than a matching wheel as a spare.

A few weeks back I bought a VW 9 spoke alloy off one of the eBay scrapies for my Passat
so I now have 5 matching wheels.

Cheers,
Paul G

loggyboy - 10/4/12 at 08:46 AM

quote:
Originally posted by MikeRJ
Have a look at this video of Chris Harris driving an AMG Mercedes on 4 space savers


Now thats why my old E30 316 was soo much fun!