Space saver wheel sizes

Camm1

War Hero
#1
My motor has one of the poxy tyre sealant pump thingys in case the tyre get sting by a wasp but are fecking useless in all other events.
There is space for spare but not much. I have the opportunity to get a space saver but I cant find out if the size is correct. A mate of mine tells me it will be fine but hes a cnut and im not sure he knows what he is talking about. Soo...

My normal wheel is 18-225-45 and the space saver is 15-165-89(i think). The bolt pattern is fine.
Any one help?

$_86.JPG
 
#2
Check the rolling radius of the tyre. I.e. the diameter of the space saver should be similar to the normal tyre.

You don't say what car it is so can't advise further, but I would just ring the local dealership who should be able to supply one or at least provide the details even if you don't buy one from them.
 

Helm

MIA
Moderator
Book Reviewer
#3
Check the rolling radius of the tyre. I.e. the diameter of the space saver should be similar to the normal tyre.

You don't say what car it is so can't advise further, but I would just ring the local dealership who should be able to supply one or at least provide the details even if you don't buy one from them.
This, the other wheel may even have a different bolt pattern/size.
 

Camm1

War Hero
#4
Check the rolling radius of the tyre. I.e. the diameter of the space saver should be similar to the normal tyre.

You don't say what car it is so can't advise further, but I would just ring the local dealership who should be able to supply one or at least provide the details even if you don't buy one from them.
Cheers DN

Its for a Merc CLA. the 'normal' space savers wont fit in the boot but the one pictured ia a 'collapsable' one which will. How close do the Diameters need to be?
 
#7
Cheers DN

Its for a Merc CLA. the 'normal' space savers wont fit in the boot but the one pictured ia a 'collapsable' one which will. How close do the Diameters need to be?
Preferably the rolling radius needs to be the same on 2 core counts.
Firstly, a differing one can set off computerised deflation warnings by fooling it with a smaller radius making the system think there's deflation going on.
Secondly, if....that "axle" has an LSD...they don't like fighting with differing rolling radius for a varied period of time especially when mechanical grip is 100%.
I've seen expensive Mx5 Sport Fujji LSD's ( Rear wheel drive) ruined over the years for similar reasons
 

Camm1

War Hero
#9
Preferably the rolling radius needs to be the same on 2 core counts.
Firstly, a differing one can set off computerised deflation warnings by fooling it with a smaller radius making the system think there's deflation going on.
Secondly, if....that "axle" has an LSD...they don't like fighting with differing rolling radius for a varied period of time especially when mechanical grip is 100%.
I've seen expensive Mx5 Sport Fujji LSD's ( Rear wheel drive) ruined over the years for similar reasons
Thanks Ecosse,

OK sorted the comparison out there is 16mm differance in Dia.

Would this cause problems? dont forget its only as a spare so wouldnt be running this way all the time.
 
#10
Give the dealers a ring. Find out what they recommend.
I have a c class with spacesaver spare but my tyres are different size to yours
As above, some cars get upset with different radius tyres on the same axle.
 
#11
Would this cause problems? dont forget its only as a spare so wouldnt be running this way all the time.
Well, fate has a nasty habit of making sure your puncture happens miles from home, so possibly.
On the other hand, a couple of miles, I'd not worry. It's a Lotto!
What Dark Nit posted is solid advice, if you happen to have a dealership which knows it's onions.
 

Helm

MIA
Moderator
Book Reviewer
#12
Also, check what speed they're rated to do as some are as low as 40mph most about 50mph.
 
#13
It's normally an option when buying the car from new to have either a repair kit or a space saver tyre so your dealer should be able to tell you the exact size of the space saver.
My car has 20inch wheels but the space saver is 18inch the difference in wheel size is because the space saver has a much higher profile 90 as opposed to 35 which brings the rolling diameter up to match the 20inch wheels.
 

Similar threads


Top