Car tyres, wheels

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S-Express

Guest
Correct
 

Drago

Legendary Member
It isn't. Diameter too small. You'd have just got away with it if the car was shod on 225/40r17, but the difference at 45 is just one step beyond the safe threshold. You could use it to drive the car off the carriageway to a safe position, but you don't want to actually take it on then road like that.
 

Drago

Legendary Member
It will if he has to brake or manoeuvre violently and and vehicle stability or braking systems don't work optimally because the maths being sent from that wheel is all wrong. Either the police or insurer (or both) will repeatedly smash the soles of his feet with a rubber hose.
 

Bonefish Blues

Banging donk
Location
52 Festive Road
It will if he has to brake or manoeuvre violently and and vehicle stability or braking systems don't work optimally because the maths being sent from that wheel is all wrong. Either the police or insurer (or both) will repeatedly smash the soles of his feet with a rubber hose.
Why?

How is this different to a spacesaver which is routinely used?

I made clear this is a limited use get you home only application, and still say it's fine in that mode.

One could argue it would be better than a spacesaver in that scenario as it has a wider profile and will be a much lower psi, so much more grip.

ETFA
Odd sized tyres on same axle are legally allowed in an emergency (e.g., original tyre punctured) and the car is then limited to 50mph.
 
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Deleted member 26715

Guest
I would say that odd size tyres should be on the back only. You would have to swap a back wheel to the front to even the sizes up. Odd sizes on the front would make the steering/tracking quite odd.
This is sage advice & should be strictly followed.
 

Drago

Legendary Member
It might be kinder to the diff on a FWD drive car to put it on the rear.

But it's kinder to your underpants to put it on the front on the basis that understeer is a lot less likely to send you to the afterlife than oversteer.
 
D

Deleted member 26715

Guest
It might be kinder to the diff on a FWD drive car to put it on the rear.

But it's kinder to your underpants to put it on the front on the basis that understeer is a lot less likely to send you to the afterlife than oversteer.
Claptrap, have you ever tried to drive a FWD car with different wheel sizes?
[QUOTE 4960979, member: 9609"]That clearly sounds very logical and may well be good advice and correct (but in the spirit of CC i will disagree) many stability issues with vehicles begin with the rear wheels losing grip (even on FWD) many say when fitting two new tyres to a FWD they should go on the rear as grip there is more important than on the front ?[/QUOTE]We are talking here about an emergency/get you home situation, lots of FWD car manufactures put this in their manual, you know the one that nobody reads.
 

lazyfatgit

Guest
Location
Lawrence, NSW
As a limited use spare, yes that will be fine, providing it goes over your brake discs.

Space savers aren't the same circumference, designed as a get-you-home only. As long as you view this in the same way, the 5.5% smaller circumference won't matter.

Data from putting both in here:

https://tiresize.com/comparison/

The space savers I've had have all been pretty much the same circumference, just a lot narrower. They've all been on same diameter rims in steel instead of alloy but narrower, so they don't use as much height in the boot or under the car.
 

Bonefish Blues

Banging donk
Location
52 Festive Road
The space savers I've had have all been pretty much the same circumference, just a lot narrower. They've all been on same diameter rims in steel instead of alloy but narrower, so they don't use as much height in the boot or under the car.
They are the nearest approximation, you're right, but not the same, by definition, hence the regulations that apply.
 
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