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[Nick W]

The spare wheel in the boot of most of our cars is a full sized spare, just because it's not identical to the alloys doesn't make it a space saver, car manufacturers have to do a one else size fits all for spare wheels - they can't make the boot shape and space different depending get on what wheels were fitted. My spare is a 205 width as opposed to 225 width fitted to the alloys, 20mm difference is not noticeable when driving and the 50 miles/mph certainly doesn't apply as it is a standard tyre and the car is safe upto the lowest speed/load rating of the tyres fitted to the vehicle.

And gollom, rolling radius takes into account sidewall height and there won't be much in it.

In this case, the 50mph doesn't apply to the tyre, but because it is different to the other one on that axle. While there may be little difference in the rolling radius/width, it is real and must be acknowledged. Treating it as an emergency temporary repair and limiting the speed is a reasonable, common sense precaution. I would suggest a critical examination of the spare before fitting it too; I've refused to fit several sparewheels due to their execrable condition.

[Kevin Wood]

There are space savers and space savers, though. At least the Omega's spare is a proper car tyre. Whilst it does result in some asymmetry, if you had a puncture on, say a 500 mile trip on a Sunday night in deepest France, when nothing's open and nobody's sober, it would allow you to complete your journey before seeking a replacement when the tyre places open.

Contrast that with the flimsy wheels bearing what look like wheelchair/pram/bicycle tyres on some modern cars. They're really only useful to stop one corner of the car dragging on the ground while you limp to the next motorway junction. Might as well not bother, because if you hit a pot hole or drive more than a few dozen miles, you'll be back stranded again anyway IMHO.

[Diamond Black Geezer]

I hate space savers. I don't understand how the two statements can both be true from Mr Marketing Man...
"this sexy new, amazing new car needs these 265 tyres, it needs them because of its sexy new-ness"
"it's perfectly safe to drive this 1.6 ton car on this bicycle tyre"

but, like so much, it's a compromise, how often to people need a spare wheel? How many times have you been in a scrap car and found the new, unused tyre, with bobbles still on? Plenty of times in my few years on this planet. How long does it have to last? Theoretically the next day when you, of course, religiously go and buy a new one with the disposable incomes the entire planet enjoys.

reality is, of course, not as simple as that. I think it's a scrimp, and a symptomatic of an industry so crammed with legislation, more and more safety (the weight and unit cost penalties of which have to come from somewhere) and ever-changing market and ever-growing competition.

[Nick W]

but, like so much, it's a compromise, how often do people need a spare wheel? How many times have you been in a scrap car and found the new, unused tyre, with bobbles still on? Plenty of times in my few years on this planet. How long does it have to last? Theoretically the next day when you, of course, religiously go and buy a new one with the disposable incomes the entire planet enjoys.

In the 28 years I've been driving, my average annual car mileage must be about 25,000. I've had to fit the spare wheel once, and that was about 8 years ago, on the M25 about 25 miles into a 200 mile trip. By fitting the spare wheel, I was moving 5 minutes after stopping on the hard shoulder. Not having to wait who knows how long to be recovered and taken somewhere to buy a replacement easily justifies carrying the sparewheels in all the cars I'd owned until that point.


In that vein, the '72 Avenger I bought 8 years ago had an unused 145R13 Goodyear G800 in the boot.

[Diamond Black Geezer]

Indeed - I mean I'm not advocating having no spare wheel. (in the last year I've been saved several times by a double-quick wheel change by the roadside/car park) or indeed a space saver, as I say, hate the things. There's clearly reasons from the manufacturer's side to not fit them is what I'm seeing. There's pressure from many angles. 


Interestingly, a future 'trend' I read recently is that narrower tyres will become the 'cool' / 'norm' for newer cars, due to their fuel saving/aero benefits. Part of why the Citroen old DS19 is rumoured to have a lower drag coefficient than the Calibra, the then-most aerodynamic car in the world.

[Doctor Gollum]

Less weight for emissions testing...

In the Omegas case, the spare is limited by the width of the wheel well on saloons... Designed when  16" wheels were considered large... Hence a 195 width tyre will fit but a 225 won't.

The estate however will take a full size wheel/tyre, although once at the 245/40/18 size, the boot floor sits proud an inch or so...

[Diamond Black Geezer]

True, I don't think they predicted the fashion explosion in tyre size, though I do find a 225 will just jam in, (might need slight deflating I dont recall) but the 235s no hope, yes.   

[Kevin Wood]

I hate space savers. I don't understand how the two statements can both be true from Mr Marketing Man...
"this sexy new, amazing new car needs these 265 tyres, it needs them because of its sexy new-ness"
"it's perfectly safe to drive this 1.6 ton car on this bicycle tyre"

You don't get the feeling, through the steering, of total disconnection from what's happening at the surface of the road unless you fit oversized tyres, you see.

[TheBoy]

The spare wheel in the boot of most of our cars is a full sized spare, just because it's not identical to the alloys doesn't make it a space saver, car manufacturers have to do a one else size fits all for spare wheels - they can't make the boot shape and space different depending get on what wheels were fitted. My spare is a 205 width as opposed to 225 width fitted to the alloys, 20mm difference is not noticeable when driving and the 50 miles/mph certainly doesn't apply as it is a standard tyre and the car is safe upto the lowest speed/load rating of the tyres fitted to the vehicle.

And gollom, rolling radius takes into account sidewall height and there won't be much in it.

'Fraid it counts as a space saver, hence all facelifts left the factory with a big yellow 80kpm sticker on the wheel.

Its different to the other on the same axle in size, and more importantly, construction.  The standard spare is an H rated item, which is too low for any Omega (V, or Z for V6)

[STEMO]

The top speed of my astra wouldn't trouble an 'H' 

[TheBoy]

The top speed of my astra wouldn't trouble an 'H' 

Its not just about its speed rating, as on UK roads, even remoulds are OK