Spare wheel size query

[Nitropodder]

In November 2015 I bought a brand new Ford Fiesta GJ65XLZ from my local Ford dealership.
The car was supplied with 4 x Continental 195, 50, 16 wheels / tyres.
Spare tyre is a Hankook 175, 65, 14
I only discovered this because I found a large nail buried in my tyre (still inflated) and drove around to my regular tyre fitters for advice.
As the nail was too close to the wall a replacement was required but because the two back tyres were fairly worn I requested a new pair be fitted. No problem, he would order them for me and fit them the next day. In the meantime he agreed to swap the defective tyre with the spare.
Having not had a puncture since buying the car this was the first time I had seen the spare. Straight away he noticed the spare was 14 inch whilst the cars tyres are 16 inches.
He refused to fit them saying it would be unsafe as there is a 2 inch difference. Apart from the car 'leaning' it would impact the suspension geometry and set off the ABS sensors due to difference in rotational speed and may affect tyre pressure sensors.
So I went to my Ford garage to question this. They were adamant that the supplied spare tyre was correct and perfectly safe to drive as long as I stuck to the 50MPH max indicated by the big yellow sticker.
Please could somebody tell me if the Ford garage is correct?

[Nick Y]

If that was the temporary (spare) wheel supplied by Ford then it should be ok to use temporarily. If those wheels could not be used in emergencies then Ford could not legally supply them for use as temporary or emergency wheels.
I'd check the handbook in your vehicle just to be safe as that will tell you what type of wheel is supplied and the restrictions for use. 
If it were to be MOT tested with a wheel of the incorrect aspect ratio then it would fail but you are allowed by law to temporarily fit another wheel in an emergency until the original tyre can be replaced and refitted to the correct wheel. Surely it would only be the same as driving with a space saver thin wheel on for a few miles

Ford told me that if I wanted an emergency wheel (instead of an inflation kit) for my 17 plate Mk7.5 Fiesta ST-Line with 17" alloys the emergency wheel that they would supply for that vehicle would be a steel wheel with 15" rims but with a larger tyre to offset the difference in size. Ford doesn't supply wheels of the same size as spares designed for temporary emergency use. 

[TomsFocus]

The rim diameter doesn't really matter.  As long as the rolling radius is more or less the same it'll be fine.  You'll notice the smaller rim has a larger tyre sidewall to keep the rolling radius correct.

However the tyre tech is sort of right, it is only for emergency use to get you to a garage though, you're not really meant to use it 'in the meantime' as it will affect handling and braking.  And if you exceed the 50mph max limit it has the potential to overheat the tyre and cause a blowout.

[Bobr]

The difference in size between the 195, 50, 16 tyres and the spare is made by the fact that, although the rim is 14" , the tyre is 175, 65, 14.   The spare is perfectly safe to drive on up to 50 mph and that tyre fitter doesn't know what he's talking about.

[isetta]

i can confirm that is the correct size spare. I assume it had a yellow max 50mph/80kmh sticker on it, they usually do.  it is not a skinny space saver as such like some cars have. It is the full size wheel from Fiesta Studio models (base model) and all the Fiesta Econetic Diesel models. It is exactly what I would have expected to find in the boot (for fiestas with a spare wheel and not the ST spec)

[matt786]

Your original wheels are alloys. The spare wheel is steel. The difference in this is compensated by the spare wheel/tyre being at different dimensions to your alloy wheels so should be ok for temporary use if it's the genuine spare wheel/tyre supplied by Ford with your car. It should have max speed rating sticker on it also.