Tyre profile query

[obewan]

My Niece, who is learning to drive, has proudly just bought her first car, a Corsa
Bringing it round to show me I noticed one of the front tyres was under inflated.
On checking the tyre sizes/pressures against the values in the handbook it would appear it has the wrong tyres on it all round.

It is shod with 195/55-R16
The book says 195/45-R16

I've checked a tyre size/speed calculator website which seems to say up to a 2.5% difference is ok - this is 6.7%
The garage has put 2 new front tyres on, the same as the rears. I'm assuming they've not checked and just copied what was on the rear

Am I correct in thinking the speedo will under read?

I've advised her to take it back to the garage and question it. I'd have thought they had an obligation to sell the car in the 'correct setup'.
Interested in your thoughts/opinions
Am I being over cautious?

TIA

 

[Smartbear]

The speedo will read lower than it did previous to the tyre change but don’t forget that speedometers over read by design.
It might now be accurate!
Rob

 

[obewan]

Good point Rob

 

[Smartbear]

It will also raise the gearing a little, possibly making the car feel slightly sluggish accelerating :?
Rob

 

[Pondrew]

I would say there are no downsides for a new driver with a bigger profile TBH:
More shoulder will equal more road impact absorption along with less likelihood of wheel kerbing
It will be more comfy to drive and the suspension will have to do less (and therefore be less likely to break).
And the tyres will last 6.7% longer!
The speedo issue, as Rob said, shouldn't be an issue. Just advise her to err on the side of caution with speed cameras.

 

[obewan]

Thanks for the replies both, appreciated.
I've also just entered the car reg in a few tyre company 'product finders'
Every one came up with 195/55. So all looks good now.
That'll teach me to rely on a Hand book!

 

[M1k3yC]

That'll teach me to rely on a Hand book!

What's written on the label on the door shut(s)? I'd expect 195/55 R16 to be listed there as one of the options if it's meant to have those on it.

 

[obewan]

That'll teach me to rely on a Hand book!

What's written on the label on the door shut(s)? I'd expect 195/55 R16 to be listed there as one of the options if it's meant to have those on it.

Unfortunately there was nothing about tyres on the door plates. I think it was just a paint code or similar

 

[ronk]

Ive just had the winter wheels fitted to the 335 _ They are a 18" v 19" and 225 v 255
I thought i would check the speedo against a mobile phone based system - I was pleased to see to see that the speedo was reading approx 1mph plus

Just to satisfy yourself i would suggest that you do a similar check.

 

[obewan]

Cheers Ron, suggested that (or Sat Nav)