Hello. I wonder if anyone can help me. I have just bought my son a 2009 Fiesta 1.6 TDCI Titanium. On the front the tyres are 195/50/16 and on the rear 195/45/16. The tyre pressure sticker on the door frame lists both sizes. Does anyone know what size it left the factory with 11 years ago?

 

I had a 2009 Titanium 1.6 TDCI some years back. It was 6 months old/6,000 miles when I bought it so the tyres would be the originals  and it was on 196/45/16 iirc.

That's great. Thank you

If you type your reg into "Blackcircles" does it tell you what the size is likely to be ?

3 hours ago, Me140 said:

That's great. Thank you

You're welcome - just to confirm, I remembered I had an old brochure for the Mk 7 Fiesta and that shows 195/45/16 for the Titanium.

9 hours ago, Eric Bloodaxe said:

 just to confirm, I remembered I had an old brochure for the Mk 7 Fiesta and that shows 195/45/16 for the Titanium.

Yep 195/45/16 for sure.

I had a 2010 Titanium and the tyre size was 195-50-16.   I also had a 2013 Mk 7 Titanium and the tyre size was 195-50-16. I now have a 2017 Mk 7.5 Titanium and the tyre size is stil 195-50-16.

21 minutes ago, Bobr said:

I had a 2010 Titanium and the tyre size was 195-50-16.   I also had a 2013 Mk 7 Titanium and the tyre size was 195-50-16. I now have a 2017 Mk 7.5 Titanium and the tyre size is stil 195

 

Attempted a shot of the old brochure which shows 195/45 as standard tyre on 16" wheels. I think both 45 and 50 may have been permissible fitments, though.

Further thoughts on this one. I recall thinking at the time I had the Mk 7 that 45 was a pretty low profile tyre for a non-"sports" version and the Titanium also had the alloy wheels which were notorious for distorting very easily. I wonder if some cars were changed to the slightly higher 50 profile early on, both in the hope of avoiding wheel damage and softening the ride a little. 

 

 

Yes, Roger, all my Fiestas have had alloys wheels.

On 5/6/2020 at 11:50 AM, Eric Bloodaxe said:

Further thoughts on this one. I recall thinking at the time I had the Mk 7 that 45 was a pretty low profile tyre for a non-"sports" version and the Titanium also had the alloy wheels which were notorious for distorting very easily. I wonder if some cars were changed to the slightly higher 50 profile early on, both in the hope of avoiding wheel damage and softening the ride a little. 

 

 

That's a good point

Wonder how it effects the speedo

15 minutes ago, Bobr said:

Wonder how it effects the speedo

There are a few calculators on line, but I think going from a standard fit 45 to 50 profile increases the rolling circumference by about 3.25% so the speedo would under-read slightly.

I think the tyre size on the facelift Mk 7.5 Titanium (late 2012 on) was 195/50x16 as standard, and when the Mk 8 came out it changed again to 195/55x16 on the Titanium. 

i was under the impression either tyre size was acceptable and the speedo was set to over read on the 45 and not under reed on the 50 mine left  the factory in 2015 with 45 but when i replace fairly soon i will probably go with 50.

The speedo on a vehicle is calibrated to the wheel/tyre size, larger profile decreases the reading (under read) and smaller or lower profile increases it, on a Land Rover Defender, the speedo is calibrated for 750x16 and when fitted with 205 R16, as was the standard tyres from the first Defenders, the speedo reads over, with the speedo reading 34mph you are actually travelling at approximately 30mph. The owners manual will tell you the tyre size combos but what ever you fit the speedo will most probably give an accurate reading as it's electronic now whereas older stuff was cable drive operated from the gearbox.

Yes, back in the day of mechanical speedo drives most would over-read to ensure you kept under the limit. With the increased accuracy of modern speedos you keep seeing rumours that the traditional 10% plus 2mph guidance might be altered and zero tolerance has been talked about.

Auto Express did an article last year:

https://www.autoexpress.co.uk/car-news/106674/uk-speed-camera-tolerances-revealed-is-your-cars-speedo-accurate

Speedo's are still calibrated to the tyre size.  They rely on the ABS sensors rather than GPS so don't actually know the speed the car is travelling, just the speed the wheel turns at. 

It's just a simple box tick to change the tyre size on a modern car though, not sure what system you'd need to use for a Mk7 Fiesta though, it was ElmConfig or FoCCCus for the Focus's, maybe Forscan can do it?

I don't rely on my speedo but rather on my Satnav.   It invariably shows that when I'm doing 30 my speedo shows 33.

6 minutes ago, TomsFocus said:

Speedo's are still calibrated to the tyre size.  

Haha. You beat me to it. - I was just doing a link to this other article making that point and explaining why sat navs can display different speeds to the speedo!😀

 

https://www.thecarexpert.co.uk/how-accurate-is-a-car-speedometer/

Interesting article Roger.

Good reed that.

So basically if your Speedo is currently reading at approx 110% on 45 a change to 50 tires it will still over read but to a lesser amount and so still be road legal?

In addition to the article about speedo versus satnav, on my car the speedo reads higher than average mph . Prior to lockdown my drive to and from work has included some 50mph average speed motorway. So plenty of opportunity to compare my speedo to the digital average speed. For 50 mph average speed the speedo reading is 53mph. I assume the average speed is more accurate as it’s calculated from wheel rotations whereas speedo has the added factor of the strength of the spring on the speedo needle.

Speedos are deliberately set to over read slightly, to try and prevent speeding.

No, it's so you aren't speeding when thinking you're at or below the limit.  

By law, car manufacturers can't sell cars that under read their speed so they always err on the safe side.

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