Original Zs vs facelift zs tyres

[Jaygee]

I note that the facelift has 55 profile tyres whilst the original has 50. I will be upgrading to the facelift but am bit upset that my winter tyres which have cost me £500 will be the wrong profile size. If I were to put the 50s on the facelift my speedo would over indicate the speed. Is there a way of calibrating the Speedo if I were to do that as I am devastated about the set being useless.

 

[macd2401]

If you're fitting 50s to a 55 profile car, presuming you're in the UK, the regulations state that the speedo must never under read, and must not over read by more than 110% + 6.25mph. The speedo is already pretty accurate, to within 2 or 3 mph @ 70, so the over read would be well within spec.

 

[macd2401]

 

[JodyS21]

Didn’t know where to post this, so here it is.
A photo of the new alloy wheels hidden.

 

[BruceT]

I note that the facelift has 55 profile tyres whilst the original has 50. I will be upgrading to the facelift but am bit upset that my winter tyres which have cost me £500 will be the wrong profile size. If I were to put the 50s on the facelift my speedo would over indicate the speed. Is there a way of calibrating the Speedo if I were to do that as I am devastated about the set being useless.

As you can see the difference is minuscule, in fact, it's not even this much because of how tyres work, i.e. flatter at the bottom

 

[BarryH]

There are some really useful wheel and tyre comparison tools for anyone wanting to change wheels and tyres for example for fitting winter tyres. The site @macd2401 used to compare the new Facelift ZS tyre size with the current model's 50 profile. I believe is Tire Size Comparison

A good alternative that shows nicely the comparison and a great graphical representation of the impact of tyre size on the speed shown on your Speedo is Tire size calculator: compare tires online

And if you are thinking of changing rims too a great tool to show the effect steering geometry (and helping you understand why "Rim offset" is important on the feel of the car) check out Rim & Tire Size Calculator. Custom Offsets and pay attention to the clearances and "Scrub Radius" where the tyre contact patch, the suspension centre line and steering/hub centreline intersect. get this wrong and not only will you have bad steering feel but a big impact on tyre wear and range.

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[Jaygee]

Thanks guys. Very helpful. Puts my mind at ease.

 

[bdeithrick]

I’ve order my rim and all seasons for winter. Question is.
Do I need a different bolt for steel rim? I think or know but not sure, it’s the m14 x 1.5 the radius head.
What bolt is in the ZS alloy. The GF has the car for a week away.
Will I buy 20. M14x 1.5 or are the ones in the ZS ok. Or are they taper heads

 

[macd2401]

I’ve order my rim and all seasons for winter. Question is.
Do I need a different bolt for steel rim? I think or know but not sure, it’s the m14 x 1.5 the radius head.
What bolt is in the ZS alloy. The GF has the car for a week away.
Will I buy 20. M14x 1.5 or are the ones in the ZS ok. Or are they taper heads

The mk1 has taper heads. If you're fitting VAG group wheels, they'll need radius bolts.

 

[bdeithrick]

Thank you I think, I will order the m14 radius then. I’m delighted