Wheel and Tyre combo puzzle

[BT@Home]

Originally Posted by Nick999

Tosh!!!! More like 10 mph out at 70 mph!! An inch I think is rather a lot. Although would make the car nice and low. Much sportier looking.
I got the correct 225/45/18" fittement on my ZT. And my speedo is only a couple of mph out at even 100 mph compared with my sat-nav.

If you look at the tyre calculator that eurorover posted then you can work it out for yourself.

[peterllewellyn75]

Anyone who changed up to the 17 or 18inch wheel did you get more miles to the gallon i am thinking of upgrading peter

[FROGGY]

OK, following on from this, why would I need a tyre rated as ZR on a diesel MGZT? Ron's box is good, but not quite that good!

Mick

[FROGGY]

..........and, what does all this mean?

225/45 R17 94Y XL

I thought buying tyres was easy but now I'm not so sure.

Mick

[tigerchubs]

Originally Posted by FROGGY

..........and, what does all this mean?

225/45 R17 94Y XL

I thought buying tyres was easy but now I'm not so sure.

Mick

225 = Tyre overall width in mm
45 = Aspect ratio (sidewall) % of tyre width eg 45% of 225
R = Radial construction
17 = wheel dia index 17 (17")
94 = Load index of the tyre (670kgs)
Y = speed rating (upto 187mph) Ha Ha Ha
XL = designated extra load tyre

The size data must be the same but you could use the tyre designated speed of V= 150mph,W=169mph or ZR= over150mph.

Tyres these days are anything but simple.

[FROGGY]

Thanks Tiger.

Long time since I heard the word "growler", brings back memories.

Mick

[Jules]

Originally Posted by Duotone

In the brochure's for the mk.1 Rover 75 the 17" Meteor and Serpent wheels were supplied with 225x45xR17 tyres..

In the Facelift brochure the 17" Star Spoke, Meteor and the Serpents were all supplied with 215x50xR17 tyres.

The pre facelift MG ZT brochure does not show 17" wheels available.

The facelift MG ZT has a 17" 5 Spoke with 215X50xR17 tyre.

So maybe MG Rover thought there was a problem with the speedo readings and changed the profile of the 17" tyres tyres supplied when the facelift models were introduced.
Although it took five years of production before the profile was changed..

Dave T

Agree entirely Duo! So much so, 2 months ago we renewed all tyres on our Meteor alloyed Tourer with 215 50 17's.
Probably the best size tyres a 75 Zt can have in terms of road holding verses road noise IMO.

[Fleckers]

I am running fat boy rubber

18 X 40 X 255


no clearance problems

[FROGGY]

Originally Posted by Duotone

In the brochure's for the mk.1 Rover 75 the 17" Meteor and Serpent wheels were supplied with 225x45xR17 tyres..

In the Facelift brochure the 17" Star Spoke, Meteor and the Serpents were all supplied with 215x50xR17 tyres.

The pre facelift MG ZT brochure does not show 17" wheels available.

The facelift MG ZT has a 17" 5 Spoke with 215X50xR17 tyre.

So maybe MG Rover thought there was a problem with the speedo readings and changed the profile of the 17" tyres tyres supplied when the facelift models were introduced.
Although it took five years of production before the profile was changed..

Dave T

My pre-facelift handbook shows 225/45 ZR 17 90W, which is what I am going to put onto my new 17" rims. Would have preferred 225/50 R17 but the tyres I want don't come in that size.

Mick

[lightpainter]

I’m looking into sourcing some new boots for my 04 facelift 75, the tyres I have on at the moment are 225/45 ZR 17, but on a previous post it says they should be 18’s and when my Speedo reads 70MPH my sat nave reads 67MPH.
Have I got the wrong wheels fitted?