Looking on mytyres.co.uk and they list three wheel sizes and five tyre choices for my 2011 Superb 170 estate. 17" 225/45 R17 94W and 205/50 R17 93V, 16" 205/55 R16 94V and 205/55 R16 94H, 18" 225/40 R18 92Y. Present tyres are Bridgestone Potenza S001 225/40 R18 92Y which will need replacing pretty soon. Are all these speed ratings valid or is there some mistake? If I went for smaller diameter wheels what sort of offset would I be looking at for 16 or 17" wheels. Is it the larger the ET number the further out from the hub the wheels sits or what?

 

Thank You 

Alan

Ok, firstly, if you want to change from 18" to 16" or 17" tyres, you need a new set of wheels in the new tyre size.

 

Next, break down a tyre size, I'll use 225/40 R18 92Y. 225 is the width in millimeters of the tread; /40 is the sidewall height expressed as a percentage of the tread width; R18 tells me that the tyre is radial construction for an 18" diameter wheel, and 92Y gives me a load index (the mass the tyre can support) and a speed rating (the maximum speed you can drive at for 20 minutes on that tyre without risking it failing).

 

And now I'm confused by those figures as well, because a 94H has a speed rating of 130mph, a 93V or 94V rates at 150mph, a 94W at 186mph, and a 92Y at 192!! 

 

As to wheel sizes, you'll probably find a number cast or stamped on your existing wheels like 18"x7.5, 112x5ET42. The first part of that is the wheel diameter and width in inches, the 112x5 is the Pitch Circle Diameter of the circle the mounting holes are on in millimeters and 5 the number of bolts/studs used, and finally the ET42 is the wheel offset in millimeters.

So if you are going to change wheels, based on the tyre sizes you quote, you'll want a 16x6.5 or 16x7, or a 17x7 or 17x7.5, same PCD and offset (you'd probably be able to fit an ET38, but I'd want to make sure before spending money).

If changing wheel diameters you are better off sticking to those printed inside the filler cap.

 

I have deviated slightly however on my car, and now won't ever go back...

 

http://www.briskoda.net/forums/topic/373406-can-i-fit-22550-r17-tyres-to-my-superb/

Thanks Ken I was thinking of different size wheels as in VAG wheels with the right offset. Pricing up some tyres when I came across those figures bit of a lack of Y rated tyres in the 16" size so it made me wonder. I think my wheels are PCD 112, ET47, 18X7.5j  but will check again. Possibly those figures for 16 and 17" wheels relate to the Superb 140 models but I did input my reg number. Need a definitive list of wheels and tyres for the Superb range. 

Is it the larger the ET number the further out from the hub the wheels sits or what?

Thank You

Alan

No, it is the oposite way: the lower ET the more the rim will stick out.

And now I'm confused by those figures as well, because a 94H has a speed rating of 130mph, a 93V or 94V rates at 150mph, a 94W at 186mph, and a 92Y at 192!!

It is the vehicles maximum speed that determines the requirement of the speed rating of the tyres. Any higher speed ratings means that you cannot exploit the tyres potential, but is of course possible. A too low speed rating related to the vehicle max. speed is not allowed (anyway in Norway and I assume it is the same in UK due to EU harmonization).

Similar for the load index, it must match the maximum allowed vehicle weight (axle load). You can of course use tyres with higher load index.

So, you need to find your vehicle's technical data and match up with speed and load rating of the tyre.

Edited 23 December, 201510 yr by fatzy

No, it is the oposite way: the lower ET the more the rim will stick out.

It is the vehicles maximum speed that determines the requirement of the speed rating of the tyres. Any higher speed ratings means that you cannot exploit the tyres potential, but is of course possible. A too low speed rating related to the vehicle max. speed is not allowed (anyway in Norway and I assume it is the same in UK due to EU harmonization).

Similar for the load index, it must match the maximum allowed vehicle weight (axle load). You can of course use tyres with higher load index.

So, you need to find your vehicle's technical data and match up with speed and load rating of the tyre.

The OP stated that all 4 different speed ratings applied to cars with the same engine. That (well and my suspicion that a CR170 is capable of over 130mph - H rate) was the source of my confusion about the recommendations for his car.

The OP stated that all 4 different speed ratings applied to cars with the same engine. That (well and my suspicion that a CR170 is capable of over 130mph - H rate) was the source of my confusion about the recommendations for his car.

Don't get me wrong, it was no criticism from my side. Your answer was indeed very good, a lot of useful information. I was just trying to give additional info.

Many tyre sizes comes in different speed and load ratings. The tyres are often higher rated when it comes to "larger" sizes, because they often fits heavier/faster cars as well. I assume the different settimgs from mytyres propably are their available spec's. This must not be mixed up with what your car must have. As I said, it is legal to upgrade the tyre speed and load ratings but bear in mind here will be draw-backs by doing so. The tyres will be stiffer, louder and wear quicker (generally speaking) to cope with more dynamic forces.

Edited 23 December, 201510 yr by fatzy

Don't get me wrong, it was no criticism from my side. Your answer was indeed very good, a lot of useful information. I was just trying to give additional info.

Many tyre sizes comes in different speed and load ratings. The tyres are often higher rated when it comes to "larger" sizes, because they often fits heavier/faster cars as well. I assume the different settimgs from mytyres propably are their available spec's. This must not be mixed up with what your car must have. As I said, it is legal to upgrade the tyre speed and load ratings but bear in mind here will be draw-backs by doing so. The tyres will be stiffer, louder and wear quicker (generally speaking) to cope with more dynamic forces.

Ok, we're in agreement then, except that I thought the OP was using a Skoda source, not a "tyre company", or I'd have said that I was pretty much certain that the H rated tyre was not suitable for his car due to its speed rating.

Unable to find any information from a Skoda source handbook just says get them replaced by your Skoda dealer. Ran a few checks on 140 and 170 SE models top speed 127 and 135mph respectively. Tyre sizes are 225/45 R17 W94 or 225/40 92Y for either power output, weights for both vehicles approx. the same. I do not want Winter tyres so I think I will stick with the wheels I have and stick some Goodyear F1 Eagles on. Of course I could go to my local Skoda dealer and ask them but that would be a waste of time.

Thanks for all your help.