Hi Everyone,

 

I have done my research and read the forum, but am still confused about my options to swap my 18" wheels for 17" with Winter Tyres on my 2016 Superb 2.0 TDI (190PS).

 

I understand that, out of the factory, Skoda uses 6.5J x17" ET41, but my search for aftermarket steel rims with those specs has not been very fruitful so far.

 

I have found some alternatives, and checked with the Wheel Offset Calculator (http://www.1010tires.com/Tools/Wheel-Offset-Calculator#) those seem to work, but I'd like to have your opinion before I go ahead and buy the wrong rims.

 

All comparisons are based on my current wheels/tyres: 235/45 x17 (which should be mounted on 8J x 18" ET44 rims).

 

- 6.5J x17" ET33 (additional inner clearance 30mm, retract from outside by 8mm)

- 6.5J x17" ET38 (additional inner clearance 25mm, retract from outside by 13mm)

- 6.5J x17" ET45 (additional inner clearance 18mm, retract from outside by 20mm)

 

- 7J x17" ET35 (additional inner clearance 22mm, retract from outside by 4mm)

- 7J x17" ET38 (additional inner clearance 19mm, retract from outside by 7mm)

- 7J x17" ET40 (additional inner clearance 17mm, retract from outside by 9mm)

 

For comparison, these are the values that come out when I enter the specs for the original rims:

- 6.5J x17" ET41 (additional inner clearance 22mm, retract from outside by 16mm)

 

So, my assumptions are that:

1. any of the above should work
2. if I want to use snow chains, I should favour the options that give me inner clearance equal or bigger than the 22mm given by the original 6.5J x17 ET41 option (highlighted in bold)

 

Is there anything that I am missing?

Any reason why any of the options in bold wouldn't work?

 

Many thanks in advance!

 

-Diego

 

Look at the pdf download at http://www.skoda-auto.de/service/serienbereifung  (I think a post by @Gizmo pointed me in the right direction).  This lists Skoda's approved wheels and tyre sizes for all vehicles since 2004.  Working on the basis that any deviation from those approved sizes could cause "insurance issues"  I purchased exact matching wheels- though I still don't understand why offsets are specified down to 1mm as opposed to a range.

The approved wheels/tyres for 17" are: 

215/55 R17 94V M+S 6½J x 17 H2 41 ja

215/55 R17 94W 6½J x 17 H2 41 ja

215/55 R17 94W 7J x 17 H2 40 nein

ja = yes to snowchains,  nein = no. 

Thanks @peter_k,

 

I understand what Skoda's approved wheels and tyre sizes are, I was just hoping that those were the "recommended" ones, rather that the "approved" ones, and that alternatives would also be acceptable as long as they fit the car.

 

In particular, I was hoping that the 6.5J x17" ET38, which can be found quite inexpensively, fit within the wheel arches with spare room (compared to the 18" my car is wearing now) and would give even more clearance on the inside for snow chains, would be an acceptable choice...

 

Oh, well...

The search continues

The reason behind the specific offsets appears to be the steering geometry "scrub radius".  See https://en.wikipedia.org/wiki/Scrub_radius. As I understand it the manufacturers' setting assists in the car maintaining stability should there be a brake or tyre failure to one front wheel. 

I've looked at the TUV certification for my winter wheels and for the Superb III and the 7J rim fitted with 215/55 R17  tyres can be fitted with (translated from German) "Only fine-meshed snow chains of not more than 10 mm including chain lock may be used
to be used on the axles specified in the operating instructions." FIt 225/50 and "The use of snow chains is not allowed."

 

I bought my wheels from here http://www.mrwinterwheels.co.uk/skoda-winter-wheels/superb-2015/ 

 

Thanks again @peter_k,

 

The "scrub radius" explanation makes sense and explains why, despite clearances, ET41 is required for the 6.5J x17.

 

Also, thanks for the link to the wheel page: although only 16" steel wheels seem to be available, at least that gives me a choice of a couple of alloys that could wear very thin snow chains.

 

I will be looking around again for 17" steel wheels with the correct specs, and if those cannot be found I will look at alloys instead.

 

Cheers!