Id like to order some 15 inch steel wheels (not into alloys) to fit to Brum.
The size are 4 x Steel wheels 6Jx15 ET35 4x98.
What size tyres should I order so that I get no rubbing anywhere? Thanks.

I looked into this recently more so I could get some decent winter tyres and came up with 165/60 R15 which gives a 0.1% difference in overall diameter and as 165 is a standard fitment width I cant see that there would be any problems.

I'd like to go wider than that. I was thinking 195 wide. I put that into the above website and it says it should be ok.
What size tyres does the 100hp have?

I'm thinking 195/50r15. Shouldn't be such a hard ride then?

Didn't realise the 195 would fit. Good call
The ET varies on fitment
155 is ET41
165 is ET38
195 is ET35

I should've looked at that.

Isn't the ET 35 on all wheels for a panda?

To be honest I'm not 100% I was quoting verbatim from the web.
https://www.wheel-size.com/size/fiat/panda/2010/#trim-13d-eudm was the site I looked at, but how accurate that is I could not say.

If you fit a wider wheel, you have to be careful how much further in the inner edge is, as this can contact the suspension or car body.
The ET35 is how far the mounting face is offset from the centreline of the wheel. As an example, my 5.00" rims (127mm) with a 35mm offset puts the inner edge of the rim about 98.5mm in from the mounting face.
With the proposed 6" rims (152mm), with the same 35mm offset, puts the inner edge 111mm in from the mounting face. So you need at least another 12.5mm clearance.
The outer edge will also be further out, by the same 12,5mm, so clearance to the arches may be an issue, especially when turning. The tyres must also be within the width of the car, so must not protrude beyond the bodywork.

The offset not only puts the wheels in the right place in relation to the bodywork, it is also intended to place the centreline of the wheel close to the centreline of the bearings. With the ET the same, this should be fine, but if a different ET is chosen to obtain the clearances needed, bearing stresses may become a problem. (Original Minis were often fitted with wheel spacers, which shortened the life of the front wheel bearings by about a third.)

Cheers for the info. I understand what ET is and it's purpose. But do you know what the correct ET is for the relative width of tyres or are they all 35?

See this thread:
https://www.fiatforum.com/panda/448950-can-i-put-these-alloys-my-panda.html

These are ET33 6x15 FIAT alloys. I have these with winter tyres on our 1.2 wearing 195/50-15 with no issues.............but they are 2mm further away from the inside than ET35.

Summer tyres are on standard Panda 5.5x14 alloys wearing 185/60-14