[Intimakki]

Hello!
I’m Focus ST (mk3 2013) owner. I’m amateur time-attack and sprint cup racer. I would like to buy a second wheels kit in 17”. But I don’t know what size of rims and tires suitable for my races. I was looking for tires and rims sizes in user's manual and on the doors sticker, but didn't find nothing for a given "17" size. Could you explain what wheels characteristics for Ford Focus ST mk3 I can try and use? I mean ET, J, width, ratio, etc. I have stock car configuration, but I have 13.1” front brake rotors from Focus ST 2014.

 

[bobharly]

What exactly is your goal and limitations (financial or event rules)? Stock is 235/40 r18 on an 18x8 rim, with an et55. Are you looking to go to a 255 or 265 tire? Wheel width will affect the et you select. For example, if you stay with an 8 inch wide rim (assume j to j, unless otherwise stated in the US) and et 55 to 42 are safe with a 235 width. Personally, I'm running et38 on an 8 inch wide rim and had just a hair of rubbing with a 245/45 r17. A small fender pinch at the rub point and I was OK. Are you looking something light, like RPF1's? Or perhaps you have a different style or brand available? Are you keeping the stock brakes or planning to upgrade? And the all powerful question... Have you searched the form yet?

Lots of good people on this forum and tons of archives of people who have asked these and more questions already.

 

[Intimakki]

Lots of good people on this forum and tons of archives of people who have asked these and more questions already.

Yes of course. But I didn't see the answer. I want to know what manufacturer thought about 17" to Focus ST.
I would like to change the rims 18" because 17" a little easier, tires 17" is cheaper.
My priorities:
1) Rims weight max 18 lb;
2) Tires max 245.
So it's important to know, should i transfer to 17" in races or not.
I don't plan on doing any changes with brakes.

 

[gemery]

My priorities:
1) Rims weight max 18 lb;
2) Tires max 245.

At that max weight, there are really only two off-the-shelf choices and I don't know about availability in your country:
Enkei RPF1 Enkei Racing RPF1 Black Painted (tirerack.com)
OZ Ultraleggera O.Z. Ultraleggera Black Painted (tirerack.com)

They both came in other colors originally. For instance, I have two sets of the RPF1 in silver and one set of the Ultraleggera in white. I don't know what other colors the Ultraleggera were available in, but the RPF1 was available in bronze (Tirerack still has these in stock).