I'm thinking of replacing my S-max 18" ST wheels for a 17" set with a bit more rubber to give a less harsh ride.

I know a lot of people go the other way and I like them but the kids & wife find them to 'bumpy"!

The question is I know that the tyres should always be XL tyres but what about the wheels? I've heard and read that people say 'other' wheels won't be strong enough for the s-max and you need XL wheels as well? I have looked long and hard but can't find anywhere details of different strength alloys that are s-max rated etc.

Also many sell wheels as s-max compatible but they are from smaller cars, Focus, mondeo etc. Who is right and where can I find out more info?

Thanks

Buy a set of 17" s-max wheels (from the Titanium model) - they will be strong enough.

Do not be tempted to go for Focus, Mondeo or other Ford / aftermarket wheels which will either be the wrong offset and/or not spec'd to handle the load of a 2 tonne vehicle with potential to carry 7 adults & luggage.

cheers for that, do all alloys come with a load rating like tyre and if so what is the s-max rating or where can it be found?

There is nothing on a wheel to determine it's load rating.

Basically the ONLY wheels suitable for fitting to the S-max are Genuine Ford S-max wheels.

The wheels dont have a load rating, but the compound of the alloy steel, gives it the durability, The issue is that if you use wheel with a finer compound from a lighter car, then put those wheels under the weight of an SMAX and its laden capacity, the alloy is not guaranteed to be able to support the weight of the vehicle without suffering strain.