Tractor birthday cake - what can I make the wheels out of?

[fedupofpeppa]

I am going to attempt a tractor cake for my three year old by baking two rectangular sponge cakes, cutting one in half and using that on top of the other to make a tractor shape. Going to use ready to roll icing to decorate as I am not a baker and my piping etc is abysmal.

I need a really simple but effective idea for wheels. Would need to be big wheels at the back and small at the front. Any ideas?

Thanks

Rice Krispies and melted marshmallow 'formed' into wheels and covered in fondant.

Ready-made black icing? Maybe make 4 small cakes (cupcakes for example), cut into flat discs about an inch thick, then cover with icing. Indent with the flat edge of a knife to make the tyre patterns.

Don't bother trying to make black icing - I've tried & you need to much colouring, even with the high quality gels, that the icing is unmanageable.

Licorice. It's got that rubbery look too.

stick some wagon wheel biscuits at the back and some oreo biscuits on the front

Licorice wheels, you can buy big ones online. You could sandwich two together for a chunkier look.

Or doughnuts covered in black fondant icing.

These

www.tesco.com/groceries/product/details/?id=255609374

Swiss roll and mini rolls chopped into slices.

Wagon wheel biscuits? Icing on top to make the inner wheel shapes?

Wagon wheels and Oroes
Then cut out circles of ready rolled white icing for hubs. The wine bottle top is the perfect scale for Oreos.

Swiss roll covered in ready to roll black icing, then put treads in with a knife

Thank you everyone! My ds is not a liquorice fan (unfortunately as I love it ) but plenty of other ideas I can try here.