my first problem is I went away and ordered tyres without making sure id two tubes..so iv a tube on the front and tubeless on the back one of them run flat things I can't think of the correct name for them..anyway the new rear tyre is bigger and I want to know if it will be ok with the sponge thing??? sizes on pic's ..I also want to know if it's easy to do wheel barings or would u need heat? ?