Hi,

I am surprised nobody has replied yet. This is the first time I logged in years I can't believe I have managed to do it. In regard of your question. If you don't replace the rubber tyre the loco will likely have poor traction. The SK800 was produced over a very long period of time and therefore many versions were available. I am not sure as I've been a bit off model railways for a while but very early models might not have a traction tyre, in those the wheels will be completely flat and generally wider than later models. If there is a slot for them I would use them because the loco will work much better. If you are very picky most of those early Marklin used clear plastic tyres but they will be just about impossible to find and you will need to sctick to the availble rubber tyres. If things have not changed in the last 6 or 7 years Marklin makes 3 sizes of tyres for HO, you should use the largerst which will fit locos like the 3048. I hope that gets you on the right track, good luck.