Randy – I have my son’s first edition Slot It McLaren #48 set up with 17″ zero grips and my newer #5 Slot It McLaren set up with 17″ zero grips. They will also take the 19″ but you will have to use spacers under the guide to get it all the way in the slot with the bigger tires as they will rub the inside of the body if they are put up high enough to fully engage the guide in the slot.
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