What kind are used in the E, Rubber, Alloy, or Alloy with a rubber tube flapp? Which type is the lightest in weight? Would like to have the tires balanced somewhat by adding wheel weights to counter balance the rim lock. Any opinions on what kind of weights are best lead, steel spoke types or stickons. Please provide a source to purchase these items, partnumbers brands please. Will be using these with Pirelli MT-21's. 90/90R-21 and 120/90R-18 tires. Also can you recommend a good heavy duty tube to use with these rim locks. Puchased a new 2002 yellow 400S on Dec 1.