VegasTriker

Using a rack for an aluminum bike has never been a problem for me. You are not putting any extraordinary stress on the frame. If you want a cheap and effective way to tie a bike to racks that do not include tie-downs, save your old bike tubes. I use a rack for my recumbent trike with the two front wheels on the roof and the rear wheel on an old RhodeGear rack. It stays firmly in place at speeds up to 80 mph on the interstate (don't tell the cops!). An alternative is to buy a spool of 1/4" bungee cord. I just bought a 50 foot roll from Home Depot for $18 to lace a seat on an older recumbent trike. I can use the leftover as tie downs. Both of these have some "give" so are really good for tying things down. If you want shorter pieces, REI carries it in bulk spools at their stores for 40 cents a foot for the 6mm/1/4" size. They call it "accessory cord".