I have a pair of solid rubber ramps. Heavy! They are likely made from recycled tires.

Only problem I have with them, is that garage floor is smooth concrete and the ramps will sometimes slip despite having a serrated rubber bottom. Sollution for all ramps, is to attach a this piece of rubber, carpet, plywood or maybe metal to under side so that car weight hold ramp in place before you drive up the incline.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5