GenesisDatum

Before you buy a used Datum

• Get the frame size right first. A bargain in the wrong size is no bargain. Check the seller's size against our size guide, and ask for the stack and reach if you're between sizes.
• Check carbon for cracks and crash damage. Ask for close-up photos of the top tube, down tube, fork, dropouts and around the seatpost clamp, and whether it's ever been crashed.
• Check it isn't stolen. Ask for the frame serial number (usually under the bottom bracket) and check it on BikeRegister. A genuine seller won't mind, and a receipt is a good sign.
• Confirm the groupset and wheels. Titles often say "Ultegra" when only the gears are. Ask what the brakes, chainset and wheels are, and how worn the chain and cassette are.
• Pay through eBay. eBay's Money Back Guarantee covers items that don't match the description, but only if you pay through eBay.
• Collection or courier? Many bikes are collection only. If it's being posted, ask how it'll be packed: a proper bike box with the derailleur protected.