Hi I am looking to buy a second-hand road bike online. I check the hub every couple of days and there are some prospects but I've found a number of better deals on Gumtree. I realise that some people who sell on Gumtree could be dodgy. Is there anyway to work out whether a bike on gumtree is dodgy or not? Whether a bike is cheap because it is stolen or because someone is merely trying to sell it quickly? Thanks