News reaches us of a scam targeting cyclists. Our correspondent says she was waiting at the junction of Wanping Lu and Zhaojiabang Lu by Xujiahui Park when she heard something and turned to find her back tire was flat.

She pulled her bike over to the side of the road and a guy rode up on a scooter and offered to help her pump up the tire. Another guy then arrived on a scooter and the two examined the wheel and told her the tire was ruined and she needed another one. The two guys acted like they didn’t know each other and had just rocked up to help out. Both seemed really helpful. Neither spoke any English.

One of the guys took her wheel off, disappeared with the tire and came back a few minutes later with a new one. They put it on the bike, pumped up the tube and everything seemed to be OK.

Then they asked for 150rmb for the new tire. Our correspondent picks it up: After they tried to charge me 150rmb for a single tire on a 350rmb bike I realized these weren't just good Samaritans. I wasn't sure what to do. I didn’t have any money with me and I wasn’t really sure what had happened so I led them back to my apartment where my boyfriend could help. When we all got back to my place, my boyfriend told them that price couldn’t be correct and he tried to flag down a passing cop car to settle our dispute. The two guys saw this and a second later they both speed away on their mopeds. It’s possible that I simply look like “easy prey” and they were just trying to give me a laowai price, but it seemed too coincidental that they were there at the exact time my tire somehow got a flat while I was stopped. Since they fled at the sight of the cop car I can only assume they must have somehow been in the wrong. We called Giant and they said a new tire was 38rmb, including fitting. So, if you get a puncture and some people stop to help you, establish a price before they start taking your bike to bits. If they tell you the problem is your tire, rather than your inner tube, call a policeman over or call some friends, because it’s more than likely they’ve cooked the whole thing up. With the heat, the fumes, the traffic and the trucks, don't cyclists have enough to worry about? Not cool, you two rascals. Not cool.