How can I tell a bike is safe after a crash? I was recently in an accident where a car pulled out on me. I hit the car around the front wheel and me and the bike went over the bonnet and landed on the road, the other side of the car. I was travelling around 20mph.

The bike is in one piece but I'm super-wary of it.

Several people have suggested getting the fork and frame X-rayed to check for fractures. How exact is this science? How certain can you be that the frame is road-worthy? 

The bike has an Aluminium frame with a carbon fork and Alloy wheels.
The easy way would be to get a qualified bike mechanic to take a look at your bike for less noticeable problems. 


It's not safe to ride a bike if the frame has been noticeably disfigured.
Re-adjust the wheel to be aligned to the handlebars. The wheel tends to twist after crashes.
Go through the final safety inspection you would normally go through, check the tyres, brakes. Replace the brake cables if they are frayed.