onguard pitbull u lock, the long version. I can lock my back rim and the back of my frame to 99% of bike stands available and it is pretty affordable. found some online reviews that mention it is not the most secure, but that depends on the lock in the near vicinity and I've yet encountered a better lock, so the thief would always go for the worse locked bikes first (my bike is not too shabby, but it is not worth a lot of trouble for stealing, resale value could not be more that 200€)