masking curved area

[elcaro]

Hi there, I make a lot of use of masking tape when painting. Anyway, I want / need to paint two trailer wheels, small wheels on a boat trailer. I can't easily take the tyres off, so I would like to mask them. Masking tape is out cos it only goes in straight lines! Is there anything you can put on, then remove after painting, e.g I've seen "masking fluid" mentioned when looking online.
Any advice please?
Regards, Terry.

 

[footprints]

Worth a try?
http://www.clasohlson.com/uk/Tesa-Flexible-Masking-Tape/34-3977

 

[foxhole]

Masking tape , then trim round with a knife. Simples.