Eventually your bike will disappear up its own bumhole! The science behind this is a bit complex, so bare with me, but basically it is due to the differing circumferences of the odd sized tyres. The bigger rear tyre will have a larger circumference so will travel further for every revolution of the wheel. As you ride along the road the back wheel will gradually catch up with the front, a few mm at a time until the space time continuum can no longer cope and a small tear will develop, then poof, your bike will disappear up its A**ehole.
The only way to avoid this while running that tyre configuration is to turn around every few hundred yards and ride backwards for an equal distance. If you do this then you will be fine. Alternatively, ignore my advice but make sure you wear a good quality helmet
