45...be careful with tires blowing up in your face. Now personally I run 120 psi...in my bmx maxxis tires. I go with what is in the owners manual because that is most likely what is best for your bike. If you are not sure ask steve.

 

45 is way too high... i think my M3s have 34/28 or something like that right now.

 

lower in the rear(better for stand up wheelies)

 

I run 175 PSI, because that is where my air compressor shuts off!! Besides, then I can use my bike on the river like a jet ski!!

Seriously, ran around 35 psi in both for years, never had any problems. The battleaxes that were origionally on my 636 said 45 psi...I dumped it because the rear tire would never heat up enough to make it stick...45 is what was recommended on the sidewall, but those tires ran better with 35 in them.
Ran 15 psi in the fighter for a while...but never really got to balance point, so I am now running 35 psi like everything else!

 

35f/38r on my Dunlop Sportmax Qualifier.

 

-3bar

 

32f/34r on my avons.

and for the record, never run your tires according to what it says on the tire. if you read it, it says, MAXIMUM pressure. any time i do work on a customers bike and check the pressures, i usually set them at between 33-36 front and rear, unless the customer asks for something different.