Hi I have a cannondale quick cx 2012 looks like a mountain bike but I want to put the widest tyres I can there's dc3.0 700cc madoux wheels on it now with 622/37 tyres that came standard so help please guys whats the widest I can go was even thinking if 650b wheels will fit
Are you riding with fenders or without? On typical all rounders you can go up to 40 c without fenders, 35 c with fenders.
Very few bikes are designed to take wide tires. You'd be better off buying a bike with mountain bike/cruiser traits like the Retrovelo Paul or the Electra Balloon Townie, both of which are outfitted with wide Schwalbe Fat Frank tires.
If you can't put wider tires on your existing bike, a bike that already has the tires you want is the way to go.
It is easy enough to figure out with the bike as its own guide.
With the current tires, measure all clearance (left side, right side, fork crown, brake bridge, BB) Figure out how little clearance you're willing to settle for... For me, I need at least 5mm... depending on your riding conditions you may want more.
With those numbers in hand you can determine the max size for you. For each 2mm in tire size, you will lose 1mm per side of tire, and 2mm for the diameter (fork crown, brake bridge etc)
On my Trek 7.3 FX which came with 32mm tires, I could squeeze up to 40mm (but the rear tire needed to be deflated to install/remove).
As a caution, some tires run large, and some small, and it can be impacted by rim width, so it could vary, especially if you squeeze the clearance too close.