I am on the stock Maxxis Refuse tires. I have a pair of Continental GP 5000’s 32 mm. How much difference in speed do you think I would notice? Risk of flats? (To the credit of the stock tires and tubes, I checked pressure each morning and never added air. Also (I have been saving up to pick your brain) do you see any problem with cutting off about 1 1/2“ off each end of the handlebars? I never use the last two inches.
Tires will have a lot of say about how a bike rides. The Maxxis are a smart choice for CB, sending their bikes out to a variety of riders. The Refuse will hit a happy middle spot between durability and speed, leaning more toward durability, meaning heavier but reliable. It's a safe choice for CB. Most tire companies, including Maxxis, offer a full range of road tires, from beefy touring tires to full-on racers. People tend to gravitate toward a preference based on their experience. I've always had good results with Schwalbe Pro Ones on my V20 (now V20c), while others have found them to be a little more prone to punctures (the next model down is the Schwalbe One--less expensive, a little more durable, a bit heavier. Most brands have that second-from-the-top-end model that suits many riders' needs and wallets). For me, I've had very few flats with the Pro Ones over the years, and I like the way they ride, so I stick with them. Tire width is a real consideration. I ran 25mm Pro Ones on my V20 for years, but when I built up my V20c, I moved up to slightly wider rims and 30mm Pro Ones. Wow, what a difference in ride quality--smoother and more planted, with no loss in speed. I recently moved up to 32mm Pro Ones, and they feel just that little bit better than the 30s. I don't think I'll go any higher than 32mm, but I'm glad I experimented with tire width. I think there is such a thing as too wide on a performance-oriented road bike, but finding that sweet spot is worth doing. When I owned a S40, I built it up with smaller 650b wheels and ran 50mm Panaracer slicks. Man, did that bike float, which was great for commuting and cruising around. I had my V for the fast stuff, so I was fine running fat rubber on the S40. But if the S was my only bike, I would have gone a different route for wheels and tires, which is to say that a lot of it comes down to what you want to do with the bike. The V is designed to go fast, so a fast tire makes sense. The S, however, is a true chameleon, ready to do what the rider wants, depending partly on the build.
You should have no trouble cutting down the stock bars with a hacksaw and a file to take off any burrs. Just be certain that you won't eventually miss what you remove. I'm a smaller rider, so I will often cut bars down to my size. When I determine how much I want to take off, I will usually cut off a little less than that. For example, if I wanted to take off 1.5 inches on each side, I will take off 1 inch, maybe 1.25 inches to start. I'll see how that looks and feels. I often end up stopping there. If I think it's still too long, I can always cut again to go the rest of the way.
Happy tinkering.