Originally Posted by
Rick Imby
The problem is you cannot have all things even with wider tires... Wider tires are heavier and unable to hold the same air pressure. As you go even wider the rims get heavier too. Historically 20mm and 140psi was thought to be the sweet spot for 700c tires. That has changed.
It is the sweet spot we are all looking for and it is different for different users and different equipment.
20mm is narrow and 28mm is normally considered a wide tire in 700c road bikes.
With 406 tire sizes 40mm is about as narrow as you can normally find and considered very narrow for 406. Too narrow for some 406 rims.
Rim width along with the matching tire width effect rolling resistance too.
Tire pressure has a lot to do with rolling resistance. Wider tires have less rolling resistance at "the same tire pressure" Narrower tires can usually be run at higher pressure. Again the sweet spot tire pressure may be different for different width tires.
Generally speaking most 451 rims have been designed for narrower higher pressure tires and narrower tires are more common with this size.
Generally speaking the bikes with 451 rims are more "Speed focused" bikes.
Higher pressure is faster--depending on tire design and just up to a point
Narrower is faster---depending on tire design and only up to a point.
I believe the sweet spot in 700c tires is going to end up close to 30mm rear and 25mm front but time will tell. Rider weight will be a factor also.
I think in 406 wheels the sweet spot will be around the same but we will not get the tire manufacturers to cater to our size wheels because of limited sales. Schwalbe is one of the few companies with multiple sizes and models of 406 tires.
Greater tire pressures do reduce the contact patch size and rolling resistance sans suspension losses. With suspension losses from riding on imperfect roads, rolling resistance will increase with greater tire pressures. My understanding is that rolling resistance is U-shaped as a function of pressure where the bottom of the U is relatively flat such that as long as you still avoid pinch flats and tire squire, you can typically keep lowering your tire pressure with little change in rolling resistance. Naturally this depends on total weight and road quality. So there is no global answer: instead there are guidelines for experimentation.
There are some high quality supple tires in ERTO 406. Today, I'd point most folks to a Greenspeed Scorcher that's 40 mm wide. I've had them for a while as a road tire and pleased with their overall performance. But there are definitely high quality tires that are both narrower and wider.