Actually its been known for years that a wider tire (within reasonable limits) does not put any more or less rubber on the road than its narrower sister if the tires are otherwise the same. The contact patch doesn't get any bigger, it just changes shape, being longer with the narrower tire. But the simple fact of the matter is that two tires make of the same compound and of the same construction, only differing in their widths, will have exactly the same contact area under the same load - the contact area only changes if you change the air pressure in one of them or increase/decrease the load on the tire.
ive always thought the same thing, and seen it backed up in car and driver. yet anytime i try to convince someone of this they look at me like im a complete idiot.
Perhaps that's because you are comparing car tires to motorcycle tires?
Wider motorcycle tires do what was expected only when the rim is widened, too. This is because the tire sidewall position/angle changes when simply putting wider tires on narrow rims.
Think of how much weight and stability you have holding a heavy object directly overhead. Now lean yourself over 20-30 degrees. Notice a reduction in stability? This is the physical principle you can apply to the tire sidewall.
A tire properly fitted to the rim has the bead on each side directly under the edge of the tread width. An oversize tire on a narrow rim pinches the bead mount points together, creating an angle between tread edge and rim stress receptor. This results in tire tread position instability, due to the lack of support of the tire sidewall. To compensate, the tire pressure for the oversize tire must be increased to "stiffen" the sidewall. Over-inflating the tire, reduces the "contact patch" as the increased pressure heightens the tire crown. When new, the oversize tire has an effective crown about the same as the proper size tire. But, the overinflation makes the tread center wear faster than the edges, leading to progressive handling issues, as the contact patch position center moves farther laterally as the bike leans over.
Increasing the width of the tire can't be looked at without also eyeballing the rim seated position. The better manufactures make data available about what rim width their manufactured tire can be mounted upon for proper performance of the tire. This relates to the acceptable sidewall angle, with which the tire is designed to operate properly. If you use a rim width outside those recommendations, you are on your own for projected performance, contact patch, and wear patterns.
In my experience, wider/oversize rear tires seemed fine when brand new. But, the requirement to apply counter steer pressure on the bars increased progressively throughout the tread life.
With the stock size tire, this progression of counter steer effort is hugely reduced. With both tires I had the ability to scrape hard bits of bike on pavement in high G turns. That's where the traction was limited in both cases. So, turning performance had no difference, be they stock tires or oversize.
My experiences are with the SOHC4, mainly the CB550 (and the design parameters of that era). Perhaps on different model/era bikes the experience is different. But, applying what worked on a different machine to the SOHC4 may well be like comparing apples to oranges.
If you are going to a wider tire because of "looks", at least use a rim width that work with the manufacturer's specs for the tire chosen. This analysis is done for you, if you just use the inch size tire that both Honda and the tire manufacturer agreed best fit the the stock rim.
Cheers,
