TIRES!! 110/70-17 front, 150/60-18 rear ????

[mossy1200]

so what does the 60? 70? mean? how round?

60 and 70 refers the height of side walls as percentage against width of tyre.(profile)
180/55/17 is same as 170/60/17 in distance around wheel as it road rolls.
the higher profile percentage of the 60 series compensates the width between the 180 and 170 for example.

[Hawker]

so what does the 60? 70? mean? how round?

It stands for the aspect ratio of the tire. Basically, it depicts the height of the tire as a percentage of it's width. A "70" series tire will have a sidewall height that is 70% of the width, i.e. a 110/70-17 tire is 110mm wide and 77mm high (110*0.7 = 77). The lower the aspect ratio, the lower the sidewall height and the lower the profile.

Of course, these numbers are guidelines and each manufacturer will vary a little from them. The only number that stays absolutely constant is the last one for the rim size.

[reelrazor]

It stands for the aspect ratio of the tire. Basically, it depicts the height of the tire as a percentage of it's width. A "70" series tire will have a sidewall height that is 70% of the width, i.e. a 110/70-17 tire is 110mm wide and 77mm high (110*0.7 = 77). The lower the aspect ratio, the lower the sidewall height and the lower the profile.

Of course, these numbers are guidelines and each manufacturer will vary a little from them. The only number that stays absolutely constant is the last one for the rim size.

Right.

And I made it a point to look for and examine The Avon fronts. A guy I know has a Honda Superhawk with a 120/70 on the front. Even though, by percentage, it is a taller tire..it seems that they (Avon) use more of that percentage as pure sidewall and less in treadwall height. The tread is nowhere near as 'U' shaped as my current BT014 110/60 front whose profile puts tread waaay down the 'sidewall' of the tire-literally unrideable. With the bike standing vertically, the 014 has tread surface at 20° off plumb