Importance of tires

[faffi]

I can only link to the teaser,  but I am a paying member and have watched the full video. But how much importance does the profile shape, carcass construction, height and width of a tire matter in your experience? Because a 120/70-17 tire can vary greatly in size, profile and construction between models, would/do you adjust your bike to accommodate every time you fit different tires? 

 

 

[Hotfoot]

I haven't watched the video but I HAVE experienced noticeable changes in handling as a result of changing tires (brand or size), and after a few of those experiences I now pick a brand and size of tire and set up the bike for THOSE tires and stay with them. If I need to change to a different brand or size of tires, I am prepared to start all over on suspension settings and bike setup.

Changing to a different model or size of tires can change how the suspension feels - is the tire stiffer than the prior one? Does it have a different profile shape that affects the turn in and steering characteristics? Does it support you differently under hard braking, or during trail braking? - and different tires (even ones that are supposed to be the same nominal size) can have differing widths which can affect the fit of tire to rim or whether the tire will rub the chain or different heights which can change the attitude of the bike. If you changed your front tire and the new one had a little less height than the prior one, it would effectively lower your front end which can affect handling, making the bike steer in more easily but feel less stable. Or if the new tire is taller it could make the bike feel more sluggish to steer but more stable in a straight line. Different stiffness/softness of the carcass changes the steering and suspension feel and the tire's profile changes the feel in the corners, too.

At a minimum, if I changed tire models or sizes, I would measure the ride height before and after the tire change and adjust the forks or rear shock to get the bike back to the ride height and attitude that it had prior to the change. I'd also research the design info on the new tires - are they race oriented? Stiffer than the prior model? Is the profile more V shaped than the prior model?  - so I have an idea of what might change in the handling and have a plan for how to adjust the bike settings to suit.