Originally posted by TRPUT
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I'll add a little more info to help out with that...
Profile refers to the curvature of the tire from a cross sectional view. Like this...
Several pieces of information in this pic... the black curve is a sample of a tire profile with a closer to correct profile. The red is an example of a deformed profile from putting a tire too large for the rim on. The blue shows the section of the tire that can never touch pavement because it's pulled over way too far. The green lines are for referece for lean angle.
Tires flex as they are being used. This in part causes heat build up. The tires are designed with that in mind for the proper sized rim. When you start deviating from that proper fitment, the tire end up flexing more due to the mis-shapen profile. More flex= more heat build up and thus hotter tires. The hotter the rubber gets, the more it is likely to wear off.
Lean angle reference...
As you can see... there isn't much more room to go before your dragging hard parts.
So, for the situation of tires and rim matches...
Talking about the 4.5" rim.
The 150-170 seems to be the general range from minimal to maximal size for the 4.5" rim to keep with in the safe operational use. Each will have variable amount of heat build up with = use due to the change in profile. The profile will change between them because the rim always stays the same size, but the tire is wider the larger you go.
Now you also have tire aspect ratio to consider too. This is a number that specifies percentage of the width to = side wall height. Just changing aspect ratio can make a large difference because going smaller on the ratio makes the tread closer to the rim and makes the profile change more extream. Going larger on the ratio will allow for less distortion on the proper profile for the tire.
All of this is limited though with the tire sizes offered by manufactures. Sometimes the numbers will work out on being able to change the tire to another size, but the manufacture does not offer a tire in that size... so people "adjust" and then you run into the issues most people get by putting the wrong size tire on their bike.
Krey
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