90/90 18 inch tyre instead of 90/100 18 inch.

hi,will a 90/90 18 inch tyre fit on a rim that origanally has a 90/100 18 inch tyre wasnt sure of how rim width sizes for tyre beads are measured.

or are all 18 inch tyres the the same rim width.

The figure after the slash show tire height relative to the width, which is the first number (in mm).

In other words 90/90 is a tire that's 90mm wide and 81mm high (90% of 90mm = 81mm), while 90/100 is again 90mm wide, but also 90mm high. And they both have inner radius of 18 inches (yeah, it's really nice how they mix up Metric and Imperial units!). Rim width does not play in this case.

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Originally Posted by Krasi

The figure after the slash show tire height relative to the width, which is the first number (in mm).

In other words 90/90 is a tire that's 90mm wide and 81mm high (90% of 90mm = 81mm), while 90/100 is again 90mm wide, but also 90mm high. And they both have inner radius of 18 inches (yeah, it's really nice how they mix up Metric and Imperial units!). Rim width does not play in this case.

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I was kind of wanting to know how the rim width sizes measurements vary just so I can match up other brand tyres to ones that are similar to mine are,like would a kawasaki 90/90 18 inch tyre fit on a yamaha 18 inch rim for example or would they have different rim widths.

Krasi is right, In this case the tire profile height will be higher if you go from a 90/90 18 inch tyre instead of 90/100 18 inch, meaning it could rub on your fender, width an rim size are the same. Only go different from stock if it has been an commonly proven modification, it could screw up your handling, although going bigger is usually better thought of than going smaller.

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Originally Posted by Next edition

I was kind of wanting to know how the rim width sizes measurements vary just so I can match up other brand tyres to ones that are similar to mine are,like would a kawasaki 90/90 18 inch tyre fit on a yamaha 18 inch rim for example or would they have different rim widths.

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The width is the first number, and to a point they'll fit physically as long as they are within about 20mm, for example a 70mm or 110mm tire would probably fit on a rim designed for a 90mm tire. Although I wouldn't recommend anything other than the tire size that comes stock. It doesn't matter on the brand of the bike or the tire, they should all be the same dimensions.

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Originally Posted by ZMC888

Krasi is right, In this case the tire profile height will be higher if you go from a 90/90 18 inch tyre instead of 90/100 18 inch, meaning it could rub on your fender, width an rim size are the same. Only go different from stock if it has been an commonly proven modification, it could screw up your handling, although going bigger is usually better thought of than going smaller.



The width is the first number, and to a point they'll fit physically as long as they are within about 20mm, for example a 70mm or 110mm tire would probably fit on a rim designed for a 90mm tire. Although I wouldn't recommend anything other than the tire size that comes stock. It doesn't matter on the brand of the bike or the tire, they should all be the same dimensions.

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the first number is the tread width right but what about the rim width,like on some car rims have a 6.5inch wide 18 inch rim and then you can get a 7.5 inch wide 18.

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Originally Posted by Next edition

the first number is the tread width right but what about the rim width,like on some car rims have a 6.5inch wide 18 inch rim and then you can get a 7.5 inch wide 18.

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Motorcycles as far as I'm aware don't have one.

Just width/profile (height) /load or speed number/and diameter in inches.

They must have standardized the rim widths for the tire width at some point. Therefore all motorcycle rims designed for a 90mm width tire will have the same rim width, so the rider doesn't need to bother to worry. I don't even know if they are referring to tread width, I think they are actually referring to carcass width.

Not sure about cars as I only know bicycles and motorcycles.

With bicycles they tell you everything except profile. So you have a rim width, external and internal and that comes with the rim. For mountain bikes the tire comes in tread width (inches) and diameter (inches), but will also have another ERTO (metric) measurement for tire carcass width minus the tread (without the knobbies), if that makes sense. :deal: