Rim Sizing

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Atomic_Sheep

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I'm trying to make sense of wheel rim sizing:

https://www.goodyearaviation.com/resources/pdf/tire-specifications-6-2018.pdf

If my understanding is correct, only the last 5 columns are related to the rim itself.

1.) Wheel (Rim)Size - what's the first number? Is that the width of the rim? The second number is the diameter.

2.) If the first number is the width of the rim, then how can the width between flanges be so much smaller (I take it flanges are those things that the beads sit against).

3.) The flange height - is that on top of the "Wheel (Rim) Size second number?
 

wsimpso1

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I love that you know you can come to us for reliable help, but this is the second question of this simplicity I have seen today, and it is only 10 am... When we get serious technical questions, we often can only skin the top and leave the rest for you to fill in. Here it is all filler. Somewhere on someone's website is the key to the wheel sizing code. Come on, you can do it...
 

lr27

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Being a curious type, I did a web search and came up with the following as the first result:
http://wattsaviation.co.uk/products-and-services/tyre-sizes-explained.html

Those are just tire sizes, and it seems only the last number relates directly to the wheel size. I'm guessing the last number, the wheel diameter, is the diameter of the bead groove or whatever you want to call it. Otherwise, it's useless. Width between the inside of the flanges should probably be some proportion of the tire's width, but, judging by what I know of bike tires, there's probably some leeway.
 

Atomic_Sheep

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I've done my due diligence on both questions, I have been unable to find any useful results on Google. (For the first question, there is some info but certainly not enough for what I'm trying to do) I have seen the document that lr27 had found, and I have another one from Boeing, but I've not found anything else and neither of them go into enough detail to explain my questions.
 

wsimpso1

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To get down to specifics for the supplied chart, the wheel sizes are right there on the chart and decoding the stated title into dimensions only takes looking accross the table. If there is any common numbers, maybe a second or third with the same apparent code to clear it up.

Just to go through one, the top line is 13.5x6.0-4. Looking across, you can see that:
The first number (13.5) is between the max and min inflated OD of the tire and is thus the nominal OD of the tire;
The second number (6.0) is between min and max width of the inflated tire and so is the nominal width of the tire;
The chart tells us that the rim diameter is 4", which is also the diameter of the ID of the tire bead and 4.75" is the rim width.
It seems that this rim is specific to this tire. You will find that repeated in a few other places, but not always.

If you need more help, Paz's book Landing Gear Design for Light Aircraft, chapter 4 goes through all of the tire designations and what they mean. Chapter 5 gets into wheels... Have fun.

Billski
 

lr27

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I feel dumb. That big white space made me think that there were two tables, not one wide table.
 

Atomic_Sheep

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I found 3 more useful docs, but they don't talk about my query either :(.

To get down to specifics for the supplied chart, the wheel sizes are right there on the chart and decoding the stated title into dimensions only takes looking accross the table. If there is any common numbers, maybe a second or third with the same apparent code to clear it up.

Just to go through one, the top line is 13.5x6.0-4. Looking across, you can see that:
The first number (13.5) is between the max and min inflated OD of the tire and is thus the nominal OD of the tire;
The second number (6.0) is between min and max width of the inflated tire and so is the nominal width of the tire;
The chart tells us that the rim diameter is 4", which is also the diameter of the ID of the tire bead and 4.75" is the rim width.
It seems that this rim is specific to this tire. You will find that repeated in a few other places, but not always.

If you need more help, Paz's book Landing Gear Design for Light Aircraft, chapter 4 goes through all of the tire designations and what they mean. Chapter 5 gets into wheels... Have fun.

Billski
Billski, I found some books online similar to Paz's book, but they don't talk about this either.
 

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