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  #1  
Old 05-01-2014, 08:33 PM
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Default RV-8 Tire Pressure

Hi All,
I have been on the site for awhile getting all the information I could on a RV-8. I just sold my Pitts and purchased an 8 and was looking for the correct tire pressures for the mains. I did not get a answer from the previous owner. I search the forum but could not find it. If I missed it, I am sorry to bother anyone with silly questions. Thanks.
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  #2  
Old 05-01-2014, 08:41 PM
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I'm running 34 at present. Not sure there is a "right answer". I asked my local RV8 guru and he told me what he uses....so I copied him....again.
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Last edited by ColoRv : 06-12-2014 at 09:15 AM.
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  #3  
Old 05-01-2014, 10:09 PM
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I run 50 psi
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  #4  
Old 05-01-2014, 11:06 PM
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Thanks to all for your answers....
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  #5  
Old 05-02-2014, 05:59 PM
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50 psi on my Goodyear Flight Custom II and Michelin Air Stop tubes too. If I recall correctly, under pressure on airplane tires is a bad thing due to flexing. I'm sorry, I can't remember where the article is, but it might be a Goodyear publication. Anybody else know?
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  #6  
Old 05-02-2014, 06:12 PM
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Quote:
Originally Posted by Gash View Post
If I recall correctly, under pressure on airplane tires is a bad thing due to flexing. I'm sorry, I can't remember where the article is, but it might be a Goodyear publication. Anybody else know?
Not a hard and fast rule as the POH for a c140 calls out 17psi. One of the only things in the 1 page POH.

Goodyear manual link
http://www.goodyearaviation.com/reso...raftmanual.pdf
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  #7  
Old 06-11-2014, 10:20 PM
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You gents running 50psi must be flying from very smooth southern runways. I tried 42 here on Colorado's bumpy runways and it wasn't a pleasant ride. Asked several RV8 guys here in town and all are in the low to mid 30's as well. I'm back at 34psi. Stock vans tires, Michelin Airstop tubes and grove gear.
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  #8  
Old 06-12-2014, 07:07 AM
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Quote:
Originally Posted by ColoRv View Post
You gents running 50psi must be flying from very smooth southern runways.
Ride quality was never a consideration. I would suggest a sharp pavement lip is even more reason to set correct pressure, as are most hangar tracks.

The Tire & Rim Association: 500-5 6 Ply - 50lbs psi
(Dresser site, page bottom) http://www.vansaircrafttires.com/pag...B47%7DFAQ.html

Michelin Tire Databook: 50-5 6 ply 50 psi
http://www.airmichelin.com/generalcontent.aspx?id=219

Goodyear Aircraft Tire Databook: 500-5 6 ply 50 psi
http://www.goodyearaviation.com/reso...edatabook.html

The Neal Willford landing gear design spreadsheet is S409. It should still be available for download at the EAA site. Plug in the values for your RV-8 and look at the drop test tire compression for various tire pressures.

As for "they say", well.....

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Last edited by DanH : 08-27-2015 at 06:18 AM.
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  #9  
Old 06-12-2014, 08:27 AM
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Wow Dan, you're pretty sure your way is the only way aren't you? I tend to put more emphasis on field data than spreadsheets and in this case several thousand flight hours in the same plane, on the same runways with actual tire wear data accumulated over years...is more relevant to me than a spreadsheet.

Monkey see monkey do is also called learning from experience. Still, I am as capable of falling back to a chart as the next guy and the chart on Desser.com says the maximum tire pressure for Vans issued tire is 50psi. Running a tire at its maximum psi when not supporting its maximum weight is unnecessary.

As in all forms of inflated tire from race cars to over the road trucking, the tire provides a good chunk of the suspension give. Harsh ride may not be a consideration, but it does tell you what the tire is doing if you pay attention. Having my tires absorb and roll over that sharp pavement edge while staying in contact with the pavement rather than bounce off of it like a brick and skip certainly merits consideration when that pavement is often wet, snowy or very cold as well. Proper inflation depends on weight and unless your RV8 weighs 2570 lbs (Desser chart), 50psi isn't necessary. The surface you land on will greatly affect the proper pressure.
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Last edited by ColoRv : 06-12-2014 at 09:19 AM.
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  #10  
Old 06-13-2014, 07:50 AM
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Quote:
Originally Posted by ColoRv View Post
Wow Dan, you're pretty sure your way is the only way aren't you?
Not at all. My way changes as I learn. I am pretty sure there is great value in studying the databooks and fundamental mechanics, and only then considering tribal knowledge.

Let's lighten up and have some fun. Are you running the standard 199-102 Cleveland wheel and brake kit on a -3 through -9? Most are, so consider this puzzle...

The technically correct maximum inflation pressure for the 199-102 kit is 31 psi per Cleveland drawing 50-76.

The maximum inflation pressure for a 199-156 kit is 50 psi, again per Cleveland 50-76.

The two kits use the exact same wheel halves, bearings, bolts, etc. The only difference between the kits is the brake disk....so why the difference in inflation pressure?

Quote:
Originally Posted by PaulT View Post
I bought the larger AeroClassic 380x150-5 6 ply.
Should these run at the same pressure as the standard tire (tyre ), or lower, due to the considerably larger footprint?
Paul, please look up the rated pressure and weight capacity in one of the databooks previously linked.
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Last edited by DanH : 06-13-2014 at 05:01 PM.
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