Another method is to measure from the ground to the axle and double it. Might be a better figure since that's all the clearance you'll get lot of the tire anyway.

CamTom12 wrote:Another method is to measure from the ground to the axle and double it. Might be a better figure since that's all the clearance you'll get lot of the tire anyway.

I think that is sort of the other side of the coin, to Hotrod's point about the height not being the true size of the tire. It would depend what you want to know.

The height measurement changes slightly with load in the aircraft, air pressure, temperature, etc. But that's relevant for ground clearance.

The true diameter of the wheel without load would be better approximated by the width of the tire. But that's relevant when it comes to rolling over rocks etc.

Measuring diameter seems to me to be a better way to compare tires. Results of measuring to the top of the tire or to the axle is dependent on inflation. My 850's change by quite a bit going from 13# to 20 or 25.

The 27" tire will be available in April. $395/tire

http://www.desser.com/store/products/27 ... UNDRA.html

Product Description
27/10-8 4 PLY AERO CLASSIC SMOOTH TUNDRA TIRE

New Aero Classic Tundra 27 x 10.00-8 4 Ply

THIS TIRE IS FOR 8 INCH WHEEL. IF YOU CURRENTLY USE A MATCO 6 INCH MH SERIES WHEEL NOW, YOU CAN BUY MATCO'S 8 INCH WHEEL AND THIS WILL BOLT ON TO YOUR EXISTING SETUP.

Our "Pillow Soft" 27 x 10.00-8 4 Ply stands 27 inches tall and weighs in "featherlight" at 20.5 lbs.

The load rating is 1,800 lbs. per tire. This tire will be available in mid December . The first run will be for Light Sport / Experimental Category use only, followed up by a fully FAA TSO'd model by 2nd quarter 2015.

Please keep your eyes peeled for future additions to the Aero Classic Tundra line.

***THIS TIRE IS CURRENTLY ONLY RATED FOR LIGHT SPORT / ULTRALIGHT / EXPERIMENTAL CATEGORY AIRCRAFT**

WILL SHIP APRIL 2015.

THIS IS FOR 8 INCH WHEEL

SKU: 27/10-8 4 PLY

Any idea why they went with an 8" wheel? Seems that there are way more 6" wheels then 8" out there and more market for 6".

Because their tooling will not allow them to make a tire that big with a 6" wheel. Their 22" was as big as they could go on a 6" wheel without buying new/expensive tooling. At least that is what they told me.

For most of us E-AB folks who have an airplane these will fit on, they will be a great option. Buying a set of 8" MATCO wheels would not be a deal breaker at all for me.

whee wrote:Because their tooling will not allow them to make a tire that big with a 6" wheel. Their 22" was as big as they could go on a 6" wheel without buying new/expensive tooling. At least that is what they told me.

Good to know. Thanks.

New additions arrived and now fitted. they look brilliant on a Savannah.





still a month or 2 off getting airborne after a 1000Hrly overhaul and serious upgrade and mods program.

I am real pleased with them over standard 6 ply 8.50x6s on my PA-11-ish clone as well. Much lighter and much softer sidewalls.

motosix wrote:I am real pleased with them over standard 6 ply 8.50x6s on my PA-11-ish clone as well. Much lighter and much softer sidewalls.

Those are the 850 / 22" smoothies? Looks great.
Is that the Cub that was for sale in Independence OR last summer?

hotrod180 wrote:

motosix wrote:I am real pleased with them over standard 6 ply 8.50x6s on my PA-11-ish clone as well. Much lighter and much softer sidewalls.

Those are the 850 / 22" smoothies? Looks great.
Is that the Cub that was for sale in Independence OR last summer?

Yes & yes.

At least by my tape measure the "tundra tires" are not any larger than the standard Aero Classic 8.50x6s 6 plys that came off this plane. These are just substancially lighter and have no tread.

re: Cub -- I have slowly been working out the squawks and finally starting to get some real flights the last few weeks.

Today's GA News e-newsletter had an article about Desser introducing the TSO'd version of their 850x6 smoothie.

http://generalaviationnews.com/2015/04/ ... fd77-17986

This one's rated at 1600#, just like their original LSA version. I was curious as to how heavy an aircraft this would be suitable for. I googled tire weight ratings and here's what I found.

http://www.desser.com/pressurechart.php

Tire weight ratings are based on ply rating. From the above chart, an 800x6 4 ply tire is rated at 1350, while an 800x6 6 ply is rated at 2050-- so the 4 ply is rated at about 2/3 as much as the 6 ply. A 850x6 6 ply is rated at 2275, so 1600 for this 4 ply smoothie seems about right.

FWIW the Cessna 170 TCDS approves 800x6 4-ply tires, which are rated at 1350, so I'd guess these 1600# rated tires would be suitable. The C180 TCDS doesn't list approved tire sizes, but a 1953 model factory equipment list includes 800x6 4-ply tires so I guess these smoothies would be OK for a 180 also.

When my current 850 GY-cored recaps wear out, I might consider a set of these 850 smoothies. Good way to knock off about 13 pounds vs a set of 850 Airtracs, and also move my CG back a whisker which wouldn't be a bad thing either. The smoothies are about $200 each vs closer to 250 for the Airtracs, so there'd be some money savings also.

hotrod180 wrote: ....The smoothies are about $200 each vs closer to 250 for the Airtracs, so there'd be some money savings also.

Checked the Desser website today, turns out I was wrong about the pricing. $225 each for the new smoothies vs $239 for the airtracs. So not much price advantage, although the smoothies are quite a bit lighter & softer-sided. Don't know where I got the $200 figure for the new tires, thought it was from the GA News article but I re-read it and no.

any reports on people flying these yet????

I've been running them on my C170 for about six weeks and like the feel alot on all surfaces. Even better, the pair saved me around ten pounds over the 8.00's I had been running.

Been running them on my Rans S7 for a couple of months unfortunately mostly on hard surface with 12lbs of air and love them. Have tubes but have not experienced any creeping on the rims. The lighter weight and softer sideswalls compared to the Airtreks make a huge difference.

Thanks for the reply's. how about anyone with the 27"????

Fitted up a set of the new Desser 8.50x6 Aero Classic Smooth Tundra tyres to my Cessna 140.

The aeroplane lives on a dirt strip and we've had a wet winter, so the strip is a tad lumpy. Wow, the new tyres really soak up the bumps nicely.

She is a lot more responsive directionally than she was with the stiffer 8.00x6's. Not twitchy but certainly a little quicker to respond to any rudder inputs. Feels very positive. Not sure what tyre pressures the engineer put in, but I think I can come down to lower pressures if I need to.

No issues at all with cruise speed. Absolutely the perfect size for the 140.

Only one small problem I hadn't thought of. Looking over the cowling when taxiing or 3-pointing it! Thankfully the seat squab has a few more upright settings left to get it adjusted right.

Really pleased with the result.

Mick
Melbourne, Australia
Cessna 140 VH-YBY

PS... Anyone know how to upload a pic into a thread? I'm an Analogue Man in a Digital Age...

Pics of the new Tyres are here: https://www.flickr.com/photos/123490082@N04/

Cheers
Mick