600-6 vs 700-6 tires

[Jetfever]

I have seen some posts here concerning 700-6 tires on a PA 22/20. I did a search here and on the web and I have not seen any information on the size difference other than both sizes are available and for sale.

What are the advantages to each and are both sizes approved? (I assume the 700 is taller, is it wider)?

Will the 700-6 fit a PA 22/20 ? (clear the brake rotor, etc). Will 700s put more stress on the landing gear? Less stress on rough runways?

Thanks, Steve

[skydogk]

Steve,

I haven't done my homework on a straight change from 6.00 to a 7.00 series tire. At least as far as paperwork is concerned.

I have flown my pacer for many years with 8.50x6 tires, via STC and now fly it with 31" bushwheels. Don't wory about the gear structurally. It will take it. In fact I believe bigger tires transfer less of the stress. Now, you must ask yourself what is your mission. If you want a nice weekend cruiser, airport to airport with no gravel, the smaller tires with allow more speed. If you want to get into backcountry stuff, the bigger the better for tires (and engines for that matter). Just remember, the bigger the tires, the more effective the brakes.

Hope this helps a little,

skydogk

[Lownslow]

Person needs to consider the added weight of the 7.00's and considerable xtra cost as well.

Lou S.

[Steve Pierce]

I ran 800x6 on my Clipper and 8.50s on my Pacer. It all depends on your mission. Bigger tires work good on rough strips. I have flown everything from 500x4 to 35" Bushwhweels. None of them seem to matter as far as directional control for me.

According to the Light Plane Components/Univair PA22/20 STC you can go up to 800x6 legally. Bigger does mean a wider foot print and lower pressure means better shock absorption. Smaller means less drag and probably a tad more airspeed and less angle of attack for a little longer take-off. Bigger does mean more weight as well.

[Stephen]

When I went from 8.00 to 26" tires, I was unable to detect a difference in cruise speeds...even with my eyes open.

[Jetfever]

Thanks guys!
1. Steve P. Great info! I will read my Univair STC conversion paperwork that came with my PA 22/20. I had no Idea 800x6 was included!!!! :D

2. Lownslow, Good point about keeping an eye on the weight. (And the $).

3. Stephan, I assume no one has done any cruise speed #s before and after fitting larger tires and that Stephan is teasing about no cruise speed change from 8.00 to 26"! :o If I ever decide to change tire size I will try a cruise comparison, but it is difficult, since density alt/ temperature/ cruise alt wind etc. changes by the time one gets the new wheels fitted.

4.SkydogK, Ever since the post about the Pacer gear failure (A Sad Day): viewtopic.php?f=3&t=1174 (http://www.shortwingpipers.org/phpbb3/viewtopic.php?f=3&t=1174)
I have been wondering about the stress on the Pacer gear by using larger tires, especially Alaska Bushwheels. You say:" Don't wory about the gear structurally. It will take it. In fact I believe bigger tires transfer less of the stress". I would have thought the opposite. There is talk on this Forum about the Trimmer mod and using Supercub gear. I wish to start a discussion on this topic, My A&P thinks these large tires may cause the stock gear to fail... You disagree? Anyone care to discuss this subject?

5. I found a Supercub Forum discussion on tire size: http://www.supercub.org/phpBB2/viewtopi ... sc&start=0 (http://www.supercub.org/phpBB2/viewtopic.php?t=13050&postdays=0&postorder=asc&start=0)
And a Goodyear tire chart: http://www.goodyearaviation.com/resourc ... atires.pdf (http://www.goodyearaviation.com/resources/pdf/datatires.pdf)

The Goodyear chart (scroll down to type III) Shows (Outside diameter) 600X6 4 ply: 17.5 inches. 800X6 6 ply: 19.5 inches. 850X6 6 ply: 22.1 inches.

[Student Pilot]

We've tried both 800's and 850's, I find the 800's the best. If you do operate from both bitumen and grass the 800's are less squirmy and still give a reasonable footprint for grass strips.

[Lownslow]

Yes, size does matter.


Lou S.

[Frank Green]

We put 700x6 on our original 20 in place of the 800x4s when we put the clevelands on. I was looking for the same look and fit the original fenders being the same diameter. They are a little skinnier though under the fenders it is hardly noticeable. The roughest thing we land on is a overdue mowing runways. Just wanted it to look original but get rid of the goodyear brakes.