Larger tires?

[jbagley]

Ok, i'm sure this has been discussed before but I can't find any thread on the subject... Search function has failed me!

Prior to my first flight I had been flying a Cub and landing on some local grass strips; some rougher than others. I've been hesitant to land on some of those strips with my RV because of it's higher landing speed and smaller tires.

I'm curious if people have installed larger tires in their RV's and what the pros/cons are. Obviously sacrificing some cruise performance for marginal increase in rough field capability. It's probably not worth the trade off.

[hydroguy2]

This link will get you some light reading: http://www.vansairforce.com/communit...ight=big+tires

I have the 380/15-5 tires on my RV-7 and raised the wheel pants a bit also. I don't think it is costing me much MPH. I still run over 175kts at cruise.

[Greg Arehart]

James,

I put 800x6 tires on my RV-9 to fly to Yukon this summer. To do so required that I get some custom gear legs built to accommodate the 6-inch wheels that are required for the tires. These tires worked great on rougher strips (now the issue is the tiny tailwheel). They are for the moment without pants, but I'm thinking of putting -10 pants on or making some custom ones. Speed penalty for the wheels without pants compared to small wheels with pants was about 10 mph. I'm guessing that I might get 5 of that back with pants.

I've been meaning to post this on the forum for some time but just haven't had the time to write it up with all the photos etc.

greg

[jbagley]

Greg,

I'd be interested in hearing your account of flying in the Yukon. Did you already go and come back? Were the larger tires mandatory? Or just nice to have?

I grew up in Alaska, I have family in Whitehorse and I plan to fly up there next summer. Though will probably stick to the main airports. Anywhere remote i'd want to fly up there would require a supercub with *really* big tires or a helicopter. I would be concerned landing an RV on loose gravel as many runways up there are.

There's a good reason high-wing aircraft are preferred for bush flying

Video linked above was from a few years ago. Found someone willing to drop us and kayaks off at the top of some remote creek for some whitewater. That's me in the baggage compartment taking advantage of the 10% over gross weight allowance granted to aircraft operating in Alaska. I don't think he did a weight and balance before we took off.

[Greg Arehart]

James,

Depends on where you are landing whether the larger tires are mandatory. I went up and back in June/July. However, I would have been somewhat reluctant to land at a couple of the strips with standard tires. And if you wanted to do gravel bars etc. even bigger tires would be nice. I was working in east-central Yukon (80 miles E of Mayo), but most of the work was helicopter supported (I just flew up for the fun of it and the options on the way home). My route up was through SE BC (Vernon) then Smithers, Dease Lake, Whitehorse and camp. On the way back I stopped in Atlin (BC) to visit a buddy in the bush near there.

I didn't really see an issue with the loose gravel on a solid runway, and most folks say that hard braking is what causes most flying gravel damage but I haven't done enough of it myself to have a valid statistical sample.

If you're going next summer, several of us are planning a 3-week trip, for which I am the nominal leader since I used to live there as well. Tentative plans are to go north through BC and make stops in Alaska at Fairbanks (customs), Manley HS, Anaktuvuk, Ambler, Nome, Lake Minchumina, Talkeetna, maybe somewhere on the Kenai, McCarthy, Juneau, and Ketchikan. All dependent on weather etc. PM me if you are interested in joining the trip and I can give you more details. Probably will occur in July.

cheers,
greg

[scsmith]

I have the 380x150-5 on my RV-8 and I love them. These fit in standard pants on standard gear. I regularly land on packed dirt at one gliderport, and loose, sandy gravel at the other gliderport. I have also landed on well-cared-for grass.

Not much need for heavy breaking on gravel because there is so much rolling drag, unless I suppose the strip is really really short.

For anything more rugged than listed above, I would still want to make the step up to 800 x 6" as Greg describes. It does mean special gear struts because of the larger spindles for the larger hubs.

[Greg Arehart]

My gear legs are almost the same as standard ones, 1.25" diameter, just have an extra 1" on the axle. They were made by Langair, who makes all of Van's axles. Cost was $15 more than standard legs (but I did have to paint them myself). I'm using Matco wheels that fit just fine - actually have two sets of rims, one for 400x6 tires (that fit in the standard fairings and are basically the same diameter as the standard 500x5 tires) and another set for the 800x6 tires. They use the same brake setup and swap out with three bolts (once the fairings are removed). Now that I'm back from the north, I have the smaller tires and fairings mounted.

cheers,
greg

[KBSUP]

We have em on or 8 and my partners 7 and the 380x150-5s are working out nicely. We occasionally land on the sod strips in the area and there seems to be no speed penality.

[49clipper]

I put 380X150s on my -6 also since I primarily fly off my grass strips and others. Works fine with the new style recovery wheel pants. I just mounted the pants higher off the ground so they stay out of the grass.
N189EM
RV-6