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Big Tires...

smokyray

Well Known Member
Guys,

After landing my Harmon Rocket 2 on my rough, short and sometimes gooey swamp airstrip and having my 500 X 5 tires dig in and get my attention a few times I needed something new. Thanks to Steve Sampson, I used his idea and installed a set of 380 X 150 X 5 tires from Desser tire and vans pressure recovery pants on my Rocket. Steve's site shows nice pictures of the installation on his -4, the Rocket was very similar in fit and finish.
On the first flight the difference was amazing, really improved soft field handling, performance and looks better too, like they are the right tire for the HR2! I don't ever scrape my wheelpants on rocks or muddy ground and on asphalt it handles even better than before. I didn't lose one knot of speed over my previously closely faired Sam James pants and I think it may even be faster up high.
I will upload some pictures of the final product for your perusal. Again, THANKS Steve!!!

Rob Ray
HR2 "Bush Mod"
 
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The Greeen Swamp Aerodrome

Rob,

Don't be dissin the Swamp...I've mowed that runway a bunch, and miss my tractor therapy.

Tell Suzanne I said hello.

Tim
 
Your welcome! If anyone wants the link to the tires its here:

http://gikonfinsh.blogspot.com/2006/08/finish-kit-ordered-or-tires.html#links

or perhaps easier go here
http://gikonfinsh.blogspot.com/
and scoll down to October '06. There are several relevent entries.

Thanks again for the kind words Smokey.

PS If you want to land on my strip go here. That's what I need the tires for.
http://www.youtube.com/bananatime2

Thanks for the heads up on these tires, Steve.
 
AM bushwheels for HR2...

Steve, One thing I found on the bigger tires was brake pad clearance is reduced with Cleveland brakes. I placed thin washers under my brake caliper rotor where it meets the wheel. So far after 25 hours the tires work very well especially when rolling over fireant mounds..:) Tim, you need to come visit after a tropical storm has passed through. (Fd33 is gooey!)

Btw, the grass could use some mowing, when are you coming back? :)

Smokey
 
Smokey - I am really struggling to understand why you needed the thin washer. Was the part that holds the outer pad (top left in the attached picture) brushing against the tire?
http://bp0.blogger.com/_n0oPgd-_rrk/RzcUdjUNywI/AAAAAAAAAgY/EjoYXOiYUbc/s1600-h/HPIM1254.jpg
It appears to have adequate room in my case. I cant think what other problem could occur. The problem is exacerbated by the fact 'the brake caliper rotor' conveys nothing to me.

Thanks Steve.

"T" - you asked for pictures. Scroll down to my previous post. You will also find the weight delta.
 
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Smokey - I am really struggling to understand why you needed the thin washer. Was the part that holds the outer pad (top left in the attached picture) brushing against the tire?
http://bp0.blogger.com/_n0oPgd-_rrk/RzcUdjUNywI/AAAAAAAAAgY/EjoYXOiYUbc/s1600-h/HPIM1254.jpg
It appears to have adequate room in my case. I cant think what other problem could occur. The problem is exacerbated by the fact 'the brake caliper rotor' conveys nothing to me.

Thanks Steve.

Steve,

That clearance is closer than you may realize. When side loads are applied to the tire the tire will rub and possibly bind on the brake caliper. This is a common problem with planes using Bushwheels and the fix is usually a spacer between the wheel and the brake disk. The spacer I used on my 6" Maule wheels was a approx 1/8" thick ring the same dimensions as the inside of the brake disk where it meets the wheel. That 1/8" extra caliper clearance is operationally significant. Could probably use a thinner spacer on the smaller tires and wheels like Smokey did and get the job done. You might be surprised at how much these tires can flex under side loads, especially when the tire pressure is lower than normal.

I really do like your idea though, and I'm going to investigate this mod further because a couple of the places I like to go are soft and/or rough. I little more tire floatation and wheel pant clearance would increase my comfort level and maybe save a little wear and tear on the landing gear and airframe on rough strips. I'd rather not have to remove my panties every time I want to go into these types of strips.
 
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I have a friend that tried 600x6 wheels and tires on his HR2 and it shimmied like crazy. Likely because the toe-in/out was so far out that having the additional contact area of the larger tires just made it worse. I have Van's wheelpants for my F1 and regularly land on rough runways with my -6, many times which I wished I had bigger tires. Flying a J3 spoils you in that regard. So I guess I need to order some different tires!
 
Size Matters...

Hans,

Yes, you can use the 380X150X5 on main wheels, but you have to use a bigger fork (as shown in the link)and a 500x5 on the nose. I've never owned a nosewheel RV but it sounds like a great idea. Let me know how it works out!

This is Steve Sampson's original idea and should be standard on all RV's and Rockets, in my humble opinion. A much better and safer footprint. My Rocket now has 300 hours on them, an absolute home run! My friend Dale went to 600X6's on his HR2 with RV10 wheel pants, even better!

Smokey
HR2

PS: Jeff, what is the full link to your 7A friend's site? Excellent machine work!
 
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Spacers???

All,

I used to fly out of Lake Corpus Christi Arrowhead which had a grass strip and used these tires for about 800 hours on my first -4. A buddy flying a -6 changed over at the same time and put about 800 hours on it before selling it.

We never thought about using spacers....:confused: ...DUH...not saying we were smart. Just didn't think/KNOW we needed them and all worked out OK.

Am just throwing this into the mix for consideration. We did modify our wheel pants for clearance and watched it closely for first 10 to 15 hours. We had a problem with gophers and thought this might give us an edge if one of the little buggers was a deep digger. I liked them....the tires, not the gophers!:p

Am on a paved strip now; but often think about going back to them for all the reasons of landing on unimproved ground.

Good thread....

___________________________
Deal Fair
RV-4 (N34CB)
George West, TX (8T6)
 
It is starting to sink in now

Hey, thanks for the info and links guys. I really like this idea. It looks like the worst part is the fairings. Interesting that Steve Sampson is using what appear to be stock fairings and Bob Trumpfheller talks of needing different fairings, maybe he means reworking the originals?

I think my plane needs to fly before I go changing things, but I suspect a "Bob Trumpfheller" nosewheel is in 164HM's future.

I think all the links and info have made this particular thread the definitive "Big Tire" thread on VAF.

Thanks,

Hans
 
Big tires.....Small spats...

Smoky has given me, quite wrongly, much of the credit for big tires. They have been around in the UK for a while, but I guess I made it public perhaps, on Vansairforce.

I can see from the number of hits on my blog that oversize tires of great interest, and the posts below made me think it was time with 80 grass landings behind me in the -4, to see just how they were getting on inside their normal sized spats. Perhaps I had 20 lbs of mud travelling with me?

I never did space the tires out from the brake calipers but its quite clear the tires are clear of everything....well, except the mud.

So I have put some words and pictures here.

If you use grass that turns to mud in the autumn, they seem like an excellent addition to a -4, and I would think all tail dragger RV.
 
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Big tires

Hi Smokey
I put on those bigger Dresser tires on my RV4 as you suggested, put on a new pair of Vans Pressure Recovery Wheel Pants, mounted them 1 inch higher than the plans say, and I love them! They make for a much better handling plane, and even help out the prop clearance a bit!
Great idea... the new wheel pants were a LOT of work !
Thanks for the suggetstion Smokey!
Dick,
Boulder, CO
 
Pay it forward...

My pleasure! I thank Steve Sampson for passing me the idea, glad it worked out...

Smokey
HR2
 
adjusting max load for longer fork isn't that simple

I don't stay in holiday inn's, but I am an engineer.

Trying to adjust the max allowable nose gear weight for a longer fork is a bit complicated.
First, using the logic from the above post:
If Van's rates the nose gear to 375 lb, and you have increased the fork length by 17%, then the reduction of allowed max nose gear weight would be based on 375 - 0.17 x 375 = 311 lbs.
However, not all the bending moment on the nose gear comes from the end moment applied by the fork. In fact, the bending moment at any point along the nose gear strut is based on its location relative to the axle. So, by lengthening the fork, the bending moment from vertical loads is actually reduced over much of the length of the gear strut. It is only the portion of the gear strut forward of the axle that will experience higher bending moment.

Whether this results in greater deflection or less deflection depends on the overal dimensions and taper of the gear strut. If it is very tapered, then the increased moment forward of the axle may make the end "curl up" more, but if there is relatively little taper, the dominant contribution to the deflection will be the aft part of the strut, and lenghening the fork may reduce deflection.
 
I'm In!

Haven't stated on my new whellpants yet so better get the big tires now! Wth my new RV-4 FASTBACK and 74 inch Hartzel BA prop, the extra ground clearance will be beneficial. Besides, use grass runways a lot and it can only help. Any ideas on the expected speed loss from increased drag?

Thanks for the great idea and posts STEVE and SMOKEY!
 
How about larger tri-gear nose tire?

Great Idea and I've been thinking about it for some time. I'm still trying to figure out what to do on my -6A nose gear. Larger tire? Grove nose wheel assy? You would think that after all the nose overs:eek: somebody would have figured out a reliable fix.

Vans denies it's a problem and blames it on PIO, and landing technique. They put this kit together which is basically metal for over $25K and making good money. I think they should fix and pay for the design deficiency. Sorry, I had to get my complaining out:mad:

Anyways, has anyone used a larger tire for their 6A?

Thanks
 
Nose Gear on a 6A

Great Idea and I've been thinking about it for some time. I'm still trying to figure out what to do on my -6A nose gear. Larger tire? Grove nose wheel assy? You would think that after all the nose overs:eek: somebody would have figured out a reliable fix.

Vans denies it's a problem and blames it on PIO, and landing technique. They put this kit together which is basically metal for over $25K and making good money. I think they should fix and pay for the design deficiency. Sorry, I had to get my complaining out:mad:

Anyways, has anyone used a larger tire for their 6A?

Thanks

Hey, did you read this thread? Because there are links to a 7A with an oversize nosewheel, and 7's and 6's have the same nosegear assembly.

I also don't think our planes are nosing over at a high rate. My interest in the larger tires is to improve rough field handling.

Hans
 
I'm just placing my order for the finishing kit.... Is there any reason why I can't order RV10 wheels, tire's and pants for my RV9a instead of the 9a ones?
 
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<<Is there any reason why I can't order RV10 wheels, tire's and pants for my RV9a instead of the 9a ones?>>

If I recall correctly, RV-10 is 1.5" nominal axle diameter, 9A is 1.25".
 
Size Matters

Guys,

The 380X150X5 tires not only work better on grass, they also work better on pavement and increase the footprint to 6 inches. They fit under a stock Vans pressure recovery wheelpant (see the beginning of this thread) with some cutting and didn't slow me down at all. Highly recommended.
RV-10 main wheels are 600X6 and the pants are much larger. Upon measurement, the 380X150X5's only lack 0.5" in width and 1.5" in height difference from the 600X6's but look better installed. The RV10 pants on a Rocket or 2 seat RV look too big to me. The 380's are the perfect RV/Rocket tire in my humble opinion. :)

Smokey
HR2
 
Vans denies it's a problem and blames it on PIO, and landing technique. They put this kit together which is basically metal for over $25K and making good money. I think they should fix and pay for the design deficiency. Sorry, I had to get my complaining out:mad:

I've never flown a tri-gear RV so I have no direct experience. But I did own a Mooney (F Model with mods to make it an "almost 201" J model).

I found it easy to land in all conditions BUT, and this was a big BUT, you had to land it on the mains first or PIO was guaranteed and, owing to the low ground clearance a prop strike.

I had this happen to my airplanes twice by two different pilots exactly one year apart. Yes two prop strikes (one was a guy I allowed on the insurance and never should have - he was an idiot - the other was a CFI when the plane was on leaseback).

In both cases pilots had a "bad" landing with PIO and prop strike; went around and in one case flew to a nearby airport and shot T&Gs; then returned to land and didn't know they had struck the prop until putting the airplane away in the hanger ("Hey, why are the prop tips bent like that?").

So I know a great landing airplane can be made to be a bad landing airplane and can even have thing break with bad technique. I'm not weighing in on the specifics of the A model nose gear "issues" but maybe Van's is on to something.

I'm just sayin'
 
Big Tires on a 6A

Just thought I would show some pictures on the best big tire thread. I did not have to change the mounting of the wheel pants, just trimmed them, mostly on the sides and the back.
BigTires1.jpg

BigTires2.jpg

BigTires2.jpg


Hans
 
Okay I took the plunge

Hans thanks for your pictures. That helped answer a couple of questions. Cutting out the bottom isn't much of a problem. Moving the mounting brackets was more work then I wanted to do. "Big" tires on order.
 
RV-10 wheel pants.

A friend here in New Zealand has an RV6 with pressure recovery wheel pants. He often has to remove the wheel pants right where he is and pull out all the grass from inside them because it feels like the brakes have jammed on. He only has the standard 5.00 x 5 tyres and not the larger 380X150X5 tyres discussed here. This problem would be worse with the larger tyres. This is not on farm strips, but ordinary airfields here. Just a function of the typography and how much money is available to maintain airfields I guess. He also had a stone jam up between the tyre and the wheel pant and take a chunk out of it, again on a regular airfield, not out in the boondocks somewhere.

I would probably be a bit more adventurous in where I would take my plane (building RV6), so would be keen on the 380X150X5 tyres, but really think larger wheel pants would help out in this regard. Taking the wheel pants off every time you land where there?s a bit of grass is going to be a real pain. Has anyone installed RV10 wheel pants on an RV4/6/7/8? Sounds like a better alternative than flying around without any at all??..

Really Vans should offer 6.00x6 as a factory option on these aircraft.

Cheers,
Andrew.
 
...

Really Vans should offer 6.00x6 as a factory option on these aircraft.

Cheers,
Andrew.
Andrew,

Contact Van's. I know of one RV-9 builder/flier (Michael Ice) who ordered custom gear legs for his -9 so he can put on 6.00 x 6 wheels and tires.
 
The RV8R...

G'Day Andy,

I have a stack of old RV8R newsletters going back to the late 80's when I started my -4. One of them showed Van's then RV-6B prototype which they installed 600X6 tires and wheels on. They extensively tested it on many surfaces but found only a modest difference in performance above the 500X5's.
Three advantages I see for the 380's over 600X6's. I compared the 500X5 footprint to the 380's footprint and it is 6 inches across the bottom (1) and slightly less tall than the 600X6 and fits easily on stock Van's PR pants (2) and requires no wheel replacement.(3) The 600X6 doesn't gain you alot more than the 380's and requires much more cost.

I now have 300 hours on the 380's with excellent overall results across the board and no wheel pant clogging. My strip is gooey most of the year and the wider footprint really helps the Rocket:)

Smokey
HR2
 
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G'Day Andy,

I have a stack of old RV8R newsletters going back to the late 80's when I started my -4. One of them showed Van's then RV-6B prototype which they installed 600X6 tires and wheels on. They extensively tested it on many surfaces but found only a modest difference in performance above the 500X5's.
Three advantages I see for the 380's over 600X6's. I compared the 500X5 footprint to the 380's footprint and it is 6 inches across the bottom (1) and slightly less tall than the 600X6 and fits easily on stock Van's PR pants (2) and requires no wheel replacement.(3) The 600X6 doesn't gain you alot more than the 380's and requires much more cost.

I now have 300 hours on the 380's with excellent overall results across the board and no wheel pant clogging. My strip is gooey most of the year and the wider footprint really helps the Rocket:)

Smokey
HR2

Bonzer reply Smokey. Steve Sampson flying a 4 out of a grass strip in Yorkshire (A up) England, fitted these tyres and has nothing but good things to say about the modification. This is on my list even though there is a slight weight penalty.
 
Tyres and wheels.

Gidday Smokey,

I concur there is didley squit difference between the 380X150X5's and 6.00x6 tyres. It's just that if they had a 6.00x6 wheel option you could then put some decent tyres on your RV if you needed them like 8.00x6 or even 8.50's.

I was pretty surprised at the story told by my RV6 friend. The first instance of the grass filling up the wheel pants was at what is to us a big regular council owned airfield. I just thought if you had a big RV10 wheel pant sitting atop the 380X150X5 tyre this wouldn't happen. Mud isn't the problem and it just doesn't get cold enough here for must or water to freeze up in the wheel pants as some have discussed here. Its just the grass!


Hi there Bill,

You put in touch with Mike Ice. He had to do it all himself, deal directly with Harmon Lange etc., all too hard for me from the other side of the world. I concluded as Smokey has pointed out that for all the effort involved it wasn't worth it as the 380x150x5 tyre provided as great a benefit. Mike also was happy to fly around without wheel pants and was planning to utilise a stone guard. RVs look really ugly without wheel pants ;) and the loss of speed is so great it puts them back within reach of some "lesser" aircraft. Of course Mike now has the option of putting some really decent tyres on...... ABW! :D

Keep the comments coming!

Cheers,
Andrew.
 
Andrew, I am quite puzzled by your friend's experience, since mine is very different. Since together with Smokey I kicked this thread off, I thought I would put a link to some follow up pictures where I investigated the build up of grass / mud / sheep sh*t in the spats.

Flying from my strip it really turns out not to be a problem. I probably take a look in every 3 months or so but while they are 'mucky' I am always surprised how little build up on the inside. The outside is sometimes more challenging.

My soil is clay. In fact about 500 years ago there was a brick works here.

I guess it raises a question. Which way up does grass gow in NZ? Roots up or down? :) Could that be the problem?

I have to say I would not fly with the spats off. My Supercub used to get filthy. I have even washed mud off the top of the wings after flying at this time of year. The spats deflect it nearly all back down.

Have fun!
 
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Flying from my strip it really turns out not to be a problem. I probably take a look in every 3 months or so but while they are 'mucky' I am always surprised how little build up on the inside. The outside is sometimes more challenging.

Ditto. We have some low spots on our runway that get very muddy, and I've had so much mud on my airplane that it looked like I went off-roading with it. Any time I've checked the wheelpants there's been virtually no mud inside, and I have about a 1/2" gap all around the tires.
 
Grass.

Yes, I'm surprised this has happened too. He was the first time as well! Considering that something like 40% (I think, so don't quote me) of the dairy products in the world come from little old New Zealand we know how to grow grass here. And we've even learned to stuff up the environment by getting even more of it to grow! Generally they don't let the cows out onto the runways 'cos of the cow do-do, so the grass tends to get away on the airfields a bit.

I've seen the pictures and video of your strip Steve and it looks like a billiard table. Sheep keep grass shortly cropped as well.

It sounds like no one on VAF has put the big wheel pants on any of the two seat RVs as the 380x15x5 tyres work so well under the standard pants. Good to hear that anyway.

Cheers,
Andrew.
 
Grass

Andrew

North island sheep s**t south island rabbit s**t and welington bs especially near the beehive must be making the grass stick.

Joking aside we operate of grass all the time and in all field conditions in Norfolk UK and we do not have any problems like these, and last time I looked wiakato cow cocky grass is no different to what I fly off. The only problem we have is mud and ice ocassionally. Is the spat a close fit or is grass getting up the side of the wheel. Are other NZ RV owners having this problem as well I suspect not.

I would put on the standard wheels with bigger tyres only, as I think that would suffice on most topdressing strips.

I do know Darton Field has perfect grass runways, well it did when all those beavers flew from there.

Caveat: These are only my opinions!!

Happy flying in Aoatearoa.
Rob
 
Bigger tires on the RV4

I installed those larger Dresser tires on my -4 also, and really love them and think they even look better as well make the plane a bit more versatil... but now I get a pretty good shimmy going on fast taxis and rollouts - not sure what to do about that and why it just decided to start doing that!?
...Redhawk
 
Mine did too...

Redhawk,

I had the same problem. After 50+ hours my gear started developing a pretty bad wheel shimmy/shake. So bad the wheel pants started getting cracks I had to repair. Took the wheels off to balance the tires and found the tires had developed some pretty bad out of round spots. Long story short, bigger tires on the same 5 inch wheel is quite a bit more rotating mass than the stock gear was made to handle. If the tire gets out of round or lumpy, this rotating mass will be an issue, was on mine. I think if you land mostly on grass, this won't be a problem but I land mostly on pavement and the rubber simply scrubbed off unevenly. In general I am easy on the brakes so don't think skidding off the rubber was an issue.

I have since switched back to stock sized tires, picked up 3 knots and can and do use the same wheelpants with no problems. I miss the big tires when landing on the farm but the wheel shimmy sucked and couldn't balance it out. Might look into 6 inch wheels in the future...
 
Thanks for your input!
I may do the same and go back to the stock tires. I decreased my tire pressure a few pounds and this seemed to help a bit, but I still get a shimmy unless I taxi very slow...
I'll sure miss them though. I think they are a overall improvement when they don't shimmy!
 
Shimmy Problems Resolved with Big Tires

Well, my original tires were flatspotted something terrible (pilot's fault no doubt), so I decided to go ahead and go with new 380's and the shimmy is gone! My point is that no matter the size any flat spotted tire will generate a shimmy. I doubt that the extra inch or so in diameter makes much difference.

I fly a 6A and I still have the bitty lamb tire up front. With the new main tires I have better visibility over the nose while taxiing. The only difference I have noticed on takeoff is that the nose has a bit of a tendency to pop into the air, likely due to the lower initial AOA. My brain has already adjusted to this effect. On landing I can keep the nosewheel up longer, which has to be good.

Hans
 
Guys,

... I used his idea and installed a set of 380 X 150 X 5 tires from Desser tire and vans pressure recovery pants on my Rocket. Steve's site shows nice pictures of the installation on his -4, the Rocket was very similar in fit and finish.
...

What are these 'pressure recovery pants?"
 
Hi Lynol...

....the 'pressure rcovery' wheelpants are the latest, lower drag wheelpants and differ from the earlier flat-sided wheelpants, in that they have a 'teardrop' shape with the rear third being concave. They're several MPH faster with their rounded, more eye-pleasing look,

Best,
 
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