What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Big Tires...

bigger tires shimmy

Hi Rocket Bob,
I can confirm that shimmy! with the larger Dresser tires. I'm going to investigate my wheel assemblies today and make sure it's not a bad bearing.
If it's just a out of balance tire the shimmy would continue even after liftoff but it occurs only on the runway. Sometimes I think my gear leg is going to break off as it shimmys so bad!
 
49clipper

Did you use vans wheel pants and did they require much hacking to make them work with the big tires? I about to order them as I fly off grass and its a real pain with the 5:00x5s. I ripped off a wheel pant yesterday in tall grass and lots of mowed grass laying on top. I need new tires anyway
 
Hi 49clipper,

A friend has the Van's wheel pants on 380 tyres on his -7. The bottom cutout obviously needs to be bigger but you will also find tha the pants need to be positioned higher too to give the required clearance on the inside above the tyre. As a consequence, the fit of the intersection fairing is different. Also, there was some interference with the brake caliper which required a small cut-out and the glassing in of a 'blister' to clear the caliper. This blister is inboard so does not show.

I have 380's on my in-build -7 but am yet to do all the above. Not long now though.

Hope that helps.
 
Smokey and others that are flying with 380 tires...what kind of tire clearance do you have at the top of the wheelpant? I have 1/4-1/2" and am wondering if this is adequate.
 
1/2 Clearance

I had a spacer during build of a 1/2 at the top so had a 1/2 inch clearance. Had NO problems and landed on everything from grass to dirt to mud to pavement/concrete. Really miss the easier ground handling, especially moving by hand.

Concerning an earlier post, my wheel pants did not need any mod to fit the brakes and my pant/gear fairing worked fine. I am using the same set up with no mods since i went back to thew 5.00/5.

Tailwinds!
 
An inch by any other means...

Hi Bob/Jim,

Close measurement on my HR2 shows exactly 1.5 inches clearance from the top and I cut 1/2 inches around the sides. (See photos in my earlier post) They are rock and mud tested with no issues, having never clogged up on me, nor required any blisters. I did however leave a small hole on the inside in lieu of one.
BTW, I just changed out the second set of 380's, approaching 350 hours with the "Big Un's modification! I will never go back to 500X5's.
http://www.vansairforce.com/community/showthread.php?t=27980&highlight=bushwheels+rocket
Link to original post

Smokey
HR2

PS: JJ, come up voice!
(check your email)
 
Last edited:
The tires I have (recapped 380's from Wilkerson Retreads) have a bit more of a square shape and aren't as rounded so they don't match the curvature of the wheel pants like the Aero Classic tires. So in order to get adequate clearance for the Grove double-puck caliper, the wheelpant, and the top of the tire, the space above the worked out to about 1/2". At the corners of the tires they're about 1/4".
 
Tall Vs. Short Gear and Larger Tires

I have the short gear with pressure recovery pants. Will the larger tires work well with the old style gear?
Gene McMullen
Angleton, TX
 
I know this is a crazy old thread, but I'm looking to see if someone has an old worn out 380 that I can use as a test fit on the matco wheels and brake setup I have.

Anyone got one? I'll pay.

Thanks

Mani
 
Oldie but goodie...

I know this is a crazy old thread, but I'm looking to see if someone has an old worn out 380 that I can use as a test fit on the matco wheels and brake setup I have.

Anyone got one? I'll pay.

Thanks

Mani

Hey Mani, I do, somewhere.
I relocated last Fall and brought along a worn out 380 I left with a friends shop nearby. If he still has it I'll get back 2U. Just cover the shipping.

BTW, it should fit on the Matco wheels no worries as I have placed a pair on 2 RV's with Matco wheels.

V/R
Smokey
 
Hey Mani, I do, somewhere.
I relocated last Fall and brought along a worn out 380 I left with a friends shop nearby. If he still has it I'll get back 2U. Just cover the shipping.

BTW, it should fit on the Matco wheels no worries as I have placed a pair on 2 RV's with Matco wheels.

V/R
Smokey

Copy all Smokey. Standing by.

Thanks
Mani
 
What have you guys found as the best source for the larger tires and what brand/series would you recommend?

I would like to put them on my -8 that is in progress.
 
Certainly some compromises that most folks might not want to make or everyone's cup of tea but works well for places I like to go. 21X8-6 4 ply

fe3d1099-c34c-4584-a817-c280b5aaa1ad_zpsfmicqwav.jpg
 
Hey Mani, I do, somewhere.
I relocated last Fall and brought along a worn out 380 I left with a friends shop nearby. If he still has it I'll get back 2U. Just cover the shipping.

BTW, it should fit on the Matco wheels no worries as I have placed a pair on 2 RV's with Matco wheels.

V/R
Smokey


Any joy on the 380's Smokey?

Mani
 
Dragging out an oldie but goodie...

Looking at my first tire replacement and upsize...but unsure of what tube to use.
What tubes, size, type will work with the 380/150-5 (AKA 15/600-5)?
I would want air stop type.
Thanks!
 
I went with the 380's and could not find a matching tube. I was told to use the Michelin Air Stop tubes, standard size 500 x 5. Fitment is perfect and the tube rarely to never has to be topped off. Had other tubes previously and they always leaked off.
 
AirStop tubes

Not to hijack the thread, but +1 for AirStop tubes! Only adjust the pressure twice per year, once when the weather warms up and once when it cools off...bought spares 7 years ago when I installed mine--They're still sitting on the shelf.

Cheers,

Vac
 
Which mfg?

In the 380 size, who makes the best tire, grass and pavement? Dresser? Goodyear? Michelin? Pretty big price between all these, so before I order just checking the consensus. Who do you buy through? (wilkerson doesnt have any retreads right now, only new)

Thanks
 
Last edited:
380x150x5 6ply Aero Classic

Here are some pics for comparison to Vans Stock Tires.. I just mounted these up to grove wheels. They weigh 2.2 lbs. more than the stock tires. Both are Aero Classics

2ag11td.jpg


2q1rs52.jpg


2a4tj15.jpg
 
Last edited:
For what it's worth, I upsized to the Desser tire option about 2 years ago, having planned for it from the beginning by installing the wheel pants high for clearance, etc. As much as I liked the larger size for rough strips, the shimmy they created drove me crazy. Onset during taxi was about 20 knots indicated per GPS. On rollout, around 25 knots. The plane shook like a paint mixer. I added wood gear leg stiffeners that only helped a bit, experimented with tire pressures, etc.

Last month my OCD got the better of me while I was doing the condition inspection. Michelin Airstop tubes, Michelin 380/150-5 tires, 30 psi, full on OCD over the top balancing using my Marc Parnes (for my BMW motorcycle) balancer, shake is gone and the value of the big tires has finally been realized.
 
Questions....

This weekend I installed the said 380/150 15 tires by Aero Classic.
I have Van's stock Matco wheels and brakes, and new pads.
I tried installing with no spacing washers between the wheel and rotor and the brake caliber touched the rubber. With two standard washers I now have about 3/16 to 1/4" clearance. I did not note how much clearance there was with the old stock tires. It must have been about the same?

What clearance do you have???

As the pads wear the spacing will get better, I assume.

Also the caliber just touches the inside of the wheel pant. Do you think this will cause problems more than the obvious wear of both parts????
 
I'm glad this BIG TIRE post came up. I had the stock 500X5's on my six and they were adequate, but I always yearned for a larger tire for grass strips and frozen lakes. I haven't fitted my wheel pants yet on my 7, so I thought I would give the 380X150-5's a try. Regarding tire pressure, what PSI are you guys running with this setup? I found with my six that a higher tire pressure all but eliminated the shimmey problem. Figure I'll go with the Michelin's and have them dynamically balanced and see how it goes.

Jake
 
Clearance to move about the country...

This weekend I installed the said 380/150 15 tires by Aero Classic.
I have Van's stock Matco wheels and brakes, and new pads.
I tried installing with no spacing washers between the wheel and rotor and the brake caliber touched the rubber. With two standard washers I now have about 3/16 to 1/4" clearance. I did not note how much clearance there was with the old stock tires. It must have been about the same?

What clearance do you have???

As the pads wear the spacing will get better, I assume.

Also the caliber just touches the inside of the wheel pant. Do you think this will cause problems more than the obvious wear of both parts????


Bruce,
I was a Big Tire "Beta Tester" having installed 380's on my Rocket and later my RV4 back in 2008. I purchased them after reading Steve Sampson's construction blog of his masterpiece RV4, G-IKON.
Cleveland wheels have close tolerance as well and I installed washers to allow for clearance as you did. I trimmed my wheel pants accordingly to increase clearance. I didn't notice any speed loss.

You're going to like the change however, especially if you operate primarily on soft turf or grass. Operating my Rocket from my home strip at the time "The Swamp" was a quantum leap better in ground handling especially during rainy season in FL (all summer)
:)
http://www.vansairforce.com/community/showthread.php?t=27980&highlight=bushwheels+Rocket
Here is a thread with more info...
V/R
Smokey
 
Last edited:
Twice the ground clearance without raising the pant, photo taken with tail wheel on the floor.
bg1shy.jpg


More contact patch...
2cgj3ib.jpg
 
Thanks Smokey! I'll let you know how it works, or watch for me in the news! :D

Bruce, any more updates since you started running the bigger tyres on the Matco wheels? Any touch issues with tyre to sidewall?

Cheers,
Ed.
 
Bruce,
I was a Big Tire "Beta Tester" having installed 380's on my Rocket and later my RV4 back in 2008. I purchased them after reading Steve Sampson's construction blog of his masterpiece RV4, G-IKON.
Cleveland wheels have close tolerance as well and I installed washers to allow for clearance as you did. I trimmed my wheel pants accordingly to increase clearance. I didn't notice any speed loss.

You're going to like the change however, especially if you operate primarily on soft turf or grass. Operating my Rocket from my home strip at the time "The Swamp" was a quantum leap better in ground handling especially during rainy season in FL (all summer)
:)
http://www.vansairforce.com/community/showthread.php?t=27980&highlight=bushwheels+Rocket
Here is a thread with more info...
V/R
Smokey

Thanks for the info Smokey...
The photos from that 2008 post are not showing up...any chance of reposting those photos or updating the old post?
 
Bruce, any more updates since you started running the bigger tyres on the Matco wheels? Any touch issues with tyre to sidewall?

Cheers,
Ed.

So far so good! A dozen or so TO's and Landings, with a couple on plush green, wet grass. Handles just fine. I did cut a small hole in the inside of the pants for clearance of the lower rear caliper bolt. It was touching the pant. I need to make a small bubble to cover it, right now it has some duct tape. :p. My pants are vinyl covered, so the patch will be easy.
And a couple cross country flights showed no noticeable speed loss.
 
I just mounted my 380x150-5's and they look great. Does anyone have a recommended tire pressure that I should be running in these?
Cheers,
Tom.
 
I had shimmy above 35PSI. 25-30 seems to work good for me. At 20 PSI they started to look flat.

Bevan
 
Thanks guys. I'm running the Matco wheel/brake assembly that came with the RV-7 kit and I've run into the clearance issue with the caliper. I've measured the clearance from 20 through to 65psi and plotted it. At 20 psi I have 0.032" at this worst case location, at 65psi I have 4 thou, and based on the shape of the curve I estimate contact at around 90 psi. I see some earlier posts regarding shimming things to improve the clearance, however it's not exactly clear what to shim. If I am to bother shimming say a 0.063" further out , in my mind that would require a 4.5" diameter disc to be fabricated between the brake rotor and the inner rim half, an 0.063" thicker shim that is currently in place against the inboard bearing, and a 0.063" thinner shim between the outer bearing and the axle nut. This would mean that I would not have to drill a new axle position, which I really do not want to do.
Or, I could just leave it at the current clearance and see how things go?
How are others achieving the desired clearance, and what should that target clearance be?
 
Great thread guys!
In a mid life crisis I've started my RV8 build. Lucky enough to have time, so empennage finished in 5 weeks.. fuselage kit will be here in 4 weeks time. I'm currently operating a 180hp Husky from a 570' strip with a wall at each end, so probably won't be taking the RV there (but I'll no doubt give it a go later!). Dropping from 26" wheels to standard Vans wheels was too much of a culture shock, so Ive ordered Grove one-piece gear, 6 inch wheels and plan on putting 600x6 tyres on, with James wheel pants for the RV10. My Husky guru, Tom Dietrich uses the same pants with 700 x 6 wheels on his Allison powered (450shp) hot rod, Pocket Rocket... take a look on youtube, they look great!. I'll let you know how I get on with them in a short while...
 
Last edited:
Big Un's...

Thanks Smokey! I'll let you know how it works, or watch for me in the news! :D

Good call Bruce!
I am certain you will be glad you made the swap. I have found after 10 years of "use and abuse" that the 380's way outperform the 500X5's on my (former) Rocket and my (current) RVX.
Steve Sampson introduced me to them while he was building his RV4 masterpiece "G-IKON" and I haven't even considered going back to the 500's since.*


V/R
Smokey

*Side note: Landings on soft turf, mud and gravel are vastly improved by the 380's however, handling on pavement is also superior. BTW, I have found 30 PSI to work well on most surfaces.
 
Last edited:
In one of these big tires thread around here someone mentioned the Sam James 5x500 wheel pants, but I cant find it anymore.

So anyone using James pants with the 380s? Looking for any lessons learned and maybe some pics.....I'm at the pants buying stage.

Thanks for any help.
 
Last edited:
Sam's Club

In one of these big tires thread around here someone mentioned the Sam James 5x500 wheel pants, but I cant find it anymore.

So anyone using James pants with the 380s? Looking for any lessons learned and maybe some pics.....I'm at the pants buying stage.

Thanks for any help.

Mani,
My HR2 had Sam James Pants on it when I bought it. When I converted to Rocket to the 380's, I attempted to retrofit and modify the SJ pants but they were too narrow, shallow and would have looked goofy jacked up above the bigger tires and defeat the purpose of drag reduction.
Additionally, the SJ pants are longer with no up-slope aft of the tire which reduces ground clearance on rough turf, gravel or mud, especially with the HR's high AOA when parked.

After much measuring, cutting and staring at Steve Sampson's blog, I purchased and installed the Van's Pressure Recovery pants.
They work well, are easily cut and fair around the tires nicely (see pic).

Post script: I didn't lose one knot of speed with the bigger tires and Van's pants :)
V/R
Smokey

screen shots
Van's PR Pants have plenty of room.


My HR2 with the 380's installed

PS:If you operate off rough turf or gravel, fabricate Thin chrome molysteel wheel pant brackets using the aluminum examples as a guide, much stronger.
 
Last edited:
I put 380?s on my HRII with the Sam James pants, but itwas too tight of a fit. In the end I used Desser retreads which are the same diameter as the 380s, but narrower.
 
Tough Mudder

I put 380’s on my HRII with the Sam James pants, but itwas too tight of a fit. In the end I used Desser retreads which are the same diameter as the 380s, but narrower.

Vern, glad the RT's and your James pants worked, but my whole reason (and anyone else) for installing 380's is the wider footprint on soft ground. Reason is, they work. They also improve handling on hard surfaces...
On my soft, sandy turf strip (especially after a good rain) the difference in taxiing (or sinking) and landing (and not flipping over) my RV's from 500's to the 380's was very noticeable. However, on the heavier HR2, critical.

If you venture off road in an RV or Rocket, these are the tires of choice IMHO, AK Bushwheels notwithstanding. :)
Something to consider on yours...
V/R
Smokey
 
Last edited:
Vern, glad the RT's and your James pants worked, but my whole reason (and anyone else) for installing 380's is the wider footprint on soft ground. Reason is, they work. They also improve handling on hard surfaces...
On my soft, sandy turf strip (especially after a good rain) the difference in taxiing (or sinking) and landing (and not flipping over) my RV's from 500's to the 380's was very noticeable. However, on the heavier HR2, critical.

If you venture off road in an RV or Rocket, these are the tires of choice IMHO, AK Bushwheels notwithstanding. :)
Something to consider on yours...
V/R
Smokey

That was my original purpose with the 380s as well. Unfortunately, the James pants are just too tight of a fit. Everything was fine until I reversed the tires on the rims, then they interfered.

FYI, I found that it's the wheel pants, not the tires, that are the limitation on soft fields. I have come to the conclusion that the Rocket is not a bush plane, go figure.
 
I am close to install the whell pants on my 7. I intent to land on gravel/grass strips later and understand that a larger tire (like the 380) should help in that regard. On the other side i hate to throw stuff away and the installed stock tires do look perfect. So my questions to the guys who switched to larger tires: Is it really a noticable improvement during TO/landing on grass/dirt strips?
Kay
 
I?d say it?s a noticeable improvement for soft field stuff. The grass strip I was once on was really soft and it helped a lot. If the grass you intend to visit isn?t really soft I wouldn?t bother with the 380?s. After I switched to the 380?s I developed a slight shimmy at around 30kts.
 
It was a noticeable improvement for me in rough/soft field ops. But it made the gear legs on my RV-7 shake like a paint mixer on landing starting around 30 knots, until I slowed to below 20. I tried balancing (repeatedly) and even another set of tires. The wood gear leg stiffeners offered for sale occasionally on this forum killed off about 99% of that. As is often pointed out, every RV is different. YMMV.
 
They shake because they can be up to 1/2" out of round NEW. All aircraft tires are this way, even jet tires. My neighbor who flies/maintains a Falcon 900 changed the nosegear tires on his jet and it shimmied bad even after perfectly balancing them. He chucked them on his lathe, saw they were out-of-round and Goodyear sent him a new set of tires. He checked the replacements and they were minimally out of round. No shimmy.

The out-of-roundness is from where the plies overlap. That also forces the tire to have a localized stiff spot as the overlap patch is run over which also causes shimmy/oscillation.
 
They shake because they can be up to 1/2" out of round NEW. All aircraft tires are this way, even jet tires. My neighbor who flies/maintains a Falcon 900 changed the nosegear tires on his jet and it shimmied bad even after perfectly balancing them. He chucked them on his lathe, saw they were out-of-round and Goodyear sent him a new set of tires. He checked the replacements and they were minimally out of round. No shimmy.

The out-of-roundness is from where the plies overlap. That also forces the tire to have a localized stiff spot as the overlap patch is run over which also causes shimmy/oscillation.

Boy, I'll say. I've cut a tire open just to look. The overlap was ugly, though that was a sample of 1. My current set (Desser Aero Classic) is ok. Worst one was less than 1/4" out of round after sitting inflated overnight. Last set was noticeably worse, which was why I changed them. Were the Falcon tires tubeless? Wondering if that makes a difference on construction. Or radial, but I assume that's getting exotic for an aircraft application.
 
They shake because they can be up to 1/2" out of round NEW. All aircraft tires are this way, even jet tires. My neighbor who flies/maintains a Falcon 900 changed the nosegear tires on his jet and it shimmied bad even after perfectly balancing them. He chucked them on his lathe, saw they were out-of-round and Goodyear sent him a new set of tires. He checked the replacements and they were minimally out of round. No shimmy.

The out-of-roundness is from where the plies overlap. That also forces the tire to have a localized stiff spot as the overlap patch is run over which also causes shimmy/oscillation.

I've observed this too. Surprising to me. One would think they would manufacture tires that were more round. Seems like you would stagger the ply overlaps at various clock positions around the tire.
 
Back
Top