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Wheel pants clearance question

mulde35d

mulde35d

Well Known Member
The instructions call for a 1-1/4” spacer on top of the wheels to be adjusted based upon wheel diameter and type. My question is how little clearance is acceptable?

I am using Wilkerson retreads and the 1-1/4” is way too much. 3/4” is better, but I would like to go down to 1/2”. Thoughts?

1st photo is 1-1/4” spacer

2nd photo is 3/4” spacer

Lots of trimming left to do I know, but want to make sure I don’t take it too low.

IMG_4571.jpegIMG_4574.jpeg
 
If you ever decide to run the desser retreads, you need the 1 1/4” as they are larger. If you use the 3/4” spacer you cannot use retreads that are larger than standard size. From what I understand, the Wilkerson tires are the size of a standard tire.
 
With the Wilkerson retreads inflated to 40psi, it has a circumference of 54-1/4” which means a 17-1/4”ish diameter.

Anyone have a set of Desser retreads laying around and care to provide the circumference or diameter. Circumference is easier to measure precisely but C = 2 x R x Pie (just so nobody has to lookup the equation like I did).
 
In addition to the retreads, the 3/4 inch may prevent the average wheel chocks from being used. I hate when some "well intended" line boy tries to kick the chocks under the skirts! But they exist.
 
N40ES said:
In addition to the retreads, the 3/4 inch may prevent the average wheel chocks from being used. I hate when some "well intended" line boy tries to kick the chocks under the skirts! But they exist.
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It really doesn’t feel like the 3/4” is that low to the ground. Even 3/4” still provides roughly 3” of clearance to the ground from the bottom of the wheel pant
 
Remember, that at 60 knots, those tires are going to expand a bit. How much is an unknown.
 
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RV8Squaz said:
Remember, that at 60 knots, those tires are going to expand a bit. How much is an unknown.
Click to expand...
On hot asphalt they expand and distort enough that there should be 3/4" clearance on the aft end of the opening. When the tires distort on landing they do not have time to recover their shape before contacting the aft edge of the opening.
 
Might think about flat tire clearance before sitting it below 1 in. Might try letting the air out with the clearance block in place to see if a flat tire would ruin your day?
 
I used Wilkerson retreads as well and went with 3/4”. Where you will find issues is on the nose wheel. I couldn’t get the clearance from the pant to the upper fairing and actually had to mold a slight divot into the rear of the front pant right where the nose gear makes the 90 to the vertical Into the pant. Hope that makes sense. If not PM me for pics.

keith
 
Webb said:
What’s the logic for wanting to shrink the space down to 1/2”?
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Main thing is that with 1-1/4” spacer the width of the fairing won’t even fit over the axle nut and mounting flange without distortion since the fairing is so high. The 3/4” spacer just fits, but still feels high off the ground to me. I am thinking I will stick with 3/4” and move forward at the moment.
 
retreads have a larger diameter than new tires. When deciding on the height,, consider the difference in height between retreads and new tires. if you change to new tires, your wheel pants could end up being too low with new tires vs retreads.
 
I ran a set of pants nearly 1000 hours with clearance above the tire at a fuzz more than 1/2". However, I also ran 50 psi, re-inflating at 45, using the cheap Desser kit tires...point being diameter probably didn't grow much at speed.

Remember, when laying out the nutplate positions, do not place any of them above the tread. It's a common error. The screw(s) will often cut an extra groove in the tire.

Leg and Pant.jpg
 
I started out with 1" with the standard kit 500 x 5 tires. Then I switched to 380 x 150 - 5.00 tires, and the gap is barely 1/2". No problems. Gosh, I have to check, I might have a screw on top too...I don't remember if I thought about that at the time or not - good reminder from Dan.
 
I was going to comment about the back end of the fairing and fitting a mini-chock under a tailragger, cuz the back end tilts down.
If this is going on a -10, then no matter.
OP's question does effect the amount of tire sticking out the bottom in the air. That 1/2" difference is sure to cost a MPH or two. :giggle:
 
DanH said:
Remember, when laying out the nutplate positions, do not place any of them above the tread. It's a common error. The screw(s) will often cut an extra groove in the tire.
Click to expand...

That's why they make AN507/AN509-8R6 screws :)
 
I think these Wilkerson retreads (6x6.00 8ply) are just big. My biggest concern now is that with 3/4” spacer on top, my Matco brake actuators are right up against the bottom of the fairing.

If someone has a diameter or circumference of a desser retread I would be really interested in that number.

And no, it’s not about too much tire sticking out the bottom, it’s about fitting everything inside the fairing and not having contact with the tire.

IMG_4582.jpegIMG_4579.jpeg
 
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mulde35d said:
I think these Wilkerson retreads (6x6.00 8ply) are just big. My biggest concern now is that with 3/4” spacer on top, my Matco brake actuators are right up against the bottom of the fairing.

If someone has a diameter or circumference of a desser retread I would be really interested in that number.

And no, it’s not about too much tire sticking out the bottom, it’s about fitting everything inside the fairing and not having contact with the tire.

View attachment 71622View attachment 71623
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It is possible to modify the fairing by creating a blister so as to clear the brakes. scsmith posted about this when fitting oversize tires to an RV-8.

Post in thread 'Improving rough-field landings in an RV-8' https://vansairforce.net/threads/improving-rough-field-landings-in-an-rv-8.204371/post-1593671
 
PaulvS said:
It is possible to modify the fairing by creating a blister so as to clear the brakes. scsmith posted about this when fitting oversize tires to an RV-8.
Click to expand...
Or accept some brake cooling. 380-150-5 tire, like Steve's, but no blister.

Caliper Cutout.jpg
 
What about cutting the axle nut to shorten it. Then drill and tap It. A threaded rod (aka, long screw with head cut off) and some red Loctite.
 
You probably realize this, but Just to be clear, you have a regular 6.00-6 tire there, 17” diameter. Standard on the RV-10 is the 15x6.00-6 tire, 15”dia.


mulde35d said:
The instructions call for a 1-1/4” spacer on top of the wheels to be adjusted based upon wheel diameter and type. My question is how little clearance is acceptable?

I am using Wilkerson retreads and the 1-1/4” is way too much. 3/4” is better, but I would like to go down to 1/2”. Thoughts?

1st photo is 1-1/4” spacer

2nd photo is 3/4” space
Click to expand...
 
mulde35d said:
The instructions call for a 1-1/4” spacer on top of the wheels to be adjusted based upon wheel diameter and type. My question is how little clearance is acceptable?

I am using Wilkerson retreads and the 1-1/4” is way too much. 3/4” is better, but I would like to go down to 1/2”. Thoughts?

1st photo is 1-1/4” spacer

2nd photo is 3/4” spacer

Lots of trimming left to do I know, but want to make sure I don’t take it too low.

View attachment 71537View attachment 71538
Click to expand...
3/4” is too close. You’ll destroy the pants with a bad landing, low air or flat.
 
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