HOW TO: Stone Stomper Gravel Guard.

[John E Davies]

 

EDIT 03/27/18. Added text to first four parts. JD

 

EDIT 03/29/18: Added road test with pics, see the below post with this date.

 

This is going to be a super long thread, I have a lot of pics and text to work on. For now I am going to get my order document (with measurements) and the install pics loaded. I am going to be away from home for a week, but maybe I can work on getting the "How To" text entered also. While I am doing that I will insert the pics into the text as needed.

 

The job is finished but I have not yet towed with it. A road report will follow somewhere, somewhen. Please look at this doc for ordering and measuring info:

 

DAVIES-Stone-Stomper-NOTES-MEASUREMENTS-013118-EDITED-FOR-POSTING.docx

 

PART 1

 

EDIT 03/27/18

 

SUMMARY AND BASIC DESCRIPTION

 

This is frustrating, a very long, 20 minute edit vanished. Completely. I should know better than to write online and not back stuff up. I hate the forum software. It is a measure of how much I like you guys that I will rebuild that post.

 

Stone Stomper is an Australian manufacturer that has been making these guards for many years, they are extensively engineered and tested over tens of thousands of miles of rough tracks to perform well under harsh conditions. The owners who use them really like the product. There are plenty of reviews and videos, so I will just send you to their site for now: …. http://stonestomper.com.au

 

At this time they have virtually zero market exposure in the USA, though they have shipped them here. I really hope that they will consider opening a small USA distributor/ manufacturer so that the issues with exchange rate, high International; shipping and possible warranty claims would be more palatable. I don’t think that will happen unless we as foreign buyers ask hard.

 

 

At the end of this thread are “unboxing” and “initial layout” pics. I will add some comments there.

 

The basic premise is that an underslung heavy mesh fabric that rides underneath the entire A Frame structure stops rocks from getting past, stopping paint erosion, gravel rash and damage to the trailer body and the tow vehicle rear hatch and glass. The design offers way, way more coverage than your typical RV gravel flaps. The mesh is suspended in front with 6 long shock cords connected to a custom crossbar, and is anchored to the ball mount with a seventh short one. During maneuvering, the inside part folds in on itself and the cords stretch on the outside part. Normally the mesh just “floats” on the six main cords. On longer installations like the Ollie, there is a central support bar that helps to hold up the fabric in turns and also has other functions. Short coupled camp/ utility trailers don’t have or need the support bar.

 

The gray fabric up front is light and fairly flexible, and it is intended to sail up to seal the gap between the TV and the front of the fabric when moving. When not being used you can roll it up and slide on optional sleeves made in a matching material.

 

The challenge on the Oliver is that there is no easy way to attach the supplied rear anchors to the hull. One could drill into the fiberglass but that would be ugly and it would not get the rear of the fabric positioned in the best place. I elected to build aluminum mount bars that extend out to provide complete coverage of the fiberglass, and also to give me a place to mount additional sheet neoprene guards to protect the steps, underneath puddle lights and the black tank rinse fitting.

 

 

The center support bar was a challenge. The instructions call for a simple one piece section of 1 inch ID plastic conduit, lying on top of the frame and slid into the two sleeves. That seemed primitive and again, I did not want to deal with a really long pipe, so I designed a system where two small pipes slide into a fixed center alloy tube. Shock cord comes down from the tubes and allows me some adjustment of the support tension. The reason for plastic supports is two fold: they are strong, cheap, UV resistant, flexible and the material can be found at any hardware store for $0.40 per foot. And if they take a hit, or I somehow jackknife into them, they will hopefully bend or break before damaging the TV. Being short allows me to carry pre-cut spare sections easily, since they are less than three feet long.

 

 

At Stone Stomper’s suggestion, I added a short length of chock cord just in front of the doghouse, with plastic hooks slid under the rear or the innermost SS shock cords. This helps support the fabric and keep it from drooping down under the center of the frame.

 

MORE TO FOLLOW.

 

John Davies

 

Spokane WA

[John E Davies]

PART 2

 

EDIT 03/27/18

 

DETAILS OF FINAL INSTALLATION

 

Detail of the front, showing how the fabric is cut out to clear the Anderson mount and chains. The opening is reinforced with heavy fabric, and there is another heavy chafe patch underneath the tongue jack, the chains and rear brackets. The small front (central) bungee anchors everything to the hitch and holds the two corners of the mesh cutout together.

 

 

Detail of the right rear attach design. The SS bracket is the bright plated steel bar that the stainless shackle is connected to. Note how well the steps are protected by the extra flap. In this shot the SS is in the “Parked” mode, folded back underneath the tongue and the right front SS bungee is clipped to the rear shackle. This keeps everything off the ground and also away from the jack shaft and foot.

 

 

Detail showing the front left three cords unclipped from the bar, the center one remains attached. The clips are quick and easy to manipulate. In this mode you might be accessing the rear hatch or the bed of the TV. Also, this allows the fabric to droop and you can get easy access to the rear Anderson nuts under the tongue.

 

 

 

 

This shows the view under the tongue when “Parked”. The fabric clears the jack and support blocks and stays clear of the ground.

 

 

Finally, this shows the left center support bar removed and lying down on the fabric. This lets the fabric lie on the ground and gives the best access under the A frame, short of actually removing it entirely.

 

 

MORE TO COME.

 

John Davies

 

Spokane WA

[John E Davies]

PART 3

 

EDIT 03/27/18

 

FRONT BAR DETAILS

 

The steel bar on my SS is 2 meters end to end and it does clear my storage basket at full “jackknife”, a position I would never achieve. My rear bumper and quarter panel would hit first.

 

 

Views of the front bar and hitch connected to the Land Cruiser. The sleeves are installed and they are longer than the bar itself, which extends out just past the width of the sidewalls of the rear tires. For more on this, refer to the pics at the end of the thread.

 

 

MORE TO COME.

 

John Davies

 

Spokane WA

[John E Davies]

PART 4

 

EDIT 03/27/18

 

CENTER SUPPORT BAR

 

The bar mount is made of 6062T6 aluminum tubing, 1 ¼ ID x 1/8 wall (Schedule 40). I had to cut and grind clearance pockets so that I could nest it in between the basket and the jack. It is a snug fit (needed to be tapped into place with a mallet) and is secured with four great big nylon cable ties. It is rock solid but quick to remove if needed, to remove the jack for example. I did not want to weld or drill into the basket. If you have access to a GOOD welder, a permanent welded join would be better overall. But you would have to remove the basket for jack access.

 

 

Detail showing the two plastic inserts that go in the mesh sleeves (9.25”) and the two main support tubes (36.25”). They are ground to clear the basket frame, I drilled then for retaining pins but I do not think they will be needed.

 

 

MORE TO COME.

 

John Davies

 

Spokane WA

[John E Davies]

More 4

[John E Davies]

More 5

[John E Davies]

More 6

[John E Davies]

More 7

[John E Davies]

More 8 - Unboxing.

 

This is the last section, feel free to comment but I may not be able to respond for a while.

 

John Davies

 

Spokane WA

[Corcomi]

Quite a job... The trip report will be crucial to see how it performs. Thanks for sharing

[mossemi]

Once again, your contributions are above and beyond my expectations.  The improvements to your Ollie are very well thought out and the detail you share with the forum is appreciated.  Looking forward to your road report.

[Overland]

Thanks for this - really appreciate it.  A few questions:

 

I thought that the cross bar that attaches to the truck was hinged with a spring so that it bends when turning.  I guess I was wrong or they changed the design, since it looks like it's depending on bungees stretching when you turn.  Maybe I was thinking about a different product.  Anyway, how does it keep from bunching up the fabric when you straighten up again, or what's keeping the wind from pushing the fabric back on the bungees?  Is there another bungee that attaches from the truck to the fabric to pull it back?

 

Are you worried about catching on anything with the front crossbar?  I don't think for us that I'd want it to extend past the truck.

 

The middle cross bar looks like it will really limit turning while backing up.  In fact, even while going forward my truck bumper almost touches the fiberglass in a full lock.  How feasible do you think it would be to move that bar back so it clears the truck in a turn, or eliminate it entirely?  I suppose it wouldn't be hard to make a hinged support with a bungee that would pull it back in a turn - you could make it out of 80/20 and tie the bungee back to the LP box.  I think 80/20 might be a good alternate for the whole project - it would look nice and then you'd be all aluminum.

 

Speaking of backing up, it seems like there will be a lot of material on the ground, and I wonder if there's any chance of it getting caught under the rear tires, esp. if you have a vehicle with little rear overhang?

 

If your flaps don't uncurl you can always add a metal strip to the bottom.

 

How difficult will it be to remove, or to unhitch with it in place?  Is it just the four clips each side?  Have you thought about how you're going to deal with the fabric when camped, to keep it out of the mud or whatever?

 

You mentioned needing to detach it entirely if it's super muddy - would you have to crawl under the trailer to detach the rear?  That's not something I'd love doing in the middle of a muddy road, so I'm thinking it wouldn't happen.  I wonder if the rear cross bar could be made so that it only uses one clip each side.

 

What's the black pipe in the second to the last set?

 

How do you feel about the width now that you have it installed?  Would you have gone wider, to protect the trailer more, or narrower so it didn't extend past the Cruiser?  I wonder if they'd make a tapered version that got wider towards the trailer, or if that would make any sense.

 

Could you share the dimensions you gave Stone Stomper when ordering?

 

 

[John E Davies]

A lot of your questions will be answered when I write this up, so I would rather not get too much into specifics yet. I am travelling at the moment. I will make a few comments.

 

Thanks for this – really appreciate it. A few questions: I thought that the cross bar that attaches to the truck was hinged with a spring so that it bends when turning. I guess I was wrong or they changed the design, since it looks like it’s depending on bungees stretching when you turn. Maybe I was thinking about a different product.

 

Nope, no hinged bar,  the system works with bungees and always has.

 

Anyway, how does it keep from bunching up the fabric when you straighten up again, or what’s keeping the wind from pushing the fabric back on the bungees? Is there another bungee that attaches from the truck to the fabric to pull it back?

 

The front of the fabric is anchored to the ball mount, the rest of the mesh “floats”on the three bungees on each side, and I assume it shifts around some. I would like to video it while moving. The six bungees are tensioned, to support the weight.

 

Are you worried about catching on anything with the front crossbar? I don’t think for us that I’d want it to extend past the truck. The middle cross bar looks like it will really limit turning while backing up. In fact, even while going forward my truck bumper almost touches the fiberglass in a full lock. How feasible do you think it would be to move that bar back so it clears the truck in a turn, or eliminate it entirely?

 

I wanted the front bar wider than the track, the distance between the sidewalls right to left. This is to maximize coverage of gravel flying up from the back tires. I am not super concerned with whacking it. (But I did order an extra bar set, just in case.) I don’t think the middle bar will contact my truck. In a hard forward turn, full lock, I have plenty of clearance between bumper and cargo basket. When reversing hard, I will need to be more cautious.

 

If your truck nearly contacts the hull in a normal turn, you need to extend your ball mount and/ or your tongue. Preferably the latter to reduce tongue weight....

 

The reason they specify schedule 40 plastic conduit is for flex, UV resistance and cheap replacement cost. The bar will move a lot or even break if smashed into something. Like your truck...

 

I suppose it wouldn’t be hard to make a hinged support with a bungee that would pull it back in a turn – you could make it out of 80/20 and tie the bungee back to the LP box. I think 80/20 might be a good alternate for the whole project – it would look nice and then you’d be all aluminum.

 

Go for it, I used Stone Stomper guidelines. The only thing I changed was using two short pieces instead of a single long one. I do plan to make extras to carry. The material is only 40 cents per foot and can be found literally anywhere.

 

Speaking of backing up, it seems like there will be a lot of material on the ground, and I wonder if there’s any chance of it getting caught under the rear tires, esp. if you have a vehicle with little rear overhang? If your flaps don’t uncurl you can always add a metal strip to the bottom. How difficult will it be to remove, or to unhitch with it in place? Is it just the four clips each side? Have you thought about how you’re going to deal with the fabric when camped, to keep it out of the mud or whatever? You mentioned needing to detach it entirely if it’s super muddy – would you have to crawl under the trailer to detach the rear? That’s not something I’d love doing in the middle of a muddy road, so I’m thinking it wouldn’t happen. I wonder if the rear cross bar could be made so that it only uses one clip each side. What’s the black pipe in the second to the last set? How do you feel about the width now that you have it installed? Would you have gone wider, to protect the trailer more, or narrower so it didn’t extend past the Cruiser? I wonder if they’d make a tapered version that got wider towards the trailer, or if that would make any sense. Could you share the dimensions you gave Stone Stomper when ordering?

 

I give up for now, most of this will be described fully later.

 

I did fix the attachment for the measuring and ordering doc, you should now be able to download it. It will answer some of your questions. See the first post.

 

Hang in there...

 

John Davies

 

Spokane WA

[John E Davies]

BUMP TO THREAD, First 4 sections have text added.

[John E Davies]

Road test report.

 

I took the trailer out for a 30 mile tow on paved roads. It works fine, with a couple of cautions.

 

 

When turning hard at full lock, going forward, the shock cords are at full stretch on the outside and the cords and fabric sag on the inside.

 

 

I have to admit that the last pic bothers me, it seems like inadequate room for maneuvering on uneven terrain. Nothing hits, but it is darned close. When backing hard, the plastic center support bar will contact the rear corner of the truck, and the steel front bar will go under the basket. On uneven ground, the steel bar could run into the basket.

 

I have contacted Anderson to see if they will build me an extended "rack" for my hitch. I asked for an extra 4 inches reach. I think that will open things up here enough and make me worry less. Plus it will get the ball coupler out from under my open tailgate.

 

I could remove the basket entirely, but that would be a last resort, since I need it for gas and water cans.

 

Here is a view underneath, right side, showing the fabric fully folded during a normal full lock front turn. It clears the ground by about 6 inches.

 

 

Here is a look at the left side, at full lock turning left, where the exhaust pipe is located:

 

 

The Land Cruiser already has a fully turned down tip. If your tow vehicle has exhaust(s) that exit more out the back, you will have to install turn down tips or risk burning a hole in the fabric. I need to remember to not park long term at full left lock while the engine is running ;)

 

 

So, for a first run I am satisfied, I need to get more room and the extended Anderson shank is my best option. Moving the front SS bar forward 4 inches on the shank will really help. Extending the tongue would also work, and I may need to go down that road eventually, but is a much more involved operation. Regardless of how I get additional clearance, it is easy to shift the position of the fabric forward, using extra carabiners or even short lengths of crimped steel cable. If there is a gap up front, the gray flaps will stop any rocks from passing through it.

 

John Davies

 

Spokane WA

[John E Davies]

Update..... We towed Mouse for 3000 miles over two weeks and for the most part the system works great.

 

We encountered a few stretches of road maintenance - chip-sealing - in Colorado. It was nice to know that the trailer was fully protected for those 40 miles, even at reduced speeds. The underside and rear bumper stayed free of tarry rocks. I saw a few nice RVs and sports cars on those stretches and I bet their owners were a little bothered.

 

There was a complete failure of one of the center support bars. I found it when we pulled off at a rest stop. The bar had parted cleanly where it exits the support tube, and was lying on top of the fabric. There was no other damage.I don't know how long it was like that, but it was no more than 50 miles. I make a habit of looking things over every time I exit the Land Cruiser.

 

I removed the entire Stone Stomper until I could get a fix made. That took a couple of minutes. The trailer looked naked and vulnerable without it.

 

I had time at Colorado National Monument, so I found some heavier walled Schedule 80 PVC conduit at Home Depot. The walls are twice as thick and should be more resistant to fracturing, while still flexing... I had to visit the local Harbor Freight for a saw and vice, so I could cut the pipe and also trim a flat  section longitudinally for it to fit into the tube. I made two new ones and kept the remaining old one as a spare.

 

 

For less than $20 this little 2 axis swivel vice is a great tool, that attaches very firmly to the cargo basket. It is heavy though...

 

 

https://www.harborfreight.com/2-1-2-half-inch-table-swivel-vise-97160.html

 

Later I found that the short tubes that go through the fabric in two places were wearing the fabric. They were sliding into the fabric and needed a way to keep them located.

 

 

I made new tubes by gluing them together with a straight coupling, then cut them apart through the center of the coupling, to provide a lip on the problem end:

 

 

 

I also made extra spare long support tubes to carry on trips, so I do not have to kneel in the dirt in 100 degree weather. I cut the flat sections using a table saw and it was very fast and neat.

 

I don't think I will add further comments to the previous sections I left empty. If somebody has a question, fire away. The installation pics are pretty self explanatory.

 

John Davies

 

Spokane WA

 

 

[John E Davies]

Update, I made some changes when I relocated the tray to the back. This shows how the front corner can be clipped back for truck access:

This shows the new aluminum support structure, welded by a local shop. I added pins with clips to retain the plastic support bars, which give anchor points for the fabric. Plus I made new lower support bars with no collars (straight across) and I added stand-off tubes (1/2" white PEX) to prevent the fabric from "walking" out to the side during tight turns. The photo immediately above this post shows the old setup, which did not work well.

This will be my fifth camping season, the system has been excellent, no issues except the original support bars were too weak (thin Schedule 40, replaced with Schedule 80), and the left SS flap continues to get scorched by the exhaust when turning VERY hard to the left, in spite of the factory down-turned exhaust tip. I try to avoid remaining in that position more than momentarily. The front of the trailer remains showroom new looking, and the rear of the truck has no rock chip damage. I do still have to remove dried bug carcasses, but they are confined to the very edges of the hull and the top third of the front. I still highly recommend this mod. I try not to tow in hard rain, but if it does happen, the back window of the Land Cruiser stays almost completely dry! And in normal conditions on gravel roads, it stays about 75% dust free.

John Daviers

Spokane WA

Edited March 6, 2021 by John E Davies

[Frank C]

Wow! Thanks for the detailed project report.   I don’t plan on doing anything like this (yet) but I enjoy reading about your modifications, and the thinking, materials and fabrication that goes into it.    We tow pretty much on all paved roads.  The only place we encounter gravel is usually on the roads inside the KOA campgrounds, and we’re driving very slowly (5mph) at that point.   I’ve had the Rocktamer flap system and after 2 years of towing, no stone chips at all on the Ollie, or the back bumper of the truck either, but again, we are on paved roads pretty much all the time.  As we explore more, maybe getting to more of the unimproved road areas, I’ll keep your design ideas in mind. 

Edited March 6, 2021 by FrankC

[John E Davies]

Thanks for the kind words FrankC, I see your Rock Tamers are rigged correctly - they should fly back at an angle, not straight up and down, so they deflect rocks down onto the pavement instead of back onto your rear tailgate and bumper. I had Rock Tamers before this mod, and they are OK, but they do not provide nearly enough protection for around here.... this part of the country has a gazillion unpaved roads, Spokane County alone has 4000 miles of them.

FYI, an easy mod to help your RTs work better is to add strips of heavy mudflap material on TOP of the bars, trimmed so that they press against the chrome bumper. They will stop the few stones that do flip back up in that direction, and the rubber won't damage the finish. Plus they will dampen any side to side rocking of the arms.

John Davies

Spokane WA

Edited March 6, 2021 by John E Davies

[Geronimo John]

@Frank 😄

I note you Rock Tamers are on a Ford Super Duty and are mounted such that the arms are up (Increasing clearance of the flaps from the ground.   Since a Super Duty sits "Taller in the Saddle" than my 2019 F-150, I am concerned that the Rock Tamers would be dragging the ground.  Your thoughts?

Thanks

GJ

[Frank C]

19 minutes ago, Geronimo John said:

@Frank 😄

I note you Rock Tamers are on a Ford Super Duty and are mounted such that the arms are up (Increasing clearance of the flaps from the ground.   Since a Super Duty sits "Taller in the Saddle" than my 2019 F-150, I am concerned that the Rock Tamers would be dragging the ground.  Your thoughts?

Thanks

GJ

The rubber flaps have molded cut lines and pilot hole locations to trim the top of them as needed to the correct length and punch through the holes to mount to the support arms at the length you’ll need.  The top edge get trimmed and new holes punched since the Rocktamers have the metal logo plate at the bottom.   The as-is length just happened to be perfect for my F-250. 

Edited March 6, 2021 by FrankC

[topgun2]

GJ - 

From your question to FrankC I'm guessing that you do not have the Rock Tamers (yet).  If that is the case you will note when you get them that you can cut them down to size via "guide" marks that are already in them.  However, Be a bit careful to not cut them too short the first time - you can always go back and trim another inch or so off if you find them to be too long.  This is what I did for my F-150.

Bill

[Geronimo John]

2 minutes ago, FrankC said:

The rubber flaps have molded cut lines and pilot hole locations to trim the top of them as needed to the correct length and punch through the holes to mount to the support arms at the length you’ll need.  The as-is length just happened to be perfect for my F-250. 

PERFECT.  Thank you!

[John E Davies]

FYI, one disadvantage with Rock Tamers is that they do need to be close to the ground to work correctly, but when you are traveling briskly on a gravel road, they can drag when you encounter a dip, and shoot up a rooster tail of gravel onto your trailer. This is a non-issue with a Stone Stomper.

John Davies

Spokane WA

 

[SeaDawg]

1 hour ago, topgun2 said:

GJ - 

From your question to FrankC I'm guessing that you do not have the Rock Tamers (yet).  If that is the case you will note when you get them that you can cut them down to size via "guide" marks that are already in them.  However, Be a bit careful to not cut them too short the first time - you can always go back and trim another inch or so off if you find them to be too long.  This is what I did for my F-150.

Bill

And, if you change tow vehicles, you can purchase replacement flaps. Actually,  most of the bits and pieces for rock tamers can be purchased online.

We've used Rock tamers for over a decade.

We don't travel enough gravel miles to justify John's stone stomper. That's the ultimate, though.