Alternative Wheels – Stolwheelz Adapters for Using UTV Wheels on the Main Landing Gear

Source: 2026 Issue 1 Beartracks

Ryan Spencer is the owner of the 4-Place Bearhawk originally built by Phil Johnson, N125PJ. Last month he made some videos and a Facebook post about using wheels intended for ground Utility Vehicle wheels. There is also a more detailed video of the installation here. Ryan sourced adapters from https://www.stolwheelz.com/ which bolt onto the typical Cleveland/Alaska Bushwheel style brake disk. That adapter then allows for bolting on a large variety of wheels that are manufactured for side-by-side utility vehicles. The machined aluminum adapter hub uses sealed ball bearings, unlike the tapered roller bearings that we see in more traditional aviation setups. There are several tire options, some of which represent a weight savings over similarly-sized Alaskan Bushwheels. Ryan is using a wheel that allows for a bead lock so that he can reduce the tire pressure. 

The Facebook post included some discussion about the structural loading of the wheels and the axle, and some questions about whether they would be as dampening as the ABWs, with their shorter sidewalls. These were good questions with good discussions, and while these wheels might not be universally better than the most expensive ABWs in every regard, they provide a significant cost savings and for many types of operation, might prove to be good enough and a good value. As a fellow Bearhawk operator I’m grateful to Ryan for sharing his experience. Compared to even traditional airplane tires and not ABWs, today’s price at Aircraft Spruce for just a single 850×6 inner tube is $227. One 8.50×6 tire is $377. I’m interested to keep an eye on Ryan’s experience with these adapters, and I hope they will serve as a viable alternative.

Beartracks 2026 Issue 1 – Technical Q&A with Bob

Technical Q&A With Bob
Builder Matthew Brennan asks about Bob’s use of aramid composite floorboards in his latest plane, instead of aluminum. Matthew says, “Curious if the Kevlar floorboards “sound” any different than aluminum when in flight.  Is “drumming” reduced?”
Bob says, “I wear ear plugs when I fly and it’s hard to tell for sure due to all of the rest of the noise, but the composite floorboards should help dampen some of the noise.”

Builder Collin McDonald noticed some ambiguity about the hardware to use when securing the round tailwheel spring to the fuselage, and made a post on the forum to seek clarity. Should those be AN5 or AN6 bolts? 
Bob says, “We’ve used 5/16 and we’ve used 3/8 bolts there, and we’ve never had any problems with those bolts. We’ve used 5/16 on the lighter planes and 3/8 on the heavier planes.” Bob has used 5/16 bolts there on his own planes, and adds, “That stinger is hardened steel. It’s a really big job to drill those out. You don’t want to have to do that.”

Bearhawk 4-Place C-FZVW, Way Up North

Source: 2025 Q1 Beartracks
Johnny Adams sends an update about his Bearhawk C-FZVW, formerly N1914M. His home base is CYVP, Kuujjuaq, Quebec Canada. To get there from the USA, start in central Maine, head north, and travel another 750 miles or so past the border!
He bought the plane in flying condition in 2013 and imported it from the USA. In 2024 he refreshed it with a 10-year overhaul, adding landing lights, ADS-B, top overhaul, a ground adjustable Sensenich prop, polished wings, and new seat upholstery. He had the panel completely redone with new avionics, and added a fresh paint job. The covering is Poly Fiber and the total time is now 300 hours.
The engine is a parallel-valve Lycoming O-360 A4M. It has a Vetterman exhaust with double heat shroud, and he has recently removed the vacuum pump. In the winter he installs 2500 Datum electric skis. Empty weight on Goodyear 26” wheels is 1294 pounds, and with wheel skis, 1389 pounds.
The first builder was Michael Moening, who used a factory kit.

Fabricating a Replacement Tailwheel Locking Pin

Source: 2023Q3 Beartracks, Jared Yates
As we know, the Bearhawks (especially the 4-Place and Five) are heavy on the tail when parked. The main wheels sit somewhat forward, so it is very difficult to nose over with a Bearhawk, but the heavy tail is a tradeoff. One Bearhawker years ago told me that he would clean, inspect, and lube his tailwheel assembly every 50 hours. This may be appropriate depending on how the airplane is operated. I try to stick to a schedule of every year or 50 hours depending on which comes first.
Two days before we were to leave for Oshkosh, (isn’t it always?) I noticed that our tailwheel was not locking and unlocking very freely. It turns out that an insect had made a nest inside the tube where the locking pin resides. There was just enough room in the area occupied by the spring, but once we started steering, the nest was broken up and the dirt dispersed in that tube. It didn’t take long for the loose dirt to jam the pin in the locked position. This isn’t a big problem to fix, but it required removing the hex-head screw that connects the locking pin to the bushing that rides on the unlocking cam. When I went to remove it, that little screw snapped off. You can see the results in the lower part of the picture below.

This was not optimal. I knew that Eric Newton at Bearhawk Tailwheels would be happy to sell me a replacement locking pin and screw, but that would take a few days. I used to keep a spare of each, but hadn’t thought to resupply those spares since the fire. If we were going to fly to Oshkosh, I’d have to make new ones. I started with a long grade 5 zinc plated bolt from the hardware store, which had a nice unthreaded shank section. The first step was to drill a new hole to receive the screw. With a milling machine this would be an easy step, but with hand alignment it took two tries to get an acceptably-located hole. The hole needs to be centered, and I found that grinding a tiny flat spot gave the center punch, and subsequent drill bit, a little landing pad. Not having anything like the original screw, I used an AN-3 bolt, so I tapped the hole for fine threads. Once the hole was threaded, I cut the new pin to length and deburred the edges. The next problem was the bushing. I found that a stack of three AN washers looked just about right, and worked great. I added just a little thread locker to the AN bolt, and worked some grease in to keep the pin moving freely. Once it was all back together, I packed the locking pin tubing with grease so that the next insect wouldn’t find it to be an attractive housing vacancy. While it was an inconvenience to have to make the new parts on short notice, I’m thankful that we found the problem at home and not while trying to maneuver in the campground or at a fuel stop while on the trip.

Ken Frahm’s Bearhawk 4-Place – N907KM

Source: 2023 Q3 Beartracks, Ken Frahm
I’ve never owned an airplane before. I’ve wanted to build one since I found out it was possible in college. What I wanted to build changed shape over the years as I figured out what kind of life I wanted to live. Then after a moose hunting trip in 2016 I realized I needed something rugged, that could carry a load. Then, my wife convinced me that we were going to have children and they would be coming with us… so a rugged plane with four seats plus a load and enough range to get around our massive state without many fuel stops? Well, there is only one option at that point.
Bearhawk on Skis
When I realized that the Bearhawk existed I immediately called Mark Goldberg to ask about it, and in 2018 I saw him in Oshkosh, went for a test ride with my wife in Texas shortly thereafter, and ordered a kit when we were blown away by the performance.
Four years later the kids are here and the Bearhawk is done. All of the attributes that sold me on a Bearhawk have already proven their worth. I haven’t gotten everything as dialed in as I would like (hence the unpainted cowling) but it is already a workhorse. Our last trip was just about the perfect example of the Bearhawk’s mission as a family hauler. My family of four flew to a remote cabin 2.5 hours from home, off the road system. We spent the night and came back the next day, spurred on by unforecast worsening weather – typical Alaska. As we picked our way through the deteriorating scud, I was picking out gravel bars and flat spots we could put down on if necessary. Due to recent experience I knew we could land and takeoff on numerous strips bars and flat spots that most planes with our load would not have done safely. It was quite a stress reducer.

Ken adds: This Fall an awesome Moose hunt a la Bearhawk ensued. Pic above is my Buddy Nick who shot the moose. I flew home over the Alaska Range with myself, my survival kit, and the whole harvestable portion of a moose (about 500 lbs including the 48” rack!) I’m becoming more fond of this plane every trip.
Editor’s note: We’re pretty sure that Ken’s is the first Bearhawk to use skis on its first flight.

Andrew Hamilton’s Bearhawk 4-Place 5Y-CFX

Here are a some pictures of my Bearhawk 4-Place. I bought her about 2 years ago while I was doing my PPL. After completing that I trained on this plane. What a wild thing compared to my school plane, which was a very tired C172, which I did not like at first but actually became very fond of the old girl.
After that, onto this girl. I love it. She has an IO 390x engine with API fuel injection. Rated at 210hp. 4 fuel tanks with usable 69
gallons which gives me amazing endurance. Definitely needed in Kenya. It has a Dynon Skyview system with autopilot. Performs brilliantly even with 3 adults, full fuel and loads of camping gear. I operate out of a dirt strip at 6250ft MSL and most days DA is about 2000ft above
that. I’m still a very junior pilot and so fly very conservatively as I learn her ways. Best regards and looking forward to meeting more Bearhawk flyers and learning more about the planes.

The airplane was originally flown in the United States and subsequently imported to Africa.

New Brake Master Cylinders Designed by Bob

Summer 2023 Update:
Do not operate these cylinders if you are running two pairs (pilot and copilot, etc). More information:
https://bearhawkforums.com/forum/safety/84366-safety-update-regarding-bob-s-brake-master-cylinders-in-dual-brake-applications

Source: 2022 Q1 Beartracks
For years, Bearhawk builders used long-shaft Gerdes master cylinders (A-110-10). They were abundant and relatively cheap. Then when those got scarce around 2006 or so, folks started using a short shaft version (A-110-4), with a longer machined fork threaded onto the end. The top end forks are a special Bearhawk part that Mark keeps in stock.
Lately, even the shorter shaft Gerdes cylinders have been harder to get. Grove and Matco have cylinders in the homebuilt price range, though they are still almost double the Gerdes price. The Grove and Matco cylinders use internal valves, but Bob had some ideas from his days as a pneumatic engineer for how to make the cylinders work with o-rings only, and no valves. The result is this new alternative.
Notice that the new cylinders are machined aluminum, vs the Gerdes which were cast. Either gets the job done, but the new ones sure are pretty. The center shaft on the Gerdes is made from a very soft aluminum that is easy to bend while handling. On our blue Bearhawk I had to straighten a bent one, and one of the cylinders I removed from our new-to-us 303AP was also very bent. These new cylinders use a stainless steel center shaft which is much more durable.
Like the Gerdes, the new cylinder ports use 1/8 NPT pipe thread, which allows for installation of an AN822-4D (90-degree), AN823-4D (45-degree), or AN816 (straight) fittings to connect to hoses. Also like the Gerdes, the threads on the shaft are 5/16×24 (fine thread) which means it’s easy to find jam nuts made from aluminum, cad-plated steel, or stainless as you prefer. Bearhawk Aircraft has the machined forks that go on the end. Both the forks and the cylinders have 3/16″ holes for bolts or clevis pins, where the cylinders attach to the airframe and the forks attach to the brake pedals.
If you replace a short-shaft Gerdes cylinder with one of the new ones, Bob’s design will be a drop-in replacement. If you’ll be replacing the older long-shaft cylinders, you’ll also need a set of the longer forks but can reuse your old jam nut. Bob prefers aluminum nuts, because, as you would expect, they are lighter. They are serving a very minor strength role here, and primarily just keep the shaft from rotating and to keep the threads from wearing. The top cap is retained by a snap ring, so like the Gerdes, these are field-rebuildable with off-the-shelf o-rings.
There is an important bit of guidance if you’ll be taking apart the cylinders. The inside of the threads near the top port are sharp, and can damage the o-rings during assembly or disassembly. Save one of the orange plastic plugs that ship with the cylinders, or procure
something similar. Before removing the top cap, insert the plug into the top port and press inward sufficiently to relieve the o-ring from being damaged on the sharp edge as the o-ring passes by the port.
If you are interested in a set, send an email to Mark Goldberg at Bearhawk Aircraft. Initial pricing is $165 per pair. The first batch of 100 has been distributed and the next batch is already in production.






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