Build Thread AC's RC Midget Special

[ahr43]

Hey guys and gals. Latest purchase to land on the ahr43 speed shop surface plate. Bought off Ebay as a Traxxas Bandit Custom Dirt Oval Conversion 2WD 1/10 roller slider.

Sold as a sprint car conversion, for purposes of my RC grass track, thinking I'll repurpose it as a LWB RC midget. It comes with 2.2 buggy wheels. Rest of my grass trackers all run 2.2/3.0 SCT wheels and tires. This build will be enough different to class it as a midget.

Looks like a lot of 3D printing went into this conversion. Roll cage shows it has been on its lid, so apparently its somewhat survivable.

More to come. Cheers. -AC

 

[Lucifur10]

That's so cool! I'm a huge fan of anything open wheel sprint car.

 

[CertifiedMike]

Hey guys and gals. Latest purchase to land on the ahr43 speed shop surface plate. Bought off Ebay as a Traxxas Bandit Custom Dirt Oval Conversion 2WD 1/10 roller slider.

Sold as a sprint car conversion, for purposes of my RC grass track, thinking I'll repurpose it as a LWB RC midget. It comes with 2.2 buggy wheels. Rest of my grass trackers all run 2.2/3.0 SCT wheels and tires. This build will be enough different to class it as a midget.

Looks like a lot of 3D printing went into this conversion. Roll cage shows it has been on its lid, so apparently its somewhat survivable.

More to come. Cheers. -AC

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Looks like a fun new project!!! Congrats!!!

 

[9x19]

Interesting conversion, looking forward to your progress.

 

[ahr43]

Interesting conversion, looking forward to your progress.

Thanks, niner. Pre-entered it in the May Champ Car 2 x 16-lapper. Will run it just as it came out of the box. Worn dirt oval tires and the oh-my-gosh dirt oval wedge it has. Got a brush motor set up in the basher stash that'll get 'er around the track. Ordered a steering servo this morning.

Already have half a page of brain storming notes on what mods and changes she may get for the grass track tri-oval. Let that percolate on the back burner for a while and see what shakes out.

Gearing it came with is 76T spur with a 24T pinion in a baggie. Tall ratio at 3.16. Don't think it can pull that on my track. Pre-event test run will tell. -AC

 

[ahr43]

Got more done than intended today. Tight fit getting the electronics in. HW 80A brushed ESC and Spektrum SR215 receiver in the well. Novak 'glitch buster' up topside. And yeah, body and cage still fits. Barely.

At issue are the stand-up battery leads off the 2s x 5000. Close to a rub on the top cover panel. Think it'll work o.k. But the 2s x 6000 2sx2p, if it gets the call, will probably need lay down connectors and possibly reverse the battery so leads are to the rear. For now, good to go. -AC

 

[9x19]

'Shoe horn' comes to mind.

Nicely done!

 

[ahr43]

Wow, you guys are busy with projects. This thread got bumped down to page bottom in no time. Here's a weekly update on the Bandit Midget project:

Saturday did the steering servo install. Opted for an EcoPower low profile metal gear servo delivery a torque average of 152oz/in over a 6.0/7.4v voltage spread. Comes with an aluminum servo arm. Had to file it down to clear the chassis plate. Being a low profile there was a pinch interference with the molded in servo mount post. Dremeling a groove in the mounting post provided needed clearance.

Yesterday charged up a battery, did a radio/receiver bind and calibrated the ESC. Along the way had to reverse servo direction. As a precaution did a radio/receiver re-bind. That's what the instructions say to do, anyway. Radio system is my veteran Spektrum DX4C and ancient SR210 external antenna receiver.

Feeling like I was on a roll, did a series of test laps out front of the house. Have room for a tight scale 1/4mile oval so I could time comparative results. Ran 3 sessions of 4laps right; then 4laps left. Gradually increasing power on the Reedy 19T brush motor fed power by a HobbyWing 80A brush ESC. 50-60-64% THR.

Track temp was 110deg F. And following the sessions, right side tires were slightly warmer to the touch than the lefts. Leaving me believe the wedge set into the chassis was loading the chassis as it should - at least for the turning left laps. Surprisingly the midget seems neutral in handling.

Oh, and removed the right side header from the body - changing it from a V8 sprint to an inline 4 midget.

Anyway, that's a wrap for now. Thanks for looking in and following along. More next week. Cheers. -AC

 

[9x19]

Wow, you guys are busy with projects. This thread got bumped down to page bottom in no time. Here's a weekly update on the Bandit Midget project:

Saturday did the steering servo install. Opted for an EcoPower low profile metal gear servo delivery a torque average of 152oz/in over a 6.0/7.4v voltage spread. Comes with an aluminum servo arm. Had to file it down to clear the chassis plate. Being a low profile there was a pinch interference with the molded in servo mount post. Dremeling a groove in the mounting post provided needed clearance.

Yesterday charged up a battery, did a radio/receiver bind and calibrated the ESC. Along the way had to reverse servo direction. As a precaution did a radio/receiver re-bind. That's what the instructions say to do, anyway. Radio system is my veteran Spektrum DX4C and ancient SR210 external antenna receiver.

Feeling like I was on a roll, did a series of test laps out front of the house. Have room for a tight scale 1/4mile oval so I could time comparative results. Ran 3 sessions of 4laps right; then 4laps left. Gradually increasing power on the Reedy 19T brush motor fed power by a HobbyWing 80A brush ESC. 50-60-64% THR.

Track temp was 110deg F. And following the sessions, right side tires were slightly warmer to the touch than the lefts. Leaving me believe the wedge set into the chassis was loading the chassis as it should - at least for the turning left laps. Surprisingly the midget seems neutral in handling.

Oh, and removed the right side header from the body - changing it from a V8 sprint to an inline 4 midget.

Anyway, that's a wrap for now. Thanks for looking in and following along. More next week. Cheers. -AC

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Going to leave it yellow, and just add (speed) stickers?

I like that setup.

 

[ahr43]

Going to leave it yellow, and just add (speed) stickers?

I like that setup.

Thanks, 9x19. And thanks for the likes guys.

Yeah, leaving it yellow. "May" do an orange-to-yellow fade on the replacement panels. Sort of a signature color with me. Easy to do.

Did stickering today. I'll pick images of that next update. Not sure if the body panels are acrylic or 3D printed (?). They are sort of a rough surface and stickers don't adhere well. Anyway, they are a bit fragile and are showing cracks. Chassis is a sort-of ladder frame so it will twist a bit. Suspect that is the reason for the cracking. Am intending to replace the current side panels with Lexan after the May event.

Oh, and R-T-R weight is 3.1lb. Coming in light. Get the gearing right and she should be competitive with the big cars on the grass track tri-oval.

-AC

 

[ahr43]

Weekly update on the midget project.

Wheels and tires came in. Cleaned, vented and glued a pair of JC Drop Step buggy rears to a pair of P-L Velocity 2.2 buggy rear wheels. No drama there.

Fronts? Different story. Cleaned, vented and did a test mount of the P-L Harpoon tires to a pair of P-L Velocity 2.2 buggy front wheels. Really tight fit and not a good bead fit. Not much left of the JC DirtTech inserts after getting them fit. Decided I needed a pair of 'narrow' P-L Velocity wheels to properly fit up these turf tires. They're in the mail for install later this week.

Next comes setting the ride height for the grass track. Tire pairs FR and RR are both low profile with very little sidewall and really lower the ride height. And of, course, proving again there is no five minute job, had a pronounced spring sag at the rear and no shock rebound. Drained, re-filled and bled the shocks. Don't know what weight came out, but 35wt (420 CST) Losi fluid went in. Got rebound back, then re-set shock mounting to raise the ride height. Finally bit the bullet and resorted to a last chance install of pre-load spacers.

Using a center-balance check, determined the midget was carrying 62% rear weight. More than I'd like. But for now it'll hit the track that way. Changed out the 26T pinion for a 24T for a pinion/spur ratio of 3.16.

Did get some stickering done. Slow process for me. Cheers. Thanks for looking in. -AC

 

[Doom!]

This is why I don't race, I would be way to confused figuring out what needs adjusting to get what results. But I love seeing other peoples stuff.!

 

[CertifiedMike]

This is why I don't race, I would be way to confused figuring out what needs adjusting to get what results. But I love seeing other peoples stuff.!

This is EASILY cured!!!
Go out and buy VERY expensive tools and NO ONE will question you and your hacky trackery!

 

[ahr43]

This is why I don't race, I would be way to confused figuring out what needs adjusting to get what results. But I love seeing other peoples stuff.!

Trial and Error for me. Lots of errors but keep on trying. Have no idea if all this is right or not. But do know that off-track in high grass need from 7/8 to 1 1/8 in ride height to get back on the short grass track without stalling out. See how she shakes out on track and go from there. First priority is ride height. Sorting out handling comes later.

Been thinking over the summer may option this build as a wingless sprint and fit stadium truck 2.2's for a try. Got a full set of off-roads in the basher stash. For now and the final track event of the 2025 season, she'll go as a midget.

Image is kind of the looking I'm trying for. High Banks Hall of Fame, National Midget Auto Racing Museum, Belleville, Kansas. Stopped there on our road trip from Houston to Minnesota and back year ago or so. Cool place.

Image reminds me, need to fabricate a shaker screen for the front of the cage. -AC

 

[CertifiedMike]

Trial and Error for me. Lots of errors but keep on trying. Have no idea if all this is right or not. But do know that off-track in high grass need from 7/8 to 1 1/8 in ride height to get back on the short grass track without stalling out. See how she shakes out on track and go from there. First priority is ride height. Sorting out handling comes later.

Been thinking over the summer may option this build as a wingless sprint and fit stadium truck 2.2's for a try. Got a full set of off-roads in the basher stash. For now and the final track event of the 2025 season, she'll go as a midget.

Image is kind of the looking I'm trying for. High Banks Hall of Fame, National Midget Auto Racing Museum, Belleville, Kansas. Stopped there on our road trip from Houston to Minnesota and back year ago or so. Cool place.

Image reminds me, need to fabricate a shaker screen for the front of the cage.

My love for vintage goes to 1:1 too!!! Such a cool car from years ago!

 

[ahr43]

Latest build thread update closes out Phase 1. More or less the slider/roller as received from Ebay purchase. A few tweaks. No major mods. Those to come in Phase 2.

Pro-Line Velocity 2.2in buggy 'Narrow' wheels arrived and fitment of the P-L Harpoon carpet tires was much easier. Image shows a comparison of the two wheel widths and a comparison of how the fitment looks. Narrow wheel/tire on the midget's RF (your left in the image) and standard width 2.2 buggy FR on the midget's LF (your right in the image).

All-in-all an interesting exercise. But in the end opted for the install of a set P-L Hole Shot buggy fronts on JC chrome rims and Hole Shot truck rears on TRX chromies.

Finally got around to fitting a shaker screen to the roll cage after the midget's Monday race debut on the tri-oval. That's a wrap for now. Thanks for looking in. Cheers. -AC

 

[WickedFog]

Man, I wonder if the Kyosho Scorpion wheels might look good on that. The Turbo Scorpion ones are 2.2. The regular Scorpion wheels are smaller, 1.9's I believe (front). Rears are like 1.55 or something.

Just a thought that popped into my head.

Loving this build man!

 

[9x19]

Latest build thread update closes out Phase 1. More or less the slider/roller as received from Ebay purchase. A few tweaks. No major mods. Those to come in Phase 2.

Pro-Line Velocity 2.2in buggy 'Narrow' wheels arrived and fitment of the P-L Harpoon carpet tires was much easier. Image shows a comparison of the two wheel widths and a comparison of how the fitment looks. Narrow wheel/tire on the midget's RF (your left in the image) and standard width 2.2 buggy FR on the midget's LF (your right in the image).

All-in-all an interesting exercise. But in the end opted for the install of a set P-L Hole Shot buggy fronts on JC chrome rims and Hole Shot truck rears on TRX chromies.

Finally got around to fitting a shaker screen to the roll cage after the midget's Monday race debut on the tri-oval. That's a wrap for now. Thanks for looking in. Cheers. -AC

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Looking Good, it is!

 

[ahr43]

More progress on the midget build. Kinda hard to squeeze in bench time with this project with an active grass track event going on the backyard track.

Cut and fit a 1/4 x 2in ballast rod and attached it under the front bumper with two (2) 1/4in nylon clamps. Only added a modest 0.5oz weight up front but it was the only rod stock that fell to hand. Band saw blade really screamed when cutting it to length. Thought it was mild steel rod stock but now think it was at least case hardened. Two longer M4x15mm FLCS secured it in place through the bumper into the front bulkhead.

Next comes the Hot Racing aluminum caster block install. Proving yet again there is no such thing as a five-minute job. Took most of last Saturday morning to bring it to done. HR specs states it is compatible with Bandit p/n TRA3632. My Bandit part number listing is [TRA] 2432. Anyway, had to modify the blocks for install. Clamping the caster block for through drilling was an exercise in frustration. Finally broke the code and got them clamped securely in place. Then had to find the proper tilt on the drill press table to get a true pass through with the drill bit. Third challenge was finding a drill bit that would allow suspension pin fit without slop. As fortune would have it, had a No.29 tap drill bit for USS/SAE 8/32 screws that did the deed. Whew!

Oh, and yeah, Kevin. Those Kyosho discs look great. Haven't wish listed them yet, but keeping it in mind for the future. Thanks.

Cheers guys and gals. Thanks for looking in. -AC

 

[ahr43]

Two update images of the Bandit Midget track test ready for 2026 season Tech & Spec. One color; the other classic black & white. Thinking of doing the entire 2026 season in B&W for a 1950s look.

She's carrying JConcepts 9-Shot buggy wheels mounting JC Sprinter tires up front and TRX ST wheels mounting JC Goosebumps at the rear.

Looking next to check into Associated exchange program to replace the 19T Reedy brush motor with an upgrade to a Reedy 13.5 brushless motor and ESC. -AC