Project Rival MT10

[ahr43]

Pulled a pair of 52mph (83kph) runs out of her last month on 3s LiHV low-charged as a LiPo. 16T pinion. Seemed stable at that speed, albeit taking a long run to get up to speed. Ran out of room to hold speed for a full 2sec. She may have been faster. GNSS didn't have time for full register? Fit an 18T pinion for the next run set. Goal is to get her into the 100kph (60mph) club. Looking for a longer run course.

Last week took out the sealed wheel bearing set and installed shielded bearings at all four corners. Little less drag on the drivetrain. Plan was to install steel driveshafts FR and RR at the same time. That fell through. Bearing install was it for the bench session. Have a 3800Kv motor to replace the 3300. That's a future install. Need to wring all I can get out of her on the 3300 first.

Cheers. 'AC'

 

[The_RC_Dude]

Pulled a pair of 52mph (83kph) runs out of her last month on 3s LiHV low-charged as a LiPo. 16T pinion. Seemed stable at that speed, albeit taking a long run to get up to speed. Ran out of room to hold speed for a full 2sec. She may have been faster. GNSS didn't have time for full register? Fit an 18T pinion for the next run set. Goal is to get her into the 100kph (60mph) club. Looking for a longer run course.

Last week took out the sealed wheel bearing set and installed shielded bearings at all four corners. Little less drag on the drivetrain. Plan was to install steel driveshafts FR and RR at the same time. That fell through. Bearing install was it for the bench session. Have a 3800Kv motor to replace the 3300. That's a future install. Need to wring all I can get out of her on the 3300 first.

Cheers. 'AC'

Ahr43, you may actually need a slightly LOWER kV motor or gear DOWN a couple of teeth. This may sound crazy, but hear me through it! When you gear too high and/or have a too high kV, your car will have a high theoretical top speed, but it will either take FOREVER to wind up to that top speed, or it simply won't have the torque to get to that speed. Bear in mind, that high top speed is only the high-RPM range, so you'll have minimal low-end torque, so your Rusty may not have the torque to push through to that top speed. Try a 14t pinion, you may actually get faster speeds, as you may be able to "unlock" the hidden top-end RPM with more torque. I could be wrong though, so don't rush out and buy a new. lower kV motor, just saying!

What's the difference between a shielded and sealed bearing again? I'm tired right now so I can't think straight.

 

[ahr43]

HaHa. Heck, I can't even think straight when not tired. . .

Regarding wheel bearings: Given ideal circumstances, a shielded bearing will turn with less friction than its sealed counterpart. A rubber or rubber-like material completely seals a bearing against entry of contaminants. The seal fits tightly against both inner and outer races of the bearing. A shielded bearing keeps the big stuff out, but still allows entry of tiny particles of contaminant. The shield usually attaches to only one of the bearing races. Trade off - more drag with a sealed bearing in doing the job. A shielded bearing spins freely. However, It requires cleaning more often.

Sealed wheel bearings definitely for bashing about the neighborhood. Shielded bearings free up a few RPM in a protected environment. The application of shielded bearings was something I did for RC drag racing where win and loss was often determined by 0.01sec. For me, it's carried over into speed run building.

Regarding speed of the MT10. Thinking it is more driver hesitation more than gearing or Kv. Need to get on full throttle sooner. Getting up to speed and braking really eats into the space available. Still feeling this whole package out. Not rushing to speed yet.

Cheers. 'AC'

 

[The_RC_Dude]

HaHa. Heck, I can't even think straight when not tired. . .

Regarding wheel bearings: Given ideal circumstances, a shielded bearing will turn with less friction than its sealed counterpart. A rubber or rubber-like material completely seals a bearing against entry of contaminants. The seal fits tightly against both inner and outer races of the bearing. A shielded bearing keeps the big stuff out, but still allows entry of tiny particles of contaminant. The shield usually attaches to only one of the bearing races. Trade off - more drag with a sealed bearing in doing the job. A shielded bearing spins freely. However, It requires cleaning more often.

Sealed wheel bearings definitely for bashing about the neighborhood. Shielded bearings free up a few RPM in a protected environment. The application of shielded bearings was something I did for RC drag racing where win and loss was often determined by 0.01sec. For me, it's carried over into speed run building.

Regarding speed of the MT10. Thinking it is more driver hesitation more than gearing or Kv. Need to get on full throttle sooner. Getting up to speed and braking really eats into the space available. Still feeling this whole package out. Not rushing to speed yet.

Cheers. 'AC'

Lol! I'm up late AGAIN, seriously, I'm turning in now!

Interesting, thanks! The outer race of a bearing is the larger, outer metal ring that all the ball bearings and the inner race go into, right? And the inner race would be the smaller, inner metal race that the ball bearings are sandwiched between it and the outer race? Just wanna make sure I get it right! But how much more drag does a fully sealed driveline have vs. a fully shielded bearing driveline? Is it noticeable by hand, when turning the wheels and stuff?

After reading this, I'm gonna say that sealed bearings are for me, as I don't really care about shaving off hundreths of a second when ripping up and down the street and neighborhood! But I also don't want to do that routine cleaning and oiling for shielded bearings, I like most tinkering, but not a bearing strip down!

Ok then, good luck getting on that throttle and brake, as well as finding a longer place to speed run!

 

[ahr43]

Hey Isaac,
You got the bearing basics down, o.k. And correct that the sealed bearing is best for all-around bashing and off-road use. A shielded bearing is special application only. Sees limited RC use.

Yes, a difference in drag is felt when comparing rotation of the two types of bearings. Again, not that big a deal when bashing about.

Regarding cleaning. My method does not remove the shield for cleaning as some do. RPM 'Bearing Blaster' and WD-40 flushes contaminates out of the bearing. Followed by a re-oil using teflon-based Rem Oil. Teflon-based oils, by the way, attract dust. I use it anyway for its 'slickreness'.

Thanks for looking in and asking questions. Cheers. 'AC'

 

[ahr43]

Adapting the Rival for a try at the back yard monster truck course.

Fit a pair of DuraTrax 2 1/2in body posts up front raising the body to clear the larger P-L 2.8 Trencher tires. Body posts came out of the basher stash without collars. Had to drill a couple of nylon spacers for 3x5mm BHCS as substitute body supports.

Dropped from a 12 to 11 tooth on the pinion compensating for the larger diameter tires. Still 2S battery power. My back yard standard. Re-programed the ESC run mode to Fwd/Brk/Rev. Pulled the ProTek shielded "speed" bearings from the wheel hubs and re-installed the AE sealed bearings.

Pro-Line 1966 Ford F-100 body in black arrived today. Still NIB but looking like a good fit. That brings this project up to speed. Thanks for looking in. Cheers. 'AC'

 

[ahr43]

Fabricated a stiffener/spreader to the newly installed DuraTrax front body posts today. 1/8in G10 fiberglass. MT10 is close to ready for test runs once the back yard track is done. Really needs a set of chevron MT tires to set it off. Not sure I can jamb them into this month's budget. May have to do with the Trencher's for a while.

Anxious now to get a start on fitment of the 1966 F-100 body for this chassis. Been tempted but have not busted it out of its bag yet. 'AC'

 

[ahr43]

Finally found a set of non-serrated wheel nuts. Even better, stainless steel to boot. Replacing the aluminum wheel nuts was an easy do and my preference for this application.

Passing along the maker and p/n in case anyone else is looking for a set. Cheers. 'AC'

 

[ahr43]

95PGTTech's excellent 1/10 ECX Ruckus 4x4 project put the hook in me to try my hand at off-road grass track speed runs.

So begins the cut over and learning process with the MT10. Took the Rival out yesterday to get baseline runs for improving speed. 36kph (~22mph) was the best it could manage. And that limited to 90% power setting. Scary handling right now. Greywolf has made recommendations on rear diff weight. That and shock oil weight will be the first two changes.

Be a 2S runner. Right now power unit is 3300Kv sensorless and MAX10 ESC. Have a 3800Kv for swap in once the chassis gets settled. P-L 2.8in Trencher belted for tires.

Track is 132ft controlled distance on a green area buffer between Beltway 8 and my residential subdivision. Key is keeping it between the trees. As speeds improve, will be looking to a county park soccer field. Cheers. 'AC'

 

[ahr43]

Somewhere in that spaghetti junction bundle of snakes wiring is a new motor install. 3300Kv out and 3800Kv in. New 3800Kv features longer 60mm can and 5mm pinion shaft.

Rain came before I could get a 2S test run in. Eventually she'll get 3S power. Cheers. 'AC'