Baja 5B Electric roller for $345 should I do it?

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Atomic Skull said:
From what I can tell the Rovan battery tray is slightly bigger than the HPI one but the cover is clunkier, it uses clevis pins instead of rotating levers to lock it down. In either case the radio compartment is awful, it's part of the battery tray and open at the top with just the battery cover over it. Water can very easily pool in it so I will be NOT using it and instead I will adapt a Traxxas waterproof reciever box instead. I will probably also mill away the useless center divider to free up an extra 1mm of space which is valuable given how tight battery fitment is. I have found that some 6S 5000mah batteries may fit such as Liperior 5000 6s. As well if the dimensions are correct a Liperior 6S 6000mah battery would fit in the tray though the cover would not fit and they would need to be secured with velcro straps (42x60x170mm).

DS Power is the OEM for the Rovan RTR steering servo Rovan just slaps their logo on it and sells it for $70 instead of $40.

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Heathen!

Keep those dirty Traxass parts off your Baja - and wash your mouth out while you're at it! 😜

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Horatio said:
They'll fit just fine. 👍

Mad max tyres are great.

If you want to keep the buggy look, Mad Max Supergrip tyres are also available.
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I've looked at the supergrips but they aren't belted (though I can strap them) and it didn't say what kind of rubber they were. Hard rubber is better suited to the asphalt I run on. Price for either is nearly the same.

EDIT: Also I may eventually convert it to a 5T body as it's a lot easier to get on and off for access to the battery compartment.
 
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Atomic Skull said:
I've looked at the supergrips but they aren't belted (though I can strap them) and it didn't say what kind of rubber they were. Hard rubber is better suited to the asphalt I run on. Price for either is nearly the same.

EDIT: Also I may eventually convert it to a 5T body as it's a lot easier to get on and off for access to the battery compartment.
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The Supergrip tyres aren't belted, but I think they're solid TBH.
 
Atomic Skull said:
Are you sure? The description says "Mad Max 188x78mm Belted Wider Street Sweeper Tyre Wheel Set (4)"
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I was referring to the Supergrip tyres, not your Street Sweeper Tyres. They aren't belted - but I think they're solid. So no, I'm not sure.
 
I ended up using a plate made out of some scrap phenolic to mount the ESC to and then mounted that to the plate on the chassis using VHB tape and a zip tie. This way the ESC is elevated enough to prevent interferance with the gearbox and also it has more surface area for the tape to bond it to the plate (the ESC has fins on the bottom in that area). In addition I also added some strain relief to the wire bundle and the sensor lead where they exit the ESC's shell with electronics grade silicone.

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Atomic Skull said:
Supergrips are not solid see here: https://www.ddmracing.com/MadMax-Supergrip-Onroad-Tire-Wheel-Set-HPI-Baja-5b-Rear
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The tyres actual carcass is thick and heavy, so very unlikely to balloon much, unlike 1/8th tyres. See the tyre and insert weight here - without a wheel.

I put mine together in March 2023 - and they're still good.

So whilst it isn't belted, they have a lot of material. Side grip is decent, but it's possible to light them up with enthusiastic throttling.

I trust that helps clarify what I meant.

Edit:

To add - Supagrip tyres actual carcass is 10mm thick! No wonder they're so bloody heavy. 10mm thick!

So they're not prone to ballooning.

Compound is medium.
 
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First test run today, decided it would be prudent to make sure everything works properly before running and securing wires. I ran into a problem I had with the XC E6 previously, channel two on a Radiomaster ER5C-i receiver puts out some kind of electronic blurb during power on before the firmware runs that causes XC ESCs to not initialize properly. This is a problem with the microprocessor in the receiver hardware not the receiver firmware. The solution is to move the throttle to another channel on the receiver and remap the output. This does not affect the ER3C-i just the ER5C-i
 
Bit weird that. Easy enough to re-gig your inputs/outputs on edge tx /open tx. But it's a bit of a pain having your usual throttle channel compromised by a receiver hardware issue. 🫤

Most RC Car users are not familiar with Open Tx or similar open source radio operating systems.

Anyway - let's see some photos of it ripping around! And give us your 0-40 mph times. 😎
 
I randomly stumbled on these, I’m sure these would give plenty grip but your driveline will be screaming for mercy lol. Never seen it done now I’m curious to see it

I just found this on AliExpress: ￡12.29 | Baja Metal double axle 2 wheel for ROVAN HPI 1/5 Baja 5B 5T 5SC rc car upgrate part
https://a.aliexpress.com/_Eua1GtO
 
I think the default suspension on the Rovan is set for bashing and sending it because it's very hard. If I drop the car from 4 feet the suspension barely responds Probably going to need softer springs and maybe different shock oil. What does the HPI Baja come with by default?
 
The primary difference is that MadMax Street Sweepers are a dedicated on-road tire with a hard rubber compound for durability, while MadMax Supergrips are an on-road tire made with a softer, medium compound rubber designed for maximum traction on hard surfaces.
Both tires are manufactured by the same brand, MadMax, for large scale (1/5th, 1/6th) RC vehicles.

MadMax Street Sweepers
  • Compound: Hard rubber compound.
  • Design: Thick, durable design intended for street use that can withstand punishment.
  • Performance: Designed to be tough and durable, with less ballooning (expansion) at high speeds, but potentially less outright grip compared to softer options.

MadMax Supergrips
  • Compound: Medium rubber compound.
  • Design: Features a full 10mm thick carcass with internal cross-hatched structure and side ribbing to hold its shape and prevent ballooning.
  • Performance: Offers superior grip and traction on various hard surfaces, including tarmac, due to the softer compound and robust internal structure.
In summary, if you prioritize durability and longevity for general street bashing, the Street Sweepers may be a better choice. If you are looking for maximum traction, acceleration, and handling on paved surfaces, the Supergrips offer a softer compound for better performance
 
They seem very reasonably priced. If they work well enough, quite a bargain. No worries if you rag them around at that price.
 
I figured out what the metal disk with the holes is, it's a motor spacer. It's to prevent the motor shaft from touching the inside of the gearbox cover. That is where I suspect the hot smell was coming from. The end of the shaft melted a divot on the inside of the cover.

The countersink holes are for fixing the spacer to the front of the motor with two provided flat head M4 screws. The manual explains none of this and does not show the spacer.

I installed a steel spur and moved up to an 18t pinion, compared to the plastic gear it's very loud. Also the steel spur and original center hub need to be pressed together to fully seat, it's not much but it's more than you can apply with just your fingers. As the gearbox cover seals the gears well enough I figured it'd be a good idea to apply some grease to the metal on metal gears (Super Lube is my go-to grease as it basically never dries out). With the 580KV motor at 18T is very lively but I have enough room for a 19t or 20t, though I don't think that would be a very good idea.

I also increased the initial throttle percent on the ESC from 1% to 2% to get rid of the cogging.

Quick and safe way to check how much room for have for screw length is use a q-tip with the end cut off as a plastic probe and stick it into the hole till it touches bottom then use a pair of tweezers to pull it out with the tweezers grabbing at the face of the motor mount hole. Compare the lenght of the probe to the screw and make sure you have at least 3mm of extra room.

Also this thing likes to destroy lawns, it can sink down to it's bottom plate in a lawn like most cars do on sand.

Left to do:

Install windows, requires some mods to the rear window to account for motor wires and to either left rear window or left side of roll cage to account for the fact that Rovan just uses the fuel version roll cage and not an electric specific one like HPI (window kit is electric specific)

Install headlights and tail light
Install waterproof radio box
Install front cable brake system and brake servo mount.
Install chassis skin
 
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