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

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Atomic Skull

Atomic Skull

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https://www.aliexpress.us/item/3256809357877839.html

$345 shipped with a $60 off coupon I'm fighting it but I'm wavering.

If I were to buy this would a 1100kv motor work? I see most people run 800kv but a Kraton 8S motor off Jenny RC is relatively cheap and has an integrated fan and heatsink.

Would a 200A 8s ESC be enough or would I need 250A? I can get an XC-ESC C6 (8S 200A sensorless) for around $100. My experience with the XC ESC E6 sensored ESC has been that it is superior to the Hobbywing Max 8 it replaced so I'm confident in the quality of XC ESC's

Is it possible to run on 6S or is that just a no go?
 
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I ran my Rofun ELT (5T) on 4S. Mainly due to my high kv motor (1460kv) and a fixed pinionsize forced me too.

The 5B is just 2WD an lighter so yes you can run in to 6S for sure, (assuming the pinion can be changed at the 5b) The lower you go in voltage you do get amps in return. I run a XLX2 so amps are not an issue.

Even tough the price is good, I am pretty much convinced a heavy 2WD car is not gonna be a real fun car to drive. Compared to what we have experienced with modern AWD's. On lose surface it will just sink down to its bottomplate and dig in the rear. My experience is my FG Marder (converted to brushless)
 
Atomic Skull said:
Oh no Aliexpresss just gave me a "special offer" and it's $320 now
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It's a no brainer - you should definitely pull the trigger. I'd be very surprised if the Baja 5B didn't become your most satisfying rig to drive. 👌👍
 
Rotauq said:
Even tough the price is good, I am pretty much convinced a heavy 2WD car is not gonna be a real fun car to drive.
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The Baja 5B is light by 1/5th scale standards, but to be perfectly transparent - the rear 'engine', rear drive combination is challenging by modern standards. It commands driver discipline and throttle finesse. Someone coming straight from a smaller, lighter 4WD Truggy will definitely find it harder to drive, especially in lower traction conditions.

Rotauq said:
Compared to what we have experienced with modern AWD's. On lose surface it will just sink down to its bottomplate and dig in the rear. My experience is my FG Marder (converted to brushless)
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I think using appropriate rear tyres is extremely important on a Baja 5B. MX Knobbly hook up incredibly well on grass. Spikes with higher HP engines.

4WD is obviously a huge advantage on lower traction surfaces, but a well driven Baja 5B on grass with jumps and decent straights - the 5B can still exhibit higher straight line speed for a given HP. I've always found the Baja to have a more plush suspension & longer arms/throw over the FG rigs.

I've literally never had my Baja sink down to it's bottom plate, ever. I suppose on dry sand or dunes that would happen, but then you'd hook up with paddles and go for it.

I've run on sandy soil here:

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But not the beach itself. The naturally undulating terrain, grass and sand surfaces were perfect for the Baja 5B on Knobbly Hostile MX tyres.

Front tyres don't seem to matter on the Baja. I'm fairly certain you could run anything. 😅🤭

On a track, the Losi/MCD/30DN 4WD machines would smoke the Baja 5B on the typical, tight, technically demanding astro tracks we see now.

For bashing or ripping around, the Baja's driving traits are exactly why a more experienced enthusiast would want to consider a 5B. 🤩👌
 
I’ve got a Baja running hobbywing 8s max5/56118 800kv and it is the most difficult car to drive that I own, so much so that I wimped out and fitted a gyro to it 🤣 it just wheelies at any speed, sends roosts of grass and dirt 20ft, great fun, but it is a car you do really need to learn to drive..😉
And it is still a heavy beast, also a grass magnet..🤣🤣

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BashingBrian said:
I’ve got a Baja running hobbywing 8s max5/56118 800kv and it is the most difficult car to drive that I own, so much so that I wimped out and fitted a gyro to it 🤣 it just wheelies at any speed, sends roosts of grass and dirt 20ft, great fun, but it is a car you do really need to learn to drive..😉
And it is still a heavy beast, also a grass magnet..🤣🤣

View attachment 10931View attachment 10932
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I love your grass collection devices. 🤣 Mine used to have those. I tried mesh and stuff before giving up and removing the body. 😅
 
So I caved and ordered the Baja along with these tires:

https://www.aliexpress.us/item/2255800095336558.html

And this servo:

https://www.aliexpress.us/item/3256804994141106.html

DS Power servos get good reviews so I've been wanting to try them.

I'm probably going to do 12S because almost all of my batteries are 5000mah and 6000mah 6S packs I use in my 12S helis and 6S cars. So it's more economical to do 12S than 8S for this reason even though the ESC is more expensive.

Hobbystar and Surpass both have a 56112 motor which is probably the same motor that should work.

ESC will probbaly be either an XC ESC E5 or an SQESC 14200 Pro, it depends on what black friday sales there are. The car is being shipped by land/sea and will take 40~60 days so it's literally on the slow boat from china.
 
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Atomic Skull said:
So I caved and ordered the Baja along with these tires:

https://www.aliexpress.us/item/2255800095336558.html
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Good call! 😎💪

As for those tyres, they're great for mixed terrain use and are hard wearing. If you run between grass/dirt onto hard paved areas, they work well enough. They are a bit angular/square in profile and can dig in, but overall are useful all rounder.

For running on just dirt/grass, these are a great choice:

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Very similar to the old Hostile MX tyres that worked so well. Night and day difference to the dirt buster tyres at any rate! 😅
Atomic Skull said:
And this servo:

https://www.aliexpress.us/item/3256804994141106.html

DS Power servos get good reviews so I've been wanting to try them.
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The Baja 5B doesn't place too much demand on steering servos, so you should be fine provided the servo is responsive enough. Speed is definitely preferable to torque in this application. You need the steering to be fast to catch slides, counter-steering and generally keeping the Baja 5B in check.
Atomic Skull said:
I'm probably going to do 12S because almost all of my batteries are 5000mah and 6000mah 6S packs I use in my 12S helis and 6S cars. So it's more economical to do 12S than 8S for this reason even though the ESC is more expensive.
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12S sounds spicy! 😅😝 It's going to be insane. Please post pictures of your rig.

I take back what I say about a fast servo. Your front tyres are never going to be in contact with the terrain anyway!

We all know how particular you are about things, so I'm going to grab some popcorn for this one. 🤣

With so many aftermarket parts, I can't wait to see what you end up with.

Atomic Skull said:
Hobbystar and Surpass both have a 56112 motor which is probably the same motor that should work.

ESC will probbaly be either an XC ESC E5 or an SQESC 14200 Pro, it depends on what black friday sales there are. The car is being shipped by land/sea and will take 40~60 days so it's literally on the slow boat from china.
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Atomic Skull said:
How do these compare to those?

https://www.ebay.com/itm/267206522406
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Very similar to the OG Hostile MX Nitemare tyres - just like the Mad Max Knobbly, these are the Rofun equivalent I believe. They work well on softer terrain but wear rapidly on tarmac/concrete/asphalt.
https://www.ebay.com/itm/267206522406
Atomic Skull said:
Any experience with these on road tires?

https://www.ebay.com/itm/131943949489
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No, but they seem to be unbranded versions of Mad Max Tarmac Busters for hard paved areas. Should grip well enough, provided the compound isn't too hard. You may also want to consider these:

27594.webp

Mad Max Supergrip.

They really do hook up well on dry tarmac.

Check out this place to see a comprehensive range of tyres. You may then be able to find alternative sellers closer to your region. 👍

https://www.rcmodelz.co.uk/wheels-tyres/tyres/rovan-buggy-hpi-baja-5b.html
 
DS-H009-C servo arrived. The internal build quality is very good and the solder joints on the leads are cleanly soldered. I've seen much worse from much more expensive servos including a set of Hitec servos that had absolutely atrocious soldering on the inside.

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The motor is press fit into the aluminum shell *and* screwed down to the bottom of the plastic upper gearbox. No silicone goop on the leads or threadlock on the motor screws but this is already a lot better than I was expecting from a $30 servo and I can do that myself.

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Applied some Kafuter K-706 semi flowing electronics silicone to the solder joints on the leads and around the big capacitor. You must NEVER use common construction silicone on electronics because it contains acetic acid used to cure it (which is why it smells like vinegar). What you want is methoxy or oxime cured silicone which uses atmospheric moisture to cure. The safest bet is to just make sure it's rated for use on PCBs. I also applied a small amount of threadlock to the motor screws before reinstalling them.

I think the red residue on the back of the PCB is flux residue from hand soldering the larger parts (the motor and electrolytic capacitor)

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The gears came with syrupy silicone oil applied which is fine but I prefer Super Lube for servo grease so cleaned everything and regreased them. Super Lube is a petroleum based grease with PTFE that is safe an almost all plastics and elastomers except polystyrene and natural rubber. It does not gas out evaporate or dry up.

The servo case is in four parts the plastic bottom cap, an aluminum center open on each side, a plastic mid section that sits on top of the aluminum center and the top cap. The bottom cap and the seal between the lower half of the upper gearbox and aluminum center have rubber O-ring seals on the case and screws. The top cap does not have a rubber seal so it is splash resistant but not waterproof. In theory water could get into the electronics by way of he gearbox and the hole for the motor pinion but you'd have to immerse it for a while for that to happen. Also the seam between the top cap and the middle section is very tight and probably fairly resistant to being hosed down. There are also two small screws in the top cap in the middle that help hold the top and middle section together that have no o-rings.

The specs are supposed to be 75kg-cm and .14sec 60 degrees at 8.4V and that seems accurate at least for the speed. I was not able to stop or even budge the servo arm with my fingers so it's at least "strong enough"
 
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That's a good price for a well built servo - you're going to find out soon enough if it lives up to the billing.

75kg is way more than you'll ever need for a Baja. The speed of 0.14secs is fast for a servo of this size and is certainly much better than my noisy Savox SV 0236.

IMG_20200514_115719.webp
For some context, the HPI SFL 10 MG supplied with the 5B SS was a 24kg servo.

The upgrade I put in is a 30kg servo, but is faster @ 60°/0.21sec. It was £50 - and to be perfectly honest, is my least favourite servo. 🤣

Your $30 servo is a bargain. 😎👌
 
While I wasn't able to find any videos on this specific servo I have found testing videos on youtube of other DS Power servos and the specs are more or less accurate.

I forgot to mention there's a trick to keeping self leveling electronics silicone from flowing down around the PCB and sticking to the bottom of the case. I put a couple strips of teflon plumbers tape across the bottom of the exposed PCB where I'm going to apply the goop to make barrier and then put the bottom cap on over it and apply the silicone to the top side. It won't stick to the tape and it can be peeled off once it cures. If I need to add a bit more to the other side on the main lead I do that after the top side application has cured.

Applying it to the leads on the potentimeter can be tricky, non slumping stuff is easier to work with here but I don't like keeping a tube of it around for just one purpose. 95% of the time when I need electronics silicone for something I need the semi flowing stuff because it creeps around and under components and wires while non slumping would leave gaps.
 
XC E5 Pro compared to the Mamba Monster X 8S I have in my Asuga, this is a 12S 250A sensored ESC.

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I don't like the exposed bluetooth antenna so I put a protective section of blue heatshrink tubing over it. In my experience whisker antennas like this like to bend right where the exposed core exits the insulation jacket and eventually get kinked and weakened there. I may also put a blob of electronics silicone where the wire bundle exits the case as a strain relief.

The motor connectors are 8mm I assume this is the standard for big ESCs like this or will I need to replace the connectors on the Hobbystar 56112 motor I'm looking at?
 
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Crap I just realized that a 780KV motor will go above 30,000RPM at full throttle which is higher than the maximum rated RPM for that motor. The max rated RPM s 30,000 and 12S would drive the motor at about 39,000RPM on a full pack or about 34,5000 on a depleted pack. Looks like I will need to return it and get the 580KV version.

Anyone know what the maximum pinion size is for a stock 57T spur gear and 55mm motor?
 
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