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

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Atomic Skull said:
It's not that easy to visualize how the transmission works when you're not holding it in your hand and are just looking at pictures of gears and it's different than anything you have used before because you've never owned a 2WD R/C car. Well maybe it is for some people, but not for me.
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Maybe so, but the correct information was provided for you on a spoon, yet you contradicted it.

It's cool to challenge convention sometimes.

But it's not cool to ignore facts when you've asked for them.

I'll not say any more than that.
 
Horatio said:
Maybe so, but the correct information was provided for you on a spoon, yet you contradicted it.

It's cool to challenge convention sometimes.

But it's not cool to ignore facts when you've asked for them.

I'll not say any more than that.
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I didn't understand it and from what you say now it seems I still kinda don't.
 
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Atomic Skull said:
I didn't understand it and from what you say now it seems I still kinda don't.
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How about, get back to us once you've given the rig a blast around on a field, or a quiet car park.

The Baja will put a massive, soppy smile on your face and you won't fully understand why.

8S, 12S - it's not going to matter. JFDI.
 
Something else to consider, a lower KV with a larger pinion means more tooth engagement and possibly less chance of the plastic spur gear stripping.
 
Atomic Skull said:
Something else to consider, a lower KV with a larger pinion means more tooth engagement and possibly less chance of the plastic spur gear stripping.
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An interesting way of looking at it.

Generally speaking, when choosing a pinion size for running an RC car, we're not too concerned with tooth contact, other than settling the mesh correctly.
We generally prefer certain pitches for certain scales (like 48dp for 1/10th for example), but we're choosing the pinion size either to match the track we're racing on, or to optimise the desired speed for the space we're running in, taking into account engine/motor temperatures.

This link describes 'the sweet spot' from an engineering perspective.

https://www.apexdyna.nl/en/news/why-does-the-ideal-pinion-have-20-teeth

From an RC car 'end user' perspective, we'll still need to optimise pinion size based on available torque/power, track size, lap times, run time, temperatures.

We wouldn't usually select our motor based on 'how can I increase the surface area of the contact between the teeth of my pinion/spur?' 😅
 
I actually do see a point for using pinions around 20 teeth. It’s not the main criteria, but it is #4-5 on the list for me. My Traxxas maxx slash has a larger pinion than my corally’s 12-13T that I normally run and they last way longer even being of lesser quality. I don’t have issues with stripping, but longevity is an issue on my corally rigs.
 
Horatio said:
An interesting way of looking at it.

Generally speaking, when choosing a pinion size for running an RC car, we're not too concerned with tooth contact, other than settling the mesh correctly.
We generally prefer certain pitches for certain scales (like 48dp for 1/10th for example), but we're choosing the pinion size either to match the track we're racing on, or to optimise the desired speed for the space we're running in, taking into account engine/motor temperatures.

This link describes 'the sweet spot' from an engineering perspective.

https://www.apexdyna.nl/en/news/why-does-the-ideal-pinion-have-20-teeth

From an RC car 'end user' perspective, we'll still need to optimise pinion size based on available torque/power, track size, lap times, run time, temperatures.

We wouldn't usually select our motor based on 'how can I increase the surface area of the contact between the teeth of my pinion/spur?' 😅
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This website is superb, a great explanation of engineering fundamentals
 
danl said:
I actually do see a point for using pinions around 20 teeth. It’s not the main criteria, but it is #4-5 on the list for me. My Traxxas maxx slash has a larger pinion than my corally’s 12-13T that I normally run and they last way longer even being of lesser quality. I don’t have issues with stripping, but longevity is an issue on my corally rigs.
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But if any of the other 4 criteria apply, you don't really get to choose a large pinions.

The irony in this case is that to prevent an over volted motor from exceeding 30k in a Baja, gearing up to a larger pinion is exactly what needs to happen anyway! But not to improve surface area of the teeth in question. 🤭

I'm terms of wear rate, I think the way you drive has much more of an impact on pinion wear, over the tooth count.

The other consideration of course is material - if you're running a hardened steel spur, alloy pinions will wear quickly and go pointy.

I run Hardened Turtle Racing pinions (as part of a hardened, enclosed clutch system) and they work very well. Unfortunately, none of it is applicable for an electric Baja.

However, a tip that still applies for all of us:

Always finish the day with the same number of teeth as you started with. 🤣
 
So the buggy arrived way earlier than expected. Also two 6S 5000mah will not fit in the battery tray. But if I remove the combined battery and servo tray and replace it with the fuel version and use the U shaped aluminum chassis itself as the battery compartment and secure them with velcro straps they will fit. I will also need to add some thick foam to the bottom to keep the screws on one end from digging into the batteries. There is also a structural member across the frame at one end that the batteries could slide into if the car decelerates hard enough to move them in the straps but it would have to be going in reverse for this to happen. Nonetheless I can make a 3D printed bukhead to prevent this. I'm also considering putting vinyl wrap on the outside of the U channel section to prevent water, grass etc. from getting through the holes in the chassis and into the battery compartment.

I found a Rovan symmetrical steering kit for the IC version on aliexpress for $24, I don't need the steering components but no harm in having spares. Also found this bumper and skid plate sets that I ordered along with it.

https://www.aliexpress.us/item/3256807251424509.html

https://www.aliexpress.us/item/2255800304234101.html
 
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Atomic Skull said:
So the buggy arrived way earlier than expected. Also a 6S 5000mah will not fit in the battery tray. But there is a solution, remove the combined battery and servo tray and replace it with the fuel version and use the U shaped aluminum chassis itself as the battery compartment and secure them with velcro straps. I will also need to add some thick foam to the bottom to keep the screws on one end from dinging into the batteries. There is also a structural member across the frame at one end that the batteries could slide into if the car decelerates hard enough to move them in the straps but it would have to be going in reverse for this to happen. Nonetheless I can make a 3D printed bukhead to prevent this. I'm also considering putting vinyl wrap on the outside of the U channel section to keep stuff (water, grass) from getting through the holes in the chassis and into the battery compartment.
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What are your first thoughts of the Rofun, quality-wise? Does it seem decent?

Angrysection8 seems to like his gasser, so I'm assuming the brushless versions should be equally good.

Essentially, these are blank canvases - just waiting for you to hang your unique combination of upgrades.

Given your penchant for detail and 'outside the box' thinking - this will likely entail a long, long list of upgrades. 😅

TBH, I can't wait to see what you come up with.

Keep us posted. I hope you enjoy your Baja as much as I've enjoyed mine. 💯
 
Horatio said:
What are your first thoughts of the Rofun, quality-wise? Does it seem decent?

Angrysection8 seems to like his gasser, so I'm assuming the brushless versions should be equally good.

Essentially, these are blank canvases - just waiting for you to hang your unique combination of upgrades.

Given your penchant for detail and 'outside the box' thinking - this will likely entail a long, long list of upgrades. 😅

TBH, I can't wait to see what you come up with.

Keep us posted. I hope you enjoy your Baja as much as I've enjoyed mine. 💯
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Quality seems excellent but I haven't really dug into it. The suspension seemed creaky and stiff to me but it has very thick springs and the creak seems to come from these springs. Loostening them made it better but I think I may just need softer springs. I'm not sure how hard a 1/5 suspensions supposed to be so I have no point of referance.

Rovan 5Bs seem to be missing a few minor "technically" optional bits like the plastic chassis skid plates and the plastic ESC mount that an HPI 5B Flux comes with but these aren't expensive. I've had a bear of a time sourcing the ESC mount though literally nobody in the US has that and I will need to order it from europe if I decide to use it (I may just 3D print something). On the other hand the Rovan version has some upgrades out of the box like symmetrical steering and aluminum shock towers (I will need to come up with protectors for those because flipping on asphalt would be ugly)

The RTR Rovan E-Baja apparently just uses the double sided mounting tape on the ESC as a shim to elevate the ESC above the gearbox that it overlaps with (the top of the gearbox is about 1mm higher than the ESC plate). The HPI version uses a plastic mount that goes betwen the ESC and the aluminum ESC mounting plate.

I'll need to make a new battery cover as well the existing one won't fit over the batteries. On the plus side by using the chassis as the battery compartment the batteries may be installed and removed without removing the body.

EDIT: I have decided to put the battery modifications off until later, for the time being I will get the car up and running with 2x 4000mah 6S batteries and the e-baja battery / servo tray. There are just too many other things to do with it to pile this on top of all that.
 
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Atomic Skull said:
Quality seems excellent but I haven't really dug into it. The suspension seemed creaky and stiff to me but it has very thick springs and the creak seems to come from these springs. Loostening them made it better but I think I may just need softer springs. I'm not sure how hard a 1/5 suspensions supposed to be so I have no point of referance.

Rovan 5Bs seem to be missing a few minor "technically" optional bits like the plastic chassis skid plates and the plastic ESC mount that an HPI 5B Flux comes with but these aren't expensive. I've had a bear of a time sourcing the ESC mount though literally nobody in the US has that and I will need to order it from europe if I decide to use it (I may just 3D print something). On the other hand the Rovan version has some upgrades out of the box like symmetrical steering and aluminum shock towers (I will need to come up with protectors for those because flipping on asphalt would be ugly)

The RTR Rovan E-Baja apparently just uses the double sided mounting tape on the ESC as a shim to elevate the ESC above the gearbox that it overlaps with (the top of the gearbox is about 1mm higher than the ESC plate). The HPI version uses a plastic mount that goes betwen the ESC and the aluminum ESC mounting plate.

I'll need to make a new battery cover as well the existing one won't fit over the batteries. On the plus side by using the chassis as the battery compartment the batteries may be installed and removed without removing the body.

EDIT: I have decided to put the battery modifications off until later, for the time being I will get the car up and running with 2x 4000mah 6S batteries and the e-baja battery / servo tray. There are just too many other things to do with it to pile this on top of all that.
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Obviously at this stage you know that resistance is futile. 😜

Can't wait to see what this turns into!

The symmetrical steering (push/pull) is a much better way of steering the Baja - definitely improved the steering response on my rig - once I'd sorted out the geometry of the track rods and their pick up points.

I'll spend more time with mine after the winter championship has completed. I'm now competing in 2 classes. 😅

My basher rigs are on standby til spring.
 
I don't think the fuel version steering is going to give you the room you think it will, even if you cut it to pieces to gain the room on the rear side you'll be left with only the front two mounting holes which is be willing to bet would allow the steering setup to move around on the chassis.

Here's mine in both the factory configuration and with the symmetrical steering, may give you an idea.
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These came with the car, anyone know what they are?

rovan_001.webp


Also these fell off the chassis from somewhere. I found them on the work surface but I can't figure out where they go

rovan_002.webp
 
The 4 matching pieces in the top pic are rear hub shims for adjustment of toe angle. Not sure on the other bit, the bottom picture is just some plastic washers that'll go on the bottom side of the front of the rollbar, between the chassis and the clips
 
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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.

rovan003.webp
 
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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 whick 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.

View attachment 11294
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Dang, that sucks, thankfully regardless of brand or octane rating fuel always seems to fit my fuel tank
 
Atomic Skull said:
Rovan 5Bs seem to be missing a few minor "technically" optional bits like the plastic chassis skid plates and the plastic ESC mount that an HPI 5B Flux comes with but these aren't expensive.
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It does in fact come with the plastic underchassis plates I don't know how I missed those. Oh well having spares is good anyway.
 
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