Custom Chinese D90 (Edited)

[HugoBiermann]

(Update) Parts list thats on the rig:

XtraSpeed body, SCX10 axles, winch and Dick Cepec tires from Banggood.
Generic D90 chassis, Roof rack, beadlocks, DS Servo and drive shafts off AliExpress.
5:1 Planetary Gearbox and 2:1 Transfer case from RC-Mart.
Lights, some accessories and driver, off ebay.

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Been wanting to build a random custom scaler for a wile now. I ended up ordering HG P-402 Diff's, a Gearbox assembly and a D90 body from Banggood. It should be here within the next two months...

So. The chassis is based on the RC4WD dimensions. The rails have been shaped like the 1/1 D90 chassis. Only missing the gearbox mounting dimensions for the HG to complete the cad.

Parts will be laser-cut.

Please don't hesitate suggesting improvements. Any help will be greatly appreciated.

[clm]

The HG axles are usable but I am not a fan of the transmission, it is a neat design but it is far from smooth. If you are building a scaler and going to want an interior, the size of it will be a hindrance as well.

Oh, it and the axles have tiny tiny bearings! tiny.. tiny.. tiny...

[HugoBiermann]

Thanks clm! I will have a look and strip when it eventually arrives, for the price its probably not bad?

Redrew the motor mount. 67mm wide center to center on width, 35mm center to center on depth. Hope the motor will fit in the chassis with that height.

I have also looked at just building a simple transfer case. Best is probably to wait till everything arrives to measure properly. If the gearbox can go up front it will move there.

[clm]

Probably be better off with an hsp 1/10 crawler(like the Everest 10 trans, it's a copy of an axial scx10 trans) trans or go for a cheap transfer case and a 1:5 planetary front mounted gearbox.

1:5 planetary - 1:5 Planetary Gear Box Transmission Case for 1/10 RC4WD D90 Crawler Truck | eBay

The planetary and transfer case is more expensive but will allow a decent low weight distribution and be good for interior room and have the cleanest install.

The axial clone trans (hsp) is just plain simple 3 gear design, much smaller then the HG and about the same price, but it's size still makes a somewhat messy front mounted with transfer case installation if you go that way.

[JatoTheRipper]

I'm excited to watch this build.

[clm]

Just noticed the trans mount in the updated drawing, You are likely going to need a clearance cut for the spur gear with the HG trans, here is a photo to show how low it is to the mounting point on the side.

It is also offset from the side of the trans mount feet by about 5mm and the gear is about 5mm wide (add in about 3mm from the center of the trans mounting hole to it)

I am not sure if this will get into the side of your chassis but you might want to check, it might require a small clearance scallop.

[HugoBiermann]

Received the front diff earlier today. Will strip and see whats going on inside sometime. Its not bad for the price. Probably another 4 weeks for the rest to pitch.

[HugoBiermann]

Opened it. Must have been the tightest diff ever. Hardly any grease. Fitted bearings and its seems better for now. Probably needs to run a bit to settle in. Not the prettiest thing either.

Cannot complain for the money spent though.

After wiping with a rag.


This seems better.






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[HugoBiermann]

Assembled and seems much better.

Slots have been cut for dogbone clearance and nylon spacers to take up the gap between the bearing and the drive hex.








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[HugoBiermann]

The reset of the Banggood order arrived.
Austar D90 body, rear diff and gearbox.

Measured the body and gearbox with a 540 on and cannot fit everything onto the chassis without cutting the interior. The hg box is in the parts drawer now and I am waiting for a transfer box and planetary box to pitch. Ball joints and suspension links are also on their way.

While I wait for RC-Mart to send this I might as well work on some other things that I am unsure of.

A couple of questions first:
I will use an 1060 esc. What motor turn should give me nice scale speed? 45t?
Whats the maximum diameter tires I can fit on here without cutting the body and not having it sit as high as a mud racer? 96mm?
I understand that the suggested shock length for this type of build is around 80mm?

Thanks in advance!


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[HugoBiermann]

Body painted. Was touch and go with that front window.











Just waiting on the nr-plate light to dry, its also black.

I stripped all the plastic chrome with graffiti remover, primed black with clear.

Also picked up an Austar 45t motor for now


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[Brake Weight]

I’ve got that $20 brushed crawler combo from BGood on an SCX10 and it does pretty good. Ima actually impressed for a $20 combo.

[HugoBiermann]

Originally Posted by Brake Weight

I’ve got that $20 brushed crawler combo from BGood on an SCX10 and it does pretty good. Ima actually impressed for a $20 combo.

Good to know! I popped in at the lhs earlier today and saw the motors lying there and thought that I should just take one and get done with it.

Now to figure out what length shock to order and find the correct drive shat length and its almost there.


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[JatoTheRipper]

Looking good so far. I'm interested to see how those axles hold up for you.

[HugoBiermann]

Its going to be a test for them. At least they’re dirt cheap.


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[HugoBiermann]

A question for the custom guys:
What thickness should I go for on the chassis rails? I have them 6mm thick atm.


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[JatoTheRipper]

Originally Posted by HugoBiermann

Its going to be a test for them. At least they’re dirt cheap.

They also have the alloy housings for not much money.

Originally Posted by HugoBiermann

A question for the custom guys:
What thickness should I go for on the chassis rails? I have them 6mm thick atm.

6mm is .236" which is overkill. The more cross braces you have the thinner it can be. You don't have much cross bracing though.

[HugoBiermann]

The main reason for the 6mm rails atm is the machining by hand afterwards. Its easy enough to drill and tap into an 6mm wide rail.


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[HugoBiermann]

I have given up with designing the chassis myself. Its just too much hassle at the moment. Still waiting on more spares to pitch. My HG axles and 1060 has been donated to the woman’s build.

Parts list thus far:
XtraSpeed assorted rod ends
XtraSpeed transfer case
XtraSpeed planetary gearbox
Austar 45t motor
Axial Y-Links
Blue Bird BMS-616DMG+HS servo.

Parts still in the mail:
Servo horn
Drive shafts
Chinese wagon wheels
Chinese Mud Countries
Chinese D90 wheels (for spare)
5A UBEC
XtraSpeed 82mm internal spring shocks
Tow hitch
Austar Chassis
HG axles.

I need to decide on an ESC again. A 1060 is cheap and simple. Then there’s always the 1080. I’m just going to use the rig casually, what would you guys recommend?





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[Brake Weight]

I would really consider the $20 crawler combo from Banggood. For $20, the ESC is worth that. It’s basically a HW 1060 with most of the adjustable parameters of the HW1080. Or just get the 1080 for a $20 more and know that it will be the last brushed ESC you’d ever need. LOL.

Link to those Chinese wagon wheels?