Widebody Locked diff Fox brushless runner
I got sick of munching stock Fox diffs and axles at $50 a throw cause I like brushless motors.
Whilst I was bored I made up a locked diff centre using a Hotshot differential gear, bevel and side gears as well as outdrives.
This is my prototype one so far and as I get more parts I will refine it up to the point where the Nova Fox is released.
This conversion is a full locker but the beauty is you can use the Fox/Spur counter gear or a Thorp one.
You will need 2 out drive cups from a Hotshot vintage or new does not matter. A small bearing from the gearset , the bevel gears , an M3 screw thats as wide as the distance between the 2 outdrives and some tools.
Firstly drill and tap the outdrives with a 2.5mm drill bit and thread them with an M3 tap.
On the RH side gearbox half push in the outdrive and mount the small bearing on it. Screw the M3 cap screw through the centre as this is what everything will mount on. You will need something to centre the differntial gear with , so I used a Supershot rear body spacer. Basically it has to be round have an M3 hole and fit in the centre of the gear.
drop a Hotshot side gear (the one with the raised section on the opposite side of the teeth) onto the outdrive.
drop the differntial gear with spacer in the centre and the bevel gears onto that. I coated my bevel gears with red Loctite Stud Locker to lock them completely. If someone has the time now i have made a start point it shouldnt be too hard to retain the diff action or used the preload/centre screw to have a proper diff action.
The next side gear goes on top ( it has to be the same as the other one to get correct spacing). Make sure the original Fox spur gear is mounted now as well as the underguard screw mount as well.
Put the L/H gearbox half on.
Put the outdrive in so it seats into the side gear.
Use a screwdriver or allen key depending on the type to tighten the centre screw and pull the L/H outdrive into the centre.
Keep turning till tight and you cant move each outdrive independently.
Dependending if you want to use Fox arms or go widebody will determine how the next step goes.
If you want to use Fox arms you will need around a 58mm (total length driveshaft) , after a bit of research it looks like HPI makes one that will fit. Normal HS axles will fit.
I went widebody so I used Hotshot upper and lower arms as well as Boomerang axle mounts (C parts sprue)
Short Hotshot driveshafts can be used but are not ideal as they are a bit long so I used some from a HBX Wild Killer as they are slightly shorter and they were spare :)
I spaced the shocks back at the top and used the Hotshot lower arm swaybar mount to mount ball studs.
The front axles use CRP axle extenders with extra bearings as spacers for now.
I will edit this later if you cant follow it or answer questions in the comments etc.
Basically I have run this car on 3s with a 4000KV motor set as max timing and punch and it literally blows the tyres off the rims :) turning radius is increased but can be oversteered very easily with a throttle blip.
Comments
Grumpy pants
Awesome, great write up. Especially 'it literally blows the tires off' bit!
TEQ86
Nothing quite like seeing the Fox launch nose high in the air with the rear fully compressed and the rear tyres ballooning like a drag car and then see it literally fly past you spinning the tyres the fact the I did this with all second hand bits including the gears and its holding up with no probs at all is awesome
BadWagon
I hear ya bud. I've got a 3500kv system in one of my foxes and I love it. Though, I've blown through a few sets of gears. i picked up a thrope set up but I'm waiting on a few parts (which should be here today) to rebuild from a bit of carnage.
I also blow the tires off the wheels, but I love it too much to pull the brushless system out.
Great write up here. I might have to try the widebody on another fox and see how I like it.
Thanks for the write up.
TEQ86
I have the Thorp stuff as well its just bloody expensive the beauty of my conversion is you can run the original arms with shorter shafts I just didnt have any at the time, but my efforts are too late with the upcoming re-re of the Fox of which I am glad to hear about. Cheap gears and a new drive shaft rear end oh and wheels and bodies and arms as well. Just have to wait a couple of months before it releases.
Want to leave a comment?