changing 4wd to 2wd
 

so my kids have 4wd cars now but want to be able to do standing spins and slides. i think this would be a lot easier if the front wheels weren't driven and i wonder if this simple mod will make it possible. it's all connected with dogbones front and rear and i'm thinking i could just remove the three dogbones driving the front wheels, and thereby releasing the front gearbox from all stress. in the pic below, i'd be removing the three red ones.
the question is really what kind of added stress, if any, does this put on the remaining gearboxes, center and rear? or is all just free power to the rear?

http://www.rcuniverse.com/forum/atta...mentid=2058435

that attachment shows up real small for some reason. but if you click it it enlarges.

remove the front shafts. but you're also going to need to lock the center diff or it will just unload and the car won't really go anywhere.
iv herd of people locking center diffs with everything from super glue or epoxy to silly putty and playdough (no joke).

oh yeah. the center diff. i would like this to be reversible so i guess i'll have to find a way to lock it.

Been there...done that.
A silly putty and Traxxas diff thread.

There was a thread about a month ago, or was about something else and ended up talking about this very subject of locking the center diff.... Anyway, long story short, I had a 1/8 scale truggy and was breaking front drive shafts way more than I liked. I thought I would turn the 4wd into a 2wd... one of the worst things I ever did to a RC. You will be able to do spins and slides pretty much on command.

I'm gonna just say to use JB Weld or something like it to lock the center diff. I don't recommend it. It'll will be pretty much permanent. I've used poster putty, silly putty...etc. that stuff all ends up the same way... a big pile of warm, sticky mess.

done this once when I lost my front driveshaft, and had no replacements...
Don't do it ;)

seriously it will drive like complete crap, and you will put more stress on the diff that is doing all the work which could cause failure.

I am not sure if this will work, but could you just remove the center diff, and just make it a regular diff? basically just remove the gear going to the front, also removing the driveshafts and whatnot

A center diff is no different to that of a rear or front differential. It transmits input momentum into ,usually, a perpendicular output force.


Most cars on the market are offered in both 2wd and 4wd setups. So If OPs car has a similar vehicle sold in a 2wd configuration it should be a simple matter of buying the parts necessary and installing them.

The OP should've mentioned that the 4wd vehicles in question are DHK Razr's. These do not have a center differential, they have a center spool. Simply taking the front center shaft out will make them 2wd with no need to lock anything. The front axles are cvd's according the to the manual I found online, not dog bones. This makes it more involved to disassemble and remove the front axles which I'm not sure will make any difference for what you're looking for. Might as well leave them in so you don't lose the parts for when they get over the donuts.

I'm guessing they're the brushed versions if they can't slide them around. I normally have no problem sliding around a brushless 4wd and the 4wd makes it easier to control the vehicle, sliding or not. Something to keep in mind when they get older or if you upgrade.

yes, they are the dhk razrs. altho i could have sworn i saw dogbones up in front as well. i don't know what a center spool is, but if it's not a differential and that makes it easier than cool. i'll just try it out in my backyard and see what happens.
one of the servos is already busted so it looks like i'll be digging into the front end anyway. i've got a couple hitec 645s on the way.

I remembered they were Razr's from another thread of yours.

A spool is just a straight shaft the outputs connect to, it acts like a locked diff. But unlike a locked diff it cannot be unlocked since it's just a straight shaft.

The manual I found for both the brushed and brushless Razr's shows cvd's. The cvd's have a dog bone end on the differential side and a cvd's on the wheel side. They can be taken apart and the shaft removed, but I don't think it will effect anything leaving them in. Up to you how much effort you want to go through.