Powered lift axle??

[tc1cat]

Looked around the site and did not find anything on this subject. What would be the best way to make a powered lift axle? Saw a truck this AM with one and now I am thinking of the option on my next truck.

[Espeefan]

If you are looking for a simple bolt on lift axle kit, unfortunately, one does not exist yet. Everyone I know who runs a lift axle on their truck has built it themselves using a varitey of home made parts, or some currently available parts, which are modified to become a lift axle. I've seen some Tamiya guys run a trailer axle, lifted with a servo. I've also seen some use a driven axle, with no internal parts, which allows the driveshaft to pass through the axle without interferance. I've modified a steering axle to fit my Wedico, even though Wedico does offer an optional lift axle kit. The scale is wrong, if you are into Tamiyas, and I personally didn't think the Wedico lift axle worked all that well.

The good news is it's not that hard to come up with a kit of your own. The parts to do the job are already out there for Tamiyas. The biggest thing you need to overcome is the clearance so the drivehaft can pass underneath the lift axle and make it to the drive axles without the lift axle hitting or block the driveshaft's way. For that, some guys make a u-shaped axle from scratch. As for myself, a standard steering axle provided enough clearance for my driveshaft, when I flipped it, but I had to do some extensive modifications to narrow the axle, so it could tuck up into the chassis, when lifted.

Have a look a IHBuilder's heavy hauler thread. He has a good idea for a lift axle that may give you some ideas. Tamiyacowboy also runs a similar set-up, if I remember right.

It's just a matter of coming up with an idea and seeing if works. None of it is to difficult. Don't be afraid to get creative and try something. All it takes sometimes is a creative streak and some thought! I am sure more will chime in and show off their set-ups. Good luck!

[SonoranWraith]

When you say powered do you mean a drive axle that lifts? I have only seen this in dummy form so that when it is lifted it isn't spinning. If you mean a lift axle controlled by servo or other means, see suggestions above. ;)

[Espeefan]

I think he means a functional lift axle. Powered up or down. That's kind of how I took it! :D

[ihbuilder]

here's some update pics that I did not put on my thread
http://i830.photobucket.com/albums/zz230/ihbuilder/PIC_0404.jpg
http://i830.photobucket.com/albums/zz230/ihbuilder/PIC_0403.jpg

[tc1cat]

Thanks for the info but I think I need to be more specific. Lift axle needs to be powered by the tranny when it is in the down position. Plus it is the rear axle not the front one which is the lift axle. I know that this seems odd but this is what I saw.

[Espeefan]

Hmm, never heard of a driven lift axle. Interesting. Do you have any photos of the truck that would have this set-up? Sounds like it would have a disconnect inside the axle, possibly the in the differential. Air actuated perhaps. Not sure how you would replicate that in a scale truck. Sounds cool though.

[SonoranWraith]

Dig unit for crawling maybe?

[tc1cat]

Wish I had pics! Just saw it going down the highway. Actually a strange truck. Straight truck with a full size sleeper, kind of short box on it, with the rear axle a lift axle with power?? Stranger part was it did not have any name on it as far as who owned it.
I am always on the lookout for different looking straight trucks!
Thanks for the ideas on making one. Just have to start thinking outside of the box on this one.

[ihbuilder]

sounds like you want to be able to disconnect it when in up position . some kind of clutch between the drive shaft and axle . this will be interesting :cool:

[Thorsteenster]

Dig unit for crawling maybe?

That would probably be a little difficult to mount on the axle.
Here's a pretty straight forward driveshaft disconnect. Use male Stampede drive shafts on the rearmost pass through axle and on the lift axle, then a female to go over the two to slide back and forth, joining the two males end engaging/disengaging drive. I did this with Revo shafts a few years back, into one of the male ends I threaded a bolt with the head rounded off to keep the female slider in place while disengaged and I used an old steering knuckle around the slider attached to a servo to move it. You'll have to figure out how to keep the knuckle in place laterally on the slider while allowing it to spin.

[Izzy]

Ive heard of drive axxels that are non-driven when in the up - the have powered differentials in the for switching.

Best way I can think of is there is a unit in the rock crawling group that will allow you to switch in and out - just like a 1:1 transfer case - link this to your transmission then route an additional drive shaft.

Another option might be to make a locking drive shaft - would have a slip collar that would lock and still allow stretch.

biggest issue is maintaining power through to the 2nd or 3rd axels.....


nice question to ponder - thanks for posting ........
- Izzy -