4WD Straight Axle SC truck

[NickRummy]

Yes I know it's been done before but I want my own

I started designing something like this years ago. I sold an MT2 to a friend a while back and ended up getting it back missing the diffs. So I thought what the heck, might as well start slapping parts together

I'm going to do a tube chassis on it. I'm not sure how much though. The rear end for sure since I plan on that being exposed. Instead of cutting on some aluminum plate and doing a ton of steel work only to find out I put mounting holes in the wrong place I decided to make a mock up chassis out of plastic. The final rear portion of the chassis won't look anything like this at all but this way I can make the chassis swiss cheese and find the right mounting locations for shocks and links and then use it for a template when building the final setup.

Wheels are only for mock up too. Turns out they have the right offset so I can just match that with a better looking wheel set. Rear shocks aren't final either. They're only 90mm eye to eye so I'm not getting the travel I want out of the rear end. Something around 100-120mm will be perfect. These lipos are for weight mock up only. I'll be using smaller packs that fit on this chassis.







This is just a box sitting in the front to hold the body up. The track width is nice and wide now.



I need to stretch the wheel base just a tad but I can do that when I make the final links.





Here's the drop out with the 90mm shocks.



Up travel won't be a problem.



As for power. I don't want to drop a ton of money so I'm thinking about trying one of these? Should put me right around 30mph on 3S which I'm thinking would be decent for my local tracks and some bashing. It's going to be around the weight of a monster truck probably. Anyone try these?

http://hobbycity.com/hobbycity/store...idProduct=6675

I also have to figure out how to take the outputs from the hyper 7 center diff and convert them to a standard 5mm shaft to make it easier to find center drive shafts.

[Slowkrawl]

Is that the rc4wd straight axle?

[_paralyzed_]

How many projects do you have going?! This one will be awesome I'm sure.

The motors you linked to have been real hit or miss, some burn up immediately, some last. IMO I would choose a higher quality motor.

These: http://www.rc-monster.com/proddetail...d=RCMdiffshaft will get your hyper 7 cd outputs down to 6mm. With that could you use traxxas center shafts? (the original t-maxx tranny had a 5mm output shaft for the 5mm side of the equation)

Just a thought. Regardless, I'll be watching this build!

[Topspeedtimmy]

Do not get a HK/turnigy/cheapo motor. It might get you the speed you're looking for, but it will overheat and/or fail very quickly in almost vehicle (especially one as heavy as yours). You simply can't cheap out on the motor. Those cheap motors are very inefficient and will heat up like none other even if it didn't fail immediately because of the quality.
I really wish there was an efficient and very low-cost motor, but there is no such thing.
An L-size Feiago would be a step up in quality, efficiency, and price. You might be able to limp around with one of those.
Really, $160-170 for "Buggy size" 1512 Tekin or mamba motor would be a very solid set-up.
If you really can't shell out the dough, maybe a used 60mm medusa or just a Feigao.

[suicideneil]

For testing purposes those hobbycity motors are fine, but for the final thing I would definately find a better quality motor- ebay always has bargains galore if you are patient, or see if Linc has anything suitable, you know what he's like for buying & selling motors

Looks great so far dude, always nice to see someone else's take on a concept

[SpeedAssault]

Awesome
Where is that rear axle from ?
any details on parts?

Hoping to build something similar some day.

watching this one

[Bondonutz]

FYI, Those HC Motors are IFFY at best.
Just received a 1100kv XL and I can't do anything with to curb temps worth a dam. Plenty of power but geared ultra conservative with 5s still gets SMOKIN' HOT ?

I however have had great luck w/the Gold canned Turnigys motors.

[suicideneil]

Originally Posted by SpeedAssault

Awesome
Where is that rear axle from ?
any details on parts?

Hoping to build something similar some day.

watching this one

Rear Axle: http://www.rcrockcrawling.com/produc...1354d29c24339c

The front end is an MT2, centerdiff motor mount from Mike (+ stock center diff and plastic bearing support, any ebay item would do as its not being used in a specific truck), custom made chassis and rear suspension; all the info you need is in the 1st post and the pictures.

[MetalMan]

Very cool! I like that you are making this into a more scale aspect, as opposed to the function-over-form version I created.

[shaunjohnson]

that is a COOL @$$ project!!

[simplechamp]

Love the remote reservoir shocks.

[NickRummy]

Originally Posted by _paralyzed_

These: http://www.rc-monster.com/proddetail...d=RCMdiffshaft will get your hyper 7 cd outputs down to 6mm.

I hope he gets them in stock again soon. Those would help out TREMENDOUSLY.

thanks for all the input on the motors guys. I was thinking about putting in an order today actually so maybe I'll hold off and search the used ads.

My newborn and wife permitted shop time last night

After some searching and suggestions from another person I got in a center diff from a Redcat Aftershock 8E because it has 5mm outputs and it's cheap. I need the hyper diff for my other truck anyway.

Here's the new diff, motor mount and a VXL motor in there for mock up. You can also see something else I am trying with the rear suspension. I went ahead and joined the lower links with a cross bar to keep them parallel to each other. I figure all I need is up travel and down travel. I don't need articulation so this will keep me from having to add a sway bar to keep the body roll down in the corners.



Then I decided to start messing with the rear suspension to see if I could get the travel I wanted. I added on to the plastic mockup chassis to give me some higher shock mounting points. Then I took a couple savage shocks I had and put them on there.



Looks like they will have the perfect stroke. I need to measure the lower link length and lower shock mounting point and start working on a final design. The wheelbase needs extended some too. It will compress fully and will actually require bump stops.



Now the drop out is where I want it



Here's how ugly the mock up chassis is looking now You can see the rear drive shaft mocked up too.



I'm thinking about maybe just using the stock MT2 chassis for the front and then bolting on a plastic plate to widen the chassis for the battery mounts kind of like they do on the 1/8th scale buggies. That'll save me fab time on getting all the holes in the front end lined up correctly for the bulk head and steering.

[MetalMan]

Did you see mine?

It's tough to make a chassis well suited to the MT2 front end. I found out the hard way

[_paralyzed_]

anything new?

[Bondonutz]

From the other thread about you being a tranny is new to us ?