depro

Hello all, having built a few offroad rc cars, I've decided to take on the challenge of building an onroad rc car from scratch using minimal off the shelf parts. Getting all the necessary components tucked onto the chassis will be difficult, but not impossible. The goal of this project is to create an onroad vehicle with easily adjustable suspension. I've spent a few days thinking about ideas and have come up with a simple yet functional chassis design to achieve this goal. Here are a couple pictures of the base chassis I just cut out today.

dragnse7en

Nice shapes. How thick is that aluminum?

Haddi Taha

Cool, what scale?

depro

The chassis is 1/8th inch thick and don't laugh, but I'm going to use Tmaxx differentials since I have a couple on hand already. The axles as well as hubs will be from the 4-tec. I've also got a Tacon 5900kv motor on its way with a Gens Ace 2600mah 55c lipo. I'll be using an old mamba max which should do fine since its just 1/10th scale. Here are some simple cad drawings of my overall design. By any chance does anybody know of any tires that squeal like full scale tires? I remember a long time ago I saw a guy driving his rc car and the tires squealed little mini high pitched squeals. Granted after a while it might get annoying, but still would be cool.

Haddi Taha

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this threads gonna be awesome.

proanti1

My Feedback: (2)

The slicks I had on my 5b squealed.

ozzie-crawl

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sloppyG

I was hoping for an on road RC that looked like a log [&o]

depro

Hahaha if somebody can come up with a log body I will run it. What do you guys think makes tires squeal? Do you think its caused by the weight of the car, or by the tire compound? Does anybody have any suggestions which tires I should run on these? I usually shop at Hobby People and I run my car on a relatively smooth paved surface. I'm looking for maximum grip, the kind that causes traction rolls

proanti1

My Feedback: (2)

Is this going to be the basic 190mm onroad car? Or something larger? Looks a little big... maybe 2.2 truck tires with super soft clay slicks?

depro

Oops I forgot dimensions and yes it'll be a 190mm car. The chassis in the picture is only 5 inches wide and 14 inches long. The distance between the upper and lower deck is 1.5 inches, hence the challenge of fitting all those parts in there. I'll but using 3/8th's thick nylon for all the suspension arms and chassis pieces.

depro

Just a little update. I cut out the part templates tonight and will hopefully start cutting out parts tomorrow.

Haddi Taha

nice job so far.

Haddi Taha

out of curiosity, where did you buy the nylon sheets and what did you cut them with?

dragnse7en

I don't want to stand on top of a soap box, but -

If you do expect to add bolt-on existing parts from ANY high-performance car, convert all your measurements to metric - just an engineer's heads up hoss I hope this isn't another thread that gets only half-finished Keep the project rollin mang!

depro

I bought the nylon sheets from McMasterCarr and I cut them with a jigsaw. McMaster has an enormous selection of various plastics, metals, and all at decent prices. Nylon unfortunately is pretty expensive across the board, but its durability is unparalleled.

As far as units go, I almost always work in inches. When it comes to fitting in parts from other vehicles such as the Traxxas differentials, they're really randomly sized and no measurement in inches or millimeters is convincing. To fit the differentials I will use the method of cutting a little bit at a time until everything fits. My main tools are a drill press and the jigsaw.

Have no doubts this car will be finished and will see at least 60mph although it will be geared for 75. Here are a couple pictures of the offroad project I recently completed. Its been up to 65mph so far and I'm pretty sure its got more left. I think the mamba max is holding it back a little, but the A123 batteries are supposed to be good for high amp bursts. I have it geared for 100 and aerodynamics might be a big factor holding it back.

dragnse7en

Okay - 190mm, right?

I think they have a 230-239mm wheelbase, 185-195mm F/R track, under 2-1/4 lbs total weight . . . . can it be done?

That front damper stay is way too tall, artoo see if you can fix that. 62mm bore size dampers/ shocks (AE TC3/4/5 or TRF dampers) are ideal.

depro

Yes you're right it will be a 190mm onroad car and I believe the ROAR minimum weight is about 3 pounds now so that's what I'm shooting for. The motor and battery should be arriving tomorrow, and hopefully the axles and other stuff will come by next week. By the way does anybody have a starting point for which weight oil I should put in the differentials? I'm currently running 10k weight in my offroad car but I've never setup an onroad car. The shocks will be 4-tec shocks since I have them on hand, and I'm also unsure which weight oil to put in them. They currently are filled with 30 weight oil. Also if anybody wants to fill their t-maxx diffs with oil and not have them leak, place o-rings on all three output shafts. Many people have had great success with the o-ring mod as well.

dragnse7en

Your answer to the diff oil fluid - you might not like it, but you might as well pack it halfway with moly grease - the synthetic oil is so thick that its grease.I hear too many guys complaining about the standard oil wchich feels like a 20 or 25 wt old skool AE shock oil. I don't blame em after I felt the oil myslef though.

The TRF417 Diff Unit says #1000 wt oil - hard synthetic shock oil. That makes more sense, or call me insane.

ozzie-crawl

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proanti1

My Feedback: (2)

Wait what? Why would you put o-rings on the three output shafts? You are supposed to be putting oil in the little cylinder shaped carrier, which is already sealed, not the actual diff case...

depro

Hmm this is interesting. I've heard grease doesn't work well with geared differentials because once the gears cut a path through the grease, the diff action is really free. Can somebody elaborate on the purpose of filling the front with thick fluid and the rear with thinner fluid? What does this do in terms of handling? Also, if anybody has ever tried to add silicon oil to the old style tmaxx diffs, it leaks right out after a few runs. The spider gear output shafts are not sealed in any way, hence the need for o-rings.

dragnse7en

The TRF417 diff gear units, numbers 1 and 2, both use a cotton/ paperlike gasket seal to keep the oil in. Built as well as the shocks too!

Yesterday at the off-road track, I think they were also running heavier oil for the front diffs. That kind of makes sense for me, but for on-road, I only need a gear diff for the rear and a front direct coupling or ceramic nitride front ball diff.

I used to have a Losi Hydra-drive conversion kit for my RC10T's stealth tranny, and the fluid was nice and thick. I'd like to use that!!!!!

ozzie-crawl

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dragnse7en

That makes sense as well. That could open up an option for me on my ver.IIR and TA06. I'll get two gear diffs then for the older car and try that out instead of the direct coupling/ spool.