Complete and running! RC Offroad Scaler conversion.

[PraetoR]

Hi folks,

as title says, I'm trying to convert my crawler into a scaler.

 

Got the RC Offroad uni chassis: http://www.rcoffroad.eu/rcoffroad-eu/eshop/15-1-ChassIs/0/5/86-uni-chassis

and the crawler is from Seben Racing, which is identical to the Maverick Scout.

 

The crawler with the scaler chassis, you can see there's no transmission mounting plate, so I had to do a bit of cutting and drilling to get the wider plate from the crawler to fit.

 

I was initially trying different mounting points for the upper and lower links, but could not find positions that allow for articulation, or changing height, without wheelbase changing as well. Also, the wheelbase is really long: if I set the links allowing the shocks to be vertical and not leaning forward, the wheelbase looks ridiculous! Far too long, and I can't find the sweet spot to allow the servo to be parallel to the ground either

 

... Especially when looking at how much smaller the scale wheels are.

 

Here's an example of how much I'm struggling. Just as an example, I've got the links different front to back: different lengths, mounting positions (inside and outside) etc. and I just cannot find how to make the thing articulate properly. Also, as an example of how long the wheelbase is sitting, the front driveshaft isn't long enough, even though the springs have been removed to allow the truck to sit low. And the driveshaft at the rear is at completely the wrong angle! I'm not planning on running it like this, just trying to show that I've changed many things about, but still can't get there.

 

 

 

 

I know a few of you have used these types of chassis' to convert Maverick Scouts; this truck would need the exact same treatment.

 

Any help would be greatly appreciated, I need you crawler experts!

 

Cheers.

Edited January 14, 2015 by Praet0r87

[Gaz!]

first job mate is ditch those shocks and look for some 90mm ish ones, this will bring the axle to chassis distance closer, then its time to play with the links, you might find you could need new links all round to acheive what your looking for.

 

once you have those 2 jobs sorted it should look a lot easier to make more progress

 

do the top shock hoops move or is that the only position they fit??

 

also lastly, many of these chassis work with the scx10 skid/gearbox mount whereas the scout/ax10 etc are wider

[PraetoR]

first job mate is ditch those shocks and look for some 90mm ish ones, this will bring the axle to chassis distance closer, then its time to play with the links, you might find you could need new links all round to acheive what your looking for.

 

once you have those 2 jobs sorted it should look a lot easier to make more progress

 

do the top shock hoops move or is that the only position they fit??

 

also lastly, many of these chassis work with the scx10 skid/gearbox mount whereas the scout/ax10 etc are wider

OK I will do, I was wondering that myself.

 

By top shock hoops, do you mean the triple-mounting pyramid-shaped things where the top of the shock bolts to? If so, the do not move, which is why I'm struggling to bring the wheelbase in a bit without having the shocks at a 45 degree angle.

 

I'm good with the gearbox mount now, since I've altered it to fit.

 

Cheers.

[Gaz!]

ahh righty oh,

 

so, you need to utilise what you got then, the shock dont have to be bolt upright, a slight angle will be fine.

 

also if you look at your axle side on (front) the servo needs to either be perfectly horizontal or slightly lower at the front by a couple of mm maybe so that gives a little to work with.

 

the rear axle on the otherhand, once the smaller shocks are fitted you can rotate the axle so the output (where the propshaft fits) can point more toward the transmission eliminating the prop angle.

 

but again a set of shocks and a day spent tinkering and making links will solve all your issues i guarantee it

[PraetoR]

Brilliant, well I'll get some 90mm shocks ordered then, and work from there.

 

Can you recommend some links?

[Swift_N_Bold]

Id suggest tube mod on your current shocks add different lengths to achive different heights then order some to the size you need.. good luck with it

[Gaz!]

i wouldnt use the tube mod as on a scaler its not the correct way to go.

 

links wise i would use some 3mm threaded rod, some traxxas rod ends and some 6mm od alloy tube.

 

if you give me the sizes you want i can make them for you if you not too good with the tools

[ghazghul]

Do you have a planned body for it?  You'd need to check it fits the chassis (which looks long, but it could be the 1.9 tyres) and get your wheelbase to fit the body.

 

Taking the springs off the shocks (as you did at the front) is a good way of seeing how 80mm shocks will make it sit and add 10mm of fuel tube on the outside section of shock shaft to try 90mm.  Obviously it wont articulate right, but lets you see how it'll sit before you order shocks?

 

Also although you could normally angle the rear axle to straighten the prop shaft it looks like you are running 4WS and doing that will effect the steering at the rear.  You want it the same as the big gaz said for the front... so move the upper links out a hole on the chassis.

[PraetoR]

Thanks Gaz, that's very helpful. I would give you the sizes if I knew them! I'll let you know when I have the chassis sitting right.

 

Yeah I won't use the shock mod, I'd rather have better shocks than the stock ones anyway.

 

ghazghul, I'd like to use the Tamiya Ford Bronco, but that's for short wheelbase trucks. I have one of those shells sitting at home. I thought of a way last night to shorten the wheelbase and reposition the shocks anyway, so we'll see how that plays out. I'm going to remove the 4ws, so the rear axle shouldn't be a problem.

 

Thanks for the advice lads.

[PraetoR]

Bit of progress made and I'm far happier with how it's going.

 

This is the chassis as it sits now: on top of a box of matches to hold it up because I don't have links yet!

 

 

 

Mounted the new shocks thusly, to reduce wheelbase a little bit. Required some drilling and it's so strong it snapped two titanium drill bits. This is the rear.

 

 

 

Obviously, the old chassis had to be sacrificed to allow me to make the shock mounts!

 

 

 

Originally had the same mounts on the front, but still too long a wheelbase, so used some lovely pieces of carbon fibre instead.

 

 

 

Shortened the chassis overhangs at both ends, too, by removing excess, which will allow the shell I've chosen to fit.

 

 

 

Chassis now has a nice squat, wide stance. Going to measure for links and either buy/make some, or maybe ask Big Gaz nicely.

 

 

Finally, I removed the 4WS and locked the rear axle. Handy, because the servo in my Mad Rat failed today and this meant I had a spare!

Edited April 17, 2014 by Praet0r87

[Gaz!]

looking much better now matey

[PraetoR]

Thanks buddy. Got the 3mm threaded rod and 6mm tube coming within the next few days. Unfortunately the rod ends are coming from over the pond and will take a few weeks.

[Swift_N_Bold]

Tinkering away there nicely mate haha what shell have you chose. ? When making my links I just re tapped original maverick rod ends the traxxas ones are a tad better built and longer than the scouts. And if you havent got access to a tapper set proberly best choice. I still need to get some 6mm tube to tidy the threaded bar but it can wait for a bit. Saving at mo for new gears motor and a lipo or two.

[PraetoR]

Yup it's starting to look more acceptable! Going for the Tamiya Ford Bronco.

 

I don't mind waiting really, it was the only place I could get 16 matching ones for cheap.

 

I wish the 6mm tube was orange though, or black, might look into painting them.

 

New gears? Are they stripped?

[djmark1984]

im planning on doing the same with my scout looks like its not as easy as i first thought lol looks good so far buddy looking forward to seeing it finished

[PraetoR]

djmark1984, don't let it put you off though, it's still well worth the challenge! Although I'd maybe choose a slightly different chassis, one with the gearbox mounting plate, for example.

 

Another little update. Please forgive the terrible image quality. I don't have my camera with me just now and my phone camera sucks!

 

 

I've moved the front upper shock mountings even further back on the carbon fibre, just because it allows the wheelbase I want without the front shocks leaning forward, as before.

 

 

 

 

Additionally, I've hacksawed-off the strengthening plate at the very front, as the steering servo fouls it during articulation. To compensate, I've added another strengthening beam across the top, on the furthest-forward shock mounting holes. It's strong enough.

 

 

 

At the back, I've made longer shock-mounts from bits of the old chassis. Haven't changed the wheelbase or anything, it just allows the shocks to be at a less extreme angle.

 

 

 

 

Removed the last remaining bit of unneccessary overhang at the back, as it still may not have fit under the Tamiya Ford Bronco shell, otherwise.

 

 

 

 

As the chassis currently sits. I've measured for the links; the shocks and driveshafts won't be sitting as they are in this picture, but not far off. The front diffs assembly will be further forward than this, and both driveshafts will be at less extreme angles.

 

 

Cheers.

Edited April 23, 2014 by Praet0r87

[Swift_N_Bold]

I had similar issue with shafts to get the ground clearance articulation wheelbase I shortened the rear shaft cut equal parts of both ends same with link arms.(still a work in progress). I think you may struggle to get your shafts to sit nice with out dropping ride height shorter springs.

Other wise you will have to set your axles at a steep angle to compensate for the shaft angle and this will effect your steering.

My gears arnt stripped no just plan to change to a 80t spur 20t pinion with 35t motor this should give me better wheel speed so when walking along trails it keeps up with me but still keeping the torque to get up and over things.

Keep up the tinkering..

Edited April 26, 2014 by Swift_N_Bold

[PraetoR]

Hark! Doth mine eyes deceive me? Progress?

 

Yup!

 

Got the links made up, measured and fitted. Big thanks to Big Gaz for the tips of what materials to use. Haven't sleeved them yet, but that's not a priority just now. Also, you'll notice the springs are different. The red ones were just too stiff, so these silver ones are actually Tamiya Lunch Box springs! They may still be too stiff though.

 

I like how it's sitting. I think the squat, low (ish) stance with still decent clearance will look pretty realistic with the shell on it.

 

 

 

 

 

 

 

 

 

 

Articulation is obviously far removed from the original donor crawler, but this is still pretty good, and much more realistic... I hope so anyway!

 

I'm having to hold the truck down in this photo, because the springs are still too stiff, I reckon. Makes the rear wheels lift, otherwise.

 

 

 

 

 

 

So next is to make some shell mounts and get the electrics/battery fitment sorted out. Then the shell.

 

Can the crawler experts advise me as to whether these springs are too stiff, and if so, which to use instead?

 

Cheers. Getting there!

Edited May 10, 2014 by Praet0r87

[ghazghul]

I suspect you are going to end up getting some shorter shocks... it's got to get a fair bit lower before those drive shafts are going to turn properly.  Getting there though, the links look pretty spot on!

[PraetoR]

I suspect you are going to end up getting some shorter shocks... it's got to get a fair bit lower before those drive shafts are going to turn properly.  Getting there though, the links look pretty spot on!

Don't worry, I've tested that, they turn OK.

[rawalker666]

why such a short wheelbase i used one off those chassis on a scout years ago and never had any issues like you seem to be having

[rawalker666]

this is what i made using all stock links and a simple skid plate to drop gearbox a little ans some 4" shocks on it rest is all standard scout

 

[PraetoR]

why such a short wheelbase i used one off those chassis on a scout years ago and never had any issues like you seem to be having

I like the size of the Tamiya crawler shells, which are shorter.

[PraetoR]

Another quick update: Cut the springs from the original crawler to size and fit them in the place of the Lunch Box Springs. Much softer now. Articulates easier.

 

Rawalker, I like the look of your crawler. Do you have any with a scale shell on? Only my brother in law wants to make a scaler conversion for relatively cheap, so a Scout is a good place to start.

Edited May 11, 2014 by Praet0r87

[rawalker666]

Never got round to putting body on myself sold it on but guy who got it off me fitted the proline jeep pick up one with very minor alterations

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