Dynahead 6wd non scale crawler build thread....with a twist!

[Losi XXT-CR 469]

This journey starts way back in 2017, where I ordered a Konghead. Which I have to say has been one of the most fun and versatile RC vehicles I've ever owned.

I built the Konghead as a fun basher with a bit of speed, well speed for that kind of vehicle. I never installed the the silvercan, went straight for a 10.5T sensored brushless setup with a 20t pinion. Never been dissappointed in how it goes and thus far only broken a dogbone driveshaft. One thing that struck me was when going slower and somewhat crawling the open diffs really held it back. I learned of the Dynahead, which I always thought seemed expensive compared to the Konghead. But also found out it used a diff putty to improve its crawling ability.

I did order some diff putty with the intention of using it, but tbh you need to strip the entire vehicle down to get to the diffs and I never bothered.

Fast forward a number of years, i.e. a few weeks back. And I stumbled across a YouTube video of a Dynahead and thought how great it looked with the simple addition of a roof rack and some different tyres:

Well this got me hooked and I decided I wanted to buy one. I still thought it was pricey, but ****!!! They are sold out everywhere..... I looked and looked and looked. Then gave up and decided to buy a Buggy Champ. But while checking prices out I stumbled across a company called EuroRC who's site claimed to have a single Dynahead in stock. I decided to take a punt and order it. A smooth process and just over a week for delivery.

I had some ideas on what I wanted to achieve, so I started buying a few additions. The first to turn up was the wheels and tyres. They were pre-mounted Proline Hyrax 1.9 G8's. A bit pricey for 6 too! I test fitted to the Konghead while waiting for the Dynahead to arrive.

 

Then on with the build. First mod was to "lock" the diffs, which thankfully is super easy:

While waiting for the kit to turn up I'd also placed an order with RCBearings for a full set of... wait for it... 76 bearings!!!

Day 1 over, well a few hours at any rate and we have an assembled chassis.

Next job was assembling all six portal drives. Fascinating how they work and quite a bit to assemble each, but also very enjoyable to build. At this point I'd decided on 4 wheel steering, so I ensured I built up 4 of the portals with the correct housings to allow steering.

Then all mounted and the stock silvercan motor installed. I think the silvercan sill be fine for this, no interest in brushless here.

 

Day 2 - and I got the shocks fitted. Well sort of. Last weekend I fitted alloy shocks to the Konghead, which meant buying two sets of four. So I had a pair left over. On the Konghead they look great, allow it sit lower, more control and the alloy shocks allow a tad more suspension droop over the kit friction shocks. So I've order another pack of four alloy shocks for the Dynahead, but for now it'll have to do with two and four old frictions ones off of the Konghead.

Speaking of shocks, the oil and pistons supplied with these shocks are quite stiff damping. The instructions say to use a 3 hole piston, but they only supply a 2 hole white nylon piston in the kit. The other pistons are black on the included parts tree, aren't 100% round and didn't really fit the shock body. For these spare two shocks I used some old Schumacher shock oil I bought around the year 2000. It is rated at 70 (different scale, its quite thick), but not as thick as the 400 weight Tamiya oil that came with the shocks. But they are still too stiff for a crawler in my opinion. When the other shocks turn up I'm going to drill the pistons out a bit with a bigger hole and drop the oil weight down to 30 or 35.

After fitting the shocks I jumped a few steps in the instructions and fitted the wheels and tyres. Having test fitted (but not run) them on the Konghead, I was expecting them to rub for the rear steer. 

While building the Dynahead, I noticed some smaller hex drives on the parts tree:

I didn't think it'd solve the rubbing issue, but thought it'd allow more lock before being an issue. Luckily the Proline rims just clear the portal drives with the smaller hexes on, but only just!

 

I then test fitted the electronics and finished off the rest of the build steps. Here it is fully assembled next to the Konghead. You can see how much lower the Konghead sits. A real striking difference between the design and usage intents, despite a common base platform.

 

As I'd got this far I thought it was time for a test drive to see how bad the tyres rubbed. So I took the Dynahead outside on the driveway and tried a few lumps, bumps and a simple step climb. The Konghead will only bound up the step with a bit of momentum and not every time. The Dynahead drove brilliantly from the off. Plenty of power and low speed control from the 27 turn silvercan. And while the tyres do rub and make a slight noise, it really isn't as bad as it seems and is quite liveable. 

While playing about on the driveway, it did strike me, I wonder how it goes in reverse. To which it seemed to excel and arguably climb better than going forwards. I found this interesting, as I'm a huge fan of the European truck trials, on which the Dynahead kit is partially based and inspired. My favourite trials truck is the Tatra 6x6, which is somewhat unique in that the tow front axles are closer together, rather than having two axles at the rear.

This was it. Decision made:

Some effort spent cutting the body out and drilling some holes for the body mounts and it seems an almost perfect fit.

Electronics tidied up, its running a Hobbywing QUICRUN Crawler ESC (which I'm yet to play with the included programming card) and twin 25kg "cheap" eBay servo's. One with an alloy servo horn. I also swapped the motor wires round, so it should work ok I think and in the intended direction of travel.

 

I also elected to not add any of the bumpers while building the kit, to give the best approach and departure angles.

 

Next jobs are to paint the body (I hate doing this!!!). And to give it a bit of a shakedown run to see if it really does work. Or if I've made a mistake and need to swap the body back round.... fingers crossed

 

When the shocks arrive I'll get them fitted, I'd like the suspension to be more compliant and allow maximum suspension flex. I also have a few alloy upgrades on the way for the servo mounts.

[Pablo68 1118]

Great build so far mate!

[OoALEJOoO 3283]

Nice build and project you have there.

If removing your front (originally rear) bumper, I would recommend reinforcing the face section where the two chassis halves meet. Otherwise, bumps could crack the corners and stress split the seam and allow dirt into the gear train.

The easiest way is to cut the original bumper part C19 so that only the reinforcing plate section is left. Alternatively, you can get some aluminum bling and get 54597. Even better, make a custom aluminum plate with some aluminum sheet material.

[OldSchoolRC1 1079]

I love it! Nice to see another dedicated crawling Dyna out there.

I run Hyrax in the 4.19 flavor, they fit great. Not sure if I want bigger tires yet or not. 

[CoolHands 949]

Nice. I fitted a hobbywing ‘555’ 11 turn motor to mine, designed for crawlers so very smooth. You can get one for £20. Still reasonable turn of speed

 

[Losi XXT-CR 469]

Prepping for painting. Not going box art as I don't have the right colours, so using what paint I've got. Will be a fairly simple paint scheme. But hopefully it'll look ok.

[Losi XXT-CR 469]

Shell painted and decals applied. Quick test run today. 
 

The remaining four shocks also turned up today. So a job for tomorrow evening to fit. 

[Losi XXT-CR 469]

Alloy shocks arrived from Aliexpress. A set of four, as I had two left over from my Konghead shock upgrade.

The stock friction shocks and standard config of the alloy shocks all feel a bit stiff for a crawler, when lifting a wheel to compress the suspension, it tended to lift the entire vehicle.

The pistons supplied with the kit are 2 hole, look to be about 1mm. The instructions do say use 3 hole pistons, but the only ones provided are the black ones on the parts tree, but they aren't round and don't seem to fit the shock body very well, as in slightly too big... maybe others have had success with these, but I couldn't be bothered faffing with them. So what I've done is enlarge the white nylon pistons to a 1.5mm hole and drilled a 3rd hole.

Filled with some old Team Schumacher 35 weight shock oil and reused the standard kit springs.

I've also lowered the ride height, it has loads of clearance with the portal axles and I felt it was a little top heavy on extreme angles.

The suspension feels a lot more compliant, although the single axle (rear) seems less willing to compress, it probably has less weight over it. But it feels a massive improvement over the friction shocks or how I had the first pair of alloy shocks.

[J@mes 2347]

I love the idea to turn it round. This chassis is such an obvious ‘push me pull you’ with the same bumper each end.

[CoolHands 949]

Can you put a link to the aliexpress shocks you bought? Are they the right length / seem decent?

[Losi XXT-CR 469]

8 hours ago, CoolHands said:

Can you put a link to the aliexpress shocks you bought? Are they the right length / seem decent?

https://www.aliexpress.com/item/1005006009010812.html?spm=a2g0o.order_list.order_list_main.5.1e921802dnUknW

Available with or without oil.

[Grumpy pants 5503]

Great thread, amazing turn around time from kit to built and then trailing to developing 👏

[Losi XXT-CR 469]

Sadly the bodyshell doesn't seem as strong. My Konghead has taken many knocks no problem. The Dynahead has only toppled over so far from less than walking pace. But the shell is showing some signs of duress. I also not the front under the grill is also way thinner than the rest of the shell.

So I've started strengthening the shell with Shoe Goo and plasterboard tape.

Still a bit to do, but I can only do so much glueing in one go

[Losi XXT-CR 469]

I also ordered up a small stainless threaded rod. You are meant to use a long grub screw for this, but of course I've swapped the mounts to the other end and the long grub screw isn't long enough. But it does make the posts more stable and less wobble with the body mounted.

[Losi XXT-CR 469]

Adding some bling...

[Losi XXT-CR 469]

Had a few goes with the Dynahead. Overall it is great fun and I'm super impressed with how it goes. It might be a little top heavy, but still learning what angles it can and can't do. I might play around with some brass weights at some point, but in no hurry. Would ideally like to get out with some other crawlers and see how it compares.

 

Short video going over some obstacles today.

 

[JimBear 1024]

From the video example, it looks pretty capable, indeed! The six wheels really does it. Will be interesting to hear how you get on with it long-term.

I was always on the fence with the Dynahead body, but in motion it looks pretty cool, like some sort of utility vehicle for severe terrain.

[TwistedxSlayer 1303]

OK, I defo gotta get me one of these at some point.

[Losi XXT-CR 469]

Fitted the last bit of bling today to replace the rear (would have been front) bumper.

As you can see above, the stock one has dug into the mud on at least on occasion. There is a big silver bumper upgrade, but it seems pricey and nowhere in the UK or sensible shipping to the UK seemed to have one.

 

So I opted for this blue one from eBay instead.

 

I'm not 100% convinced on the look, it sticks out a bit too far for my liking. But I'll run it and see if it is an issue or not.

[Losi XXT-CR 469]

ok, so one more bit of bling!

Although it should add a little protection for the motor too.

[Losi XXT-CR 469]

Took the Dynahead out with a local crawler group at the weekend. A 2-3 hour stroll with the RC's over some varied terrain.

 

I was really keen to see how it would perform against other more conventional crawlers. To which, I'm pleased to report that it went very well and performed brilliantly.

Sadly there isn't much in the way of rocky outcrops where I live, so this was very much a wooded area with muddy hills and quite a chalky clay like soil. Lots of leaves on the ground too.

 

 

I've been running the Dynahead on 2S I used 2 packs while out, both TrackStar 5600mAh. The 2nd pack had loads of power left and first wasn't fully flat. Low speed control is good, the portals give reduction gearing, but maybe not as low as some other rigs. For pure rock use maybe a tad slower would be ideal, but no real complaints. And mostly it had plenty of power on longer climbs. Although some of the hills we went up where as high as the front of a house. And on occasion a little more wheel speed might have been ideal.

In terms of performance and ability I learnt a lot. The G6-01 chassis has quite a high centre of gravity with everything on top of the chassis and the big gear set inside the chassis. This means it will flip over backwards or sideways at times. But it didn't really seem any worse than most of the vehicles out playing. Again, a purpose built rock coarse might be slightly different and it won't simply won't climb such a steep grade without flipping over. The steering also has more steer on the rear axle (remember I reversed the chassis, so it'd normally be the front axle). This is good at times for manoeuvrability but on slippy climbs can cause the back to swing about and get you sideways. It also isn't the best on a side slope.

To this end, crawling over roots, logs, boulders and objects it works better the way I have it with two axles to the front. But for long slippy climbs it does better going the other way with the twin axles at the back. That said, this is largely a stability thing. It still climbs very well the way I have it, you just need to keep it straight and be gentle on the steering. A number of slopes the Dynahead cruised up where the 4 wheeled vehicles where struggling.

Despite quite a few tumbles and flips the Dynahead performed flawlessly with only the loss of a rear body clip to show for it. The bodyshell also held up remarkably well too, very glad I spent the effort with the Shoegoo.

While out on the day conversations turned to brushless setups, such as the Hobbywing Fusion Pro and SE. But having got home and thought bout it a bit more. I won't be rushing to buy one just yet. It seems the Fusion's only really offer the benefits on 3S. And while they will go slower than my silvercan, the calculated  high rpm speed is less on 2S, e.g. the 1800kv SE is just over 13,000rpm on 2S, while a silvercan should be around 14,000rpm. So I wouldn't gain the wheelspeed for the longer hills. Although I could probably gear up on the pinion and still get good low speed. But still..... something for another time perhaps.

What it did do is get me thinking that my 1080 ESC is also 3S capable. So I tried a 3S in it this morning. Only in the house. Oddly it crawls slightly slower on 3S than on 2S. I guess the motor is making more torque, thus allowing it to spin slower and still move the Dynahead. And it should offer the higher wheel speed too, without need to change pinions or spend out on a new motor/ESC combo.

The only downside is, all of my 3S packs are slightly too tall for the battery clamp, this is the taller battery:

I think some velcro straps will work as there are slots in the sides of the battery tray, so I have ordered some up today.

I also thought I'd add a few extra body clips for storage on the bottom of the body posts, should I lose one again I'll now have a spare.

[Losi XXT-CR 469]

Not my footage of the day, but the Dynahead makes an occasional appearance.  

 

 

[Losi XXT-CR 469]

Battery straps arrived. 3S now installed, although gets a little close to the body. Will need to give it a try out now.

[Losi XXT-CR 469]

Nothing too challenging, but giving it a little try out on a 3S pack.

 

[Old_Corny 315]

3 hours ago, Losi XXT-CR said:

Nothing too challenging, but giving it a little try out on a 3S pack.

 

I've never done any "crawling" but I get the sense that it would benefit from some ballast for additional traction. Would that work do you think?