GF01 - Heavy Dump Truck

[Nikko85 3453]

I'm about to start my first proper Tamiya, a GF01 Heavy Dump Truck. Although I've been on the forum a while, having got back into RC cars after 20 year break (due to pandemic and trying to find a hobby that avoided screens) I've yet to make a car from a kit. I've modified quite a few toy grade cars, including my only other Tamiya,  a QD Pumpkin which got modern electronics and a brushless motor.

That 1/14 QD Pumpkin is a favourite, and it now lives with a few other cars that share the exact same body size (including a few other 4x4 Monster Trucks) but nothing that has a full 540 motor. When I saw the Beetle Trail I wanted it (with a view to adding a Pumpkin Body instead) but then realised that the Dump Truck would make a cheaper, faster car and still work, the yellow of the truck matching the pumpkin. Recently I've also started to realised that although I could probably fit a Pumpkin body on, having an RC dump truck is also very cool.

The truck arrived yesterday and the bearings arrive tomorrow, so I'll start work then, and 'll probably ask lots of stupid questions. At the moment I'm going for stock, with the standard motor and speed control. I know I'll want to add a servo/system to tip the bed, ideally a system that pushes the car back on it's wheels when it flips over, but apart from that I'll keep it simple. 

Any building tips before I start? 

Thanks

 

 

[J@mes 2326]

I love the Heavy Dump Truck, great choice! 
 

If you don’t already have 74085 it’s worth the money. 74035 is worth having too as the flat side gives a nice finish. 

[Nikko85 3453]

Yep, it looks killer. I was keen to swap it out for a Monster Truck body, but the more I look at it, the more I want it as is.

I've also got one of these at 1:24 so I could legitimately make a 1:24 scale gravel pit and haulage company!

 

[TurnipJF 9192]

You have the first of the "big 3" hop-ups on the way in the form of a bearing kit, so how about ordering the other two - a steel pinion and oil shocks?

[Nikko85 3453]

1 hour ago, TurnipJF said:

You have the first of the "big 3" hop-ups on the way in the form of a bearing kit, so how about ordering the other two - a steel pinion and oil shocks?

I may go for the steel pinion, and see where we are at. I've got an option of a 20 tooth or an 18, which would be the gear for speed?

Thanks,

[TurnipJF 9192]

1 hour ago, Nikko85 said:

I may go for the steel pinion, and see where we are at. I've got an option of a 20 tooth or an 18, which would be the gear for speed?

Thanks,

20t

[Nikko85 3453]

Brilliant, it seems the acceleration is already pretty good (and will just wheelie at full throttle) so lowering the initial torque doesn't sound like it's too much of a problem.

I've ended up working till nine each evening this week, but hopefully will start making tomorrow.

I've genuinely not been as excited about a toy since I was about 11!

Andrew

 

[Nikko85 3453]

 I need a little help please.

My bearings arrived, and I started the build today. All's going ok, it's a nice little build. However the front diff are somehow locked. 

When I rotate the rear outdrive cup the other cup spins in the opposite direction, but on the front this doesn't happen. I attached a 1.5 volt battery to the motor just to test, and when the motor is going I can stop one rear outdrive cup (and the other rotates) but I can't stop the fronts, as they are locked together.

I'm 99% sure I used all the pieces when making the diffs - does anyone know what might have happened please? I feel I'll have to open it all up and have a look.

I'm done for tonight now - got about 1/3 of the way - although I feel I'll have to go backwards tomorrow.

Edit - I couldn't get to sleep with it bugging me, so I opened up the entire thing and found the problem. The diffs worked fine in themselves, but would stop working when the two haves of the chassis were tightened. It was the diff cup bearing in the chassis that wasn't quite pushed in. As it was a little proud it rubbed against the diff which was enough to bind it up when the motion of the cup was contrary to the diff gear.

What's funny is how quickly I put it back together again the second time round!

It's a fun kit for sure - I see what people mean about the screw that holds that suspension together (not idea what's that called) it looks like it could back out really easily as there's very little thread for the diameter. I think I'll get an M2.5 or M3 bolt and nylon washer. 

 

[J@mes 2326]

very rewarding to solve a problem solo, nice job 

[J@mes 2326]

On 8/16/2021 at 7:50 PM, Nikko85 said:

Yep, it looks killer. I was keen to swap it out for a Monster Truck body, but the more I look at it, the more I want it as is.

I've also got one of these at 1:24 so I could legitimately make a 1:24 scale gravel pit and haulage company!

 

Is it your video? That’s good driving with the unhitching & hitch of the trailer. 

[Nikko85 3453]

22 minutes ago, J@mes said:

Is it your video? That’s good driving with the unhitching & hitch of the trailer. 

Afraid not, although I upgraded mine to a full proportional control with a mini servo releasing the trailer!

Probably way more spent than it was worth, but it's so cool.

I've since upgraded the motor to a little 370 that fits in the motor bay, and I've cut the power down to a 6 x AA 7.2 stick, as it was just crazy at full power. Now it's pretty nippy, will now do a donut on my wooden floor, and can pull a 2.5kg weight without much hassle on the trailer, which is about scale. 

It's also much easier to control with full proportional control.

 

[Nikko85 3453]

Well, after a few days this week after work I've been able to complete most of this truck.

I've only driven it on the kitchen floor but first impressions are that it's really fun and works well. The steering circle is tiny, the gearbox seems pretty quiet and smooth. I will upgrade the shocks at some point, but to be honest I'd rather just appreciated it for now, they get to enjoy it again when it works better. 

When I first bought this truck I thought I'd swap the body out with a 1/14 monster truck, but I've really fallen for its goofy looks. I think it could also be made to look a fair bit better, with a small amount of work too.  I will spray paint this weekend, and add the transfers. I also want to use some parts of the tree to make hand rails around the cap, as this would break up some of the yellow.

On the rear of the truck I've put some Radio Shack 115mm tires and I do have a full set of these. I do like the look of these on this truck (they didn't really work on the Monster Trucks, but here they work nicely I think). 

Here are some pictures:

Here it is with a Peterbilt truck by Nikko. The Nikko is 1/25 scale, so it matches the Heavy Dump Truck nicely. I've upgrade the Nikko to full hobby grade electronics, and it can pull the heavy dump on the trailer.

And here it is with a 1/14 scale monster truck, which is based on the same sizes at the QD series.

I've got a few questions, some pretty basic (this is my first build!)..

• On reverse there does seem to be some wobble. Is this usual? If not, any idea what I've done wrong? I'm using quite a cheap servo, but they seem to work ok in my other builds. The steering rods were all to the given Tamiya specification. Everything else seems to be quite tight. 
   
• I take it I cut off the excess mount post?
   
•  Lastly, the wheelies are fun, but I'd rather something wheelie on full throttle, not at 30% or so. Has anyone tried a  smaller fast but low torque brushless motor in these? The Hot Machine truck I've got was very low geared with a powerful 390 motor. When I added the much smaller 5200KV EZrun 2030 motor the top speed increased, but as the torque was lower the acceleration dropped and now it'll wheelie less. I was wondering if something like that might be possible here. Essentially I want to lower the torque but keep or increase the top speed, so it's a little less wheelie prone.

 

Thanks in advance, it's been a fun build. I'll get it look nice, and then I'll take it to the park.

 

 

 

[J@mes 2326]

Wobble reversing is probably due to slop. I cut the posts but that’s down to personal preference. 20T pinion & sport tuned will massively reduce the wheelies. Great little truck, love it! 

[Nikko85 3453]

2 hours ago, J@mes said:

Wobble reversing is probably due to slop. I cut the posts but that’s down to personal preference. 20T pinion & sport tuned will massively reduce the wheelies. Great little truck, love it! 

Many thanks, I'll see what I can tighten up.

It does seem like a nice truck, quite quick for me (I'm used to slower speeds) but I'll see when it gets out into the open. I've got a local BMX track, so looking forward to seeing what it will do.

[J@mes 2326]

Regarding the wobble, I noticed on my Heavy Dump (and a lot of my big wheel Tamiya) the tires & wheels are not true or balanced, there’s serious wobble when they spin due to this.

[Goudar 526]

I got the same problem with my Blackfoot, front left wheel woble like a crazy cartoony old wheel. The others wheel don't woble that mutch, it make me sad...

[Nikko85 3453]

On 8/24/2021 at 8:33 PM, J@mes said:

very rewarding to solve a problem solo, nice job 

Thanks - yes, all my previous builds have been DIY jobs on Radio Shacks and Nikko, so there's no manual to consult and a lot of head scratching. Although I've wanted to stick to the script on this, it does feel a little less problem solving - so it was nice to have to find the fault and sort myself.

13 hours ago, J@mes said:

Regarding the wobble, I noticed on my Heavy Dump (and a lot of my big wheel Tamiya) the tires & wheels are not true or balanced, there’s serious wobble when they spin due to this.

Thanks - I'll have a good look over the tires too - there might have been some unbalanced areas.

Still no updates, because I'm waiting for the paint. In terms of upgrades I want to try this
 

As it just looks nicer to me. 

I also want to add some rails around the cab area, to give a slightly more scale look

I've also ordered that 20T pinion.

 

[Nikko85 3453]

So, I was able to finish this today - at least until I start adding a few mods!

 

First time spray painting a kit, I used frog tape which worked well when I used it right. The paint I used was Hycote black. For the exhaust I did a light coat of chrome in between coats of black to give a metallic appearance. 

The front grill was easy, but the exhaust pipes took much longer than needed. I didn't do a great job of masking it off to be honest so I ended up taking off the paint on the entry tube into the exhaust, and covering the join with some black electrical tape. I then added copper strip over the electrical tape, and then more copper on the ends of the exhaust pipe too. There is a little overspray, but only when you look for it.

Despite the mess up it looks ok to me.

A few more pictures. You can see I messed up cutting out the body as my cutters were too close, leaving white marks in the shell. Everything else I cut with spare plastic and then trimmed with a blade, so it's a little annoying I messed up on the visible parts. 

Tires are from a Radio Shack 4x4 Intruder, they are a little bit harder than the originals but look the part, and should run ok. It might reduce grip, but that could help it slide, rather than roll perhaps.

Despite a few small mistakes I'm pretty happy with my first kit - I think there's some slop I need to shim out at the front, and I'll have to play with a 20t pinion. Sadly my local park is running a massive festival next weekend, so my usual places to run are all gone, but I'll take it for a play somehow.

[Nikko85 3453]

I've ordered the 20T pinion and a Lunch box front bumper. I'm also looking at the stainless steel suspension shafts, just to stop anything backing out.

I enjoyed running it in the park, although I was wondering if it could do a little more than the stock motor.

I was considering a small brushless motor. Does anyone have a recommendation for a brushless motor that might work please?

In terms of specs it needs to work with the TBLE-02 and six cell NiMH.

I'm not looking for much more speed, perhaps 10% or a little more run time. Something cheap would be better - perhaps one of the finned 390 sized motors? I've seen videos of very powerful GF01 however, and those are not for me. I don't want a monster - but given that I've got a brushless ESC (and the Torque tuned will find a home) this seems to make sense.

 

 

 

[Nikko85 3453]

So, this truck has now got a lunch box front bumper. Like the video above, I used spare parts from the tree, with no permanent modifications on the car or stock parts. 

The first part of the build was exactly the same as the video but for the suspension U pin I did something a little different.

I used the original suspension pin retainer plate, but in a different orientation, screwed into the new bumper but lying flat.



It would appear to work perfectly. I can't pull out the U pin with the plate there, so I think it's working. 

And now the truck looks like this. Personally I prefer this look compared to the giant sprung bumper, it was also an annoyingly different shade of yellow than the rest of the truck too. It's a little less obvious now, and although it doesn't look like it, this one is almost as wide as the original. The video I stole the idea from seems to suggest this is pretty strong too.

I also added the proper tires, a lot more grip than the Radio Shacks, great for dirt. I'll keep the RS as spares.

It's not a high end Tamiya, but I'm really enjoying this little guy. I  did try a 1/14 Monster Truck body on it, and it looked great, so a small part of me is tempted to get a GF01 in black and turn into a little Monster Truck too, but I already have too many 1/14 scale trucks.

[El Gecko 1344]

Love those Intruder tires... do you have a pic of how the chassis lines up with the 1/14 Nikko monster truck body? I'm still undecided with my Nikko conversion, these GF01 chassis look like a lot of fun! But I'm also kind of itching for a kitbash......

[Grumpy pants 4485]

The truck looks great and those that own them on TC give them a massive endorsement @berman and @J@mes for sure are big fans.

The stainless steel shafts are excellent and a worthwhile hop up imo I picked up from @toyolien and they are a nice quality touch as well. 

You could use plumbers tape or gorilla glue on the screw thread as a TC recommended tip as a budget alternative 👍

[Nikko85 3453]

11 hours ago, El Gecko said:

Love those Intruder tires... do you have a pic of how the chassis lines up with the 1/14 Nikko monster truck body? I'm still undecided with my Nikko conversion, these GF01 chassis look like a lot of fun! But I'm also kind of itching for a kitbash......

I'll get some pictures today. I don't have a Nikko 1/14 but I've got a QD shell and some Taiyo/Tandy shells that all are mix and match. 

They are fun trucks for sure, I don't need a second, but it is tempting!

[Nikko85 3453]

2 hours ago, Grumpy pants said:

The truck looks great and those that own them on TC give them a massive endorsement @berman and @J@mes for sure are big fans.

The stainless steel shafts are excellent and a worthwhile hop up imo I picked up from @toyolien and they are a nice quality touch as well. 

You could use plumbers tape or gorilla glue on the screw thread as a TC recommended tip as a budget alternative 👍

Many thanks, I think for £6 I may just go with the hop up version.

Yes they are fun trucks, they don't do anything technically amazingly, but will jump, go over long grass, cover rough terrain and are fast enough for fun on a flat surface. 

4WD gives lots of grip on loose surfaces, where as my 2WD MT slides the back out a lot.

But mainly they are just fun.

[Nikko85 3453]

Well, I can say that the 20T pinion has given what seems like a boost to the top speed. It doesn't wheelie quite as much, but that's ok with me. Seems set up very nicely now, a great little truck and surprisingly capable.