jon hirst

I am endeavouring to build an 8 wheel truck chassis but I'm struggling to come up with compact combinations of steering with suspension and axel drives with suspension but at the same time keeping the track width to a minimum (I'm working on 17 studs as a maximum I'll attach photo's, one is the concept so ignore the strange superstructure, the others are the best I can do at the moment but this is what I've managed so far: Rigid drive axels . . so not fully independent. Steerable independent front axels but still fighting with the short steering rack as it's too long for ease of use. So if anyone has any ideas . . . please let me know Many thanks Jon

I pressed on . . 3 rebuilds and I've had enough, so although a few bits are unfinished . . . this is as far as I go. And I have 9 black flip-flop beams, 5 short yellow panels and 4 x 1 stud little yellow panel/beams left over ! So on to the next project. A big 8-wheeled mobile crane !

Finally got a simple working ripper . . .

Struggling but tenacious . . . 2 studs narrower although the apparent width has been reduced by 4. Two studs longer so the general scale has hopefully improved, 2 control boxes and room for lots of motors. A long way to go but wondering if it would pay me to wait for someone clever to publish a full build ! Quick update . . getting complicated now, mainly due to my poor skills with drive chains and gearboxes The 2nd control hub will have to go back in the engine compartment, but I've managed to get 3 motors side by side just above the chassis while the remaining one will fit just under the cab and work the upper rear ripper arms . . then a full rebuild of the cab and platforms, hopefully to an approximate scale ! Pics will follow in due course . . .

Didn't even think of that . . thank you . . So until some clever person finds a way to but the drives to the upper wheels . . they stay put

Guys . . . some thoughts please . . . 3rd rebuild and going for the 6 motor 2 hub one in a reduced width chassis. I'm already using the old 5 stud tracks so this combination will reduce the apparent width by 4 studs and if I stretch the whole thing by just say . . 2 studs I think it'll look far better, but . . . I'm rubbish a clever gearing and gearboxes . . preferring to keep it somewhat straight line pretty basic stuff. So, keeping the 'base frame' the same height as the Lego original, I can get the outrigger and lower ripper motors as shown here . . . they would be better in that remaining lower void but as said my gearing abilities are limited . . and above the 'void' and below the cab I plan to put 2 motors to work the front main blade and the ripper angle thingy. So I'm just looking for better ideas before I get started please ! Would it be worth laying the 2 drive motors down into that wasted void ?

We learn something every day, and that does makes sense . . . thank you Maaboo35

Very early thoughts on the ripper outrigger . . I'm kinda happy with the two blades, the carrier box and the actuator positions but . . . they currently stick out too far (I'm using 2 x 11 stud tapered panels to try and mimic the original), and I've ordered 2 shorter actuators (I'm building this thing mainly from my existing parts), the drive motors are way too intrusive and almost in the way and as hard as I try I cannot come up with a decent idea for the 2 uprights above the weight box . . . need Lego to produce more triangles and slopes ! Next . . yet another rebuild (or several). I've already narrowed the footprint very slightly but need to narrow the main chassis by the previously mentioned further 2 studs. Then get both control boxes into it, the 4 primary motors and go from there. Sheesh !

Great stuff nugnug . . and I look forward to the results after moving the drive motors. Your skills far outshine my 'Heath Robinson' style of building so please keep us updated. So far I've had to locate the second hub in the engine bay but I wonder if the chassis could be adapted . . . . yet another couple of rebuilds methinks.

Well then . . . several re-builds later (and a few more to go) . . the 'chassis' is finished and finally working. The proportions are looking reasonable, I need to strengthen the track unit supports and think about colour mixes, then that dreadful ripper assembly, the horrid railings and finally it'll be attention to the little details . . . Such Fun !

Thank you kind people . . . I'm kinda new to modifying so learning all the time . . and finding even simple solutions are difficult and very time consuming, but it's they're interesting challenges ! Yup . . . time to strip the main body down again and see if there is a way to fit 2 control box things into it, and then attend to the dozens of little details that bother me. One thing I can say is that stretching it, even that little, looks more realistic when sat on the table . . . I'll post more photo's as things develop. A quick update . . All 6 motors and 2 magic boxes in, 3 studs narrower, (no dummy motor), 1 stud longer, an auto-tensioned track footprint of 35 studs and, a half decent ripper and guess what . . . half built only to discover the connection to the blade arm pivot drive was 1 stud too low ! . . . back to the drawing board as the whole lot will need rebuilding yet again . . .

No laughing . . it is very early days. temporary actuators and 5th (small() motor in after removing the gear-chain to the ladder and lots of gearbox parts. I don't need a dummy engine drive either (silly exposed pistons) so all I need now is to pick up the courage to rebuild the whole lot from the ground up . . and the second control box may have to go where the dummy motor now sits ! I dunno . . . !

Testing photo . . . if this works (from FB !) a very early build photo should be seen . . . apologies, the top section very roughly added for photo

Many thanks to Howitzer and Nugnug115 Not sure (I'm way too old) how to use external sites to link photo's . . . but progress here is going well and the build is looking quite good, and although not quite true to the original . . it's slowly becoming a great dozer. Tread to ground length is around 36 studs, seat in medium grey, the access ladder has been done without using flip-flop beams and now considering a double blade ripper and new roofs . . . . all a bit time consuming

My first attempt at modifying Just a little longer and a brick higher, old grey treads and 'wheels' and a much longer tread footprint. I've removed the manual tensioner, kept the rack and introduced a small shock absorber to allow for auto-tension Yes I know the colours are not as it left the factory but I needed to use what I had . . and I think it looks kinda okay . . Another 1 or 2 rebuilds still planned (I'm not good at this stuff !) to do away with the motorised ladder (horrid) add 1 large and 1 small track support rollers and motorise the ripper . . then look at the over-heavy railings. I will try again to post a photo but so far I don't seem to be able. It says . . There was a problem processing the uploaded file. Please contact us for assistance. . . . help please !

Just some thoughts . . rather than fight to narrow and hopefully improve the looks . . what about cheating a little and stretching the model by say 5 studs in length offering possibilities for ripper motors, and if it helps also add a couple of studs to the overall height to maintain proportions. The cab seat is lost in black . . . and the railings are way to heavy . . . . Just built it using older grey treads and feel it looks better Yes I agree . . manual ladder and get rid of the drive chain As for the track to ground length . . this really needs looking into I don't like the blue pin ends . . so I've tried to use black where I can but the little axel to pin ones remain as they are so expensive Unable to post photo for some reason . . . but these are just my initial thoughts

Just some thoughts . . Yes it needs narrowing by say 4 studs. So do we still need the diff ?Has anyone tried the drive motors on the upper cog yet ? Rather than the manual track tensioner I've kept the rack but adopted a small shock absorber to maintain front wheel tension over rougher ground The cab seat is 'lost' in black beams . . . and the railings and ladder are way to heavy . . . . It will need 6 motors and 2 hubs but by getting rid of the gear boxes it might be possible . . . . . . Just built it using older grey treads and feel it looks better Yes I agree . . manual ladder and get rid of the drive chain As for the track to ground length . . dropping the lower 'cogs' seems essential and it looks better I don't like the blue pin ends . . so I've tried to use black where I can but the little axel to pin ones remain as they are so expensive Unable to post photo's for some reason . . . but these are just my initial thoughts

Has anyone tried working with the new toothed quadrants and worked out what the narrow grove is for as nothing except the little bevels seem to fit . . . it must have a purpose ! My attempt at roller bearings using little bevels . . . 16 to a circle, but of course the standard 'joiners' cannot be used so some form of firm support would be needed. Just my 'newby' thoughts . . . and my TINY photo (23kb . . . 0.023mb) upload has failed again and if they get any smaller they'll disappear !

Thank you M_longer . . . I'm still learning !

Well it all works . . unfortunately not all at the same time as I haven't enough motors and very limited RC gear . . . . It's very heavy, 1 metre long and 375mm high (over 100mm longer and nearly 30mm lower than the kit) It moves and steers really smoothly and the boom is now almost straight and is perfectly balanced (with the aid of 200gram chocolate bar !) The turntable assembly is still wobbly so lots of work needed here, perhaps loads of rollers and stouter fixings. I need to find a way of installing the base unit battery box into the base and still have access to it and I need to pretty things up (more part shopping) Now to strip down and try to improve further and I may try something even more outlandish but more akin to the real thing ! Still learning 4 weeks in . . . perhaps by this time next year eh ! ! ! I'd post a decent photo but I'm only allowed 30kb . . . not sure why. Here's a tiny tiny photo anyway . . .

Thank you for the very warm and encouraging welcome. So appreciated! Yes using the subtractor diffs the model now ambles around my lounge as well as any model car and at sensible speeds too. As it stands the upper parts as per the kit fit perfectly with no mods required but I as still trying to improve upon things. I've now added an L motor to allow rotation and hope to add a further L motor as suggested in previous postings to adjust the bucket elevation. The only work the original XL motor now has to do is drive the conveyor belts. Give me a few months 'cos I'm still learning ! Great site ! ! ! !

This is my very first attempt at building in Lego so I hope everyone will forgive my lack of skills and experience 'cos I find it quite difficult to achieve what others have . . .however: This model out of the box does have a few issues and I still believe it is well worth the challenge and making a few modifications to improve things. The addition of additional motors and RC is already beautifully covered, (although 4 or even 5 motors will be required.) The first issue is the lack of steering and slow nodding movement forwards and back. This is due mainly to a long drive chain and the fact that the track footprint is much shorter than it's width. To overcome these issues I've used one XL for the drive and a L motor for the steering and run them through a simple subtractor unit. It works well . . . now if I could only incorporate the battery into the base as well ! I'm currently moving the whole upper assembly a few blocks towards the back in an attempt to further reduce any 'nodding effect and is looking possible . . . The discharge conveyor is easily extended and lowered by a block or two but the main working boom is not only a little short but also bends under the weight of the bucket wheel assembly . . . this is now work in progress so wish me luck. I'm hoping others can improve on my weak attempts !