hpil

MOC 1:12 tractor - help with custom wheels

Recommended Posts

Good evening cognoscenti

I am working on a (roughly) 1:12 MOC of a Massey Ferguson 6716S tractor, and need a bit of help with getting some custom / 3d printed rear wheels. For the front wheels I'm using the Claas / 6x6 tow truck tyres 23798 with light grey six spoke 15038 56mm D x 34mm wheels (although loader style solid wheels would be better if i can find some). For the rear i have bought some RC4WD ZT0129 2.2" mud basher tyres (https://www.modelsport.co.uk/index.php?product_id=401784), which fit pretty neatly (with a bit of fiddling) onto the Porsche rims 23800 62.3mm D x 42mm. However, I would really like to get some custom or 3d printed wheel loader style (ie solid dish) rims with an axle connection, six pin holes and a more neutral offset to match the real tractor for the reat tyres. 

Any recommendations on whether anyone has already made such a wheel, or who could make one? I have already had a look at the third party tyres for technic rims thread, but not found quite what i am after yet. It would be even better if i could also get solid dish loader style wheels in 56mm D x 34mm to go on the front.

I think the simplest fix would be a combination of the Porsche rim and a solid dish. However, a neater solution would be to mimic the 'beadlock' arrangement that the RC models use, but make in lego technic - ie a main dish & rim, a slide on collar, and a locking rim (which pins the tyre in place against the slide on collar and the main rim) held in place with eg 6no 3/4 pins (RC beadlock uses tiny screws here).

31589276217_b135451427_b.jpgbeadlok by hpil 102, on Flickr#

Creating a beadlock type technic wheel would then open up a whole range of RC wheels fitting better onto lego (or lego compatible) rims...

So, any suggestions of offers to create some 3d printed rims for me?

hpil

mf6716s.jpg

Share this post


Link to post
Share on other sites

Hi,

First of all congratulations on taking challenge to build tractor with "missing" tire choice. Perhaps most simple  (and cheapest) solution for you will be to follow example by @TeamThrifty with his Axion

About tires; usual tires on this model are 540/64R28 front (overall diameter 1422mm) and 650/65R38 rear (overall diameter 1855mm), so if you plan to use 107mm CLAAS tires, you should make 1:13.5 scale model to have properly dimensioned tires :wink:

Good luck

Share this post


Link to post
Share on other sites

Thanks I_Igor - Team Thrifty's Axion (which is stunning - hats off @TeamThrifty!) was one of my first inspirations. I spent a while looking for the tyre / wheel combination that TeamThrifty had used but in grey to suit the Massey colour scheme, but couldnt really find anything that was quite right at a reasonable price. Then looking at the tyre scales, and going by height rather than width, the 2.2" RC tyres equate roughly to a 580/70 R38 rear at 1:12.2 and the Claas tyres roughly matched a 480/70 R28 at 1:12.9. According to the Massey brochure those tyres are the standard fitment on the 6716S and so that set the scale for me. 1:12 also gives me a bit more space to squish in the various motors, transmissions, fake engine etc and given my newbie status i'm going to need all the space i can get!

Cheers

Share this post


Link to post
Share on other sites

I understand what you mean. Tire dimensions I wrote were two days ago at salesman where o drive side by side with Wendy Vario 5 series... The reason that I mentioned 1:13.5 scale is that is some kind of standard for truck movers (together with 1:17.5). Ok my mocs are in 1:15 scale so perhaps I'm not perfect example, but in order to replicate correct proportions, you will have to maintain some front to rear wheel ratio...there is also less powerful version of MF 6 series which use a bit smaller front and rear tire, 540/65 R24 front and 600/65 R38 rear. The reason I use wider tires as reference is chronic Lego tire problem - they are always to wide (except truck tires); example is my current project JCB Fastrac 4220 based on 710/60R30 tires in 1:15 scale (you got the picture 107 mm X 15 is approximately 1605mm in diameter which corresponds tires 600/70R30 and mentioned 710/60R30). Did you plan to have fully RC or just to use pf for pto and 3 point hitch?

Share this post


Link to post
Share on other sites

Full RC - XL for drive, M for steer. L or M for rear linkage with changeover catch to switch to front loader lift and another changeover to connect front linkage lift to work with the rear linkage. M or L for rear pto, with changeover catch to switch to front loader tip / crowd and another changeover to connect front pto to the rear. If I have space, a pneumatic pump on another changeover connected also to the pto motor, and an air tank. 

It's going to be a long project! 

Share this post


Link to post
Share on other sites
11 hours ago, hpil said:

Full RC - XL for drive, M for steer. L or M for rear linkage with changeover catch to switch to front loader lift and another changeover to connect front linkage lift to work with the rear linkage. M or L for rear pto, with changeover catch to switch to front loader tip / crowd and another changeover to connect front pto to the rear. If I have space, a pneumatic pump on another changeover connected also to the pto motor, and an air tank. 

It's going to be a long project! 

There is also JCB Fastrac 4220 by @Technic BOOM that could be helpful for some solutions.

Regards

Share this post


Link to post
Share on other sites

Hi, loving to see more ag mocs on here, its a sub-niche!!

Is 1:12 the right scale? doesn't that tractor have 215cm rear tyres.. that would mean you need an 18cm tyre. My 13cm ones allow me a 1:16.5? Even if they're 200cm its still only 15:1... Just a thought! But great to see the 3rd party tyre option being explored!

Share this post


Link to post
Share on other sites

See

17 minutes ago, TeamThrifty said:

Hi, loving to see more ag mocs on here, its a sub-niche!!

Is 1:12 the right scale? doesn't that tractor have 215cm rear tyres.. that would mean you need an 18cm tyre. My 13cm ones allow me a 1:16.5? Even if they're 200cm its still only 15:1... Just a thought! But great to see the 3rd party tyre option being explored!

This model has rear tire 520/85R38, 580/70R38, 650/65R38 or even 710/60R38 tire and all belong to Group 46 that are 1855mm in diameter, so you are free to recalculate :wink:

Brochure with general information is here

https://www.google.hr/url?sa=t&source=web&rct=j&url=http://www.masseyferguson.com.au/documents/Massey%20Ferguson%206700S%20Brochure.pdf&ved=2ahUKEwjKj4i35snfAhWGESwKHQmzD5wQFjABegQICBAB&usg=AOvVaw2M-MKpSTBgju7V8SyHmD4Y&cshid=1546250234709

 

Edited by I_Igor

Share this post


Link to post
Share on other sites

Surely thats still 15cm tyres?! I'd love some 15cm Ag tyres... i do like a big moc!

The 13's generate a LOT of torque.. the axles twist more than expected. Portal hubs would be a good call, but don't fit 3rd party hubs, or suit a tractor really.. but it would help on the twisting.

 

Share this post


Link to post
Share on other sites
Just now, TeamThrifty said:

Surely thats still 15cm tyres?! I'd love some 15cm Ag tyres... i do like a big moc!

The scale that @hpil chose would result in huge moc and if he used 1:13.5 scale as I supposed, your solution with rear tire could be perfect for himself.

I would also like bigger, but I'll be more than happy with 120mm tractor tire, or smaller, but my subconscious says - I'm happy with current situation because I have no extra savings for completely new (big) set with this kind of tires, and my feeling is that eventually based on CLAAS and LEGO cooperation we could have only harvester that uses new xl sprocket wheel and tracks at the front and existing tractor tire at the rear (surprisingly it perfectly fit to 1:15 scale). Other groups of CLAAS products are telehandlers and wheeled loaders that are not trailers, ballers... I suppose that Volvo is better choice for wheeled loader and Scorpion (telehandler) is developed together with Liebherr and I do not know if LEGO and Liebherr have any kind of agreement.

Honestly lots in this post is more suited content for technic pub, but it is up to @Jim to decide about that.

Share this post


Link to post
Share on other sites

Loving that Fastrac! 

I think that mf brochure is the Australian version - i'm working off the UK which is definitely 480/70 r28 and 580/70 r38. Having said that, all models in the line up have the same wheelbase and width (c/c across the front axle), so I guess it boils down to fit the tyre combination I have, what tyre combination does that most closely match on the real tractor, and therfore what is the resulting scale?

@TeamThrifty the 2.2" mudblaster tyres are 150mm OD. I can put some photos up later today (and I'll double check my scale calcs 😉🤞

Share this post


Link to post
Share on other sites

I have two years calculated, searching for tire solution and did not find 3rd party tire that suits LEGO tire tread, so I have decided to make machinery where it fits most products, so I have ended up in 1:15 scale. First model was Unimog U423, second is Fastrac, but mine have only motorized functions like pto and hitch because I have not enough of elements and here in Croatia they are very expensive. My Fastrac needs few pieces when they will be available here, but in my tread you follow development:

 

Share this post


Link to post
Share on other sites
1 minute ago, hpil said:

2.2" mudblaster tyres are 150mm OD

I think i saw those on ebay a while back, might be different ones. I went with the 130mm as they were a tractor tread pattern - not identical to the claas tyres, but close enough (and on my xerion with 4 of them, it doesn't matter!)

6 minutes ago, I_Igor said:

we could have only harvester that uses new xl sprocket wheel and tracks at the front and existing tractor tire at the rear

That sounds like a great set/moc option to me... 

@hpil have you started the build yet? It would be great to see your solutions to stuff, not many big scale tractor mocs around - pretty excited to see another! (i'm going to photograph my xerion moc and start a thread for it shortly)

 

Share this post


Link to post
Share on other sites

@TeamThrifty - will put up a separate thread for my wip, but here's a taster. Apologies for the colour mix - up till last week my colour collection was pretty limited and so i was working with whatever i had to hand to get things started, with an idea to then rebuild once i had more DBG. Everything backwards from the front wheels is just thrown on so i could attach the rear wheels and see how it all looked - the wheelbase (2670mm in real life) should be about 28 studs @1:12, so the mock up is about 2 studs too short. The RC4WD tyres are quite soft and i was worried about bulging, hence the trial with a 1.5kg bag of flour. The front linkage i'm happy with, but the front axle is getting a complete redesign, using small turntables for the pendular axle mount. The current front wheel mounts are inspired (copied!) from your Axion, but the redesign will use either triangular flat plates or possibly small turntables.

The flour test...

45629952695_1449177308_z.jpgDSC_1057 by hpil 102, on Flickr

45819889794_0fa08dece1_z.jpgDSC_1110 by hpil 102, on Flickr

44726243140_b5b22f87e7_z.jpgDSC_1120 by hpil 102, on Flickr

46491728582_6353b81176_z.jpgDSC_1112 by hpil 102, on Flickr

Share this post


Link to post
Share on other sites
8 hours ago, TeamThrifty said:

I think i saw those on ebay a while back, might be different ones. I went with the 130mm as they were a tractor tread pattern - not identical to the claas tyres, but close enough (and on my xerion with 4 of them, it doesn't matter!)

That sounds like a great set/moc option to me... 

@hpil

 

@hpil

What is the overall diameter of rear tire?

You will have to recalculate differential ratio for rear and use central differential...like on my old John Deere 7230R here

Share this post


Link to post
Share on other sites

Well, I do admire your ambition.  But I would say that it will be very difficult driving those rear wheels unless you use some sort of final reduction in the hub.  A typical axel coming from a differential will be subject to twisting from an XL motor, due to the turning diameter and momentum needed.  As a push along model you will have no problem. 

Have you ever thought about why LEGO do not use wheels of this size? 
As has been pointed out, you will need to drive from a central differential due to the variation in wheel size.  Also have you ever thought about having it front wheel drive only?  As if you are having a loader on the tractor, then traction at the front end would not be a problem.
Finally, your front linkage top link needs to be reworked, as it will just pull apart under load.
Of course I would love to be proved wrong in all these issues.  I suppose we are all learning.  Happy New Year

Share this post


Link to post
Share on other sites

Oh my life! Look at them tyres!!! I'm fully in love with them... are they 150mm? Its like tyre poker - i'll see your 130's and raise you :laugh:  Please send me the link for them, i have massive tyre envy, i need them - it adds 4cm to my xerion's wheelbase. I'm so excited right now!! Ha!! Happy new year!

ps i didn't use a central diff, (the real ones don't either), i used about 4 sprockets to match the ratio needed

Share this post


Link to post
Share on other sites

@TeamThrifty - they are indeed 150mm. Link to where I got them from (modelsport - Otley, West Yorkshire) in the first post on this thread.

 

Share this post


Link to post
Share on other sites
2 minutes ago, TeamThrifty said:

Ha! Really? Now thats weird... i was born in Otley... Small world.

and I have Yorkshire Terrier as you can see on my avatar :laugh:

That is wired combo for tractor mocers...

Share this post


Link to post
Share on other sites

Indeed, I'm even building JCB Fastrac at the moment :laugh: and Bella the Terrier is jealous on my hobby...

Edited by I_Igor

Share this post


Link to post
Share on other sites

Few minutes ago I have finished chassis and most mechanical parts. There are few things missing, but I hope it will sort it out... I can post images that show current stare of project tomorrow in my tread. Despite needing to make stairs, mudguards, bonnet, cab and it's interior, I'm not sure that it will be several hours if work. I have chassis rebuild several times in the past to get it low enough, proportional and narrow as it should be for this scale and at the same time to allow small steering circle and max suspension traveling with yellow shocks...just a glimpse info - to make drivetrain (4wd + engine), steering, front and rear PTO and front and rear 3 point hitch I have used 10 CV joints and 16 universal joints 

Share this post


Link to post
Share on other sites

@trekman - I've played around with the top link a little, and it seems it can actually take a reasonable load before pulling apart.

46560718571_15b12baf97_z.jpgDSC_1123 by hpil 102, on Flickr

The reciprocating power harrow MOC (which i made initially to go on the rear of the 8284 tractor/dune buggy - again, apologies for the colour vomit but my collection was a bit more limited when it was made) weighs about 150g and the battery box with batteries about 190g, and it has stood up fine to that. Adding a second battery box (with batteries) pulls the top link apart - so its limit (without going into leverage etc) is somewhere between 340g and 530g. An alternative top link with two 6L thin lift arms would work, but wouldn't be as aesthetically pleasing to my mind.

Drive via a central diff between front and rear was always going to be the plan, although i might play around with some ratio calcs and see if a reasonable set of gearing can be used in lieu as per @TeamThrifty's post. Having said that, when turning all wheels will follow different tracks so a central diff may still be the best bet. I'll also need to think about gearing to get a suitable forward speed with the big wheels. Torsion twisting the drive axles is also going to be an issue and i've a few ideas to address that - ideally i would have used mini-turntables to mount the rear wheels, since these have a bit less wobble than the portal hubs, and used a z8 pinion to take drive onto the turntable sprocket. However, the centres don't quite line up and so i think that option is out.

32670529528_a2cacbcfe1_z.jpgDSC_1116 by hpil 102, on Flickr

Overcoming issues like this is all part of the fun and challenge!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.