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I'm playing with an idea to put some of my retired projects and un-needed spares into something fun.

I want something to run on rougher terrain; the kind of places I rather don't run my race stuff in.

The main components would be: a set clodbuster wheels and tires, a 32dp ultima transmission, and the front and rear transmission + full suspension of an inferno10.

The ultima transmission would go in the middle and be connected over dogbones to the front and rear transmissions of the inferno10. I think that should give it plenty reduction: to compensate for the larger diameter tires and slow down matters to provide a little more torque.

If possible I'd like to use my old NiMH stick packs on it; so the lipo stuff can stay in the racers. And just 1 pack: I don't want something that will twist axles or requires electronics I don't have yet.

All the rest is pretty much open to suggestion; So shoot!

This sound like one heck of a contraption you got brewing. I’m not sure what all those parts are or look like but with the size of tires/wheels you got planned you might want to consider axles mated up to that transmission. You might find down the road that the dog bones or universals depending on which route you go will snap like pretzels.


I’m curious to see how this is going to go together.

I assume you don't need any of the stuff I have for sale in the BST section, I have a full JG Optima Mid monster truck conversion kit there, including the wheel adapters, special wheel nuts, wheels & tires, etc...if you need anything, let me know.

http://www.rc10talk.com/viewtopic.php?f=6&t=30434

I also have a big assortment of Robinson Racing spur gears that were intended for this conversion, nearly all of which I won't need for my OptiMutt car; 75T, 78T, and more importantly, the larger ones like 87T, 90T and 93T...I think the larger spurs are better for the gear reduction you'll need for a monster truck. Looks like you're going a different way but I'm glad to help out if you need it.

Regarding the axles (and bones): I'm hoping that by limiting the speed I can keep the momentum on those parts low.
But, yes, it certainly is a point which might go wrong.
If it does go wrong, I do have some 12 mm hex 2.2 truck rims at hand still which will work with these tires :

And if worse comes to worse: I 've still got both normal sized stadium truck tires and low diameter street-racing truck tires.

I've got my own optima mid stuff, including the spur conversion, so, thanks but no-thanks

How about wheelbase? short long, super-sized? And suspension? closer to truggy or crawler or monstertruck 4link?
Pretty hard to get right I learned with this one:

Reminds me of Mud4funs project Thunderfoot over on TC.
http://www.tamiyaclub.com/showroom_model.asp?cid=23214&sid=1721
http://www.tamiyaclub.com/showroom_model.asp?cid=25832&sid=1721

The gearing would still be pretty high for a crawler with Clod size tyres, the gearing in my Clod based crawler has an overall gear ratio of 49:1, but it does just about manage a walking pace at full speed.

Thanks for the link Terry; always encouraging to see someone has made the idea work succesfully.
It sounds like I'd be after a gear ratio of around 1/25 (putting together your description and my desire for a little speed).
I'll check on thursday where I'm at currently. That way I can already pre-select the most suitable tires.

SFC K wrote:This sound like one heck of a contraption you got brewing. I’m not sure what all those parts are or look like but with the size of tires/wheels you got planned you might want to consider axles mated up to that transmission. You might find down the road that the dog bones or universals depending on which route you go will snap like pretzels.


I’m curious to see how this is going to go together.

"heck of a contraption" is Erik's middle name

Can't wait to see what you come up with Erik. I really enjoy seeing how you use different parts to build something that's really unique.

Regards,
Roger

Less talk, more photos....


We need something new to follow...not to many outside-the-box builds on here lately.


I always love to see semi-scratch built stuff, it inspires others.


Can't wait to see it.

Thanks Roger, how about throwing some of your ideas in the hat?

Pictures, I'll try my best tomorrow.
My new job has me away from home for about 90% of my working days, and at least 50% of those days I spend the night in hotels.

But tomorrow I'm taking a day off, the wife and daughter will be out to disneyland (Paris) and for once I'll have all day for the dog and myself
Now, I just have to make sure I don't crash at 160 (km/h) on the German Autobahn on the way home tonight

The original idea was for the inferno10 to become electrified, but space on the chassis is too limited for putting the battteries, I just couldn't find a long enough propeller for the center, and I didn't feel like investing in a slipper setup to end up with... well, just another 4wd buggy that would not be as competitive as my wyvern.

I wish I was more fimiliar with the parts you plan on using. I was looking over on RCCRAWLER.com for some IS (independent suspension) or IFS build for you to check out but there are a ton of them.

It's coming...

I'm mocking up stuff and counting gears.

ULTIMA
diff 37T
top 19T
out 28T
cluster small 18T
cluster large 41t
INFERNO10
ring 37T
bevel 11T

so 1 full turn of the ring gear equals ?
37/11X37/19X28/18=10.19 turns of the spur
And I have pinions between 10 to 15 teeth
So the final ratio will be roughly between 1/42 to 1/27

What do you guys think: can I keep the clod tires? (their diameter is 2Xbuggy tire)

guys, I have 2 solid axles to replace 3 geardiffs...

option 1 : I use the solid axles in the front and rear, and use a ball diff with friction pegs instead of balls in the center
option 2 : I use the the solid axle in the center and rear, and stuff the front geardiff with play-doh
option 3 : stuff the rear diff with play-doh
What do you think?

What type of terrain are you going to run this on? That might help determine which option for you.

Option 1 is the one I like the best. I would lock the front and rear and just run a slipper on the center, but if you want more steering in front make it an LSD using heavy weight diff grease and lock the rear.

http://www.amainhobbies.com/product_info.php/cPath/1_25_1460_134/products_id/6935/n/Kyosho-Silicone-Differential-Oil-500000wt-40cc

I agree with SFC K here. make the center diff a slipper, set to pretty tight. Use a limited slip/locked rear axle, and a heavy weight diff/limited slip in the front. This gives you the best all around performance, ie, if one wheel unloads, you won't get stuck.