Keyword

TOPIC:

Richard's Marui Big Bear resto projects. 1 year 3 months ago #66380

Looking at some pictures of idle gears and differential, there is an heavy work to consider before putting a Brushless (even soft) on this beast... And considering the idle gear is not running on ball bearings (and it is too small to do it, unlike the Galaxy/Hunter), there is fair chance of damaging parts which are already quite difficult to source...
Best way is probably redo the gearbox completely and make it look original... But heavy modeling work, and probably lot of mock ups using gears easy to source to find the proper way to go...
Well, probably what Richard is intending to do. I'll be sitting here with the popcorns 
I buy kits to built and ru(i)n them :-)
The following user(s) Liked this: jord001

Please Log in to join the conversation.

Richard's Marui Big Bear resto projects. 1 year 3 months ago #66383



Hope your popcorn has a long expiry date 
The following user(s) Liked this: silvertriple, jord001

Please Log in to join the conversation.

Richard's Marui Big Bear resto projects. 1 year 3 months ago #66384

It will be only more popcorns ! :-D
I buy kits to built and ru(i)n them :-)
The following user(s) Liked this: jord001

Please Log in to join the conversation.

Last edit: by silvertriple.

Richard's Marui Big Bear resto projects. 1 year 3 months ago #66389

I place this calculator here so I can find it more easly when I start on the gears...
www.technobotso...lator.html

Mostly for my self I need to write down this:
Stock Big Bear diff and small idler gear seems to be 0.6 mod.
Lunchbox pinion is 0.8 mod so that won't work with the stock Big Bear diff.

Big Bear gear ratio is 60t diff, 11 idler, then 32t spur to 16t? pinion. Gear ratio 10.90:1
Lunchbox is 50t diff, 17idler to 50 spur to 10t pinion Gear ratio 14.7:1

Standard pinions is 1/8=3.17mm
Stock Big Bear idler shaft is 3mm.
To much slop to work safely.
Idea to change the 3mm shaft for 3.2mm drillbit and drill out pinions to 3.2 or 3.3mm or...
Change to 3x6x2.5 flanged bearings on pinions if there is enough meat left on the pinion, depending on the pinion size used.

I need to look into what space there are actually inside the gearbox, 
Hope there is enough roof for a Lunchbox diff 
They are strong and I have been driving my re-re since 06' without changing any gear at all. I'm running 2s and Technigold motor...
The following user(s) Liked this: stingray-63, silvertriple, jord001

Please Log in to join the conversation.

Richard's Marui Big Bear resto projects. 1 week 2 days ago #72314

Since I was helping Marc aka Silvertriple with Big Bear tires and these is already out of the storagebox, it was a perfect time to clean both the wheels and tires.

I put them in the dishwasher machine at low temp for 30 minutes (@ 45C ), which worked perfectly!
Just make sure you missus is not home doing so. If you're single as me, there is nothing stopping you lol



Big Bear wheels consist of 3 parts. Inner sleeve and two half wheels sides.
They interlock perfectly with eachother even without the 4 small screws.
Pictured is the inner part on both halves


Very wide wheels indeed! They have same diameter as Lunchbox (1.9") but they are wider by a good bit.
Tires are 82mm wide, vs 65 for the Lunchbox


There 4 pieces to the right shows both sides of both front and rear halves.


I still have a full set to clean
These tires are a bit softer since they have been good used, and this is how I remember them being back in the day.


A bit difference between cleaned and non cleaned
The following user(s) Liked this: stingray-63, Al, silvertriple

Please Log in to join the conversation.

Last edit: by caprinut.

Richard's Marui Big Bear resto projects. 1 week 2 days ago #72315

Thanks again for the heavy contribution to my CAD project :-)
This put me to use my neurons to get this working as much as possible... Too bad the prices of the MJF printing makes this totally economically irealistic. Mould and casting may be an options, but cost is still quite important. I contacted a company doing some manual injection press to understand if there is any HoliPress available in a fablab nearby so I can try eventually to do tires without investing the initial cost (the injection press is about 2500 euros without taxes,a nd a mold would be about 250-400 euros range without taxes for a professionnal printed mould)... And even if I suceed to get find a press nearby, i would still require to do and learn on smaller tires first...

Any case, remember you have heavily contributed to the result you see below, and that will land on Thingiverse or the desk of a tire maker at some point...

I buy kits to built and ru(i)n them :-)
The following user(s) Liked this: caprinut, yogi-bear, stingray-63, Al, jord001

Please Log in to join the conversation.

Moderators: Jonny RetroAndyAus
Time to create page: 0.090 seconds
Cookies are required to make this site work. If you continue to use this site you permit us to use cookies.