Tokyo Marui Big Bear RC Truck Page

The original axles used a simple sleeve-bearing system.

I would like to change this to a ball bearing system, because the stock design has lots of friction related drag.

Pictures on the left show the axle assembled with the plastic piece in place that holds the wheel from slipping on the axle. Picture on the right shows the plastic piece removed, the nut that it is held in place by, and the back side of the plastic peice.
All pictures show where I would like the ball bearings to mount. The original bearings in desired position and are about half at thick as the ball bearings, so the axle needs to be thinner in those areas. Similar to the threaded sections on the end. The axles are actually able to be reduced to this diameter except for where the "nut" and the plastic "c-clips" are.

- Click on a picture to view a larger version -

Short Axle
Short Axle
Large Axle
Large Axle

COMPLETED: Here is the design and pictures of modified axles to use ball bearings

Marui Big Bear Axle Assembly Modification Diagram

The axles were turned down on a lathe to fit the ball bearings in place of the original sleeve bearings. I am using Duratrax DTXC1553 bearings, they are 5mm X 11mm X 4mm (center x diameter x width). My axles were 1mm off, I updated the design drawings to get it perfect. Please verify the measurements before cutting your axles. The rear wheels would barely free spin 3 revolutions before stopping. With the ball bearings, they spin 10+ revolutions. Not super-scientific, but shows a drastic reduction in bearing friction.

Most places sell them for $4 a pair. You need at least 4 bearings to do this modification. I'll let you decide where to purchase them.

VXB Bearings Link (standard bearings)

VXB Bearings Link (high-quality ceramic bearings)

Tower Hobbies Link (Duratrax stainless steel sealed bearings)

- Click on a picture to view a larger version -


Modified Large Axle
Modified Large Axle With Ball Bearings
Modified Large Axle With Ball Bearings
Gear Box With Ball Bearings Installed
Gear Box With Ball Bearings Installed
Gear Box Showing Old Bearings and Ball Bearings