Wheel bearings

[Veggyhed]

Has anyone serviced their wheel bearings? What size cone wrenches do you need for the front of the mini 4? What about the rear wheel? What kind of bearing setup does it have? I have not been able to find any info on the net about this any help would be greatly appreciated.

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[JimL]

The cone flats are 15mm (thin) wrench.  I made one by grinding down a forged 15mm open end wrench.  The stamped metal type will NOT do the job.  Only grind one side, to give a flat side that will fit close to the hub/seal area.

The outer (locker) nuts are 17mm.  My best results are to NOT disassemble the right side nuts (which have the cone nut and two locker nuts).  Use a pair of 17mm wrenches on the right side, and the 15mm and 17mm on the left side.  Unscrew the left outer (17mm) lock nut, if you can, from the 15mm cone nut.

I have done 4 of these bikes and only one would come apart this way.  Usually, the right side wrenches can be rotated to turn the shaft out of the left side cone and single nut (while they are still stuck together).  The left side nuts unlock as you reach the ends of the hollow axle threads.  The primary tension on the left outer nut (17mm) is keeping the left cone nut from actually distorting the axle threads.  I am squeezing the two nuts in a position that is trying to unlock them, as I unscrew the entire axle from them.

I have not had any damage occur using this method.  I leave the right side nuts in place, to be sure that I am not moving the front wheel sideways, in relation to the right side mount location, as delivered when new.

I use my bench vise, rotated about 45 degrees, to clamp the front tire (inflated to about 40 psi), so that I can manage the 4 wrenches by myself.  It really helps to have another person.

Don't get too crazy trying to lock the left outer nut back against the 15mm  cone nut.  Give it a firm set and it absolutely stays in place.

Replace the 6mm plated ball bearings with higher quality hardened bearings.  Note that the "seals" (such as they are) simply pry out easily with a flat screwdriver.  Clean out all the old grease, install the 9 new bearings (on each side), the push the seals back in place.  I use a small flat punch, gently tapped with the screwdriver plastic handle, to set the seals.  They are very easy to install.  Do NOT use a hammer!

I am having good luck with Mobil 1 synthetic grease.  I have used it in motorcycle wheels and steering heads for about 50 years and it is very water proof.

[JimL]

Added note:  The rear wheel bearings are better than the front....have not seen or heard of any problems there.  Those are part of the motor, as provided for Rad, and certainly not the cheapo type that are in the front wheels.