Dirt Bike Wheel Repair


Wheel Repair on a 1992 Suzuki RM125

Difficulty:  Medium
Recommended Tools:  Vice, spoke key, can of lubricant with straw, chalk

When I got my bike, the wheels had certainly taken a bit of a beating, the front wheel bearings were shot, both rims were buckled and the front rim also had a hefty ding on one side.  Not a big deal though, I was able to get them back close to running straight and true with some simple tools.

The first thing to do was to replace the bearings in the front wheel, no point in trying to true the rim if the hub is orbiting!  I took the old ones out, identified the part number and picked up two new ones from an industrial bearing supplier (Canada Bearings I think it was).  While the wheel was loose for bearing installation, I took it out to the garage and used the vice to press the ding straight again.  I placed a long block of wood on the back rim to spread the load and placed a rag over the front jaw to protect the rim while pressing.

It took a LOT of effort to press the ding out and because there is some spring in the metal, you have to bend it past straight so that it yields and only springs back to straight when you release the jaws.  IMPORTANT Always wear appropriate safety goggles doing this, there can be a heck of a lot of load on the rim that could launch a projectile with high speed if something fails.

Nearly there …


And this was close enough for me …

Now we move on to truing out the buckles.  If your rim is old like mine, it’s a good idea to spray penetrating oil on them and let it soak in well before proceeding.  My buddy loaned me a spoke key but it wasn’t big enough to do the rear spokes so I picked up this one for about $15 from Twin Seasons Recreation.


Install the rim back in the forks or swing arm and stand the bike so that you can rotate the wheel freely.  Then set up a pointer at a short distance from the rim and grab some chalk or bits of masking tape or something you can use to mark locations on the rim/tire.


Now you can rotate the wheel and look for deviations in the distance to the pointer.  I mark two arrows around the start and finish of a deviation indicating which way it needs to go to be true, let’s say in this case it needs to go towards the far side of the pointer.  Then I look at each of the spokes within the range of the markers, if they are attached to the near side of the hub then I loosen the spoke nipple 1/4 to 1/2 turn and if it is attached to the far side, I tighten the nipple.  I always try to start with loosening a nipple to relieve tension before applying it to the next spoke.  Spin to check again and adjust as necessary.

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