V-wheel and Idler Assembly Instructions

V-wheel assembly

Item	Part Number	Part Description	Count
For each wheel
1	MW1	V-wheel sleeve	1
2	G5	5 × 16 × 5 mm bearing	2
3	W5Pa	5 mm precision washer	1

Lay one bearing on a flat surface. Push a V-wheel sleeve over it. The parts are designed to force-fit, so push firmly straight down. Thread this on a long M5 bolt, bearing side first, followed by a precision washer and the second bearing. Place the second bearing on a flat surface, and push the V-wheel sleeve over it too. Make sure both bearings are in as far as they will go. Remove the bolt.

If the V-wheel does not rotate smoothly, see Troubleshooting.

Smooth belt idler wheel assembly

Item	Part Number	Part Description	Count
For each wheel
1	MW2	Smooth idler wheel sleeve	1
2	G5	5 × 16 × 5 mm bearing	2
3	W5Pa	5 mm precision washer	1

Lay one bearing on a flat surface. Push an idler wheel sleeve over it (lip up, of course). The parts are designed to force-fit, so push firmly straight down. Thread this on a long M5 bolt, lip side first, followed by a precision washer and the second bearing. Place the second bearing on a flat surface, and push the idler wheel sleeve over it too. Make sure the bearings are all the way in, with the first bearing resting against the lip of the sleeve. Remove the bolt.

If the idler wheel does not rotate smoothly, see Troubleshooting.

Troubleshooting

If the V-wheel or idler wheel does not rotate smoothly when mounted on a bolt and tightened, it is very likely that a washer (or the internal shim washer) is rubbing against a bearing shield.

To prevent the outer washers from rubbing, always install them with the convex face toward the bearing, and the concave or flat face away from it.

If it's the old-style internal washer that's rubbing against the shields of the bearings, or the outer shield protrudes too much and rubs even against the convex face of a washer, disassemble the V-wheel and examine the bearings carefully. Of the two shields on each bearing, identify the one that is recessed the least, and remove it. Install the bearings with the open side toward the middle of the V-wheel; the shields aren't needed inside the V-wheel. This should eliminate the possibility of the shim washer rubbing against the bearing seal or shield.

With 625-2RS bearings (the ones with rubber seals), removing one seal is the best option. If you have 625ZZ bearings (the ones with metal shields), you can also remove one shield, or you can try to gently push the shields in, to deform them just enough that they no longer touch the washers. Don't overdo it, or the shields will touch the innards of the bearing (the ball cage) and make things worse.

Note that the above information pertains only to the old internal washers. The new precision washers are purposely made with an outer diameter small enough not to rub against a bearing shield or seal, so the need to remove or bend shields should not arise. The new washers are also much more precisely manufactured.

If the wheel makes a crunching noise when turning, you may have encountered a defective bearing.