Idler Wheel Inspection

[Derailed]

Hello Everyone,

I’m in the process of inspecting/changing the idler wheel bearings in my viper, the sidewinder next. A few of the wheels have a wobble to them, I rotated each with a dial indicator the best are .020-.030” variation and the worst are .050-.075 (these are obvious by eye). Does anyone know a spec or have a rule of thumb they follow for this?

Also, for bearings I’ve done similar with side to side play and have found the brand new bearing is about .005” and my reused bearings about .010”, I had one at .020 which felt quite loose so it was replaced.

My third question is about the fit of the upper idler. Does anyone see an issue with sanding the shaft it sits on so that it can be removed by hand? I managed to get them off with some C clamps but it wouldn’t be very easy to do on the trail if need be.

Thanks

 

[DVW]

I have much hands on experience with skid frame bearings because I repack them. Your measurements and variation seems what I have experienced. I have observed a bit more wobble with time. A year ago I replaced my bearings after 20,000 miles because one bearing had a cracked seal. This year with new bearings I did not notice any difference in vibration coming from the skid frame. With regard to the tight bearing fit of the upper idler, I do not hesitate to sand off the the paint on the shaft for a more serviceable fit. Hope this helps.

 

[Derailed]

Ok thanks, good to hear. There’s not really a point of reference unless everything was checked from brand new. I also repack the bearings.

Something I found interesting - the rear tri-hub bearings were NSK made in Poland, the lower idler were made in Taiwan NTN and the upper idler was made in China TSB.

Maybe it was because it was in the tri-hub but the NSK was the only one rust free and still very tight tolerance.

 

[DVW]

Ok thanks, good to hear. There’s not really a point of reference unless everything was checked from brand new. I also repack the bearings.

Something I found interesting - the rear tri-hub bearings were NSK made in Poland, the lower idler were made in Taiwan NTN and the upper idler was made in China TSB.

Maybe it was because it was in the tri-hub but the NSK was the only one rust free and still very tight tolerance.

I have had the same experience with regard to good condition of the bearings in the Tri-hubs. Early Tri-hubs had quality issues but once they sorted that out the superior design of the Tri-hub came thru. Think of the Tri-hub as a single wheel with two bearings. Most wheel bearings are arranged in pairs (think inner and outer bearings). With this arrangement the wheel will not wobble. Wheel wobble on a single bearing skid frame wheel creates an impossible task for the bearing seal. Without wheel wobble the Tri-hub bearing seals can keep the oil in and the water out. I think this is the reason that later Tri-hubs with removable bearings look so good when serviced.

 

[Dr. FeeLGooD]

I agree wobbly wheels will take out seals and bearings.

 

[DVW]

I agree wobbly wheels will take out seals and bearings.

And now they are going back to wobble wheels for the rear idler wheels. Can’t Blaine them. Our Tri-hub is a wobble free design whose reputation got tarnished by initial quality problems. It was faster to change negative perception by going back to the old wobble wheel than to slowly earn back respect with a superior design. Another example of this is the change to the Team clutch.

 

[yamadoo]

I have had the same experience with regard to good condition of the bearings in the Tri-hubs. Early Tri-hubs had quality issues but once they sorted that out the superior design of the Tri-hub came thru. Think of the Tri-hub as a single wheel with two bearings. Most wheel bearings are arranged in pairs (think inner and outer bearings). With this arrangement the wheel will not wobble. Wheel wobble on a single bearing skid frame wheel creates an impossible task for the bearing seal. Without wheel wobble the Tri-hub bearing seals can keep the oil in and the water out. I think this is the reason that later Tri-hubs with removable bearings look so good when serviced.

I have replaced my trihub with the Trihub with replaceable bearings up grade model is this the 'Superior Design" your reffering to? When did this appear on stock sleds...2016?

 

[DVW]

I have replaced my trihub with the Trihub with replaceable bearings up grade model is this the 'Superior Design" your reffering to? When did this appear on stock sleds...2016?

The Tri-hub is the superior design that had initial quality problems. I do not know for sure if the Tri-hub manufacturing problem was tied to the way the bearing was retained. I think it is probable the heat required to retain the non serviceable bearing may have created manufacturing challenges. Regardless the assemblies with serviceable bearings did not have problems. These assemblies showed up in 2015 or 2016.

 

[yamadoo]

Thanks
I have the Tri hub- reduce the woble stress- and can replace the bearing if gets rough. I am a belt and suspenders kind of guy and did the 4 wheel kit and so far so good.
This fall hope to pull the skid and check slides, bearings and Tri hub.

 

[Mills]

Have a '14 RTX and just made my Tri-hub bearings servicable. First i took it apart and then put a bolt through the bearing with a washer large enough to cover the bearing to protect it and tightened the washer/nut on the back side to capture the whole bearing. Next i clamped the bolt in my vice and then used my air grinder with a nerled tool (12 piece nerled tool kit from Harbor Frieght for $8.50). I ground out the plastic that makes up the inner beaeing hub down to the washer cast in place. I then removed the bolt and used a socket to drive the bearibv out to service it and put it back in. I left the inner washer out of the assembled tri-hub as the shoulder on the axle holds the bearing in the wheel.