Bearings

[Will's]

So this weeks club nights I had a steering issue and one of the points we noticed was quite a bit of play in bearings ( currently running a Schumacher KF)?. So this has now got me thinking about bearings and I have the following questions,

1). How good are standard kit bearings?

2). Can you replace them with upgraded bearings?

3). What are the best type to replace them with?

4). General advice

Thanks everybody!

[mark christopher]

1/ good
2/ yes
3/ kit or ceramic if you want
4/ keep em clean and lubed

[chrispattinson]

1 - good
2 - yes, but not really worth it. Spend your money on tyres
3 - kit
4 - leave them alone .... Change them when they degrade.

[SlowOne]

Bearing play is not related to the grade of the bearings sold. It is the bearing fit that dictates the play in the bearing, not the grade of bearing you buy. In RC there are two considerations for this...

First, the fit of the bearing into the housing and onto the axle or shaft. It is important that bearings do not move axially when in operation. If (say) the inner race on the shaft/axle can move then it will. If the outer race can't move because it is a tight fit in the housing, then there will be an end load on the bearing that leads to friction, premature wear and poor operation. So for the best bearing performance, the bearing should be an interference fit in both the housing and on the axle. That would make it almost impossible to remove, so inevitably one or the other (or both!) is just 'sitting' there and free to move.

Secondly, the fit also dictates how much the race shrinks (outer) or expands (inner) when fitted into the shaft/housing. If the fit in the housing is very tight, then with a high grade nearing it is possible to crush the outer race onto the balls creating higher wear and premature failure.

The best feature in any bearing are the shields. The Schumacher ones I have on my Supastox have rubber seals and every time I take them off to look inside they are clean. Meatl shields by definition have a clearance between inner race and the shield that will let in water and dirt. The very (very!) best sealed bearings were the Tamiya ones with blue shields.

Follow the advice above. If you want to reduce the play that is best done with better fits in housings and axles - but I guess you aren't going to buy a shedload of those just to get a better bearing fit!! Don't be tempted by expensive, higher grade bearings because, if the fit on your components is wrong and they have all their clearances removed, they will wear out prematurely. Keep an eye on them, keep them clean, and replace with the originals if the seals are working OK. HTH

[Will's]

Thanks for all the comments!