Main Crank bearings

[Guest]

I am gathering parts and info on my next rebuild which will include a total crank rebuild. Falicon offers either ball bearings (which are stock) or roller bearings on the main bearings...do any of you guys have experiance with the roller bearings?

Hap

[Anonymous]

Cranking.......

Rollers are best as they distribute the load better, but both are very prone to "dirty" oil damage....think about it ...a small particle wedges its way between the 'rollers' & the races...depending on the hardness of the particle...That is the benifit of standard style babbit high pressure bearings is the ability to absorb 'dirt'. Is falicon going to be the ones to strip apart your crank & are you going to weld it once its' been indexed?
Rick......

[Hap Call]

Yes, they will be doing the indexing and welding. My major concern is the vector forces on the main bearings...the roller bearing does not handle axial forces at all but the ball bearing can handle some. The advangages of the roller ar that there is more bearing contact in a vertical direction and thus more support in that direction. Is there any axial loading on the main bearing on a GS1100?

Hap

[redliner1973]

There shouldn't be, only verticle load, otherwise the case would be beat from the crank trying to sideways itself out. :twisted:

[Hap Call]

There shouldn't be, only verticle load, otherwise the case would be beat from the crank trying to sideways itself out. :twisted:

That is what I was figuring also but just wanted some confirmation. I know that everytime I have had the crank out it has checked good but because it has ball bearings the rods always had lots of "play", something that is disturbing when you are used to plain bearings.

Hap

[saaz]

The only axial load there would be is the crank/clutch drive if it is not a straight cut gear. Otherwise the main force is definitely from the pistons. For street use seems a bit of a moot point, except I suppose Hap wants to spend less on his 1,000,000 mile rebuild!!!

[Anonymous]

Axial loads?????Hmmmmm?

Yes, they will be doing the indexing and welding. My major concern is the vector forces on the main bearings...the roller bearing does not handle axial forces at all but the ball bearing can handle some. The advangages of the roller ar that there is more bearing contact in a vertical direction and thus more support in that direction. Is there any axial loading on the main bearing on a GS1100?

Hap

Hap:
I suppose you could mix & match....say balls on the outer end bearings & rollers on the rest....I would betcha falicon would have some interesting input & technical razzle dazzle on this!
Rick..........

[Anonymous]

I don't remember seeing any thrust bearing surfaces on my crank when I had it out. This leads me to believe that the ball bearings do handle the axial load.

I would think that most of this load would be eliminated with straight cut gears.

[saaz]

I just found a copy of a Cycle World article on bearing types (November 1978). As already said, rollers are great at axial loads, no so with thrust load. Ball bearings handle thrust a little better and axial very well. It seems that cranks can be made either way, or even use combinations of balls and rollers, as long as it is designed to take it. If you are running a straight cut primary drive, possibly no problem. Otherwise the thrust force has to be handled somehow.

Depndes on the application, power and life expectancy.