Custom Fighters - Custom Streetfighter Motorcycle Forum banner
1 - 17 of 17 Posts

·
Administrator
Joined
·
5,264 Posts
Discussion Starter · #1 ·


Talking about (8) in the fig. above ^

Why? Other than making it a fucking bitch to remove bearings. It's known as a spacer but the bearings are sat in their own recesses with no-where to go in that direction.

Anyone have any insight into it? And remember this is Custom Fighters, the answer: "If they put it there at the factory there must be a reason...." isn't going to wash.

Cheers gents!
 

·
Administrator
Joined
·
5,264 Posts
Discussion Starter · #3 ·
Thanks for your answer, so it's main function is to just stop the inner races from moving inwards in the case of a total bearing collapse, right? My thinking is that for that to happen the lateral force on the bearing would have to be huge or the wear on the bearing be significant enough for the balls to release the race. Is it a case of "belt and braces" safety? A hangover from when bearing construction was less tight maybe?

I'm inclined to think that it's absence would not be very likely to kill me, (assuming a basic schedule of checking the bearing health) would i be right?
 

·
BAD MOTHER FUCKER !
Joined
·
642 Posts
its absence means you will stress the bearing and it will fail, my 5c leave it there.

the way you torque the front axel it will add lateral forces to the bearing causing it premature failure.

simple test get the old bearings put it back on without the spacer and torque it to the recommended Nm or Pounds ... see if you notice it caving in.

but u definitely should not ride your bike without it,

it is safer to shave your balls with a piece of glass then ride your bike without the #8
 

·
Administrator
Joined
·
5,264 Posts
Discussion Starter · #5 ·
Thanks for the mental image. :D

OK, noted, spacer stock on the shopping list. Rep'd
 

·
Administrator
Joined
·
5,264 Posts
Discussion Starter · #7 ·

·
moron with a hammer
Joined
·
119 Posts
It keeps the inner races apart when you torque the front axle. Otherwise you'd end up putting so much side load on them they'd fail almost instantly.
Not "instantly". You'd probably get at least 70 or 80 miles on them...



Yeah. The spacer is necessary.
 

·
|||||||||||||||||||||||||
Joined
·
30,434 Posts
Why not cut a slot in it so you can use a screwdriver or something similar to ease bearing removal in the future. So you would essentially end up with a spacer shaped like a C.

Just a thought.
 

·
Administrator
Joined
·
5,264 Posts
Discussion Starter · #12 ·
Why not cut a slot in it so you can use a screwdriver or something similar to ease bearing removal in the future. So you would essentially end up with a spacer shaped like a C.

Just a thought.
Beat me to the punch. Yep, already ahead of you in my... head. I'm still not sure what fork/spindle i'll be using but when I do i'll probably have to fab a spacer. Fuck it, even if the stock one could go back in it won't be because it's badly designed. Factory ones have a pathetic little slot, i'll be doing something a little more useful but not so much that it defeats the point of the spacer.
 

·
moron with a hammer
Joined
·
119 Posts
I was rushing to get the wheel back together before a move. The bike wasn't going on the road anytime soon, and I needed a longer spacer than what I had, so I just threw it together with one that was about 5mm too short. Left out the cush drive spacer too, to remind me that I still needed to do the wheel spacer.

Eight months later, I'd forgotten both, and put it on the road.

I made 79 miles before the rear end started bucking. Within a half mile, it was unrideable. You can't tell from the picture, but the other outer bearing was seized solid.

So yeah. I recommend using the spacer, and the correct one at that.
 

·
Old, bold rider
Joined
·
179 Posts
When making a center spacer it is essential to follow these guidelines:
1 -- The spacer must be slightly longer (approximately 0.005") than the distance between the two bearing mounting faces machined into the wheel in order to prevent excessive side loads that can shorten the life of the bearing. This leaves a small clearance that will compensate for spacer compression when the axle is torqued down, and allows a small amount of "float".
2 -- The spacer must have full contact with the inner races of both bearings. Any less can promote misalignment or excessive crushing of the spacer when the axle is torqued down, again causing excessive side loads.
3 -- The spacer end faces must contact at least 80% of the width of the bearing inner race for sufficient strength and support.

When driving the first bearing in push against the outer race only. When driving the second bearing in, obviously after placing the spacer, support the first bearing against both races and push against both races of the second bearing at once -- ordinarily this would not be the case, but since the spacer is longer than the width of the registers in the wheel, seating the second bearing against the register will apply a side load that may or may not be corrected when the wheel is put into service. When driving against both races it will stop when the bearing contacts the spacer and you're good to go.

Rob
 

·
Old, bold rider
Joined
·
179 Posts
what about crush tubes in swingarms? same principle, or less impactful?
From my experience as an auto tech the only use of crush sleeves is in differential pinion shafts which use tapered roller bearings. They make setting the preload much easier by specifying the torque figure for the pinion flange nut, which is rarely loosened.

On the other hand a shaft that is cycled often (loosened and tightened) would require a new crush sleeve every time, and it would not insure the zero thrust that deep groove ball bearings need for long life. Add to that the fact that a custom crush sleeve would be very expensive to have made and nearly impossible to make in a home shop.

Besides, how often is it necessary to remove the bearings? Too frequent replacement will eventually wear out the bearing registers in the wheel, and usually indicates there is a basic problem with the wheel, way too many hard landings from wheelies, or constantly changing your mind about the color. In order: correct the problem with the wheel, learn how to land more gently, or decide on a color and live with it.:LolLolLolLol:

Rob
 
1 - 17 of 17 Posts
Top