Needle roller cages

[akendall1966]

Not quite sure which forum this qustion belongs to, mods please move if needed.

Q - should the cage of a needle roller bearing be contained entirely within the bore the needles are bearing upon or can it extend outside into free space. Application is piston pin / wrist pin, I am playing with a conrod where the small end is 17mm wide but the OEM cage is 24mm wide, so I could use 22mm wide bearing and put spacers either side to stop the bearing wandering out of the centre. Or use a 24mm wide bearing and have the cage / rollers out of the rod small end eye.

Concern is unsupported the ends of the cage under acceleration and deceleration may fatigue at the corners of the slots for the rollers and in time break up.

The rod is guided at the big end so not a factor in this case

Gut feel is telling me that narrower bearing and spacers is the way to go but more fiddly to assemble.

Its a T500 so OEM rods are unavailabe, rod I have is correct length but the compromise is the width 17mm vs 22mm hence why I have this question.

[dinogt]

see a little better the Head diameter... you need 31mm and not 30 so, you can't do with the origin BE bearing

[akendall1966]

Hi Dinogt,

Yes I have bought the 24x31x17 BE bearings, and will use Suzuki OEM BE pins. I will probably use 2x 1mm and 1x1.5mm thrust washers each side for the guiding.

[dinogt]

impossible, suzuki OEM pin is 3mm diameter

[akendall1966]

impossible, suzuki OEM pin is 3mm diameter

I think you misunderstand me, by suzuki OEM big end pins I mean the 24mm pin also known as the crank pin I think. Not the needle rollers. I understand these were loose in the OEM part and 3mm diameter, clearly in a 24x31 bearing they would have to be a nominal 3.5mm dia. The type I will be using is a modern design and has captive rollers, so I wasn't thinking of the them as separate to the cage, rather as a complete bearing assembly as in the link below.

https://www.hardpartsdirect.com/Product ... 22.243117F

We seem to be a little off topic, as the original question was about small end cage width,and should I go the same width as the rod and use spacers on the wrist pin to stop the small end cage floating to the left or right. Or, use a wider cage and have the ends of the cage and needle rollers outside the con-rod small end eye. On the rod I have the small end eye is 1mm smaller so the cage is thinner, and needle rollers smaller diameter (weaker). So in my mind, spacers is the way to go unless some one can offer an argument as to why spacers are a bad idea.

[dinogt]

Ho yes, I was misunderstanding.
I think it does not exist over than 24/31/17
it exist 3 type bearings
GX cooper or silver or black coating, at left in your link
GUZ normaly silver coating, at the middle, for high rpm
GU silver coating free pins for very high rpm
I don't like GX because the cage touch the con rod
Prox must be GUZ or GU

[tz375]

Dino,

This is a little off topic, but you mention GU type with free pins. Does that mean no bars between the rollers so that all the rollers touch each other? Honda cranks used to use pairs of rollers (pins) but they seize because of teh double speed between adjoining rollers. The Race Kit cages had less rollers but they were single none touched the one next to it and they could stand higher RPMs.

In a GT500/550/750 high revs are not a problem because of the long stroke but I would expect a full race 250 could probably rev to 10k - 12k if fully developed. For the street any of the above should be OK, but for racers, it may be a good idea to upgrade.

[dinogt]

See at the middle this is a GUZ BE bearing
See at right, this is a GU BE bearing with a plastic in to hold the pins.
There is also GU with out the plastic, pins out of the cage.
For a 250T you can found 20/26/16 GU BE Bearing, but difficult to find 20/26/17.

[Vintageman]

I think the BE on T500 was the "regulated end" The one not designd to move axially about the needle bearings rollers.

And, The SE end was the "unregulated" , rod allowed to move axialy over rollers

I think the cage is longer than rod when with SE unregulated and fits tight between piston bosses but, not sure if needle rollers ever exit rod end. i doubt for then unsupported one side and i am think they flex when force on side only and snap.

I think you need to keep the BE regulated via thicker thrust washers. It must be qaulity material

Maybe call these guys for example and ask that question

http://www.eurospares.com/graphics/engi ... arings.pdf" onclick="window.open(this.href);return false;

or

http://www.ntn.co.jp/english/products/c ... 00E_03.pdf" onclick="window.open(this.href);return false;

[akendall1966]

The small end that came with the rod is as you described. The cage is a little wider than the rod, but rollers are inside the rod. The cage is not as wide as the gap between the bosses of the piston. I will use the bearings that came with the rod and make some spacers.

BE is OK I have suitable bearings and thrust washers.