INA combined needle/ball bearing

[chaterlea25]

Hi ALL,
I have been doing a search for another source for the INA NKIB5906 BEARING as used on SRM's
conversion
SRM list the bearing as having a C3 clearance,
I can source the bearing from several sources but not in C3 spec
My local bearing factor says its not listed?
Has anyone here found a source??
I am also looking for the roller drive side main with a brass or steel cage, Any suppliers??

Cheers
John O R

[MG]

Hi John!

Both FAG INA and SKF only list CN versions of that bearing. Generally all needle roller bearings with an inner race are only available with standard CN clearance. All C3 versions I have seen so far were special production runs, mainly for automotive applications. So unless you order a waggon full...

Maybe worth asking SRM for one?

[chaterlea25]

Hi Markus,
SRM's price is £80 + VAT
the standard clearance bearings can be picked up for a fraction of that, ebay for $15?
Thats why I'm asking on the forum

Cheers
John O R

[bonny]

Hello john
I seen you looking for a non-standard bearing for your conversion , i have to tell you i was looking for some pretty mundane imperial sized bearings in dublin and found even large bearing factors dismal in what they stock, the trouble is they have all moved out of the city centre and got rid of all their old stock. You could try e.fox engineers and dicksons but i wouldn't hold out much hope.
If you google that bearing number it seems to be used by mercedes.

Finally the chap in this article below says he wouldn't buy a srm overpriced bearing and found them elsewhere, might be worth an email or call.

http://www.customcycledevelopments.com/BSA_bobber.html

[chaterlea25]

Hi Bonny,
Yes I had read that Article, What I think happens is that guys just buy the bearing without knowing or bothering about the C3 reference,
That might be OK if you were machining the cases / crank yourself and you could allow a looser fit and use some bearing fit or similar dodge. Needle bearings are really critical to clearance issues, so I wouldnt take any chances with fitting them

Markus,
http://www.peters-bearing.de say they have "brass caged"  roller bearings
Could I ask you to contact them? My German isnt up to much!!!
I am looking for the drive side main bearing as well as the needle roller one

Best Regards
John O R

[MG]

Hi John!

No problem at all, I'll drop them an email and let you know what comes out of it.

[bonny]

http://www.obsolete-bearings.com/

[manosound]

Can't say I understand the CN v.  C3 issue,  but Motion Industries,  where I buy bearings here in the US,  list your bearing in stock at $90, a savings over 80 GBP even wth postage,  I think.

You will need to do a model number search after using the link below.

http://www.motionindustries.com

Richard L.

[kommando]

On bearings the tolerences for the CN and C3 clearances overlap, so if you can find a CN bearing at or near top limit it will fall in the C3 lower limit. So for a 75mm OD bearing the CN clearance is 10 to 30 microns and C3 is 25 to 51 micron. So there is an overlap between 25 to 30 micron where a bearing could be CN or C3.

[manosound]

kommando,

Hello, and welcome. Go ahead, jump right in, but I'll save our administrator the trouble of suggesting you check the following post on how we get along here:

http://www.audioworld.net/BSA/forum/index.php/topic,4723.0.html


Thanks for the detail on how the clearances work.

Richard L.

[MG]

A loose(r) fit in the alloy cases probably isn't the best idea, and finding a dealer who will search his stock for a CN bearing near top limit will be next to impossible I guess (how will you measure that anyway?). So best to find a source for C3 bearings methinks. Oh yes, no response from Peter's Bearings yet, maybe on Monday.

Bye, Markus

[dynodave]

I did this conversion to a set of A-10 cases about 20+ years ago. So my recollection may be foggy.
IIRC I believe the bigger C3 clearance allows the outer race to have a tighter than normal fit in aluminum since:
1. Bearings shrunk fit like this (in aluminum) are undesirable by engineering standards.
2. The aluminum grows with heat and the race would spin in the case when hot, unless a tighter fit..
The tight fit would result in potentially binding the bearing and making it tough or impossible to insert the inner needle.

http://atlanticgreen.com/bsarbc.htm
I'll have to see if I can find/post the associated pix-sorry
cheers
dynodave

[chaterlea25]

Hi dynodave,
Well put! a good explanation
This is my understanding of the references as well,
I know needle roller bearings are more critical on fit than large ball/roller bearings
Waaaay back when I had and worked on loads of BMC mini's the transfer gear bearings were needle roller bearings
In normal service they were quite reliable, then there seemed to be a rash of failures???
Guys and garages started adding STP or similar additives to the oil!!!
This closed up the bearing clearance and they failed in short order

Cheers
John O R

[wilko]

Are you sure that wasn't because of the needles skidding?

[kommando]

Waaaay back when I had and worked on loads of BMC mini's the transfer gear bearings were needle roller bearings
In normal service they were quite reliable, then there seemed to be a rash of failures???
Guys and garages started adding STP or similar additives to the oil!!!
This closed up the bearing clearance and they failed in short order

When I did my training at Longbridge I spent a week on the Mini A series gearbox assembly line, I spent 1/2 a day on each work station doing the operators task. The transfer gear needle roller bearing was fitted using an air operated press hanging above the line by a spring compensated sling, the location method was crude and so a far proportion were pressed in cock eyed, the line ran at 30 boxes an hour and 2 or 3 failed inspection each hour. Later on during a day with the gear noise expert downstairs he said that this needle roller was the main issue he had, if it could be pressed in straight then most noisy box problems would dissappear.