The BSA A7-A10 Forum

Technical (topic titles must be descriptive) => A7 & A10 Engine => Topic started by: Steveba10 on 14.10. 2020 15:34

Title: A10 Roller main bearing Again.
Post by: Steveba10 on 14.10. 2020 15:34
I’ve been reading the forum discussing this bearing and am still confused as to the best practice to be used.

My drive side bearing has 15 rollers each 8mm diameter and 8mm wide.
I thought they were 5/16” at first but the bearing catalogue for the NF series says it’s metric.
No maker’s name just R130 V3  and a ‘B’ see photos.

The bearings I see for sale have usually 13 rollers (NSK), 11 rollers (RHP), 14 rollers ( Draganfly, made in USA). But none with my original 15.  And I counted twice just to make sure.
Looking through bearing catalogues it seems that along with common sense the greater the number of rollers the higher the load capacity and longevity.

My bearing looks reasonable, I had 0.003” end-float. The bearing was a firm push fit so no trouble putting a slightly thicker shim in to get the end-float within spec.
I’d replace it if I could find one like for like, just to be sure I’m not doing the job twice.
But I don’t want to replace it with a lower capacity, fewer rollers, item.

There seems to be many bearing manufacturers with names I don’t recognise and those I do seem to be like Hepolite where it’s just a name and unknown manufacturing source. Often they are advertised in plain plastic bags or simple cardboard boxes. Even my local bearing supplier seems to be buying Chinese items.

So who do I buy from?
Can anyone tell me the name of the original supplier to BSA?
What would you do?
Thank you,
Title: Re: A10 Roller main bearing Again.
Post by: RDfella on 14.10. 2020 17:55
I wouldn't worry about the number of rollers. Whatever the number, the bearing will last a lot longer than you probably need.
But quality? Yes, that's important. Buy from a reputable dealer (I always used to use RHP supplied by BSL) and of recognised manufacture (eg SKF).
Title: Re: A10 Roller main bearing Again.
Post by: berger on 14.10. 2020 18:06
i have not been to the pub, it could be another long time before I go again *eek*. Well steveba10  my answer to one part of your question is get the magnifying glass out and give it a good inspection on the rollers and the outer race. if it looks good and feels nice when spinning it in your hand once well washed out with petrol etc I would add a little oil and spin it feeling for any restriction or hesitation when it is spinning, if ok put it back in. just my opinion after years of changing bearings as a matter of because I could. over the years I have wasted money doing this but not any more.
Title: Re: A10 Roller main bearing Again.
Post by: metalflake11 on 14.10. 2020 21:46
S.R.M. certainly used an NTN- NF206E.

Mine was in perfect condition when I checked it after many tens of thousands of miles while changing my cam.

Unfortunately, after cleaning it with brake cleaner, I dried it by spinning it with compressed air without its outer race.

The nylon cage expanded, and rollers shot into every corner of the garage. I still haven't come across one of the rollers! *smile*

Title: Re: A10 Roller main bearing Again.
Post by: BSA_54A10 on 15.10. 2020 10:07
Quality bearing makers brand their bearings and always put them in branded boxes
That is the only way  to buy bearings
If it is not in a branded box and does not av the same brand on the bearing itself then it is counterfit.
As fro element numbers your assumption is correct however a lot of bearings used in the "olden days" were way over specification.
Years of useage data & computer modeling has allowed bearings to be optimised for price & durability .
Thus replacements often have fewer elements