Spent part of the weekend removing the bearings from the swing arm of my Spark and repeatedly found the new bearings were notchy after being pressed-in – out of 10 bearings only 2 were smooth after installation, so that was 8 wasted…. The bearings were unbranded full stainless with caged-balls.

I was using a bearing press (ie not a socket/hammer) and ensuring the bearings were straight each time, the bearing cups were all clean/swarf-free and greased. Any idea of the cause – is it simply poor quality/tolerance bearings??

Poor tolerance between bearing outer and frame. Try a bit of wet and dry paper on the frame and then try again. Basically it is crushing the bearing in the frame. Only take a thou or 2 .

Is your bearing press definitely pressing on the outer race and not the inner?

Otherwise your problem is probably here

The bearings were unbranded full stainless with caged-balls

poor quality/tolerance bearings

stainless bearings are unlikely to be the hardest, unbranded are unlikely to be the highest quality, best materials and finest tolerance.

I’d guess your bearings were squashing when they were wedged in place.

Yes I had this when I changed the bearings in my Tracer. Individual bearings felt notchy although the movement of the linkages feels nice and smooth when you put everything back together so I wasn’t that bothered

……except for the fact that the notchy feeling was the reason I pulled them all out in the first place!!! So 1 day and £35 completely wasted as the old bearings were in fact fine….and felt nice and smooth after they came out of the frame.

Play is the only reason I will swap out bearings in future

The bearing press plate is flat, so pressing on the outer/inner at the same time (so my mind is fine as long as the inner race isn’t slightly proud). The old bearings that same out, just like with the poster above, were fine….so I just re-used most of those, having cleaned/re-packed them with grease and they went it spot-on so I’m thinking it’s poor tolerance on the outer race.

I take the point that you get what you pay for! However, I’ve been using unbranded bearings for several years now as found that branded one ie SKF and NSK weren’t lasting any longer than a year, which is the same I’m getting out of unbranded bearings.

Id say the tolerance issue is with the frame not the bearings.
Well what do you expect from a premium, hand made frame!!!!
I’m not bitter at all
I don’t think it makes much difference though – movement feels fine when built up with no shock.

You would think it would decrease bearing life, but it doesn’t seem to….so just suck it up and forget about it man.

I had this with my old Banshee Wildcard. It drove me crazy trying to work out what was clicking whenever the suspension compressed or bike was pedalled

tried different wheels, spare fork, new pedals, cranks/bb, greasing bolts, skewers, etc.

eventually noticed the driveside bearing on the main swingarm pivot was running very notchy. this could not be felt when moving the swingarm up and down. just when turning the bearing inner race with fingers.

I thought it was knackered and got some new bearings. when I remove the old bearing it was not in bad condition, just a little rusty on the outside.

the new bearing became notchy when pressed in. removing that bearing showed it was still as new, and not notchy.

realised the bearing socket (seat) in the swingarm was slightly too small for the bearing.

solution was to take the old rusty bearing and repeatedly press it / remove it until the notchy feeling went away. This took about 10 pressings and removals. Noticed thin slivers / scrapings of aluminium alloy coming out of the swingarm during this process.

new bearing went in no problem, and felt smooth. problem solved, lesson learned.

Sounds like you’re getting your bearings from the same place as BMW Motoraad. My f800gs is only 18000 miles in and the headset bearings have been replaced twice under warranty…

Random unbranded bearings can work out OK or it can be a total waste of money, so I’m going to blame that… I bought a 5 pack, sent 2 back because they were rough straight out of the box, had a barney with the seller because another 2 were rumbly as soon as I fitted them… And weirdly the last one lasted ages.

Buy decent bearings, basically. Kaesae (Katec) has good stuff at a bit less than the name brands.

warm the swingarm bearing area in boiling water for awhile and cool the bearing in a freezer overnight. Drop the bearing straight into the swingarm without a press. sorted.

The bearing press plate is flat, so pressing on the outer/inner at the same time

… as long as it’s the right diameter

Only takes a few thou too small on the frame or housing OE clearances & your trusty steed will feel like a right old back of bones, one thing I would certainly not do is use Wet & Dry to a frame, warranty issues galore there, though it may feel like the right thing to do but can you imagine explaining that one to the supplier.

We regularly use a large about two foot square SKF industrial induction bearing heater to allow us to fit bearing on high speed shafts & the like but also we do some times cool them, put them in a freezer if the tolerances are a tad tight, were talking 50 to 100 ton presses to get the buggers of some times, personally buy the best quality bearings your pocket can stretch to, you get what you pay for, steer clear of Chinese bearings, I worked over there for 10 years jeez the quality of some of the parts we received was a joke we just binned a lot of it, they generally flaunt copyright laws & produce inferior products passing them on as OE specification.

yorkycsl

The problem is not that you cant get them in – although the methods you mention certainly do make things easier – the issue is the tolerances on some frames (like my Tracer) are out to such an extent that even though you can press the bearings in they feel notchy in the frame due to the tightness of the fit. Proven by the fact that the original bearings felt notchy and so did the new ones… Once taken out old and new feel smooth.

All you can do in this instance is either nothing or get the frame re-bored. Like you I wouldn’t set to work with wet n dry…..you will never get an even finish.

Depending on how old the frame is I’d be straight back to the manufacturer, I seem to remember Lappy having issues with BB30 Zesty’s & Spicys a few years ago & cracking BB shells galore, turns out something to do with worn out marchining tools making the shells undersize thus press in the bearings & in no time many including me had cracked frames.

If all else fails then make some sort of mandrill, basically a small socket on the end of T bar, wrap in Crocus paper, (wet & dry) with light oil polish of any machining marks or high spots, could even use a dab of engineers blue dye to reveal high spots, but have a vernier caliper & measure your bearings & frame, speak to the bearing manufacturer / supplier & ask for the recommended clearance be it interference / press fit etc & go from there.

Hope you get it sorted.
Cheers
Mark