ImperialBearingsizes

I suppose it could be simply the eccentricities of the French, but I find it really unlikely that a front hub would be spec’d to have a different number of bearings on each side, as the Atom example in the post does. More likely the hub had been repacked previously and a bearing was left out, or it was a Friday afternoon at the Atom factory et le vin avait commencé à flotter….

I can infer that 1/8″ balls are therefore the smallest, even with my lack of mathematical nouse. However, I’m not even sure you could confidently identify a 5/32″ ball just by looking at it. In other words, when a person opens up the races of their headset, it’s not going to be clear if the balls inside are 5/32″ or 3/16″. I wonder why there has to be two different sizes of balls for very similar sized races, but I’m no engineer.

Bearingcodes and sizes

Park tool’s ruler includes a ball gauge. Start at the small size and move up a hole until the ball passes through. Very useful. It also has a set of holes for crank cotterpins for those unfortunate enough to still have cottered cranks.

If you are going deep enough into own-cycle maintenance that you’re counting/repacking/replacing bearings, you owe it to yourself to get a digital caliper- somewhere like Harbor Freight will have one for about $10.

Sealed Bearings bysize

Bottom bracket bearings are bigger than headset ball bearings, and are normally 1/4″ in size, though vintage Campagnolo Super Record cups take the smaller 3/16″ size. Safe to say, the number of balls in each cup is 11.  The last thing you want is to service your bottom bracket and put it all back together, only to find one little bearing sitting on the table. Sometimes they can go missing in the cloth you are using to clean them, or be overlooked by sheer overconfidence. Don’t believe your own hype that you won’t lose any of the buggers.

I think freehubs are mostly cartridge bearings these days. And you don’t really want to mess with rebuilding freewheel if you can help it.

The confined space of a hub means that working with wheel bearings can be a finicky business. The races which they roll on are much smaller than bottom bracket cups, and the balls can easily fall out as you try and get to them. Servicing the front hub, with its small balls and bearings, can be a frustrating process. The front hubs of vintage bikes use 3/16″ balls, but the rear hubs mostly use the larger 1/4″ inch size, which are the same as for the bottom bracket. There are normally 9 in the rear, as in the case of this Taiwanese brand below:

Imperial bearings catalogue

Hi, just found your site. I am looking for the correct size of ball bearings for a headset on a Gitane TdF 1975. I cannot find the detail anywhere. Thank you

I’m changing the bearings on a “standard” 3-Speed beach cruiser. I changed them out a few years ago and may have used the wrong ones. I found what may be the old ball cages, but they have 9 bearings. The ones currently on the bike have 10 bearings. In the photo, the current ball cage (10 bearings) is on the crankset and the old one (9 bearings) are in my hand. Can somebody help me figure out the best bearings to use? Thanks in advance!

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Deep grooveball bearing

Found this article of great interest but I ended up a little confused about different sizes in front and rear hubs. On my vintage road racing bike the ball bearings in the rear hub look like 3/16 inch but many articles I have read dictate and specify 1/4 inch ball bearings. I counted 11 3/16 ball bearings each side, still not convinced this is the correct size. The bike is a Steve Thornhill.

Hi – I’m renovating a Parkes Lightweight from the 40’s or 50’s. Taking off the pedals to clean them of rust, I lost some of the inner pedal balls. They seem to be 3/16 in both sides and 12 in each but is that right. Does anybody know?

If you’ve ever dropped ball bearings while servicing a headset, then you’ll know how frustrating it is to find them once they’ve clattered about the floor. Chances are, you’ll lose one or two forever, as they bounce so far and hide themselves in the most bizarre places. It easily happens; you are carefully loosening the threaded top race of the headset, when click click click..a few of the little blighters have escaped and dropped away. I’ll be making a video of how to avoid this one the next few days. Nevertheless, once the bearings have escaped their long held captivity, you may very well be wondering how many you require to put the headset back together again.

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Sutherland’s has a chart for all the different variations of headset ball bearings used, so there’s no basic standard for vintage headsets. The ball bearings will either be 5/32″ or 3/16″ size, and the number can range from 22 balls to 25. I think for vintage French bikes, most balls will be 5/32″, but there will be exceptions. The general rule is, pack the balls evenly next to each other, and leave space for one. Unsurprisingly, Campagnolo have all kinds of variances, but so do Shimano, Ofmega and Stronglight; there seems there was no clear or set formula that these brands were working to. Here is a Stronglight headset I recently filled:

Bearing sizecalculator

So, two headsets of the same era, from the same brand, hold different amounts and different sizes of balls. And this is just the start of it.

I opened up three pedals last week, and each had a different ball bearings set up to each other. What’s more, there seems to be little information online about the variances of ball bearings in these components. Unlike the equal number of bearings in the races of headsets and in the cups of bottom brackets, the two races of a pedal bearings can hold different numbers and different sizes of bearings. One race may contain 5/32 size balls, the other may hold the smaller 1/8″ balls. There is not therefore, no standard amount of bearings in pedals, and they can vary according to the brand and their age. The inside bearings of a pedal is on the side of the pedal which is nearest the crank, and the outside bearings are held in the race furthest away from the crank.

Ball BearingInchsizechart

Hi, thanks for the question. I believe your Campagnolo Record pedals require 5/32 bearings on both sides, 12 on each side, so it would be 48 in total for the two pedals. Here is a link to a set on Ebay: https://www.ebay.co.uk/itm/Campagnolo-pedal-bearings-5-32-Vintage-Racing-Bicycle-NOS-x-10-packs/273007300240. Hope that helps.

Forget numbers for a minute. And different grades of balls?? Yeah, no let’s move on. What about sizes? Would a layman be able to tell the difference between a 5/32″ ball and a 3/16″? Referring to my Sutherland’s again, it states that the difference in mm is thus:

I bought some nice vintage Campy Record pedals with the strap guides 68-72 I think. They weren’t smooth at all. When I serviced them both they had the same size bearings 12 each side. I need to know if each side have different sizes. They are smoother now but still don’t feel right. Please let me know size or sizes needed. I just want to make these right.

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Very helpful, thank you. One pedantic comment: You refer to small balls used in bearings as ‘ball bearings’. A ‘ball bearing’ is a bearing made up of ball, as a ‘needle bearing’ is a bearing made up of needles. The small balls are ‘bearing balls’

I have just started renovating a pair of Brampton B8 pedals. When I took them apart, it clearly not having been done for decades, one side had a total of 20 ballbearings and the other side 22! The ball size is 5/32″.

ImperialBall Bearing sizechart pdf

I am rebuilding a 1974 Schwinn Super Sport pedals with 1/2″ posts and 20 (5/32″) ball bearings in each pedal. on teardown I found 10 bearings on each side, but a video i watched said there should be 11 bearings on one side and 9 on the other.

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Note to self: don’t write a blog about ball bearings in bike parts, it’s a bloody nightmare. In fact it would be a mammoth task for anyone to precisely evaluate the amount and size of ball bearings for each component over the years. To be honest, the ball bearing question is downright confusing, and information isn’t really that forthcoming on all the different types and variances within parts. First off, there are 4 different sizes of ball bearings used for bike parts: 5/32″, 1/8″, 3/16″ and 1/4″. Oh, and some Shimano pedals even use 3/32″ size balls. Now, to show how confusing it can be, just look at Campagnolo’s headset ball bearings entry in Sutherland’s Handbook For Bicycle Mechanics: 4th Edition:

I actually prefer to use loose ball bearings, rather than caged ones, even though I see the very practical reason of keeping small metal balls imprisoned in a cage. Doesn’t having a much larger number of balls mean that the headset will effectively be a better performing mechanical device? It seems to me it would, though I just cleaned up a caged headset from a 1981 French bike, and the headset was as smooth as silk..