Mystery Hub

Here's a mechanical puzzler for those so inclined. Today I was doing a tune-up on a Raleigh Super Course, probably a late 60s or early 70s model, definitely before 1973. The tag specifically said to true the rear wheel well. It had some very loose spokes (luckily loose in the right direction) so I started truing. Then I noticed that the hub had play, so I removed the freewheel (a very odd 3-prong freewheel made in England that I'd never seen before, though our shop had the proper tool to remove it) to adjust the hub. The hub had quite a bit of play, but was also binding in spots. I adjusted it as well as I could and started truing again. The wheel was impossible to true. I'd spin the wheel in one direction, find where the rim hit the truing stand caliper, spin it the other way, and that spot missed the caliper by 3 mm. What was wrong with the hub? I'll let you all guess the usual things first, then I'll tell you what it's not and give a couple more clues. This is such an odd one that I may have to give out a prize if someone guesses correctly.

Since you adjusted the hub I assume that you checked that the axle wasn't bent or broken, that you had the right number & size of bearings, the cups & cones looked OK, and both locknuts were tight. I'm suspecting that at some point in this hubs life it's been serviced and a damaged dustcap was replaced with an eyeball fit, or that some of the spacers were replaced but not the correct size. I want more clues, please.

I'm not sure if I can phrase this concept correctly - I'm going to guess that the hub was of an excessively malleable metal, and over time being out of true, the flanges became bent so they're misaligned with each other. Like, when both flanges are vertical, the axle is NOT horizontal.

That's my guess and I'm sticking to it :D

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Originally Posted by newfsmith

Since you adjusted the hub I assume that you checked that the axle wasn't bent or broken, that you had the right number & size of bearings, the cups & cones looked OK, and both locknuts were tight. I'm suspecting that at some point in this hubs life it's been serviced and a damaged dustcap was replaced with an eyeball fit, or that some of the spacers were replaced but not the correct size. I want more clues, please.

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I was not supposed to overhaul the hub (beyond the scope of work), so I was trying to avoid opening it up. By adjusting it, I knew that the locknuts were tight and the axle wasn't broken. I first suspected a bent axle, but inspecting with the hub together indicated the axle was straight, and that was confirmed when I did open the hub and roll the axle on the bench. Here are the most telling clues. I opened the hub and looked at one cone. It had normal wear: a ball-track line about 2 mm thick with obvious wear but no significant pitting. The 2nd cone had very abnormal wear, and a type of wear I'd never seen before. Instead of the usual narrow ball-track, it had wear over it's entire surface and some pits towards the edge of the inner surface, far from the normal wear area. I looked inside the hub where the cone with normal wear had been, and it looked normal, nine 1/4 inch ball bearings. But what did I see in the other side?

3/16 bearings, maybe even 10?

Marbles? Bee-bees? Gumballs? birdshot?

Karen

Ten 1/4 inch bearings. They didn't fit in a single circle, so two were out of the plane they should have been in. Hence the wear over a wide part of the cone. And the odd behavior truing the wheel, as the location of the out-of-plane bearings could change. So I removed one bearing, put the hub back together, and trued the wheel easily.

My other adventures with the 1960s Raleigh Super Course included attempting to remove a cotter pin to adjust the bottom bracket. The shop had the 15 inch long VAR cotter pin tool like we had at my shop in the 70s (except ours was wooden and this was metal), but the only thing that did was start bending the threaded part of the cotter pin. So I decided to leave well enough alone and managed to adjust the bottom bracket with the arm and cotter pin on. Then I spent some time truing the steel crankset. The inside ring trued pretty easily by bending the arms, but the outside ring had all kinds of small-scale wobbles. The VAR chainring truing tool allowed me to improve it, but I didn't get it perfectly true. It has Simplex plastic derailleurs, and the cage on the front derailleur is quite narrow, hence the gears couldn't be adjusted well with an out-of-true chainring.

Deb, are you working at a shop? Where????

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Originally Posted by Crankin

Deb, are you working at a shop? Where????

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I was going to ask the same thing! I know you went to the Bicycle Institute...must have paid off?????

oh, was it missing some of it's ball bearings???!

It had one too many bearings on one side. Hence the very odd wear pattern on the cone. BTW, the customer was really impressed that I found the problem with his wheel.

I'm working at Frank's Spoke'n'Wheel in Sudbury. Love it. All the cool bike tools from the 70s can be found hiding somewhere in the shop. Today I needed to replace an axle and cones, and we had them. There are even 10-20 year old brand new bikes and frames sitting in the attic - Bianchis, Bridgestones. I've got my eye on the 52 cm Bridgestone MB-3 from 1994.