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trek, helicomatic, bearings

15 May 2009 _ 19h25m40 EDT
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~ the rear hub on our trek 460 is an outdated and oft-disparaged ‘helicomatic’ from the french company maillard; every few hundred miles, the wheel begins to wobble, and we have to tighten the outdated cones. a couple of weeks ago, we tightened them just enough feel no resistance when spinning the wheel, but when we mounted the wheel and tested it, there was a terrible grinding noise, and the wheel would sometimes stop suddenly.

we opened the hub and looked inside. the bearings on the ‘left’ side of the wheel were scarred and some of them were split to pieces. our plans for an afternoon ride were dash’d.

we don’t know anything about bikes that any tool can’t learn by using google. so any knowledge that we utilized in ‘repairing’ our trek could be checked against online information, if there was any available. in the event, we were unable to find any definitive information.

for example, sheldon brown [w] states that the hubs ‘used 13 5/32″ balls on the right side’, but he doesn’t specify what they use on the left side – the same, or something different? meanwhile, a flickr page has photos of the helicomatic states that the hub uses 3/16″ bearings. the folks at yellow jersey [w] are able to tell us that the bearings are not 1/4″, at least.

the point of all this is to preface our list of procedures with a statement that we were working with contradictory information, so anyone reading this page whilst dealing with their own helicomatic issues should bear that in mind.

the bearings that fell out of the hub were 5/32″, so we figured that’s what we would replace
however, maybe the reason they splintered in the first place is that they were the wrong size. sheldon brown’s half-info and our personal experience persuaded us to stick with the 5/32″ bearings.

here’s the hub. note the scarred spokes!

5/32 inch bearings
5/32″ bearings. 1/4″ bearing in background.

there’s a big difference.

replace the axle and pour in the bearings.

helicomatic bearings
13 bearings.

pack in the grease.

place the plastic ring over the bearings.

helicomatic cone
poor pockmarked cone. will i ever find another?

continued in ‘trek, helicomatic, bearings, part 2

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