How Things Work: The Freehub Body - Part 2

Mountain Biking Magazine


Technical & Maintenance

How Things Work: The Freehub Body – Part 2

A load of you also wanted to know what goes on inside Hadley and Mavic rear hubs, and now you need wonder no more…

Hopefully that video has also shown you that the vast majority of quality cartridge bearing rear hubs share many similar design characteristics, and so you should have a bit more confidence about delving inside yours even if it’s not one that we’ve featured. Basically they don’t bite, so why not have a go.

If you missed the original instalment then you can find it here, and below are a few more detailed shots of the inner workings…

The pawls of the mighty Hadley. As you can see there’s not a blob of grease in sight, but a fair old bit of super slippery oil. These hubs are all about speed, but it does come at a price. You can’t just leave these hubs for months and expect them to still perform at their best, they need regular love. I suppose they’re best described as racers hubs and are ideally suited to riders who don’t mind putting in a little bit of graft in order to help save fractions of a second.

Rather than using a coil spring on each pawl Hadley use one circular spring which you can see running around the outside and when each pawl is pushed down this deforms the spring, with the result of course then being that the spring wants to push each pawl back up. You used to see this design a lot more years ago but it seems to have fallen out of fashion. I think the reason for that could well be that several hubs used poor quality springs that didn’t produce a very strong return force, and some of them also snapped which left you with no pawls working, unlike if you have a separate spring on each pawl. Don’t worry though, Hadley have the design dialled on their hubs and it’s as good as any ratchet and pawl system.

Here you can see the ratchet part of the Hadley hub along with the seal which does a pretty good job of keeping the fine oil in (and dirt out), and the fancy needle roller bearings which help to give the hub such low drag when freewheeling.

A special shout out goes to the North West Mountain Bike Centre who kindly sorted us out with this hub. They are the UK importers for Hadley, stock all the spare parts, and are generally a font of knowledge for all things Hadley (and basically everything else related to mountain bikes).

Next we have the pawls of the Mavic Deemax Ultimate and as you can see the design is very similar to a Hope hub. Each of the pawls is contained to make dismantling and assembly easy, plus each one is operated by its own coil spring. You’ll find this design right across Mavic’s range of high-end wheelsets and over the years it has proved to be a reliable system, and it’s very easy to work on if things ever do go wrong.

This is the ratchet part of the Mavic hub and as you can see from the photo the seals do a pretty good job of keeping the filth out (this is exactly as I found it when I took the hub apart). These wheels have been used in some awful conditions, plus they’ve been jet washed, and yet they’re still looking pretty healthy inside.

And finally if you’ve ever wondered what this rubbish tyre lever with a funny bit on the end is for then it’s actually a tool for adjusting the bearing pre-load on Mavic hubs. I think you get one as standard with any new set of Mavic wheels, but don’t worry if you haven’t got one because a Park pin spanner will do the job too. Just make sure that you don’t over-tighten it as apart from causing unnecessary drag you’ll also be wearing the bearings prematurely.

So there you have it, the inner workings of two more quality hubs, and hopefully proof that looking after this part of your bike really isn’t that complicated

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