A hub connects the spokes of a bicycle wheel to the frame, hopefully via a set of bearings, allowing the wheels to rotate. The rear hub of a bike has a second function, namely to hold a set of cogs, and transmit the torque from this drivetrain into the rear wheel, via a freewheel mechanism.
There are essentially two types of hubs on the market today, those using traditional adjustable bearings, (e.g. Shimano) and those using 'sealed' or 'cartridge' bearings (e.g. Hope and most other aftermarket hubs). What the bike industry calls "sealed bearings" are what the rest of the world calls "bearings". The bearings in your car, vacuum cleaner, lawnmower and washing machine will all be 'sealed' or 'cartridge' bearings. In fact the only situation where they are considered novel is in a bicycles, where the old adjustable design has survived for a century. Almost no other device, except a bike, uses permanently fitted adjustable 'cup-and-cone' bearings.
Shimano hubs all use adjustable bearings. These are comprised of three parts, cups, cones and balls. The cups are hardened steel races, pressed fitted into the aluminium hub shell, the cones are hardened steel, and screw onto the hub axle, and the balls are precision steel bearing balls. Once the cones are adjusted correctly, by screwing them along the threaded axle, the whole assembly can support both vertical and side loads. I have calculated that a typical Shimano hub using 9 quarter inch ball bearings on each side, can support a load of 1000kg, and even more once it is rotating. This is at least twice as high as even the best 'cartridge' bearing hubs!
So what are the disadvantages of adjustable hubs, and why are they not used in expensive aftermarket hubs?
Well, you'll notice above that I mentioned that the cups and cones are made from hardened steel. All bearing surfaces must be made from extremely hard steel, to prevent small indents being formed by the balls, which would cause the whole bearing to wear at an alarming rate.
This means that to manufacture such a hub correctly the cups and cones must be forged, then heat treated, then ground and then polished, before being used. This is a very expensive process, and only occurs on top of the range hubs such as XT, XTR and Dura Ace. In lower quality hubs, the polishing, grinding, or even the heat treatment processes are skipped, and the end result is a hub with a dramatically reduced lifespan.
I know of a 7 year old Dura-ace hub, and a 3 year old XT hub. I have owned several LX hubs, and the average lifespan was 12 months! If you buy Shimano hubs, then treat XT as a minimum, and at £30-£40 for a rear hub they are by far the best value-for-money of any hub on the market.
The other disadvantage of Shimano hubs, is that once the bearings are worn, it not possible to renew the bearings as the cones are permanently press fitted into the hub shell (unlike Campagnolo hubs, where the cups can be replaced). The only way to rectify a worn bearing in a Shimano hub is to replace the hub, and this also requires new spokes and a wheel rebuild, which adds significantly to the cost and hassle. Then the next question is whether the rim is worth salvaging, or should you buy a whole new wheel?
Shimano also use a significantly different freewheel mechanism to all other hubs. As Shimano invented the freehub concept and patented it, Campagnolo were forced to develop a rival 4-bearing system, which is now used by everyone else, including Hope. The body of a Shimano freewheel is remarkably thin, and manufactured from steel. The accompanying photographs show what can happen to a Shimano freehub, after it gets too sloppy. This LX rear hub's freewheel exploded in the middle of the Red-Bull trail, leaving me to complete the ride on fixed wheel!
As Shimano freehub bodies are so thin, it is impossible to use weight-saving aluminium for this component, and even the titanium freehubs of recent XTR and Dura-Ace hubs have a reputation for shattering. However, as I said before, an XT rear hub is by far the best value rear hub you can buy, and only weighs about 350g (the disc version weighs a lot more, so beware).
The original reason why aftermarket manufacturers were attracted to 'sealed' or 'cartridge' bearings, was that they couldn't easily manufacture the standard type. Any 'Fred-in-a-shed' with a lathe could machine an aluminium hub shell and axle, and press in a pair of bearing, and he has a hub. I have even considered making my own hubs.
In the early days only aftermarket front or 'screw-on' rear hubs were available. The complexity of the freewheel mechanism meant that aftermarket freehubs were much more expensive when they eventually appeared on sale. Hope screw-on rear hubs, singlespeed hubs and front hubs cost around £50. Cassette hubs are a cool £135+!!
With 'cartridge' bearings, a manufacturer with a three letter abbreviation has performed all the heat treatment, grinding and polishing before the first piece of swarf spins off the hub maker's lathe.
The other great advantage with 'cartridge' bearings, is that when the bearings wear out, they can be replaced easily, without recourse to a new hub and wheel rebuild. This is fortunate however, as cartridge bearings contain fewer and smaller balls, and therefore don't last anywhere near as long as a properly manufactured (and adjusted) standard hubs (XT, XTR). Hope Ti-glide hubs use 6001 bearings, which have a load capacity of around 500kg, half of that of XT or XTR units. This reduces the life of cartridge bearings. Some manufacturers may still manage to cut corners, and fit substandard bearing cartridges, but when they wear out they can be simply replaced with better quality items.
I fit stainless steel SKF bearings, and replace the grease with Castrol waterproof grease. These cost about £5 each - so £20 per hub. You could even splash out on ceramic bearings!!
I have a Hope Ti-glide hub in the back wheel of my racing bike. The axle and hub flanges are aluminium, with a titanium tube forming the centre of the hub body. The freehub body is also beautifully machined from titanium, and is still gleaming bright with razor sharp edges, even after 4 years of being buried under 8 oily cogs. Hope fit SKF (the best) bearings as standard. The hub creaks, but I'm damned if I can find out why. The bearings have needed no attention in 4 years, but I've had the hub apart, just to look at it. The bearings and axle slide out easily with a few taps from a hide mallet (no vice needed), and no tools except the hammer and circlip pliers were needed. The freewheel is a direct copy of a campagnolo, with three small pawls and minute coil springs.
Re-assembly required some sockets, to use as press-in tools, and the mallet again. 30 minutes of tappity-tap and the hub is fully dis-assembled, and re-assembled. The Ti-Glide weighs 315g.
My trusty MTB uses one of the legendary Hügi hubs. However legends can be deceptive, and my bearings were shot after only 4 months. Hardly acceptable for a £120 hub. The hub seals were very poor, so the entire hub and freewheel mechanism was full of muddy water and badly rusted. The original bearings were not SKF. Insult was added to injury when it was found that the bearings were press fitted into the hub shell. A hydraulic press was required to remove the bearings.
The second set of bearings were SKF stainless with waterproof grease, these lasted 8 months. I'm on my third set now, (and getting pissed off!). Part of the problem may also be that the Hügi uses slightly undersized 6000 bearings, which support 20% less load that what everyone else uses.
The freehub however is a different proposition altogether. Two 18 tooth ratchet rings engage to give rock solid transmission, with only two moving parts; one ratchet, and a single huge coil spring. The idea is patented, so do not expect to see Hope using it in the near future. The freehub is so simple that it could be completely disassembled, oiled and re-assembled on the trailside in 10 minutes!
The freehub body itself is aluminium, and despite predictions of gloom (Hope switched from aluminium to titanium bodies many years ago), it is running fine without significant notching. Strangely, the axle is 10mm diameter steel with aluminium end caps.
Provided that your Hügi has not been press fitted together like mine, a hide mallet, vice, 17mm spanner and sockets are all that are required to replace the bearings. The second set of bearings were fitted in a few minutes. The Hügi (97 Sport) hub weighs 330g.
Hügi have a new range of hubs out now (the Hügi 240), which use massively oversize hollow aluminium axles (like the excellent Campagnolo 2000 road bike hubs), and weighs only 240g with bigger bearings - they definitely look interesting, especially as they cost only £130 or so. They can also be fully stripped (except removing the bearings) with no tools at all!
Simon Barnes from Bogtrotters MTB club wrote to me about his Hope Bulb rear hub. Apparently the bearings had given faultless performance over 2 years, and he puts in loads of miles in pretty shitty conditions. Wheelpro also recommended the Bulb as the most 'bombproof' rear hub on the market - "as used by all the trials boys" they said.
The Bulb uses even bigger bearings than the Ti-Glide, in fact the same internals as the enormous Big-Un hub. With it being a British product the seals are excellent.
Simon gave a thorough (in fact exhaustive!) description of how to replace the bearings. The cut a long story short, it involves first removing the axle end spacer with a pair of water pump pliers, allowing the freehub to be slid off by hand. Then the usual tappity-tap with a soft faced hammer, gets the bearings out. Again, using convenient sized sockets to press the bearings in, saves you a lot of money buying purpose-made press tools.
If this means nothing to you, then it is wise to have a go anyway, as a set of four bearings can cost £20, so you don't want to pay another £10 for a bike shop to do the hammering for you. As long as you use a plastic or hide-faced hammer, you shouldn't be able to cause any real damage.
Also remember that should you wish to replace any pawls, springs or seals, Hope are only a phone call away and are always helpful with sensibly priced spares. Just try that with Hügi, Syncros or King hubs!
By changing the bearings and axle, a Bulb hub can also run a 20mm hollow axle, which is stronger, stiffer and lighter than a standard one. As soon as QR20 axles become more common, this could be very important for even the XC boys.
The Bulb hub with the standard axle weighs about 350g, with the 20mm axle barely more than a Ti-Glide.
Syncros hubs cost £170 to £200, and use extremely high quality bearings. The outside bearing is an angular contact bearing - a type that is a sealed cartridge, yet also adjustable. Angular contact bearings can support very high vertical loads, as well as side loads. They weigh 315g with an aluminium axle and freehub body.
King hubs weigh an incredible 270g, and if they have a lifespan anywhere near those of the headsets, may outlast your bike. Unfortunately the price is also typical King - well over £200! The freewheel design is a patented instant drive ratchet which is massively strong like the Hügi. Again both axle and freehub body are in aluminium.
Tune hubs (from Germany) are so advanced that the sealed bearings are bespoke manufactured. The standard rear hub weighs 230g (gulp!); by substituting a carbon fibre axle (gulp#2!) for the stock alloy one, the weight drops to 200g (gulp#3!). A ceramic bearing version (gulp#4!) is even lighter at 180g (gulp#5!). Remarkably these hubs (like all Tune components) have an astonishing reputation for durability and strength, and are used by many marathon competitors (100km to 400km races in Germany and the Alps). They are also one of the few components that Gary Fisher buys with his own money. If anyone is interested in paying the £200 to £300 for a Tune rear hub (gulp#6!) or any other Tune components (see www.tunecomp.com) then contact me and I'll try to get hold of some from Germany.
Hope now manufacture a 'budget' hub called the Hope Sport, which costs £85. It uses cheaper bearings than SKF, and has a steel freehub body instead of a titanium one. It weighs over 400g, which is heavier than a standard XT, but a lot lighter than an XT disc hub.
Mavic manufactured some of the earliest cartridge bearing hubs, and use superior angular contact bearings, which have to be kept adjusted. The reputation of all mavic bearing components is exemplary, and I have no reason to doubt that their hubs would be an exception to this rule. These hubs are also found on the popular crossmax wheelsets.
Campagnolo hubs have always looked and performed superbly, and they now use angular contact cartridge bearings. The new year 2000 hubs use a massively oversized hollow aluminium axle, cutting the weight to only 270g. The excellent Hügi 240s are without doubt copied from the campag road hubs. But that is the crux of the problem; campagnolo hubs will not accept Shimano cassettes, and don't come in 135mm axle lengths. If they did I would use them on my mountain bike without hesitation. (Are you listening campag?).
After market hubs nearly always use sealed cartridge bearings, as well as being lighter and much more expensive than standard (Shimano) hubs. However the bearings will not last as long as those on a good quality Shimano XT or XTR hub. If you are interested in an 'everlasting' rear wheel, or weight saving then aftermarket hubs are a good idea, but you need plenty of spare cash! At £35 and 350g the XT is unbeatable if it last 3 years. For those with cash to splash and looking for the ultimate in strength, a Hope Bulb is the best idea. For those with cash to splash and looking for lightness, the Hügi 240 would be a good idea. There are many other similar aftermarket hubs on the market with similar design and price tags, however I have no experience of using them.
If you do decide to use sealed bearing hubs you must be prepared to replace the bearings every year or so, which is not a difficult job for an amateur mechanic, and requires few special tools.
Last Updated 21-12-2000
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