Get Set for a Head Rush - The Headset

Get Set for a Head Rush - The Headset 

Most things that turn have to be held in place, otherwise they can fall over.  Car axles turn, but have to be held secure.  On bikes, the turning parts that must be held in place include the crank, hubs and the steering tube of the forks.

The crank is secured by the bottom bracket, which, with the Shimano Hollowtech system used on my build, has two sets of enclosed bearings threaded onto each end of the bottom bracket, and the crank shaft (aka spindle) passes through each bearing ring.

Leaving aside the hubs, which are self-contained units held in place with a pair of quick-release skewers, a direct analogue of the bottom bracket is the headset.

The front wheel, held in place in the forks with the quick-release skewer, must be able to turn if the bike is to change direction.  The fork steering tube passes up through the head tube of the frame, to have the handlebar stem bolted on to the top of the steering tube.

Securing the steering tube within the head tube, so that it can turn smoothly and spread the load, requires what is known as the headset, and which has a similar structure to the Hollowtech bottom bracket, but with some differences.

The early headsets are what is known as threaded, and these are still used on many bikes, owing to their tough design.  The bearings are held in place by ring-shaped cups that are threaded onto each end of the head tube.  

The threaded rings hold the bearings secure - the steering tube just fits snugly down the centre of the bearing cups. Road bikes moved away from threaded headset when design shifted from one-piece quill stems, which were inserted into the top of the steering tube and secured with a an oblique anchor nut, and began to use the modern system of a stem that bolted directly onto the steering tube.

Introduced in the 1990's are the threadless headsets.

The bearings are contained in enclosed cups that are pressed in to each end of the head tube.  A defining feature of the threadless headset is the star-fangled anchor nut.  Above the head tube are spacer rings that are used to set the height of the stem, and the bolt-on stem.

  The top edge of the stem must stand slightly above the top of the steering tube, and the top cap secures the anchor bolt. Tightening the anchor bolt through the star nut screws the top cap down onto the stem, essentially drawing the steering tube up towards the top cap.  This provides the tension that holds the headset-bearing-steering tube system in place.

Threadless headset. Note the external bearing cups.

Of note is the importance of not tightening the stem bolts until the headset is correctly tensioned, otherwise the only achievement will be to strip the star bolt, and to have a loose, rattly headset with dodgy steering.

Common on road bikes are integrated headsets. Similar in design to the threadless system, the bearing cups of the integrated system are recessed into the head tube, which must now provide lateral support for the bearings.  Recessing the bearings removes them from sight, giving the clean visual transition from the forks straight to the head tube, with no visible bearing cups.

Integrated headset.

Some manufacturers, notably Chris King, are critical of the integrated headsets, owing to the greater stress placed on the head tube itself, with the associated greater risk of structural damage to the head tube.  Metal head tubes can be repaired with some skill with a TIG welder, but for many carbon frames such damage can result in total frame replacement.  This is in contrast with a regular threadless headset, where the bearing cups are outside the base of the head tube, thereby eliminating the likelihood of irrepairable damage.

For mountain bikes, which experience a much greater degree and frequency of forward compression impacts on the steering column, integrated can be a very bad idea.  For road bikes, a well-made head tube can support a matched headset.  And that is the main issue - that the headset bearing cups match the head tube.

My current ride has seen many thousands of kilometres over the last 4.5 years, and the internal headset is a little worn, with some notchiness creeping in, but it rolls nicely and there is no damage to the alloy head tube, so the big conclusion that I can draw from this is that for a road bike ridden where, how, and as frequently as I do, an integrated headset will do quite nicely.

Which is just as well, as there are not many semi-integrated headset available, which are the fourth kind of head set available.  The bearings are recessed as with an integrated headset, but are supported by a press-fit race.

There are many headsets available, of a range of weights from (about) 50 gm up to 200 gm, depending on the metal used and the size of the parts.  Some Asian manufacturers have their ranges, but with relatively unknown brands and no discernible review history in the bike forums, I decided to forgo the marginal weight advantage and to opt for a product from an established company with a reputation for well-engineered products.

The headset that I ended up purchasing is the Prolite Ampezzo integrated headset, compatible with the industry-standard Cane Creek unit.  Bought from Chain Reaction Cycles, the cost to me was NZ$41.81.

Of some importance are the dimensions of the bearing cups.  6.5 mm deep with a 45° 1.5 mm bevel, the headset has an outer diameter of 41 mm.  The head tube, then, must be machined to fit one of these cups top and bottom.

If you are going to go to the effort of a unique build, it helps if the parts fit together properly, so  while I get the frame design and quotes sorted details such as the headset and the bottom bracket cannot be overlooked, otherwise some replacements will be needed - and the frame will always stay.

Saddle-Up the Palomino

Saddle-Up the Palomino

A bike has four contact points - where you (normally) come into direct contact with the machine.  Handlebars, two pedals, and the saddle.  Note, saddle, not seat. A seat is a flat thing that you park your butt onto.  Like a sofa.  A saddle is more of a ridge-like feature, with your legs coming down either side.  Think horses, think motorbikes, think bikes. 

 The only bikes that have seats are recumbents, those odd-looking machines that ride low with the rider in a reclined position, legs pedaling high up front.  Although 'bents may invite ridicule, the world speed record for human-powered bikes was set on a 'bent.  To quote Wikipedia, "The IHPVA hour record is 90.60 km (56.30 mi), set by Sam Whittingham on July 1, 2009. The equivalent record for an upright bicycle is 49.700 km (30.882 mi), set by Ondřej Sosenka in 2005. "

But, this project is for a regular road bike, so we are talking saddles.

The basic form of the bike saddle has changed little over the decades.  A wide rear to support your derrière, and a narrow nose that supports the base of your pelvis while your legs come down either side.

Many saddles are sprung in the rear, with varying amounts of padding.  To secure padding, a rigid shell gives the saddle shape, and a flexible surface is stretched over the padding and stapled underneath the seat.  This surface can be anything from leather, still used on Brookes saddles and high-end racing saddles, through to vinyl and plastic.

Saddles are secured to the top of the seat post by either a ring-clamp that tightens around the top of the tube, or the more modern arrangement of an arc-grip that secures the saddle by its rails, two frame-rods that give structural tensile strength to a lightweight shell, made from either nylon or carbon fibre.

The modern, light road saddles have minimal padding, the comfort coming from the light shell that flexes with the weight of the rider.  That is, instead of having compressible foam on a rigid shell, the shell itself curves to suit the rider.

Choosing the right saddle is the feature topic of many forum discussions, both online, on rides, and in magazines.  This is a consequence of the saddle being perhaps the most intimate of the contact points.  The risks of having a bad saddle choice include numb-nuts (that is, loss of sensation to your genitals, caused by compression of certain nerves and blood vessels), chafing, and pressure sores.

First off, get the width of the saddle right.  

The bottom of your pelvis is shaped like a ring. This is smaller in guys, as they don't have to push a baby through it.  The rear of the pelvic girdle (yeah, I know.  That is what it is called.) has two projects about 13 cm apart when you sit down.  These are referred to by cyclists as the "sit-bones".  These should be centred in the middle of the side pads of the saddle, so the wider apart these bones are in your butt, the wider the saddle is that should be on your bike.  if in doubt, take a look at saddles that are labelled as women's saddles.  They will typically be wider and shorter than mens' seats.

And that brings us to the numb-nuts issue.

The main nerve to your goolies runs from the base of the spine to a point in front of your anus, and then along to your genitals.  It just happens that that point between your wedding tackle and your anus happens to be the principal pressure point on the saddle, so sustained pressure will cause a temporary loss of sensation that will not enhance your sex life.  That concentrated pressure, together with the regular lateral motion from your legs will also promote the development of chafe spots and pressure sores, often caused by tension on hair follicles.

Some saddles have different cushioning materials along the prong of the saddle, and others have nothing at all - the cut-out saddles.  Personally, I prefer these to traditional saddles, as I find them more comfortable on long rides.  The challenge is finding one that works.

My saddle choice has the same (narrow) dimensions as the saddles I have been riding for the last five years.  My current saddle provides a good platform, but at times it feels as if I am sinking into padding on an inflexible shell, so my main priorities were first dimensions, followed by materials, price and weight.

A carbon shell made specifically to flex is ideal, and after considering a few options, including the Selle Italia range, Specialized Body Geometry range, and the Ritchey Biomax saddles.  The weights of the considered saddles ranged from 219 grams (Selle Italia Flite, NZ$150 from Torpedo 7), through to 325 grams (Ritchey Comp Biomax, NZ$48.85 from Ribble).  There is a distinct premium on weight, and there are many ultralight saddles with non-ultralight prices, which is fine if you are on a professional contract and the manufacturers give you their saddles to road-test for them.  But aging riders on teacher salaries cannot be so picky.

This aging rider on a teacher salary ended up buying a 280 gram Ritchey Pro Biomax saddle (microfibre surface, carbon shell, alloy rails) for NZ$92.43, from wiggle.co.uk.  This is it:

It has the same dimensions and shape as my last two saddles, although I will need to ride it for a few thousand km to confirm that it is the right saddle for me.  

It is not the lightest or cheapest, but it is at the lighter end of the scale and the price compares favourably to other saddles of similar specifications.  If you ever find that your saddle gives you problems as described above, try a different saddle. 

In addition to the cut-out style, manufacturers are experimenting with some decidedly odd-looking shapes, each designed to boost comfort, if not performance. 
if you ride with a group ask around, as other riders often have old saddles sitting in a cupboard somewhere.  I do - but from different bikes, different designs and purposes.  Just make sure that you get it right, even if it means trying a few different saddles before you find the one for you.  It is worth it.