[ www.fixedwheel.org.uk ]
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Going Fixed ...

Hastily cobbled together by Simon Ward, with a little help from Arthur Clune, John Curtin and others.

 

Read this first ...

The material contained in this page represents the views and opinions of the authors alone and is intended solely for guidance.

The intention is the provide a body of information to aid those considering building a fixed-gear bike, not to provide recommendations as to which products to use. The authors accept no responsibility for events which occur as a result of the use or misuse of the information contained herein. In other words, if your bike drops to bits or your hub flanges explode, don't whinge at us.

 

The Boring Preamble Bit ...

Not so very long ago I visited a local bike shop to purchase some spares and the owner, as is his wont, asked me which of my bikes I'd ridden on. I told him I'd ridden out on the fixed gear and he said something along the lines of `You're using clipless pedals on a fixed?! You're either very brave or suicidal'. This typifies some of the mystique which surrounds a bike with only one gear which doesn't let you freewheel ...

Of course, before the hub gear and the freewheel were invented cyclists didn't have a lot of choice in the matter - it was either fixed or nothing. With the advent of gears, somebody riding a fixer was either a die-hard trackie or a seriously hard clubman. Despite that, fixed gear riding has enjoyed a renaissance of sorts in recent years either as a way of developing and then maintaining fitness over the winter months, because of its inherent simplicity or because a fixer makes for a practically maintainence free winter hack. My own theory is that this resurgence in the `Art of Fixed' has come about as a result of the increased profile of track riding, in particular Chris Boardman's breaking of the Hour record. I may be wrong, of course! The aforementioned Mr. Boardman has also ridden sub-19 minute `10's on an 88" fixed gear, thereby proving that you don't need massive gears in order to be quick.

But ... why?!

As Sheldon Brown says in his excellent fixed-gear pages, every enthusiastic cyclist should have a go at riding a fixed-gear machine at some point - you don't have to be a full-on `trackie' to enjoy it. My main reason for going back to riding a `fixie' was to improve my pedalling technique. I do a lot of touring and tend to freewheel far more than I should, so this is an ideal way to `train' myself not to freewheel. Contrary to popular belief, it is possible to freewheel on a fixed gear, just not for very long!. Riding fixed is also a great way to improve the souplesse (suppleness) of your legs and also allows you to learn to spin effectively (very useful when attacking steep climbs on geared bikes).

Fixed gear (not fixed wheel, that's different - think penny-farthings) bikes have a certain amount of mystique attached to them, notably because a large number of cycle couriers use them, be it for reasons of efficiency or just because having one gear and no ability to freewheel is a good theft deterrent. It's also widely believed that people who ride fixed away from the track are speed-mad adrenalin junkies. Not so!

In my opinion, fixed-gear riding is cycling in its purest form - nearly all your effort goes into making the bike move, no larking around with derailleurs and the like, the linkage between rider and machine is almost perfect. Although I'm not a track rider (and don't plan to become one) riding fixed is the most exhilirating cycling experience imaginable, plus your cycling friends will either view you with added respect or (more than likely) with the sort of look that says `this guy is a lunatic!' .... either way, it's worth it!

All you need to build a fixed gear bike are:

This document assumes that you're going to build a utility fixed gear bike, that is, a machine which will be used for commuting or other more general riding (I use mine for commuting and the odd randonée, for example). The differences between the kind of machine I'm describing and a proper track bike are: Of course, whether or not a suitably de-braked utility bike would be suitable for riding on the track depends entirely on the attitude of the people who run your local velodrome :-)

Choosing a Frame

For a fixed gear, any frame will do providing it has horizontal, or approximately horizontal, dropouts. This is essential in order to allow the chain tension to be adjusted, something which vertical dropouts do not allow. On the other hand, it is possible to build a fixed gear bike around a frame with vertical dropouts but then you're likely to have to resort to the use of a half-link and even then will be restricted in the number of viable gear combinations. For our current purposes, vertical dropouts will be ignored (this is not to say that it's impossible to convert such a bike - Fixed Innovations (http://www.peak.org/~fixin/) have a website which deals with just this problem)

Types of horizontal dropout The image shows the two different types of horizontal dropout: the `standard' variety and the rearward facing sort which are found on track bikes, some of the better BMX machines and dedicated singlespeed MTBs. The best kind of frame for converting to fixed is the 80s-vintage road bike since they not only have generous clearances for wide tyres, mudguards or whatever, but they also tend to utilise the very long horizontal dropouts made by Campagnolo, amongst others. Many of the better bikes of the era came fitted with dropout adjusters, which look like small, springloaded screws - these are worth keeping since it takes the guesswork out of refitting a wheel in the correct plane. Without exception, track bikes are fitted with the rear-facing dropouts.

Although it is possible to have such dropouts retrofitted to almost any frame, the process is very labour intensive (ie. expensive) since for the most part the dropouts need to be shaped by hand before brazing into place. Although a competent framebuilder will do this, many advise against it. On some older frames it may not be possible to change the dropouts at all without running the risk of breaking something (older Raleigh touring frames fall into this category, for example)

Alternatively, if you're mad keen on riding fixed but can't handle the geometry of a track bike for road use, then there's nothing at all to stop you going the whole nine-yards and getting a frame custom built - this way you can have proper track ends included as part of the spec! If you go for a custom geometry option, you can then be sure that the frame will fit. The majority of framebuilders will be prepared to undertake such a project, usually on the grounds that it's something a bit different (my own fixed gear Audax bike was built by Dave Yates of M.Steel Cycles in Newcastle Upon Tyne)

Chainsets

There's a fair degree of latitude in the choice of chainset since anything that can be bodged for a single ring is sufficient - for example, when I started riding fixed I used an old Suntour XCE triple with the inner and middle rings removed and a replacement set of stack bolts. Track chainsets are available from the usual suspects, most notably Shimano and Campag, both of which are in the appropriate top-of-the-range groupset (DuraAce and Record, respectively). This is, of course, expensive.

Crank length is potentially important, too, especially in view of the fact that you won't be able to freewheel round corners. For this reason many track cranksets are built with 165mm cranks in order to provide sufficient ground clearance on steeply banked tracks - after all, a pedal strike at 40mph can be potentially catastrophic.

Of course, there's nothing to stop you modifying a Shimano or Campagnolo chainset for a single ring only. Although road chainsets are more conducive to this sort of modification, there's nothing to stop you using an MTB chainset if need be (I used a modified compact-drive LX chainset for a short time, for example). Since Shimano chainsets are effectively self spacing, you need to be able to pack out the space where the inner ring would be - hub spacers usually do the job.

When it comes to chainring bolts, if you are able to mount the ring straight onto the crank spider without using spacers, you can use Odyssey single chainring bolts. These are actually designed for BMX use, but I've been using a set on my own bike for a while with no problems. Cost is about £ 5 a set. Both TA and Stronglight do stack bolts suitable for a single ring; the TA bolts look particularly attractive, since the `visible' side of the bolt is `blind' (ie. the hexagonal cutout for the allen key isn't visible)

Hubs

Choice of hub for a fixed gear bike is largely a matter of personal choice and, in general, there are two possible options. The first of these is to use a standard threaded hub designed for a multi-speed freewheel, whilst the second is to buy a hub designed to take a fixed sprocket.

Obviously, the latter is more desireable but matters are complicated by the fact that there are very few fixed hubs readily available at reasonable prices. What follows is an incomplete overview of what is available (additions welcome):

For those with serious money to spend, there's also the option of Transatlantic exotica such as Phil Wood fixed hubs (lots of dropout spacings, different drillings, single or double sided fixed etc.) - these cost upwards of $200 (dollars, not pounds) which could easily become £200 after import duties etc.

Wheels

The big advantage of fixed wheels is that they can be built with only minimal dishing or, better yet no dishing at all. This means that you don't need to use shorter spokes on the drive side because you don't have to accomodate the large number of cogs that make up the cassette or freewheel. The advantages of a dishless wheel are twofold:
  1. The wheel is stronger - the spokes are under roughly the same tension.
  2. When it comes to building the wheel, all the spokes are the same length.
From a practical point of view, building a rear fixed wheel is no different, or more difficult, than building a front wheel. Rim and spoke selection is a personal choice, but personally I like my wheels to be as strong as possible as I subject my bikes to a fair amount of pounding. For 700C wheels, a good quality road rim, such as the Mavic MA-3, will do nicely, laced up three-cross to the hub. My current bike uses Mavic CXP-30 rims and the rear wheel is immensely strong. Obviously, there's nothing to stop you experimenting, especially if you intend to use the bike with a fixed (sic!) aim in mind (eg. time trialling). The big disadvantage with my own choice of wheelset is that it's a bit on the heavy side - after a successful trial on my Marin Point Reyes, Mavic Open Pro rims get two thumbs up.

As far as sprockets are concerned, both Shimano and Campag manufacture track sprockets to go with their hubs - these are meant for 3/32" chains, so you can use an ordinary chain with them. The only problem is that they're only available in a limited number of sizes, usually 13-16T. For those who are prepared to use 1/8" chains, as a lot of trackies do, the choice is larger. Cyclo (available from St.John Street Cycles, see sources) are available in a large number of sizes, up to 22T. Quality isn't as good as the Shimano or Campag offerings, but once they've worn in they run sweetly enough.

My own machine has a 16T 1/8" DuraAce sprocket which, as you'd expect, is nicely machined out of steel. The `other' side of the hub has an 18T Cyclo sprocket which is starting to look a little bit shabby after about 5000km of abuse (including use through a rather soggy winter). The DuraAce sprockets are to be recommended, if you can find a use for the limited sizes available (as it happens, 42x16 is a good, useable gear on the flat). Some time in the near future I'll be testing a Sub-11.0 fixed sprocket - these are also machined (and rather nice they look too) and are available in both 3/32" and 1/8" formats, in sizes up to 19T, possibly 20T as well. The cog I have ordered is an 18T, to replace the existing Cyclo, and time will tell if it is up to snuff. Sub-11.0 sprockets are distributed in the UK by Ison Distribution (also known as ID) who, in turn, deal with most decent bike shops.

Brakes

In the UK, a fixed gear bike with a front brake is road-legal since the rear fixed wheel is recognised as a brake in its own right in the eyes of British law, assinine as it may be in other respects. Slowing down by altering ones cadence is a well known method but it could be bad for the knees in the long run. Save the `no brakes' riding for the track.

For a commuting bike you'll probably get away with a single front brake but for more serious use two brakes are definitely preferable. For drops of up to 57mm good brakes can be obtained - my personal vote would go to Shimano 105 long-drop dual pivots, which are totally evil stoppers. On the other hand, if you have an older frame with longer reach then brakes can be a bit more difficult to come by - good bets for longer drop brakes are old-style Weinmann or Mafac centrepulls, although you may need to retrofit cable hangers on the headset stack and seatbolt clamp. Most bike shops still sell these as spares - if you do have to buy cable hangers, make sure that they have adjusters. Of course, if you have a suitably equipped frame there's nothing to stop you using either V-brakes or cantilevers (I use the former)

Gearing

Gearing is another matter of personal taste - tradition usually calls for a gear in the mid-60s, usually 66" or 68", and a moderately fit rider should be able to push such a gear up all but the steepest hills. For the `dodgy knee' brigade or those who don't live in the flatlands something like 59" or 63" is usually the gear of choice. Since I live in the flatlands I run something a little bit higher, notably 72", but then I have no qualms about dismounting and walking up a hill. Contrary to popular belief, running a fixed gear in very flat country isn't necessarily a good thing unless you either a) like saddle sores or b) are prepared to get out of the saddle from time to time.

In many cases, gearing is decided according to what is available eg. if you have a chainring going spare you buy the sprocket which give you the gear that you want, or vice versa. It has been reported that using large chainrings and sprockets can minimise chain wear - whether this is true or not is open to conjecture, but I run a gear of 42x16 and have only had to replace chains when they've broken.

Chains and Chainline

Choice of chain is a matter of personal choice - most trackies use 1/8" chains on their bikes although there's nothing wrong with using a normal 3/32" derailleur chain. It is difficult to quantify which type of chain is stronger. 1/8" chains can be used with 3/32" pitch chainrings and sprockets although the opposite does not apply. Recommended chains are:

3/32" chains 1/8" chains
Sachs/SRAM PC-41 (old Sedis Black) Sachs/SRAM S/A 3-speed chain
Sachs/SRAM PC-61 with PowerLink Taya 1/8" s/s chain
  Wippermann Weissturme

The Sachs/SRAM PC-61 is a good chain and the PowerLink is re-usable. The Taya 1/8" chain is OK but their Sigma Link connector is rubbish. Either replace it with a proper chainlink or with a Sachs/SRAM master clip (used on 3-speed bikes). The Wippermann chain is made for German utility bikes but has turned out to be about the best chain I've used - it's nickel plated, so it isn't as susceptable to corrosion as others, and so far seems to be pretty sturdy - like the Sachs/SRAM chain, it uses a Sturmey-Archer style master clip. PowerLinks and Sturmey-Archer master clips should be available individually from good bike shops.

If you don't know what `chainline' is, then you probably shouldn't be reading this, but in case you don't know the the chainline is basically a measure of how straight the chain runs between the front and rear sprockets (a fuller definition is available from Sheldon Browns Bicycle Glossary).

To minimise chain wear, both sprockets should be in the same plane, and this is especially true with fixed gear bikes, since a bad chainline means you run more risk of dumping your chain, which isn't a particularly sound thing to happen on a fixer. In most cases, the length of the bottom bracket will determine the chainline, although some hubs come with spacers to fit between the hub and the sprocket.

Good and Not So Good Chainline If you have a straight chainline then a chain should last practically forever. Seriously skewed chainlines are definitely not a good thing for two reasons: first, the transmission will be noisy and there will be considerable wear on both chain and sprockets (the chain will probably go first!) and secondly, there's a risk of dropping the chain at high speed - this will usually culminate in a skid after the rear wheel locks.

Chainline can be adjusted either by fitting spacers on the hub (some hubs have these as standard) or by changing the bottom bracket length. The parameters will vary depending on the equipment used but, for example, I use a TA Zephyr chainset with a Goldtec hub and a 118mm bottom bracket gives me a perfectly straight chainline. On top of this, the chain should not be too tight, again for reasons of wear. On the other hand, a chain which is too loose is positively dangerous - about 1/2" vertical play (1/4" either side of `horizontal') in the chain is preferable.

Sources

The following is a list of potential sources for the various bits and pieces mentioned in this article. Their appearance in the list is not a recommendation nor should be construed as such.

Contribute

This page is under constant development, and I attempt to keep on top of various fixed-related happenings, including results of equipment testing where appropriate. If there's anything you'd like to add, let me know and I'll include it if appropriate.

All included material is credited to the appropriate author. -------------------------------------------------------------------------------
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