Fixed Wheel and Single Speed Bicycle FAQ's (part 1)

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VeloSolo Fixed Wheel And Singlespeed Frequently Asked Questions:

Welcome to our updated FAQ with new info, now split into three parts.  For the full easy to use version complete with numerous clickable links to Sheldon and various photographs please Google: velosolo faq

This guide contains lots of information on the VeloSolo disc mount cog system but also includes a guide to running your bike as a normal singlespeed (with freewheel) as well as many other tips for running without gears.  The fully accessible and easy to use version of this FAQ appears on our website. Using your road or mountain bike as a fixed or singlespeed is really easy and well worth a try.  If you are unsure of anything please email us and we will be happy to help.  Do please ask first if you wish to reproduce any of this information on your website or otherwise.  With thanks to the late, great Sheldon Brown who kindly granted permission to publish links to his site in 2007.  Ebay does not allow outside links (ie to Sheldon) so whenever he is mentioned below you will need to check the relevant section of his website.

Disclaimer: Dislike these things but we have to state this:  The advice and opinions that follow are provided for information purposes only and this information is used at your own risk.  VeloSolo cannot be held responsible for any damage, claims or mishaps that may occur by following the information given here.

If you find this guide useful please do remember to rate our guide at the base of this page - thank you!

Part 1 = General fixed wheel questions and Can I run a fixed wheel on my bike?

Part 2 = Set-up questions

Part 3 = Other technical and miscellaneous questions

Part 1 questions:

a) General fixed wheel questions:

1. What is a fixed wheel bike?
2. Why ride a fixed wheel?
3. Fixed, off-road?! Are you mad?!
4. Why choose bolt on cogs over normal track hubs and screw on cogs?
5. What are the advantages of a VeloSolo bolt-on cog?
6. How does the bolt-on cog work?
7. So why do you sell traditional threaded cogs as well?!

 b) Can I run a fixed wheel on my bike?: 

1. Can I use a fixed wheel on my road/track bike?
2. What if my road frame was designed around gears?
3. My single speed mountain bike has track dropouts, horizontal dropouts or sliding dropouts. Can I run it 'fixed'?
4. My singlespeed mountain bike has vertical dropouts and I use a chain tensioner. Can I run it 'fixed'?
5. If not, is there any way around this?
6. How about if I am using traditional threaded track hubs and cogs?
7. I'm not interested in fixed, I just want a 'normal' single speed - how do I convert my bike?

Part 2 questions (see link at base of page):

c) Set-up questions:

1. Which (drilled cog) hub/set-up is best for my singlespeed road/track bike?
2. Which (drilled cog) hub/set-up is best for my mountain bike?
3. Tell me more about chainline.
4. So what will my chainline be if using a cog mounted on a disc hub?
5. How do I adjust my chainline then?
6. Tell me more about frame spacing.
7. Tell me more about wheel dishing.
8. Tell me about the various types of drop-outs.
 9. Use a Shimano hub?! On my fixie?! 
10. Do all normal threaded track hubs and cogs have the same chainline? 
11. Any tips for installing traditional threaded cogs on track hubs? 
12. Left-hand drive - what's that all about?
13. Can I use the bolt-on cogs for a double-fixed (Surly 'Dingle' style) set-up?

Part 3 questions (see link at base of page):

d) Other technical and miscellaneous questions:

1. Do I have to fit a rear brake?
2. If I mount a cog on my disc mount how do I use my rear disc brake?
3. Can I use a QR on a fixed wheel?
4. Can I use a 1/8" chain with a 3/32" cog?
5. What is a magic gear?
6. Is using a cog on a disc mount a good idea?
7. How about using a front mountain bike hub on the rear of a road bike?
8. How do I fit a solid axle and spacers?
9. How do I fit the cog to my disc hub?
10. Which bolts should I buy to secure the cog to the hub?
11. Tell me about singlespeed tensioners.
12. What is a (chain) half-link?
13. How do I know what BCD my chainring is?
14. Why do chainrings need different length bolts?
15. What is the difference in bottom bracket tapers?
16. Any advice on gear ratios and chainring/cog sizes?
17. How do I fit bars to quill stems without scratching them?
18. Tell me about the various handlebar and stem sizes.

VeloSolo Fixed Wheel And Singlespeed Frequently Asked Questions - part 1:

a) General fixed wheel questions: 

1. What is a fixed wheel bike?

On a 'normal' bike a freewheel is fitted that allows the rear wheel to turn without the pedals turning. On a fixed wheel the cog is 'fixed' to the rear hub. If the wheel is turning the pedals will too (and your legs).

2. Why ride a fixed wheel?

We all know the benefits of riding a singlespeed - simplicity, minimal maintenance and weight, smoothness, a near silent transmission but mostly that wonderful feeling that comes from being freed of gears. Big hill? - push harder. Fast downhill? - spin faster. You are in control.

A fixed wheel takes it to the next level with the ultimate link between you and the bike, a wonderful feeling of connection that comes no other way. You learn to ride with real smoothness and control, the rear wheel always turning like a flywheel, driving you along. Many never go back.

3. Fixed, off-road?! Are you mad?!

Hmmm, well, are you the sort who gave singlespeeding a go and a few rides later never looked back? Geared bike relegated to the back of the shed? Niche it up a bit more - fixed off-road is a challenge at times but all the more fun and rewarding for it. Give it a go.
 
4. Why choose bolt on cogs over normal track hubs and screw on cogs?

Good question. Threaded cogs have been around for years and many people use them without any problems whatsoever. However, search the 'fixed/singlespeed' section on any popular bike forum and you will find reports of damage to cogs or threads if not done up tight enough or too tight.  Seized cogs, worn threads, incompatibility problems etc - many of these issues especially caused by the use of cheap cogs or incorrect installation.

Modern trends create further strains on components - off road fixed riding with low gears, urban riders doing skids and skip stops or equipment abusing tricks.

Time trialists and riders on the velodrome once up to speed simply sit and spin (with lots of power) but they don't impart sudden extreme braking forces and unusual abuse in the way some urban and off-road riders do.

Securing a cog and lockring onto a threaded aluminium hub takes care in use.  The VeloSolo disc mount cog simply offers an alternative for those unhappy with traditional threaded cogs.

Most threaded track hubs are only available in 120mm spacing.  The Disc cog easily mounts to any MTB rear disc hub allowing any 135mm frame to be converted to fixed.

5. What are the advantages of a VeloSolo bolt-on cog?

  • An end to the possibility of damaged hubs, seized cogs and stuck lockrings.
  • You can change a cog with one small torx or hex key - no bulky chain whips or lock ring wrenches needed.
  • It gives a 100% solid mount - six M5 hardened steel bolts give the stiffest most secure interface possible. Zero slippage or movement possible, simply 100% power transfer - forwards or backwards.
  • Allows precise dialling in of the chainline to match front and back, something that can be more difficult with a screw-on cog.
  • Converts a mountain-bike to fixed in the easiest possible way.  Flip the wheel round, bolt on our cog and ride.  No other expense involved and reversible in a minute.
  • Flexibility in set-up; left hand drive, dual fixed cogs etc.
  • Compared to alternative bolt-on cogs that may be stamped or laser cut, VelsoSolo bolt-on cogs are precision machined in the UK the old fashioned way from solid blanks of EN36 chro-moly to be perfectly round - sounds odd but not all cogs out there are as round as you might expect.
  • After machining (teeth are milled on traditional hobbing machines), our cogs are heat-treated for strength and wear resistance, in addition they are reversible without affecting chainline for even longer life.  The mounting holes are drilled to very tight tolerances to ensure perfect mounting on any standard 6 bolt disc hub.
  • The VeloSolo bolt-on cog is guaranteed for life to the original owner.  If you wear one out we will replace it absolutely free of charge.  See shop for details.

6. How does the bolt-on cog work?

It's very simple.  Instead of using a thread on the centre of the cog to screw onto a matching thread on the hub, the VeloSolo cog bolts directly to the hub.
 
The majority of mountain-bike disc brake hubs use the ISO standard 6 bolt mounting.  Instead of mounting a brake disc onto these mounting holes we manufacture a custom made series of cogs with the same drilling pattern.  Thus our cogs simply bolt onto the hub in place of the disc.
 
As the cog is bolted (fixed) to the hub it can be driven by the chain forwards or backwards and becomes a fixed wheel.

For full details of set-up please have a look at the other FAQ's listed here.
 
7. So why do you sell traditional threaded cogs as well?!

For many valid reasons plenty of fixed wheel users are perfectly happy with the traditional threaded cog system.  It has been around since the dawn of the bicycle and will always be hugely popular.  There is an endless range of matching components available, both classic and new, including those from well known and much loved hub makers.  For many riders the threaded cog has always worked  perfectly.  The bolt-on cog is an alternative system as well as one which allows mountain bikers an easier way to try fixed using their existing disc brake rear wheel.
 
We are happy to offer a very high quality UK made threaded cog to this market as well as a range of top quality cogs from other manufacturers.  Our own Track cogs are made the old fashioned way exactly like our Disc cogs but this time from lightweight high strength 7075-T6 heat treated aluminium alloy.  Teeth are hobbed and the cogs machined and anodized.  The main thread is cut post-anodizing for a precise fit. 

b) Can I run a fixed wheel on my bike?:

1. Can I use a fixed wheel on my road/track bike?

All track frames and singlespeed specific modern road bikes (Specialized Langster, Kona Paddy Wagon, Surly Steamroller, Fuji Track, Bianchi Pista etc) use track dropouts. Most (but not all) older steel road bikes have horizontal dropouts. As long as your frame allows the wheel to be moved forwards or backwards to tension the chain you can run it fixed.

See also: Tell me about the various types of dropouts.

If your bike is a modern (probably aluminium or carbon) frame designed around gears and with vertical dropouts you will not be able to run it fixed. The exception is if such a frame has an eccentric bottom bracket (very unusual) or you use an ENO eccentric rear hub with disc mount. Oh, there is of course the final chance of finding a magic gear.

See also: If not, is there any way around this?

2. What if my road frame was designed around gears?

If you have an older road frame with horizontal dropouts designed to be used with gears the rear frame spacing will probably be 126mm or 130mm. Most of these older frames will be steel which can happily be squeezed in or out a few millimetres.

If spacing is 126mm use the set up as per a road/track frame with 120mm spacing and add another 3mm of spacers or washers each side (see shop) or you could squeeze the dropouts together as you tighten the wheel nuts - steel will not complain. Chainline in this situation will be the same as a 120mm spaced frame.

If spacing is 130mm on your frame then simply add another set of 5mm CNC spacers to the hub taking it from 120mm to 130mm.  If a steel frame then another option is to use a 135mm mountain bike rear hub and spring the dropouts apart slightly.  This gives the advantage of being able to use a flip/flop fixed/free set up. Chainline in this situation would be around 53mm so a longer bottom bracket or a mountain-bike chainset may be necessary.

If you have vertical dropouts see here too: If not, is there any way around this?

See also: How do I adjust my chainline then?

3. My mountain bike frame has track dropouts, horizontal dropouts or sliding dropouts. Can I run it as a fixed wheel?

Yes. More about dropouts here: Tell me about the various types of dropouts.

4. My mountain bike frame has vertical dropouts and I run it as a singlespeed using a chain tensioner. Can I make it into a fixed wheel?

No. You cannot use a singlespeed style chain tensioner with a fixed gear bicycle. See question below for further options.

5. If not, is there any way around this?

Yes, if you have vertical dropouts that do not slide then you may also have a frame with an eccentric bottom bracket (as fitted to the latest Santa Cruz Chameleon for example). If not you may be able to find a magic gear.  Lastly there is the option of using an ENO eccentric hub with disc mount.  Sheldon Brown has more on these various options.

6. How about if I am using traditional threaded track hubs and cogs?

All the information in this FAQ regarding frames and drop-outs and suitability for fixed applies just the same.  A threaded track hub can be fitted to any frame spacing from 120, 126 or 130mm just by adding spacers to the hub axle in the same way as on the disc hub pictured below.  Equal spacers are added to each side.  For example to fit a 120mm track hub to a 126mm spaced frame simply add a 3mm spacer each side.  Chainline will always remain the same (normally around 42mm with threaded hubs) regardless of frame spacing.

7. I'm not interested in fixed, I just want a 'normal' singlespeed - how do I convert my bike?

This is usually very quick and simple to achieve with little outlay.  If desired, you can buy a specific singlespeed wheel with screw on freewheel but your normal cassette wheel is in many ways preferable.  It involves little extra expense, allows simple and precise chainline set-up, provides an instant return to gears and unless you pay for a very high quality freewheel usually has a better freewheel mechanism.
 
Firstly you will need to replace the cassette of cogs (maybe 6, 7, 8, 9 or 10) with a spacer kit and a full height tooth single cog such as those supplied in our shop.  You can use an old 'ramped' cog from a cassette but a dedicated SS cog will perform much better.  Measure your front chainline (see questions above) for the front ring you will be using and mount the rear cog using the various spacers so the front and rear chainline match within a mm or so.  Our 7 piece CNC spacer kits allows easy and precise adjustment of chainline.  Secure everything at the back with a standard cassette lockring.
 
(If you have an older wheel with a screw on multi-speed freewheel (probably 5 or 6 speed) then you can usually remove this and fit a Shimano singlespeed screw on freewheel in it's place.  However, this can be difficult to line up with a front chainring to obtain a satisfactory chainline).

For the front chainset you can buy a dedicated singlespeed chainset but a double or triple with the surplus rings removed works just as well.  As with the rear cog a full height tooth, non-ramped chainring is a much better idea than a typical geared chainring with it's cut down teeth, ramps and pins.  As for ratio, the typical starting point for most singlespeeders off-road is a 2:1 ratio, so 32/16 or 36/18 or similar.  For on-road work a more typical ratio might be slightly under 3:1 so 45/16 or 48/18 or similar.

The only thing left to do is to tension the chain.  As with the questions above this will depend on the sort of frame you have.  If you have horizontal or track drop-outs you simply move the wheel forward or backwards to achieve the correct tension (around 1/2" deflection or so in the middle of the run).  If you have vertical drop-outs (see questions above for more on drop-outs) you will need a simple singlespeed chain tensioner.  This acts in a similar way to a derailleur to spring load the chain.  These are available from our shop in normal sprung or specially modified un-sprung.  See also: Tell me about singlespeed tensioners.  A possible alternative (and usually slightly un-reliable) way to tension the chain is with a 'magic-gear' - see question/link above.

That's about it - throw that heavy cassette, old gear levers and other clutter in the parts bin and enjoy the immense pleasure of peaceful, efficient singlespeeding bliss!

If you have found this guide useful please do remember to rate our guide at the base of this page - thank you!

VeloSolo 2011

Please visit the VeloSolo ebay shop for over 150 fixed and singlespeed products

Please see Part 2 for: Set-up questions

Please see Part 3 for: Other technical and miscellaneous questions

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