# Simulating single speed



## Tin Pot (4 Apr 2015)

before I buy a SS/fixie I was thinking of simulating it on my roadie simply by staying in a set gear throughout my usual training run.

How can I tell what you usually get on a SS/fixie and how that would translate on a multi speed?

My main concern is hills - I drop to absolute lowest gear and slowly grind up hills.

Cheers,

TP


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## ColinJ (4 Apr 2015)

39/15 would be a good guess? (And you will probably find that a real grind on the hills!) That is the gear that I chose for my s/s bike and the gear was ok from 12-24 mph and ideal for me at about 18 mph. (On the flat!)


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## GGJ (4 Apr 2015)

If you're running a compact chainset on your geared bike you could try putting it onto the big ring at the front (50T) and the 20T ring on the rear. That will give you approximately a 66 inch gear which only an inch or so shorter than you would have fitted to a Genesis out of the box with its 46T-18 gearing at 67 inches.


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## Tin Pot (4 Apr 2015)

It's compact, I think 50/34 and 12-27.


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## mjr (4 Apr 2015)

Don't you need to factor in the greater drivetrain losses of a derailleur? So pick 5-10% fewer gear inches than the single speed you're considering?


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## Citius (5 Apr 2015)

Tin Pot said:


> before I buy a SS/fixie I was thinking of simulating it on my roadie simply by staying in a set gear throughout my usual training run.



In my experience, the determination to do this evapourates as soon as you reach the first incline - then common sense takes over.


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## mjr (5 Apr 2015)

Citius said:


> In my experience, the determination to do this evapourates as soon as you reach the first incline - then common sense takes over.


I find it more tempting on the flat, when your legs are spinning away and you know you could cover the ground quicker with just a flick of a lever...


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## Crackle (5 Apr 2015)

Tin Pot said:


> before I buy a SS/fixie I was thinking of simulating it on my roadie simply by staying in a set gear throughout my usual training run.
> 
> How can I tell what you usually get on a SS/fixie and how that would translate on a multi speed?
> 
> ...


This is how I used to ride until about 10 years ago, when I started to spin more. It just requires you to take a different mental approach and find the right gear.


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## Smurfy (6 Apr 2015)

I'd aim for 65-75 inches, depending on terrain. Use this calculator to do it.
http://sheldonbrown.com/gears/


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## ayceejay (6 Apr 2015)

A tough one this. Have a medium gear and flat pedals so you can get off easily to walk the hills.


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## totallyfixed (6 Apr 2015)

Riding fixed requires a very flexible approach to cadence, you can forget all the stuff about ideal rpm's unless of course you live in the Fens and the wind never blows. Today I was going as slow as 8mph and top speed was 38mph. You soon learn a good climbing out of the saddle technique though. To go back to your original question, I did exactly that, rode my geared bike in one gear on a hilly route.


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## SSmatty (6 Apr 2015)

I agree it depends where you live.
However you can commit (a bit ) fairly cheaply.
You can buy a SS chainset for about £15 on eBay.
You might need a new BB to get a chainline that works, and a tensioner if you have vertical dropouts, but it will give you a good idea if you like it.
I had a GT peace that I didn't really use so I sold it.
Now I use an old 70s road bike converted for less than £100.
Just choose an entry point


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## Broadside (6 Apr 2015)

Tin Pot said:


> before I buy a SS/fixie I was thinking of simulating it on my roadie simply by staying in a set gear throughout my usual training run.



I did this on my commute bike and didn't change gear for about 12 months, it was interesting to see how it quickly became normal to honk up hills. I need to go the whole hog now and buy a fixed gear bike.


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## mjr (7 Apr 2015)

totallyfixed said:


> ... live in the Fens and the wind never blows.


  pull the other one, it's got bells on!


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## Tin Pot (7 Apr 2015)

YellowTim said:


> I'd aim for 65-75 inches, depending on terrain. Use this calculator to do it.
> http://sheldonbrown.com/gears/



34&14 or 50&21 according to the calculator for 65"



ayceejay said:


> A tough one this. Have a medium gear and flat pedals so you can get off easily to walk the hills.



Might be an idea, plus I'm messing with pedals anyway.


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## Smurfy (7 Apr 2015)

Tin Pot said:


> 34&14 or 50&21 according to the calculator for 65"


Check out the chain angle for both of those. I'm guessing that neither will be perfect. If you normally use the lowest gear to climb, maybe best to start with 50-21, as it is slightly lower than 34-14, and also has the advantage that larger chainrings and sprockets wear slower than smaller ones. The only down side is that it will be a bit spinny on the flat. If you find it a bit of a slog on the hills, don't be put off straightaway. The extra strength builds quite quickly in a few weeks.


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## jazzkat (7 Apr 2015)

Lots of sensible comments already so I've not much to add.
I've been riding about 68 inches over winter and it's a bit too spinny on the flat but it's a lot easier on the up hill bits. In summer when I don't need lights and 'guards and my bike is lighter, I'm on about 75 inches. Much quicker overall, just a little bit tougher on the hills.

Another way to think about this, is work out your comfortable cruising speed at a comfortable cadence then work backwards from that. 
So for example, if you usually ride with a cadence of around 85rpm and you feel you could easily hold 18mph on a flat then try something like 50x18 (73 inch).

I use this calculator:
http://www.bikecalc.com/
it seems a lot easier to play around with the numbers.
Good luck, don't forget to report back


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## Tin Pot (7 Apr 2015)

ColinJ said:


> 39/15 would be a good guess? (And you will probably find that a real grind on the hills!) That is the gear that I chose for my s/s bike and the gear was ok from 12-24 mph and ideal for me at about 18 mph. (On the flat!)



Managed to (replace inner tube without breaking never levers, woot!) get out for half an hour this evening on 34/15.

It was depressingly boring on the way out, flat and downhills, but a bit more demanding than usual on the way back.

Positives
I can immediately see why you attack the hills more. 
Overall for an easy route I definitely worked harder.

Negatives
To be peddling all the time I had to have the brakes on a lot
I would have died on a fixie when an oncoming white hot hatch "appeared from nowhere".

Inconclusive. I'll try a week like this to see where it leads.


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## fossyant (7 Apr 2015)

mjray said:


> Don't you need to factor in the greater drivetrain losses of a derailleur? So pick 5-10% fewer gear inches than the single speed you're considering?



Drive train loss. God how crap is your rear mech ? The difference is not noticeable


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## mjr (8 Apr 2015)

fossyant said:


> Drive train loss. God how crap is your rear mech ? The difference is not noticeable


I push a gear 8% higher than I do trying to simulate it on a derailleur bike. Rear mech is whatever was bottom-but-one from Shimano five years ago, but there's also the small matter of a thinner chain running at a slight angle.


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## mjr (8 Apr 2015)

http://forum.ctc.org.uk/viewtopic.php?f=5&t=83381 links to some estimates.


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## fossyant (8 Apr 2015)

I don't notice any difference. And that's running with rear mechs over 20 years old but on ceramic bushes.


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## Tin Pot (11 Apr 2015)

Went out yesterday on 34/14, my usual 20k training run up Biggin hill and back.

On the positive side I'm working harder on the up hills and netting 2kph faster

I know I'm only two rides in but I really cannot imagine doing this on a fixie. I'm hitting 60kph on the down hills, I can't imagine my little legs keeping up with that.

is there some sort of technique I'm missing to get the legs moving round fast enough on downhills?

I start bouncing around on the seat and wobbling the bike...


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## jim55 (11 Apr 2015)

I do this as well , I physically can't spin fast enough


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## mjr (12 Apr 2015)

Might get better answers if the thread title says fixie rather than single speed, @Tin Pot


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## jazzkat (12 Apr 2015)

It's a bit hard to describe but for me the bouncing means I'm letting the pedals push my legs and that there's too much of my weight going through the saddle. 
I suspect it's actually harder to control on a single rather than a fixed.


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## Old Plodder (12 Apr 2015)

Seeing as you are riding in my old area, I was using a 63" fixed, others were on 68". Around Biggin/Cudham/Downe, & the North Downs/Weald areas regularly.
As you use a fixed more, your hips get more supple, so you 'bounce' less going down hill. Don't even think of not having 2 brakes, the hills are too steep.


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## totallyfixed (12 Apr 2015)

Tin Pot said:


> Went out yesterday on 34/14, my usual 20k training run up Biggin hill and back.
> 
> On the positive side I'm working harder on the up hills and netting 2kph faster
> 
> ...


It takes a while [a few thousand miles ] before your pedalling technique becomes smooth enough to handle very high cadences. My record in km is 71, not something I would care to repeat any time soon! I see so many cyclists "pedalling squares", really awful waste of energy, riding fixed soon cures that!


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## swee'pea99 (12 Apr 2015)

I'm not sure all the 50/16 type tips, however well meant, are really all that helpful. I'd go for a ride - one which you know will after 10-15 minutes give you a straight, flat mile or two with no interruptions. Ride on it for a while, shifting up & down a bit till you find your ideal gear for cruising comfortably at a reasonable speed. Then stop changing - stick with that gear for a week or two and see how you go. And yes, expect to find hills very hard going, but don't wimp out.


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## jonny jeez (12 Apr 2015)

Tin Pot said:


> before I buy a SS/fixie I was thinking of simulating it on my roadie simply by staying in a set gear throughout my usual training run.
> 
> How can I tell what you usually get on a SS/fixie and how that would translate on a multi speed?
> 
> ...


If you are serious, then find the perfect gear ratio, disconnect the cable and use the stop limit screws ro fix the chain into that sprocket...you will truly experience. The dependency of a 
single gear choice and get a much better idea.

Keep in mi d your from rings will still offer a choice for an emergency uphill.


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## ayceejay (12 Apr 2015)

I have ridden fixed a lot when I go down hill and I feel the bike is pushing me faster than I can pedal I use my brakes to slow me down.


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