Choosing a ratio

[3narf]

Hello

If I decide to build my £10 Falcon as a singlespeed (and I'm not saying I will, right? ), how do I go about deciding on a gear?

I'm currently commuting on an MTB and spending the most time in the middle ring & smallest two cogs, at a guess 42 / 11 or 12.

Obviously going to 700c from 26" slicks I'll be a bit faster, but there are a couple of sharp climbs where I'm at the mercy of the traffic...

Should I ride it as a 6 speed for a while & see what I think?

Cheers, Andy

 

[Rob3rt]

Ride it on your route and select the best ratio from the ones you have. When going SS you will want to compromise between not spinning out on the flat and being able to get up the hills. Your hill climbing will improve fairly quickly though, so if you are stuck between choosing from 2 gears, I'd go with the harder one.


Guesswork can be expensive, so if you can try it out on a geared bike, do so.

 

[tyred]

Somewhere in the region of 60 - 70" gear is what is recommended. Something like 44/18 or 46/18. You will be genuinely amazed at what you can climb when you don't have any low gears to play with.

 

[GrasB]

Ride is 6spd for now, leave it in one gear & see how you get on. I find that I want to have range of gears so I can adjust my gearing for general conditions & training purposes. I use 45t, 47t & 49t chainrings with 14t, 15t, 16t & 17t turning a 650c wheel, that gives me a gearing range of 65" to 86". My nominal gear is 47:15 or 77"

 

[fossyant]

What this lot said. Find what's about right for your commute, and go for the slightly harder gear when you go SS/Fixed.

I started with 70/74 (flip flop fixed) - found 70 to spinny, so switched over to 74. Been on that for nearly two years, but decided to up to 77.5 when I needed to replace my chainring/sprocket and chain.

 

[marzjennings]

I've just dropped from 99" to 87" (53x14 to 53x16) and find it just about right for me. At a cadence of around 79-81 I'm cruising at 20mph depending on tyre size.
But I've no hills to worry about on my rides.

 

[3narf]

When the gearing is stated in inches, how is that calculated? Is it the inches of wheel travel/circumference per crank revolution, or something like that?

Ta

 

[jayonabike]

You can calculate your gear/inches (Here) scroll down the page a little. Where i live is quite hilly so i run 42/16 which gives me 70'', i find this easy enough to climb up most hills around my way.

 

[PpPete]

When the gearing is stated in inches, how is that calculated? Is it the inches of wheel travel/circumference per crank revolution, or something like that?

Ta

number of teeth on chain ring / number of teeth on sprocket x wheel diameter

 

[Ibbots]

I have been commuting on both road and mtb based single speeds for a couple of years now, I have a fairly hilly ride with a big hill at the end. On the mtb with slicks I have stuck with 45/17 combo which was a struggle at first but found it reasonably easy going this winter and now only tend to use this when weather is crappy. On the road bike I started with 50/19 which was fine and much quicker in perfect conditions but hell climbing into a head wind which is quite common on my return journey unfortunately. Changed this to 47/19 for a while but have now dropped to a 47/18 which seems about perfect for my ride, maintain a decent average speed without busting my thighs on the last climb home. There's lots of stuff on the Sheldon Brown.

 

[yashicamat]

I use a 65" around here, but a lot of my cycling ventures into the Peak District.

 

[3narf]

I decided on 46 x 17 in the end, which gives 73". Pics are here: https://www.cyclechat.net/

 

[iendicott]

Guys I have used an app for the iphone to generate the gear size but what exactly are skid patches as they differ depending on the gear lenght ?

Sorry if this is a daft question.

Ivan

 

[redjedi]

Guys I have used an app for the iphone to generate the gear size but what exactly are skid patches as they differ depending on the gear lenght ?

Sorry if this is a daft question.

Ivan

I believe it is to do with fixed skidding like this

[media]
]View: http://www.youtube.com/watch?v=HxFOBmO1CLg[/media]


If you do a lot of it it you will wear out certain sections of your tyre. If you have a gear that gives you 1 skid patch you'll always be skidding on the same spot and wear it quickly so you want a high number of skid patches to spread the wear around.

If like me you don't intend to ever do it on purpose then don't worry about it

 

[iendicott]

Very impressive but something that looks very dangerous. I take it to stop the wheel you simply place most of your weight over the front wheel than lock the rear up ?