Single speed gear ratio question

[Kenton]

Hi, just joined today and have a single speed gear ratio question?
We have a single speed bike with a 18 / 40 set up

But looking at a new bike with 16 / 44

Question is , which is easiest for up hill ?

 

[andyfraser]

40x18 is 60 gear inches and 44x16 is 74.3 gear inches so 40x18 will be easier to get up a hill.

 

[Dan B]

http://sheldonbrown.com/gears/ is good for these kinds of questions

 

[Sharky]

"easier" also depends on the terrain.
If a gentle hill or a short hill, the higher gear will get you up in less revs than the tiny gear. Using the smaller gear you could be over rev'ing and that could be uncomfortable.
A single gear is a compromise for all the different gradients you can encounter and which gear is an individual choice. In the two combinations you have mentioned, for me, I would go somewhere in between, but it's your choice and fortunately, sprockets are quite cheap and easy to experiment with.

Good luck,

Keith

 

[Kenton]

Thanks for replies ! I'm familiar was Sheldon Browns site but the gear page makes me scratch my head

 

[Smurfy]

44/16 will be at the higher end of what most ordinary people (i.e. non-professional athletes) would use for cycling on road

40/18 will feel very spinny for most people on road

If you want to ride on road, I'd start with 65-70 inches, then adjust up or down according to preference.

 

[SSmatty]

I'm running 44/16 on mine and its OK as long as I don't encounter any hills.
My route to work is fairly flat so I'm ok with it

Im building another and contemplating 48/17 ~(because the chainset I like comes in 46 or 48 teeth versions and I think 46/16 will be too much for me)

 

[Sharky]

Going to be on 50 x 14 for tomorrow night's 10!

And it will hurt

Cheers Keith

 

[Sharky]

Update.
It did hurt, but some interesting stats.

Slowest, going over a flyover bridge @ 12 mph, cadence 43 rpm
Maxed out at 30.2 mph, cadence about 108 rpm
Average for the 10 miles just a bit slower than 21mph or 76 rpm
Did some long stretches on the return at 26mph or 94rpm, which was reasonably comfortable. Slightly down hill, with side wind.

Don't have a cadence reader, but as fixed all the time, have used one of the online calculators.

Overall time still a bit slower than my age standard @ 28:36

But this gear (95") definitely not an everyday gear.
Cheers Keith

 

[Smurfy]

Update.
It did hurt, but some interesting stats.

Slowest, going over a flyover bridge @ 12 mph, cadence 43 rpm
Maxed out at 30.2 mph, cadence about 108 rpm
Average for the 10 miles just a bit slower than 21mph or 76 rpm
Did some long stretches on the return at 26mph or 94rpm, which was reasonably comfortable. Slightly down hill, with side wind.

Don't have a cadence reader, but as fixed all the time, have used one of the online calculators.

Overall time still a bit slower than my age standard @ 28:36

But this gear (95") definitely not an everyday gear.
Cheers Keith

Number of hills? Gradient profile? Feet per mile? etc etc.

I suspect that gear would break most people on anything but very flat!

 

[Sharky]

It was on the Q10/24 - The Grain course in Kent. It's a typical English time trial course, No hills, but not pancake flat like some courses and no gift starts or finishes.
I'm not a Strava person, but the course should be on there. It's a popular course - we had 38 riders last night and was won with a 22:21.
Like I said above, a 95" gear is not an everyday gear, but is a time trial gear. The ones riding gears were probably using much bigger gears on the return.

44*17 is my "leisure" gear.

Cheers keith

 

[smutchin]

44/16 will be at the higher end of what most ordinary people (i.e. non-professional athletes) would use for cycling on road

40/18 will feel very spinny for most people on road

If you want to ride on road, I'd start with 65-70 inches, then adjust up or down according to preference.

Agree with all this.

It's worth bearing in mind not just how easy it is to go uphill in a given gear, but also how easy it is to go downhill...

40/18 on a steep descent would be terrifying. How's your souplesse?

(At 40kmh, your cadence would be about 140rpm. At 50kmh, your cadence would be about 180rpm.)

 

[Kenton]

Thanks for all the answers !

 

[SSmatty]

If you just want to try something I would go for 2.5 - 2.75 as many teeth on your chainring than you have on the back.
eg 53/8 or 53/20, 39 /14, 39/15 or 39/16

 

[biking_fox]

Useful thread thanks!
I've just got a SS and had my first ride. Probably need to get a slightly bigger ratio, but not by much more - need to go and count the teeth and find out what I have at the moment!. Pics to follow of the shiney!