What's the equivalent

kalex

Retro Guru
On a single speed set if I go up or down one tooth what would be the equivalent on the chainring to keep the same gearing.

for some reason I've got it in my head 1 on the back equals 4 on the front. I can't remember where I heard this from or even if I did hear it.
 
The ratio of what you have now depends entirely on what gearing you're running, so we'd need to know that to work it out.
Googling 'single speed gearing table' will give you many tables of ratios for you to work it out without any maths.
 
Re:

I haven't finished building my bike yet but on riding it before hand when I had the full range of gears I was happy with 2.6:1 or the other way around depending how you write it.

I was wondering what the simple measure of rear teeth to front teeth.

i think it could have been when altering my motorbike sprockets the mechanic basically told me 1 tooth at the rear is the same as 4 teeth on the front. tbh it could even be the other way around now lol.

I'm starting to wonder what I'm asking myself and why haha.
 
Just had a quick look at the table and it looks like 42/16 or 46/18 is what you're looking for - the former is just above 2.6 and the latter is just below :)
I just had a look and I run 2.9:1 on my road bike :shock:
 
Re:

I was using the smallest ring on my cassette and that was 13 and middle ring was 34 I think. so yes it gives the same ratio of what you said.

i've read the single speed thread on here and gear ratio is the main talking point. i've never had a single speed before but my pub bike gears packed up yonks ago so I was stuck in 1 gear for a few years. so I suppose I have been ss for a while, but the gear I was stuck in was Ok for just tootling about on so it doesn't really help me.

i've got the bike to how I want it, just need some replacement cantilever brakes, work out what saddle I want and obviously what rings to get then all sorted.
 
Re:

You have told yourself the answer in that ratio you gave.

For every 1 tooth at the back add 2.6 teeth at the front. Then round

If you want a pure 2.6 then 15rear x2.6 = 39 front.

It easier just to multiply the rear by your perfect ratio to get the front.
Or divide for vice versa


Assuming you are using the same wheel/tyre size as that alters things.
 
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