# Gear Ratio Question

ed1973
Posts:

**219**
So to cut a long question short, I used a gear calculator to work out the difference between running a 32t chainring and 30t chainring with a 42t rear cog:

32t is 0.83

30t is 0.78

So anyone know if 0.05 will have a big difference on a tough climb?

Also are the ‘Snail’ narrow wide chainrings on the ‘Wish’ app any good they are £9 plus p&p or will it just get chewed up after the first ride?

32t is 0.83

30t is 0.78

So anyone know if 0.05 will have a big difference on a tough climb?

Also are the ‘Snail’ narrow wide chainrings on the ‘Wish’ app any good they are £9 plus p&p or will it just get chewed up after the first ride?

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## Posts

2,240I'm puzzled how you get 0.83 and 0.78

A 32t driving a 42 is 32/42 = 0.76

A 30t driving a 42 is 30/42 = 0.71

But if all you are changing is the front ring, you only need to consider the difference between the 30 and the 32.

I'll assume that you are going from a 32 to a 30. So the change is 2/32 which is a 6.25% difference.

I agree that this is a small change, in fact it is less than half the gain you get by changing one gear on the cassette. Some shifts will make it less than one third.

But the key question is will you notice it?

If you ride very steep hills and/or need to climb out of steep bomb holes, and/or have dodgy knees, then

yesyou will see the benefit! But you will also spin out a little bit sooner when accelerating downhill.You could always change to a cassette that has a 46T. That will give you an extra 46/42 = 1.095 or 9.5% extra lower gear. That is better than the 6.25% from swapping the front ring. And you won't be spinning out sooner at the other end of the cassette because your front ring will still be a 32t.

219Thanks for the detail. I’d considered changing from 42 to 46 at the back but it’s a difference is £50 odd for new cassette to £9 for new chainring. Perhaps the answer is more training to get stronger legs plus a weight loss ha ha!

2,772And it all promised so so much”

Giant Trance 2 27.5 2016 ¦ Sonder Broken Road 2021¦ Giant Revolt Advanced 2 2019 ¦ Giant Anthem 3 2015 ¦ Specialized Myka Comp FSR 2009

219Very true!!

1,3663,380When going for a single chainring the thing to avoid is struggling with gear ratios that make it very hard going but promising yourself I will get fitter and lose weight. When you do get fitter and have lost the weight, that is the time to make the change and the main thing is to enjoy your riding.

2,240I entirely agree. I first went to 1x11 from 2x10. The 1x did not replicate the range and I had to compromise, so I chose to have the easy gear replicated and left the harder end to look after itself. My priority was always climbing and not going fast. I started with a 32t front ring and I still struggled in some places, so I fitted a 30t, the smallest gear I could fit on my crank. OK it was only 6.25%, but it made a difference!

A year or so later, I can get up that slope with a few gears lower down the cassette, but I still don't want to go any faster, so I can't be arsed to refit the 32t, or even opt for a 34t.

3,380I have been there with the wrong gear ratios on long steep hill climbs and that is why I am still a mountain biking neanderthal on 2 x 11 and 2 x 10 to give me all the gears I need

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