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Old 01-16-21, 07:51 AM
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hokiefyd 
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Originally Posted by CanadianBiker32 View Post
Just recently I am about to be in the need to replace my front ring.

I am running 28T on it at the moment and I do feel i need that ratio. As often in my lowest gear when riding up a big climb in snow. I need to spin.
However seems to be a shortage of 28T's around just 30T.
Would i see much difference if i got 30T for my Fat bike?
I recommend figuring out the gear inch range that you use and then go from there. For example, if you currently run 26x4" tires, a 28t chain ring, and an 11-46 cassette, your gear inch range is 18.2" on the low end and 76.1" on the high end. Is that the right range for you? It sounds like you want or need the low gear you currently have (a 30t would increase your low gear from 18.2" to 19.5"). Do you spin out of your high gear or is that sufficient? A 30t would increase your high gear from 76.1" to 81.5".

If these changes look consistent, it's because they are. It's about a 7% increase in gear ratio.

I recommend figuring gear inches because, depending on your cassette, you MAY be able to approximate what the change will be with different gears. For example, if your second tallest sprocket is a 42t, then the combination of your existing 28t chain ring and 2nd gear 42t sprocket is 19.9". That's almost the same as your low gear with a new 30t chain ring and 1st gear 46t sprocket (19.5"). So could you live with your second tallest sprocket as your bike is now as your lowest gear?

Obviously, all of that changes depending on the configuration of your bike (tire size, cassette, etc.). But trying to imagine a 7% change can be difficult, so doing the math may enable you to find a combination on your current drivetrain that will be equivalent to your new setup and would allow you to "try before you ride".
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