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-   -   Opinion On 28T to 30T (https://www.bikeforums.net/fatbikes/1221441-opinion-28t-30t.html)

CanadianBiker32 01-12-21 04:59 PM

Opinion On 28T to 30T
 
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?

HerrKaLeun 01-12-21 05:53 PM

in the lowest gear it will be proportionally harder. If it matters, only you can know after trying. Over the years I went the opposite to lower and lower gears on my fatbike. Especially in the low-speed and high resistance situations like deep snow.

trailangel 01-13-21 11:32 AM

you would see a two tooth difference.

hokiefyd 01-16-21 07:51 AM


Originally Posted by CanadianBiker32 (Post 21875099)
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".

xroadcharlie 01-16-21 03:38 PM

Going to a 30T chainring from a 28 would make it 7% harder to climb. The longer the hill, The greater overall effort required. The short hills where I live I can climb with tall gears. If I had to climb a moderately steep hill 1/4 mile long I would need a much lower gear.

On the plus side though it will pay off under light loads. Sometimes it ballances out. A little more effort to climb is rewarded with more efficient riding at other times.

DangerousDanR 01-17-21 12:04 PM

To the OP:
I just took a look at Chain reaction Cycles web site. They list 40 different in stock 28 tooth chain rings for SRAM, Race Face , Hope, Shimano, and a lot more crank sets. I just received a Hope crankset with Bottom Bracket in less than a week. Your LBS doesn't have wholesalers with the inventory of the online giants like CRC.

Dumpngo 01-27-21 11:11 PM


Originally Posted by xroadcharlie (Post 21880991)
Going to a 30T chainring from a 28 would make it 7% harder to climb. The longer the hill, The greater overall effort required. The short hills where I live I can climb with tall gears. If I had to climb a moderately steep hill 1/4 mile long I would need a much lower gear.

On the plus side though it will pay off under light loads. Sometimes it ballances out. A little more effort to climb is rewarded with more efficient riding at other times.

I have 28T and wanted to go 30T and change my cassette from 11-42 to 11-50. That should be ok right?

xroadcharlie 01-28-21 03:17 PM


Originally Posted by Dumpngo (Post 21898595)
I have 28T and wanted to go 30T and change my cassette from 11-42 to 11-50. That should be ok right?

I don't know much about the mechanics involved with what you are suggesting. But I believe the rear derailleur has a max limit as to the size of the largest sprocket as well as the max difference in teeth You could google your unit for starters.

Actually 30/42 is pretty low. I would try that first if you can't find a 28.

hokiefyd 01-29-21 07:06 AM


Originally Posted by xroadcharlie (Post 21899580)
I don't know much about the mechanics involved with what you are suggesting. But I believe the rear derailleur has a max limit as to the size of the largest sprocket as well as the max difference in teeth You could google your unit for starters.

Actually 30/42 is pretty low. I would try that first if you can't find a 28.

I have a 26t with an 11-46 Microshift 9-speed setup. If 30/42 is pretty low, then 26/46 is really low...but still nice for spinning up stuff that I'd prefer to ride rather than walk. :commute:

hokiefyd 01-29-21 07:08 AM


Originally Posted by Dumpngo (Post 21898595)
I have 28T and wanted to go 30T and change my cassette from 11-42 to 11-50. That should be ok right?

If your rear derailleur can handle that range, then a 30t combined with an 11-50 will increase your high gear ratio and will also decrease your low gear ratio compared with a 28t with an 11-42. You'll have more gear range and your low will be lower and your high will be higher.

Dumpngo 01-29-21 09:05 AM


Originally Posted by hokiefyd (Post 21900339)
If your rear derailleur can handle that range, then a 30t combined with an 11-50 will increase your high gear ratio and will also decrease your low gear ratio compared with a 28t with an 11-42. You'll have more gear range and your low will be lower and your high will be higher.

Exactly how I want. Thanks!


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