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Discussion Starter · #1 ·
What are the benefits of running a smaller chainring, aside from the obvious? 30x20 vs 32x21. Mathematically they both are basically the same.
I’m thinking of running 32x21 for Marji, but I know a bunch of the riders run 30 fronts.
 

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I've been using 28/19 combo which is pretty much same as 32/21 or 30/20. I think most consider bigger ring/cog combos friendlier on chains but the smaller rings may give a bit of clearance in the rocks or other rough stuff. Other than that not a whole lot of benefit advantage either way. I actually started using the combo as my Riot FS SS has a Rohloff tensioner which is 21t max but even 20t was a PITA to remove the wheel but 19t was OK so there is that benefit (I switch the wheelset over to the ROS9 to save wear tear). Now have the same combo on my Radimus.
 

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Discussion Starter · #3 ·
I was running a 34 but it seemed to cause stress and flex on my frame. (Pivot Les)
I was thinking the 30 would help with that, but I don’t want to be spinning like a madman for the 1st half of Marji
 

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It depends a lot on how your gearing is setup and your fitness level.

When I started out, I tended to favor the small chainring more. It was good for hills, and moderate paces on the flats. As my fitness is improved, I tend to use the large ring more often than the small one.

Generally, the small chainring is good for slow climbing, and medium speed cruising. The big ring is good for medium speed, high speeds, and descending.

If you're mostly riding slow and medium speeds, try staying in the small chainring. If you're mostly riding medium to fast speeds, try staying in the big chainring. Try to reduce the number of times you shift the front.

Avoid cross-chaining (big>big, small>small) where possible.
 

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Biggest benefit of smaller chainrings for SS - 1) they clear wide chainstays. Particularly with oval rings, you can be working with millimeters of clearance, so the difference between a 34 and a 30 is massive. Beyond that, 2) In 104BCD the smaller rings (30 and 32) are typically threaded, so no chainring nuts necessary. However, this can sometimes be an issue if you need/want to run the ring on the outside of the spider for chainline/clearance reasons. No issues with direct mount rings, and you can get them in smaller sizes. 3) maybe the extra rollover clearance, but you should be able to get yourself over things without bashing your ring. 4) if you’re a weight weenie, it’s lighter.

Obviously you can give yourself almost identical gain ratios by swapping ring and cog combos (Sheldon Brown’s gear calculator is your friend).

And like mentioned above, smaller combos probably wear chains faster, but chains are relatively cheap.


Sent from my iPhone using Tapatalk
 

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It depends a lot on how your gearing is setup and your fitness level.

When I started out, I tended to favor the small chainring more. It was good for hills, and moderate paces on the flats. As my fitness is improved, I tend to use the large ring more often than the small one.

Generally, the small chainring is good for slow climbing, and medium speed cruising. The big ring is good for medium speed, high speeds, and descending.

If you're mostly riding slow and medium speeds, try staying in the small chainring. If you're mostly riding medium to fast speeds, try staying in the big chainring. Try to reduce the number of times you shift the front.

Avoid cross-chaining (big>big, small>small) where possible.
Mongoguy's question was about singlespeed gearing.
 

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I was running a 34 but it seemed to cause stress and flex on my frame. (Pivot Les)
I was thinking the 30 would help with that, but I don't want to be spinning like a madman for the 1st half of Marji
Since I started running the 28/19 combo it seems a bit smoother and quieter than the 32/21 combo, not sure if the decreased diameters makes for less sensitivity to any misalignment due to torqueing and/or chain alignment(plus ends of drivetrain are closer together so concentricity effects may be lessened). But seems to be something there.
 

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Discussion Starter · #11 ·
Since I started running the 28/19 combo it seems a bit smoother and quieter than the 32/21 combo, not sure if the decreased diameters makes for less sensitivity to any misalignment due to torqueing and/or chain alignment(plus ends of drivetrain are closer together so concentricity effects may be lessened). But seems to be something there.
I noticed it too when I went from 34 oval to 32 oval. Definitely less stress on my frame.
 

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A smaller chainring keeps me from pining for an eMtb. I figure I got a couple more years on the 30, and then maybe another 5 on the 28 before the knees give out. Hopefully, someone will make a 23-60 cassette and I can go to my grave without ever turning into an e-hole.
 

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Rippin da fAt
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Biggest benefit of smaller chainrings for SS - 1) they clear wide chainstays. Particularly with oval rings, you can be working with millimeters of clearance, so the difference between a 34 and a 30 is massive. Beyond that, 2) In 104BCD the smaller rings (30 and 32) are typically threaded, so no chainring nuts necessary. However, this can sometimes be an issue if you need/want to run the ring on the outside of the spider for chainline/clearance reasons. No issues with direct mount rings, and you can get them in smaller sizes. 3) maybe the extra rollover clearance, but you should be able to get yourself over things without bashing your ring. 4) if you're a weight weenie, it's lighter.

Obviously you can give yourself almost identical gain ratios by swapping ring and cog combos (Sheldon Brown's gear calculator is your friend).

And like mentioned above, smaller combos probably wear chains faster, but chains are relatively cheap.

Sent from my iPhone using Tapatalk
Gear ratio calculator

Fill in the blanks and get some insight for a gear change or build.

For the wear and tear thing, shorter ratios will use up components at a faster rate than would taller ratios.
 

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A smaller chainring keeps me from pining for an eMtb. I figure I got a couple more years on the 30, and then maybe another 5 on the 28 before the knees give out. Hopefully, someone will make a 23-60 cassette and I can go to my grave without ever turning into an e-hole.
We're talking about relatively fixed gear ratios for single speeds like within +/-3% not a smaller ring with a cassette. But your e-hole point remains valid.
 

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Unit, Anthem, Stumpy, Secteur
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It depends a lot on how your gearing is setup and your fitness level.

When I started out, I tended to favor the small chainring more. It was good for hills, and moderate paces on the flats. As my fitness is improved, I tend to use the large ring more often than the small one.

Generally, the small chainring is good for slow climbing, and medium speed cruising. The big ring is good for medium speed, high speeds, and descending.

If you're mostly riding slow and medium speeds, try staying in the small chainring. If you're mostly riding medium to fast speeds, try staying in the big chainring. Try to reduce the number of times you shift the front.

Avoid cross-chaining (big>big, small>small) where possible.
No-one here has any issues cross-chaining :)
 

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Armature speller
Unit, Anthem, Stumpy, Secteur
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I prefer running bigger rear cogs to smaller front rings.
It's easier to change a chainring though.

My go-to gear for the trails here is 32/22. I aim for 1,000m of climbing in a day.
 
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