34t vs Rotor- Mtbr.com
Results 1 to 16 of 16

Thread: 34t vs Rotor

  1. #1
    Gigantic Hawk
    Reputation: dubthang's Avatar
    Join Date
    Apr 2009
    Posts
    1,563

    34t vs Rotor

    The background first,
    I started riding ss with 32x20 which I soon swapped to 32x18. I then switched to a 34t Rotor ring and a 19t WI freewheel which I ran for an entire season. This season I have been running 34x19. I have done much of the same trails, and one race with all three setups.

    The Rotor ring comes as a 34 tooth ring. In reality, it is more like a 36t in the power zone, and a 32t in the dead zone to average out to a 34 tooth. The ring has three different positions that it can be placed in depending on your requirements. I didn't notice a whole lot of difference in either position, but my knees felt better in the easiest setting. The ring is well constructed, and I never lost my chain due to running it slightly slack. I did find it to be a hard gear to push on the techy, punchy trails here in Maine. It's great for flowing singletrack, and quick uphills, but it burns me out over long distances. I also found I was more likely to hit it on things since it is slightly bigger than I was used too. The 32t dead spot is nice on hills to help get my feet around, but I find the 36t power zone to be draining.

    This year I switched to a standard 34t ring (with the same 19t WI trials freewheel.) I like this combo better. My legs and knees like this combo too. The biggest difference is that the pedaling is less tiring, and more consistent. By being able to keep the same pedaling motion, I can catch a little break instead of always pushing through the power zone. I used this combo at this year's Single Speed-A-Palooza (last year I used the Rotor ring,) and while I didn't much better, I felt much better.

    What does this all mean? Honestly, I don't know. The comparison is slightly flawed when gear inches are brought into the equation. I base everything off of 32x18 since I feel that is the ideal gearing for Maine.

    On my bike, 32x18 equals 51.8 gear inches.

    The Rotor ring (with a 19t) equals 55.2 in the power zone, 49.1 in the dead zone, and averages 52.15.

    The 34x19 is 52.1.

    The Rotor ring with a 20t (I've not tried this combo) equals 52.4 in the power, 46.6 in the dead, and averages 49.5.

    A 34x19 vs a Rotorx20 may be a more fair comparison, but I am not sure. I do know that 36x19 is a lot of gear to push, and that the dead spot doesn't really make up for it. That said, I am switching back to 32x18 for my upcoming race this weekend.

    /rambling

  2. #2
    mtbr member
    Reputation:
    Join Date
    Feb 2012
    Posts
    167
    Wait, what? Biopace is back? I really have been under a rock...

  3. #3
    Gigantic Hawk
    Reputation: dubthang's Avatar
    Join Date
    Apr 2009
    Posts
    1,563
    Um, it's not Biopace. Biopace is the complete opposite.

  4. #4
    mtbr member
    Reputation: Cygnus's Avatar
    Join Date
    Jan 2004
    Posts
    481
    don't know about rotor ring (eccentric?).

    but 34x19 is the sweet spot for me, given where i ride.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Jul 2004
    Posts
    917
    I think you will get a 101 opinions here. I rode the Rotor ring for two seasons and loved it and felt it worked well. The only reason I'm not on it now is because I'm using the Gates Centertrack belt drive.
    OB1 Kielbasa

    One is good!

  6. #6
    CB2
    CB2 is offline
    Jam Econo
    Reputation: CB2's Avatar
    Join Date
    May 2006
    Posts
    4,214
    I know a number of people who tried Rotor Rings and were psyched at first, but went back to standard round rings. I don't think the benefits out weigh the price and hassle.

    One guy I know who raced the Pro / Open at SSAP dropped his chain a number of times running a Rotor Ring, but honestly his chain was pretty loose (his "tight" spot was looser than my "loose" spot).

  7. #7
    mtbr member
    Reputation:
    Join Date
    Feb 2012
    Posts
    167
    My bad.

    Wait, what? Non-round chainrings that try to improve the efficiency of the pedal stroke are back?

    Do you need a tensioner to run one of those?

  8. #8
    mtbr member
    Reputation: RiderInTraining's Avatar
    Join Date
    Apr 2005
    Posts
    347
    Quote Originally Posted by anthonyk View Post
    Do you need a tensioner to run one of those?
    No, you do not.

    I'd love to try the Rotor chainring, but $150 is just crazy.
    I'm Confused . . . Wait a Minute, No I'm Not . . .

  9. #9
    Gigantic Hawk
    Reputation: dubthang's Avatar
    Join Date
    Apr 2009
    Posts
    1,563
    I never dropped a chain when using my Rotor ring. Not once and I was running a pretty loose chain. I wasn't really searching for opinions. It was more just stating what I have discovered so far.

    I think the big thing here is for people looking into using a Rotor ring that it really isn't a 34 tooth ring. My rear hub is a Chub which uses freewheels. This makes gear experimentation more difficult. I feel that if somebody is looking to try one of these that they may want to add a tooth in the rear as well.

  10. #10
    mtbr member
    Reputation:
    Join Date
    Feb 2010
    Posts
    176
    I kind of had the same experience though on the road. I have 36x50 rotor rings with a 25 low out back on one bike and a 38x50 round rings with a 26 low in back. You would think the 36x25 would feel easier than the 38x26 but it doesn't if you are cranking a lower rpm. Where rotor rings seem to make the big difference is when I stand or really cranking out the power at higher rpm's. Which has led to the question of which ring set I go with on my mtb. Currently running 27x40 with a 11 - 36 9speed out back. I thought I would go with the 27x40 rotor rings but with what I experienced with the road rings I think it would be considerably harder. Bought a 38 rotor ring to see how it feels compared to the round 40. Only got a couple rides in on it but it feels, effort wise, like the 40.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    12
    Quote Originally Posted by dubthang View Post

    On my bike, 32x18 equals 51.8 gear inches.

    The Rotor ring (with a 19t) equals 55.2 in the power zone, 49.1 in the dead zone, and averages 52.15.

    The 34x19 is 52.1.

    The Rotor ring with a 20t (I've not tried this combo) equals 52.4 in the power, 46.6 in the dead, and averages 49.5.

    A 34x19 vs a Rotorx20 may be a more fair comparison, but I am not sure. I do know that 36x19 is a lot of gear to push, and that the dead spot doesn't really make up for it. That said, I am switching back to 32x18 for my upcoming race this weekend.

    /rambling
    I think your thought process is spot on, but would like to add my own experience and why I'm sticking with the Rotor. I initially went with a 19t rear cog with a Rotor ring, same as you, thinking my true ratio was around a 34x19 because of the 'dead spot' on the Rotor ring. However, I eventually came to the conclusion, just like you did, that really you're pushing a 36x19 around.

    I now base my gearing on the 36t upfront, so I'm running larger rear cogs (22-24t's). My 'normal' setup is 22t in the back, which is 36x22 with the Rotor, or the equivalent of 32x18/19 for a round ring.

    When your pedal cadence slows down, the Rotor ring does help turn the cranks over, but not that much, thus you still have to push through that harder gear. On steep climbs, or techy sections, I truly believe you're pedaling with a 36t upfront and the 'dead' spot on the Rotor ring only helps so much.

    So, my two cents, I suggest trying the Rotor with larger rear cogs and I think you might find it's similar to 32x18 you just put back on. If you’re trying to duplicate 32x18 with a Rotor, go with a 22t in the back. On flats, or uphill’s < 8%, I feel there’s a benefit to running a Rotor. Once the incline gets steeper than that, a hill is a hill and you still have to push that harder 36t gear.

  12. #12
    Gigantic Hawk
    Reputation: dubthang's Avatar
    Join Date
    Apr 2009
    Posts
    1,563
    Cerebus, I hear what you are saying. I ran 32x19 earlier this week (my freewheel was stuck on) and I quite enjoyed the easier pedaling. That said, my knees didn't like it as much. I wonder if I'd feel it in my knees if I setup the Rotor ring to match the 32x18 gearing in the power zone? Rotor x 20 would be the closest match in my mind. The dead zone would be quite a bit lower than the 32x19 I ran earlier this week, but the power zone would be slightly higher. Wonder how this would feel? I'm not in the market to buy a 20t freewheel anytime soon, but I'll keep it in mind.

  13. #13
    mtbr member
    Reputation: SeaBass_'s Avatar
    Join Date
    Apr 2006
    Posts
    2,100
    Um, You felt better at the end of Singlespeedapalooza this year because you stopped for half an hour at the beer stop 3 miles from the finish!

  14. #14
    Gigantic Hawk
    Reputation: dubthang's Avatar
    Join Date
    Apr 2009
    Posts
    1,563
    Quote Originally Posted by SeaBass_ View Post
    Um, You felt better at the end of Singlespeedapalooza this year because you stopped for half an hour at the beer stop 3 miles from the finish!
    I stopped at the beer stop on both laps actually.

    Last year's race didn't have an official beer stop, but I made sure that I put back a cold one between laps from the 'mystery' cooler.

  15. #15
    awesome
    Reputation: dblspeed's Avatar
    Join Date
    Jan 2006
    Posts
    800
    anything against using the q-ring with flat pedals?

  16. #16
    Gigantic Hawk
    Reputation: dubthang's Avatar
    Join Date
    Apr 2009
    Posts
    1,563
    Flat pedals should work fine. If you can ride with them now, then the Rotor shouldn't make that much difference if it's geared similar.

Members who have read this thread: 0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.