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Oval rings and suspension "bob"


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So the oval vs round ring have been debated over and over, this is not that topic.

 

I have been riding oval rings for a good few years. Seeing how the mechanics of the oval ring work (increased power on the down stroke and easier to get over the dead spot) is the ring not accentuating pedal "bob"?

 

I am on the heavy side and i run my rebound almost on the slowest to counter bob ( did a bike fitting and suspension tune) as soon as i ride district roads it seems i'm bobbing quite a lot.

 

 

anybody else experienced the same thing of any thoughts on the topic?

 

 

Regards

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If oval rings do what they claim to do and provide more evenly distributed power throughout the pedal stroke it should actually decrease pedal bob in theory.

 

Haven't noticed any difference whatsoever in pedal bob between round and oval rings though.

Edited by Grease_Monkey
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So the oval vs round ring have been debated over and over, this is not that topic.

 

I have been riding oval rings for a good few years. Seeing how the mechanics of the oval ring work (increased power on the down stroke and easier to get over the dead spot) is the ring not accentuating pedal "bob"?

 

I am on the heavy side and i run my rebound almost on the slowest to counter bob ( did a bike fitting and suspension tune) as soon as i ride district roads it seems i'm bobbing quite a lot.

 

 

anybody else experienced the same thing of any thoughts on the topic?

 

 

Regards

Can't say I noticed any when I switched over, but I dunno what you classify as heavy. It did seem to pedal nicer, but not the the extent that I'd swap to it on my other bike.

 

It could also be your own power or perhaps frame design, specific shock.

 

Are you noticing significantly more compared to a normal round ring?

 

Like I'm 96 on a Scott Spark 930 Alu frame 120mm travel with the fox Evol.

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Can't say I noticed any when I switched over, but I dunno what you classify as heavy. It did seem to pedal nicer, but not the the extent that I'd swap to it on my other bike.

 

It could also be your own power or perhaps frame design, specific shock.

 

Are you noticing significantly more compared to a normal round ring?

 

Like I'm 96 on a Scott Spark 930 Alu frame 120mm travel with the fox Evol.

100kg on a merida 96.

 

pedal stroke is much more efficient than with round.

 

Trying to figure out if its suspension or weight or ring or just "normal".

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100kg on a merida 96.

 

pedal stroke is much more efficient than with round.

 

Trying to figure out if its suspension or weight or ring or just "normal".

That seems like a trial and error thing, you may need to swap to a round ring and do some test rides to see.

 

When I swapped 8 noticed it was different and seemed better, but meh. I noticed little tangible impact from it, climbs were not really easier, wasn't going any faster or using any less energy.

 

The only tangible difference I noticed was I could pedal 2.5kph faster before spinning out.

 

Its possible it may have helped prevent muscle cramps, but the time between the 2 big enough to cause them races I had changed too much else, 1 of which was nutrition.

 

Oh yeah, and it cost me a derailure, wore out my clutch. I leave it on the spark but personally found no good reason to put one on the genius.

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i can safely say that my experience has shown me that I have less bobbing since riding the oval ring compared to round (i am a meaty 105kg), even when my cadence is up around 100rpms. all i can deduce from my experience is that the application of power is smoother as a result of the oval ring, something which i also notice on climbing loose terrain - traction is more consistent.

 

just my 2c, but it sounds like your suspension is a bit soft. have you considered a volume spacer? 

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Interesting question and thanks for posting. I just bought a new bike (got in 2 rides before the lockdown) and as such, changed from 2x10 to 1x12 and hence pondered the question as to 34T oval or round. In the end, I went for round as most of my mates and people I spoke to personally, said that the oval either hurt their knees or made zero noticeable difference to their rides. Not one person claimed a benefit. Anyways, as to the BOB issue, I tested a few bikes before I made my choice and found that some bikes, the Bob was inherent in the suspension design, even after pumping the shock higher than recommended for my 82kg mass.

 

If I were you, I'd up the shock pressure but also try a round ring and then an oval and see for yourself. I'd love to hear your feedback on this experiment (after the lockdown of course).

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I only ran an oval ring briefly and found that at lower cadences the power transfer was reasonably smooth, but as soon as I got above 80rpm or so it felt like the bike was surging on the downstroke and slowing down in the 'dead spot', if that makes any sense...

 

Years of road riding have given me a very even pedal stroke which I felt the oval ring wasn't at all compatible with, so I went back to round. Maybe this is what you're feeling?

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Chainring size will affect the anti-squat numbers. Going to a smaller chainring will give more anti-squat (less bob) vs a large chainring which will give less anti-squat (more bob). The same will apply for an oval ring. Set the bike up with the correct sag numbers and ride it. Going up in pressure to eliminate bob will also eliminate the benefits of rear suspension i.e: traction and comfort. Pedal bob with a correctly setup bike is nothing to worry about, sure it saps the tiniest bit of energy, but so does friction in your drivetrain. If you absolutely mist get rid of it, engage the bike's lockout, get your shock tuned with heavier compression and rebound valving or get a hardtall

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Chainring size will affect the anti-squat numbers. Going to a smaller chainring will give more anti-squat (less bob) vs a large chainring which will give less anti-squat (more bob). The same will apply for an oval ring. Set the bike up with the correct sag numbers and ride it. Going up in pressure to eliminate bob will also eliminate the benefits of rear suspension i.e: traction and comfort. Pedal bob with a correctly setup bike is nothing to worry about, sure it saps the tiniest bit of energy, but so does friction in your drivetrain. If you absolutely mist get rid of it, engage the bike's lockout, get your shock tuned with heavier compression and rebound valving or get a hardtall

Or get a different bike... [emoji6]

 

Pedal Bob annoys me and makes me sea sick... Hence Spez EPIC with brain for me... But I think that's maybe another discussion altogether...

 

I'm not sure that I get the small Vs large chainring concept you explained but I'd be really annoyed if I had to go to a smaller chainring to avoid Bob and then loose massive top end on gearing...

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i can safely say that my experience has shown me that I have less bobbing since riding the oval ring compared to round (i am a meaty 105kg), even when my cadence is up around 100rpms. all i can deduce from my experience is that the application of power is smoother as a result of the oval ring, something which i also notice on climbing loose terrain - traction is more consistent.

 

just my 2c, but it sounds like your suspension is a bit soft. have you considered a volume spacer? 

How do you perceive bob on a hardtail? Asking for a friend.

Bob normally refers to the rear suspension, but I may be wrong.

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I am also heavy and use oval chainrings on my full suspension  bikes .If i had to choose one advantage over round chainrings that i am sure about ,it would be that technical climbing is smoother and thus easier to keep momentum .If i notice bob it is usually the shock pressure that is to low .I tend to ride with a stiff  suspension setup anyway .IMO oval rings suite torque riders better than cadence riders .It is not for everyone ,but i like them enough to have them on all my mtb,s and it feels as-if standing climbs are also smoother and easier 

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Mmmmm.

 

When I first saw the launch video of the YT Jeffsy the first thing I noticed in the vid was lots of pedal bob. I now have a Jeffsy of my own and the pedal bob comes in 2 settings. Depressing and Ignore.

 

I've upgrade the shock, run gigantic air pressure but the bob remains. I do have an oval ring up front and I have been told that that is the cause of my pedal bob but I'm inclined to believe the pedal bob is more an inherent part of the suspension platform and that the front ring is tiny. A 32.

 

But the bike is a hoot to ride so I run the pedal bob in setting 2.

 

*Disclaimer

I don't claim to know anything about suspension. I don't use the word kinematics in casual conversation and I ride flat pedals on my MTB's. I'd describe my pedal stroke as panicked rather than smooth.

Edited by Duane_Bosch
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Jeffsy is a trail bike. It will bob more because the suspension is dialled for going downhill not up or for long flat sections of trail. Even Weagles trail bikes bob. The best cross over bike is probably the Ibis Ripley range. But its not the best trail bike and not the best marathon bike. That's the compromise. And no matter good it is its still limited by the riders weight. anyone outside of it designed weight range, well its gonna bobalot.

Chainring size will influence antispuat but its minimal. What is important is how much tension you can impart into the chain and that requires power. ore power, more anti squat, the less sensitive the suspension is going to be.

 

they all have a sweet spot.

 

And no anyone who says an oval is going to eliminate bob either sells them or has drunk too much of the marketers coolaid. The biggest influencer for eliminating bob is the rear shock and getting it set up correctly to minimise bob . Bu then you lose some sensitivity.

 

all trade offs. So by like Duane and just ride your bike. Don't want it to bob, then set sag at 20% or get a lock out rear shock. Otherwise just enjoy the bike for what it is

 

back to the original question. "Will an oval cure bob or make it worse?" Both and none, It depends.

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