Oval Chain Rings

[horncpa]

2 hours ago, Barry said:

$56 and have it tomorrow. Anyone doing their own wrenching really ought to have a decent one for the low torque range. 

 

https://www.amazon.com/dp/B0849LNJ36/ref=cm_sw_r_em_apa_i_9hq2EbA62R3H5

I ordered this one just because it was a little better rated, but thanks for the thoughts.  

https://www.amazon.com/Venzo-Bicycle-Torque-Wrench-Socket/dp/B00811WQT8/ref=sr_1_1?dchild=1&keywords=venzo+bike+wrench&qid=1591288619&s=sporting-goods&sr=1-1

[bestbike85]

1 hour ago, horncpa said:

I ordered this one just because it was a little better rated, but thanks for the thoughts.  

https://www.amazon.com/Venzo-Bicycle-Torque-Wrench-Socket/dp/B00811WQT8/ref=sr_1_1?dchild=1&keywords=venzo+bike+wrench&qid=1591288619&s=sporting-goods&sr=1-1

That’s the one I have and it works great. Just pay attention to instructions. Always store it at 2nm. 

[olddbrider]

2 hours ago, horncpa said:

So the torx bolts that attach the chain ring to the crank need 5-7nm, however the main 8MM hex bolt for the crank needs 54nm.  

So basically I need the 1/4 inch small torque wrench and a bigger one for the big bolt.   Am I thinking about this right?

 

I'm not sure I've ever used a torque wrench when tightening cranks.  I've just gone with "tight as hell".  I have the Park deflection torque wrenches and the big one only goes up to 70nm.  Maybe newer cranksets are more finicky about torque... I'm typically more concerned with over-torque-ing things with very low specs.  Somebody else can chime in, but I feel like 54nm is probably pretty close to as tight as you can get it.

[Barry]

1 hour ago, horncpa said:

I ordered this one just because it was a little better rated, but thanks for the thoughts.  

https://www.amazon.com/Venzo-Bicycle-Torque-Wrench-Socket/dp/B00811WQT8/ref=sr_1_1?dchild=1&keywords=venzo+bike+wrench&qid=1591288619&s=sporting-goods&sr=1-1

Interestingly that looks 100% like the one I have. But mine is branded Nashbar. 

[AntonioGG]

3 minutes ago, olddbrider said:

 Somebody else can chime in, but I feel like 54nm is probably pretty close to as tight as you can get it.

Depends on how long the lever arm is.

[Cafeend]

you anywhere near Cedar Park?

I do. NW Austin .. planning on hitting BC today. I am skipping work tomorrow as well

Sent from my SM-N960U using Tapatalk

[olddbrider]

3 minutes ago, Cafeend said:

I do. NW Austin .. planning on hitting BC today. I am skipping work tomorrow as well

Sent from my SM-N960U using Tapatalk
 

That's true.  I should have said "with a standard socket set" or something like that.

[horncpa]

Completed my chain ring switch out.  Crazy how easy that was.  Love the AbsoluteBlack Oval ring.   Can’t wait to try it out tomorrow. 

[Mattlikesbikes]

Alright, dust this thread off.

Looking to try oval on my SS. I was geared 32/24 and could climb everything. Just regeared to 30/21 and love it. Looking though at maybe sticking with the 21 but throwing a 32t oval on. It's a 104bcd XT crank, so the 30t options look less awesome.

The Absolute black stuff looks great, but is there any reason not to go cheap for a trial?

 

 

[mack_turtle]

for singlespeeding, I am under the impression that some, but not all chainrings will work without a tensioner. I have used AB rings with no problems on SS, but I emailed Garbaruk about their SS rings and they said I would have to use a tensioner with their rings. weird.

I think a well-designed oval ring should cause the chain to "lengthen" and "shorten" and would appear to move up and down when pedaling, but if is made right, the actual tension in the system should not change significantly.

[Tree Magnet]

10 minutes ago, mack_turtle said:

for singlespeeding, I am under the impression that some, but not all chainrings will work without a tensioner. I have used AB rings with no problems on SS, but I emailed Garbaruk about their SS rings and they said I would have to use a tensioner with their rings. weird.

I think a well-designed oval ring should cause the chain to "lengthen" and "shorten" and would appear to move up and down when pedaling, but if is made right, the actual tension in the system should not change significantly.

I run an Absolute Black oval on my SS without a tensioner.  My mind said it wouldn't work but the design of the oval ring is such that the tension never changes.  It's a trip.

[RedRider3141]

12 minutes ago, Tree Magnet said:

I run an Absolute Black oval on my SS without a tensioner.  My mind said it wouldn't work but the design of the oval ring is such that the tension never changes.  It's a trip.

Wait what? on my 1x10 with AB chainring the derailleur absolutely moves back and forth as the cranks turn. I assumed this was because as the larger diameter of the oval grew and shrank the spring-loaded derailleur was adjusting to keep the tension relatively constant. Maybe its just moving because the tangent point of the chain is moving up and down... my brain hurts.  

[mack_turtle]

I wish he had done this on a bike without a tension to prove that the tensioner isn't really doing anything that would not happen on a bike with sliders, track ends, etc.

If you spend enough time in this rabbit hole, you'll find that some people get more consistent tension then others on a SS-oval setup. I would go nuts if mine varied as much as some of the ones I have seen. even if it does not drop the chain, hearing and feeling the chain get tight and then loose would be a deal-breaker.

[AntonioGG]

I'm not sure what's on my SS, but I think it's an absolute black and I absolutely don't have perceivable varying tension.

[ssorgs]

Sold me.  Just order AB 30t.

[mack_turtle]

28 minutes ago, AntonioGG said:

I'm not sure what's on my SS, but I think it's an absolute black and I absolutely don't have perceivable varying tension.

what kind of crankset? I'm curious to know if there consistent difference among chainring mounting options—4-bolt, Cinch, SRAM, etc.

[Mattlikesbikes]

3 minutes ago, mack_turtle said:

what kind of crankset? I'm curious to know if there consistent difference among chainring mounting options—4-bolt, Cinch, SRAM, etc.

This. With any bolt on chainrings it is often pretty hard to get them mounted perfectly center. I regularly see a little chain rise/fall even on round rings.

 

There also has to be the just right amount of elipse/flattening of the circle in order to maintain generally the same tension. Low dollar rings probably do not take a lot of time to look at how much of an oval they are making, but that would have a significant amount of impact on how well the chain is tensioned.

Edited May 19, 2021 by Mattlikesbikes

[TheX]

I have an oval ring free if anyone needs it. 38T - BCD 104.

 

 

[AntonioGG]

1 hour ago, mack_turtle said:

what kind of crankset? I'm curious to know if there consistent difference among chainring mounting options—4-bolt, Cinch, SRAM, etc.

I'm pretty sure it's an XT crank 104bcd.  I just mounted the chainring with the little tab on the crank.

Come to think of it, I think mine may be a Wolftooth and not AB.

I think the reason why you see a tensioner move around is because the vertical position of the chain is moving, but the actual effective chain length is not changing (or changing much in any case).  When the oval part is forward, the horizontal length is now 2x.  When the oval part is vertical, now you've added a vertical component.

[ssorgs]

On 5/19/2021 at 12:46 PM, ssorgs said:

Sold me.  Just order AB 30t.

Whoa, this shit's for real! 1st ride yesterday afternoon and I was blown away! 

Rode road to TC and flats were a little awkward, with a weird dead/gap spot at the top of my pedal stroke.  Really only went away if I was pushing my cadence or going up hills - though it was smooth climbing seated or standing (standing so long as was in big enough gear). Sounds like that's pretty common and I should adapt in short order. Though I did feel it some on way back.

Trail was phenomenal!  While still some of the gappy sensation on flat stuff, it made a huge difference climbing and let me cruise through rocky/loose stuff. I could climb really well seated, which is my preference for traction, and I just didn't stall out on ledges.  When needed, I could stand and power up and over far more consistently than the before times. I could keep my weight back, which is something I have to work on as I sometimes find myself leaning far enough forward that I lose traction and while making it more trouble getting the front end up (great combo ;-). Another great 'use case' was through baby head-type sections, especially at the top of tricky climbs, where you can really lose momentum trying to crawl over them, I could just keep pedaling.

My legs really felt less tired too, especially quads. I kept same tooth count as my round, though I did feel like I was often riding in a higher gear because...I could.

Basically, every bit of absoluteBlack's 'Why  Oval...' was true for me!

Fuck alll y'all for not getting me on it sooner!

[RedRider3141]

Gald you liked it, I agree with everything you've said about the AB oval except my experience wasn't quite as drastic, but enough where I prefer it over round.

[ATXZJ]

On 5/19/2021 at 1:41 PM, TheX said:

I have an oval ring free if anyone needs it. 38T - BCD 104.

 

 

That's actually a really good ring as it's entirely indexable 

[Mattlikesbikes]

Just installed and playing around on the asphalt, the whole pedal stroke feels smoother for sure. And no noticable change in tension.

eBay chinesium. $18. 104bcd 32t

Edited May 26, 2021 by Mattlikesbikes

[Mattlikesbikes]

Alright, did a whole drivetrain swap around. I moved my XTR power crankset to the green bike. Actually waiting on some parts for that swap, but it will be a 32-19 oval setup (it's the WC, SATN, XC racing bike). Then yesterday I picked up a 30t AbsoluteBlack 104BCD ring from Velorangutan to run on the XT cranks on my more trail oriented SS. Chainline is perfect. While the tension changes ever so slightly, it is not noticeable. Wheel mounted/tensioned based on the tightest chain point, there is no chance of dropage when in the slackest point of the oval, I'll have to take the wheel off to take the chain off either cog/ring.

Super excited to get this on the trail. I am sure the 30/21 will be spinny, but for where I ride this bike, I am totally fine with that. I love dab free climbing all the hard stuff near me, even if I spin getting there.

I'm sold on Oval. Going to have to save up to get the setup on the road bike.

 

 

and yes, I need to clean my chain.

Edited June 17, 2021 by Mattlikesbikes

[Bart]

I bought a AB oval for my Trance after I wore down my Sram ring and also I liked the ano purple. Looks great and feels a little different in the stroke but cant say its anything beneficial during climbs like they say. Awesome craftsmanship in the machine work.