Absolute Black Oval Chainring

[snilard]

Has anyone tested this oval rings?

 

[LarryOz]

Has anyone tested this oval rings?

I have not. I used SRAM rival cranks because I need 140mm length.
I don't think I can without investing a bunch of money to buy and modify the CF crankset.

 

[RojoRacing]

Rival cranks don't have a removable spider?

I've use AB rings on the Mtb two years ago when they first surfaced and they were good. Only issue was back then they couldn't keep up with demand and I couldn't get a new ring after wearing out the first one. After waiting 2 months on back order I bought different crankset that used different rings. I hear they have more machines now and production is increased but I don't know first hand. I'm sure CruzBike riders aren't going to chew threw rings nearly as fast as I was on a SS Mtb so lead times won't be much of an issue.

 

[ratz]

The only question about them is (based on the videos I've seen of the direct mount, and a quick glance at the older ones.) they don't have rotational adjustment; so they will likely be ineffective and out of phase on a recumbent bicycle.

 

[RojoRacing]

That is actually a great point I hadn't considered. So you can't clock a direct mount SRAM and your 4-5 bolt pattern rings could be clocked if the bolt spacing was even but I'm not sure you land where you need it. With race face or E13 cranks you could clock the ring anywhere along their 18 points.

What is the general angle offset from DF to Vendetta?

 

[trplay]

Oh my! This whole O ring thing is so Ovalwhelming. I went with the Doval rings and now you are saying the fixed point of these rings might not allow them to be positioned correctly. Certainly this is way Oval my head!

 

[RojoRacing]

So peak power phase on my DF is 80-118 degs

Peak power phase on the V is 6-60 degs

So if we choose the center of each phase we have DF at 98 & V at 33 so a 65 deg different between optimal clocked angle.

 

[ratz]

So peak power phase on my DF is 80-118 degs

Peak power phase on the V is 6-60 degs

So if we choose the center of each phase we have DF at 98 & V at 33 so a 65 deg different between optimal clocked angle.

In General yes; height of BB will affect that some; The chainring trough that engages the first chain roller at your stated 6 deg will vary based on rider body size. This is why we've focus on the Rotor solution; and mostly the 5 bolt ones as they have maximum adjustability.

Oh my! This whole O ring thing is so Ovalwhelming. I went with the Doval rings and now you are saying the fixed point of these rings might not allow them to be positioned correctly. Certainly this is way Oval my head!

Darn it; I read that you had been looking at those and I completely forgot to mention that. I had intended to, sorry man. But yeah that could be the case.

Basically the rule is for Q-ring like effect: you want the tooth that begins the minimum radius of the ring to; just be engaging the chain at the dead spot of your pedal stroke. If it's a little before that you get early engagement of the maximum radius good for massers; if it's a tad late to engage you can spin.

If you want bio-pace like effect than you reverse that and engage the biggest radius at the dead spot.

They might work; but it's going to be more by luck and happen-stance than by design.

 

[trplay]

Oh-vell, another little lesson in the hunt for free speed. Another thing that has me curious, it has been mentioned that these rings dont work when using cranks towards the 140mm end. Can you explain why?

 

[ratz]

Oh-vell, another little lesson in the hunt for free speed. Another thing that has me curious, it has been mentioned that these rings dont work when using cranks towards the 140mm end. Can you explain why?

The whole point of the qring is to minimize the time you spend in the deadspot; the 140 mm crank does the same thing with the smaller radius crank by shorting the distance the feet travel. So if both are done, they you are attacking the problem with two very effective solutions. The cost-benefit of doing q-rings on the short cranks doesn't really justify itself. UNLESS you are doing long (+2 hr) TT efforts on rolling hills or in wind where micro accelerations matter. Mark Stonich of short crank creation fame can go on for hours about what he's learned helping DF TTers and it's fascinating. Larry's experiences also bear this out too. All totally unscientific and snake oil; but I certainly prefer them and my cadence on the trainer with them is 100-105 no problem; round rings are 80-85. That's why I ride them; for the smoother pedaling.

We are going to try an experiment this spring. I'm missing a Q-Ring 52 Aero big ring and a QXL 38 little ring. In theory that little ring will have more oval and might make climbing easier.

 

[snilard]

I am not sure if anyone noticed that Absolute Black also make oval rings for 5 bolt 110 mm BCD cranks so you have basically 5 possible positions of ring.

 

[RojoRacing]

So maybe I'm just low on sugar this morning but suddenly the statement that recumbents required a hugely offset clocking of a oval ring when compared to a DF bike makes no sense. The idea is that the larger diameter of the ring is perpendicular to your crank arms and since you mount the ring in relation to the arms it doesn't matter what angle your sitting at. Now what does matter is if a recumbent requires a slightly different clocking due to our hips being straiter vs the normal seated position of a DF bike. In that sense I can see the need to be able to adjust the clocking of the ring by 10-30degs but nothing like the 60degs I stated earlier.

Ether Ratz was confused with his original statement or I didn't quite understand exactly what he was applying.

 

[RojoRacing]

Difference is the fact the drivetrain angle on the V is slightly tipped toward the rider. If you look at a DF bike from the side the rider sits right between the cassette and crank, maybe slight closer to the crank. From the side you can see the ride on a V sits just slightly rear of the cassette. The difference is about 30degs give or take and this is why the oval ring need a different clocking.

Sorry if I'm going back and forth a bit but I believe we need to state why something is the way it is instead just just stating that it is.

 

[ratz]

Ether Ratz was confused with his original statement or I didn't quite understand exactly what he was applying.

It's a little of both; I was being abbreviated and the left some points off the table which can confuse matters

1) Recumbents in general have a large variety of angles in there drive trains
2) BB height relative to your butt changes the location of the deep spot
3) BB height changes the point of intersection of the chain ring and the chain

So a tall rider and a short rider will find that 2 and 3 are variable and then need a different micro adjustment to keep the ring in phase.

On the Cruzbike the variables drop because it's 2 types of bike with a similar boom and minor adjustments between riders. Two riders both 5'9" (175cm)will likely use the same settings on a Q-ring; and it coincidentally happen to be almost exactly 2 spider arms out of phase with a DF. Such a rider could use an absolute black rotated on the spider in all likelihood. Someone 6'0" (182cm) probably not. Basically it will work as Sinard suggests for a select subset of rider with the correct body dimensions.

http://www.rotorbikeusa.com/pdf/Q-Ring Recumbent instructions.pdf

Very long discussion here:
http://cruzbike.com/forum/threads/q-ring-upgrade-ahhhhhhhhhhhhh.7784/

On a DF if you road with a seat positioned behind the rear wheel then you would need a Q-ring orientation the same as what you have a vendetta.

 

[JOSEPHWEISSERT]

Also, the point of intersection of chain and chainring depends on which cog in the cassette has the chain on it.

 

[jond]

did i tell you i love round chain rings of any shape . they remind me of why i dont ride with expensive oval wheels

 

[DavidCH]

Love the Oval... Saved my knees and does the business. Works better with larger cranks than 155mm (as far as I can tell) but more swing on the front steering if the wind is howling.