Q ring upgrade - Ahhhhhhhhhhhhh......

[BJ686]

Thanks Ratz. I ended going back to square one and then reinstalling with the rotor instructions. As you alluded to, I ended up with the "lead" bolt shown in your picture at the "4 dot". This also turned about to be fairly consistent with the geometry in the diagram I referred to above, so I think I am good to go. Thanks again, Brad

 

[Brad R]

I bought a 4 bolt 104bcd crank for my T50.

I was concerned that I wouldn't be able to find oval rings that could be aligned properly since most oval rings with alignment flexibility come in 5 bolt patterns with larger diameters.

I found Fouriers oval chainrings on eBay. I chose 40 tooth. They have a wide range of tooth counts available. It arrived in 10 days which was 6 to 36 days earlier than estimated.

They have 3 different alignments possible so I could get it pretty close to

I mounted it today and took the bike for a 30 mile ride. It felt very comfortable.

If anyone else has 104bcd 4 bolt cranks and wants to try oval, here is a link.

https://www.ebay.com/itm/272333102671

I would post a picture, but the chainring is mostly hidden by my bash guard.

I did notice some vibration at high torque in 11th gear. It felt like it was probably at chain link frequency and occurred about twice per revolution at the peak torque points of the pedal cycle. I have never had oval rings on a short (normal bike length) chain. Is this normal?

I have a Shimano shadow derailleur. I mounted my crankset with chainline a few mm closer to center because the nominal mounting had too much chain bend when on the 46 tooth cog.

Any suggestions for getting rid of the vibration?

Thanks.

 

[ccf]

On a V20 90% of people can just use this bolt here as the reference bolt and use the factory dots. Most use start with the "four" dot positioned on that bolt.

Is the alternative reference bolt marked in the photo in factory position #5?

 

[ratz]

Is the alternative reference bolt marked in the photo in factory position #5?

In more cases if you put "4" on that bolt that leads the crank arm; that's equal to "2" on a Upright.

 

[Jeffrey Ritter]

Newbie question on an amazing forum. Anyone installed Q rings with SRAM eTap controls? Any reason to be concerned Q rings would not work with eTap?

 

[Bruce B]

I have a 50 Q & 36 QXL set up with SRAM eTap. Installation was straight forward and has worked beautifully.

 

[ratz]

QXL 50/38 works like butter with Etap

 

[ccf]

What's a good starting point for QXL rings on a S40? Do the settings that apply to a V20 also apply to a S40? Is factory position 4 on the bolt that leads the crank arm a good starting point?

 

[ratz]

Don't think anyone knows. But if you follow the photo protocols we did for the V20/S30 I'm sure we can figure it out for you.

 

[DavidCH]

This is an interesting subject. I have changed to a long chainstay so my boom is more horizontal. I have a curved slider so my bars are as low as they possibly can be (but still not as low as Larry's). I find now that it is more difficult for me pushing off on a hill start and so am thinking of adjusting the oval chainring to compensate the situation. Which way does the oval chainring need to rotate and by how much. I frigging woke up with this idea at 4 in the morning and can't get back to sleep. Any ideas?

 

[ratz]

Photos needed of the dead spot to answer

 

[DavidCH]

Here's the pic... as usual I've jumped the gun a bit and swapped over to my QXL chainrings. They cost a bomb so why not use them? I'm a little unique. My strongest leg is my right but I prefer to lead with my left. So my left leg is always the one to push off and be clipped in.

 

[Bryan H Walker]

I have been looking into putting a set of oval rings on my Vendetta. They have stopped offering the QXL. Should I just go with the Q-Rings? or try to find a set of QXL rings?

 

[ratz]

I have been looking into putting a set of oval rings on my Vendetta. They have stopped offering the QXL. Should I just go with the Q-Rings? or try to find a set of QXL rings?

They use to do 10% in the main product, because that made OCP work on BCD130 with tons of settings; then when they went to BCD110 they lost all but 5 positions. The 16% was the next logic optimization of that if only going to have 5 positions and mount to 110 BCD leading to QXL. With the shift to the Infinite direct mount spiders they went to 12.5% which they "claim" is the size they always wanted.

The QXL is still made but it's considered legacy.

For me 10% always seemed too little and 16% too much I like that they are splitting the different with the new 12.5% reports on how it works to follow.

 

[Andrew Wilson]

Reviving and old thread to show my initial setting.
Crank is at my dead spot, OCP #2 is in the fwd chainring hole like others have theirs set and the Min Dia is marked with a sharpie and is just engaging the chain roller.
I think this is correct ? Thoughts ?
I left the 39 as a round ring and I must say at the same speed and RPM The Q ring does feel smoother than the round.
I would switch back and forth between the 2, shifting the rear to maintain cadence and speed and could notice a difference.
Time will tell.

 

[castlerobber]

I think this is correct ? Thoughts ?
I left the 39 as a round ring and I must say at the same speed and RPM The Q ring does feel smoother than the round.
I would switch back and forth between the 2, shifting the rear to maintain cadence and speed and could notice a difference.

If it feels good, it's probably right. Ride it as-is for a while. If your knees start to bother you, or you feel like the max diameter should come a little sooner or later in the pedal stroke, adjust the ring by one OCP #.

I had 50/34 Q-rings for years. The 34T is so small that it's barely even ovalized; it might as well have been a round ring. A few months ago, I swapped the 34 for a 36 QXL (both larger and a higher % ovalized). It feels way smoother, much more like the regular 50T Q-ring.

 

[Brad R]

I have a 4 hole chainring. When I put my bike back together after getting home from Sebring, I put my oval rings on 90 degrees offset from where they should have been. This is, of course, the worst that you can make it.

I didn’t really notice it as “wrong” when I was riding, but I did feel like I was having trouble finding the right gear and my knees hurt that evening much more than they should have. It occurred to me overnight that I might have put the chainring on wrong. Sure enough, I did. Once I fixed it, everything was more comfortable and my knees didn’t hurt.

I might have had the chainring in the same wrong position on my century at Sebring. My knees hurt more than I expected after the ride. Maybe it wasn’t just the lack of training.

I should have done a better job of documenting my orientation before taking off the chainring for shipping.

 

[ratz]

The Data is in; for N=1. Thank you Garmin Vector Pedals.

Power Phase starts -65degree
Power Phase ends +155 degrees
Regardless of effort 215 degree of smooth power

Data on smoothness and left/right balance probably tainted by being mounted in a trainer...... to be continued on the outdoors roads eventually.

 

[Mathew Fy]

The Data is in

Didn’t you switch to Rotor’s new Aldhu cranks and direct mount chainrings? I’m curious how that went. Do you think their power-meter cranks give the same data for those who want more choices with pedals?

 

[ratz]

Didn’t you switch to Rotor’s new Aldhu cranks and direct mount chainrings?
I’m curious how that went. Do you think their power-meter cranks give the same data for those who want more choices with pedals?

Yes I went with the 150mm, Aldhu on 30mm and it worked well; they are light, and stiff; so good I will change them on the other bikes even though I have working solutions on them.

Power meter is mostly a function of what do you want to do with it. I'm using the dual sided vectors because I wanted access to cycling dynamics left/right to answer question about q-ring timing and other old lingering questions.