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-   -   Front shifting with oval chainrings (https://www.bikeforums.net/showthread.php?t=1251700)

grissley 05-13-22 06:02 PM

Front shifting with oval chainrings
 
There are several threads already about oval chainrings (with no consistent conclusions, though). Anyhow, majority of them relate to 1x, while about 2x there is also inconsistent feedback about the shifting performance on the front. Some say it is hopeless and hard to regulate, the other say "just move the derailleur a bit up and it works like a charm" etc. Do we have any 2x oval users that could elaborate on how the front shifting actually works (in general and in comparison to rounds)? No Biospace, I just refer to modern derailleurs and Chainrings. Q-rings of Rotor interest me the most, but I guess with absoluteblack it would be the same.

cxwrench 05-13-22 09:31 PM

I've had ok luck w/ getting them to shift decently but I'll always blame them first if there are any problems. I've got a guy that I work with that tries all the wacky stuff. He's got a 10 speed wheel with some crazy alloy 11 speed cassette that I have to mess with every now and then. He's also drank the Koolaid with the oversize pulley cage bs. Never a dull moment working on his bikes. His rings (Q) do shift pretty reliably I have to say.

jolly_codger 05-14-22 05:32 PM

I have had absoluteBLACK 50/34 10-speed on two bikes for 3 years and I have never had any shifting issues. Like you mentioned, the FD has to be raised wayyyyyy up and when you watch the crank rotate it looks as goofy as all get out but it worked for me. For the record, I run Ultegra & Force FDs on the two bikes.

oris 05-16-22 09:42 AM

AbsoluteBlack user here. Running 50/34 rings on SRAM Red 22 and the front shifting needs to be timed well. However I'm not a fan of SRAM FD performance to begin with. SRAM FD's are temperamental as it finds the ramps while Shimano always works.

I have a 52/36 set coming in my for other bike with Ultegra so I'll see how those get on. However another riding buddy on Dura Ace Di2 and AbsoluteBlack rings was having chain drop issues this weekend when moving from the small to big ring. He's actually going back to round rings.

As far as set up, you will have to move the FD up and set the distance from when the ring is at it's highest point.

Hermes 05-20-22 10:47 AM

I had the Rotor Q rings 50/34. SRAM red manual. Generally, okay but the mechanics hate them and if there is any problem with shifting it is the Q rings. And that may be true.

I thought they were okay but power will be off by a couple of percent. Also, I race and train at the track so I did not want to train on oval rings on the road. In practice it took about a lap or two to adjust to round.

I was thinking about putting them back on but I am not sure that I can endure the flack from the bike shop mechanics.

JohnJ80 05-23-22 07:12 PM

I run Absolute Black oval chain rings in 50/34 on two bikes. IMO, they shift just as well, if not better than the Shimano chainrings. You have to follow their instruction to the "T" and the spacing over the highest point of the chainring at 1-2mm is critical. You can't just pop the FD up and see if it will work, you need to get it right and within spec.

The other piece that was really essential was making sure that chain line was perfect and correct. I had been having problems occasionally dropping the chain off the outboard side on really rough roads with round chainrings. And when I installed the AB chainrings, the ramps would tick against the chain when I was on the second cog in the back up from cross chaining. I spent a lot of time corresponding with AB's very helpful tech support and I wound up putting in about 1-1.2mm of spacers to move the crank slightly outboard. Man, did that make a huge difference! The bike never had shifted better.

I'm a fan of the AB chainrings. I really like them and I'm super glad I made the switch. My pedaling seems "rounder" and more fluid and is much more comfortable to me. I'm on the verge of some knee issues from a sports injury years and years ago, and this seems to calm down and help mitigate knee pain. But, as above, installation much be done precisely. It's not hard when you realize this and that they are not kidding when they give a spec on the clearances. And don't be surprised if your chainline is a bit out of whack wither. Can easily happen when the BB was faced for threaded BB's. A very small spacer paid huge dividends for me.

J.


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