Problems with Rotor Carbon Q rings and Sram Red crankset

Discuss light weight issues concerning road bikes & parts.
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AlgaeHater
Posts: 84
Joined: Sun Jan 27, 2019 2:53 am

by AlgaeHater

Has anyone successfully installed a set of Rotor Carbon Q Rings on a Sram Red GXP crankset? I'm trying to install these now and noticed that the drive side crank arm rubs against the large Q Ring. As a result you have to slightly bend the entire chainring to get all of the other bolts to install. This leaves the chainring slightly warped which is obviously not going to work.

Has anyone else run into this issue?
2019 Bianchi Oltre XR4 eTap
2019 BMC Timemachine Road 01 Di2
2018 BMC Roadmachine 02 Di2
2018 S-Works CruX 1X Di2

by Weenie


tabl10s
Posts: 571
Joined: Wed Aug 23, 2017 5:40 am

by tabl10s

Had Quarbon's on two cranks simultaneously(have switched to THM's)with no problems.
2015 Pinarello F8: 13.04lbs/5.915kg
2016 Rca: 11.07lbs/5.048kg
2018 S-Works SL6 Ultralight: 11.04/5.007kg
2018 S-Works SL6: 12.04/5.625kg

TobinHatesYou
Posts: 4624
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

It’s because the Qarbon chainrings are 5mm thick while most chainrings are 4mm thick. That doesn’t play nice with the hidden-bolt design. I asked Rotor if they would ever address this and they said no...they’re more focused on their own direct-mount system and 5-bolt 110bcd stuff is going to be an afterthought.

AlgaeHater
Posts: 84
Joined: Sun Jan 27, 2019 2:53 am

by AlgaeHater

TobinHatesYou wrote:
Fri Nov 01, 2019 5:33 am
It’s because the Qarbon chainrings are 5mm thick while most chainrings are 4mm thick. That doesn’t play nice with the hidden-bolt design. I asked Rotor if they would ever address this and they said no...they’re more focused on their own direct-mount system and 5-bolt 110bcd stuff is going to be an afterthought.
Thanks for your reply. What's really frustrating is that lists their Q Rings as compatible with Sram Red GXP cranks:

https://rotorbike.com/wp-content/upload ... rt-0.1.pdf

I wonder if this is an issue with the carbon Q Rings only. Do you know if the regular Aero Q rings have the same clearance issue? I may end up returning these and going with Absolute Black rings instead.
2019 Bianchi Oltre XR4 eTap
2019 BMC Timemachine Road 01 Di2
2018 BMC Roadmachine 02 Di2
2018 S-Works CruX 1X Di2

TobinHatesYou
Posts: 4624
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Regular aero Q-Rings are 4mm thick and will work with Red cranks. The Qarbon rings do work with some “Red” cranks...namely the BB386EVO and Quarq power meter versions because the separate spiders don’t have the same kind of hidden-bolt arrangement.

Be careful with AB rings...they don’t have anti-drop pins.

AlgaeHater
Posts: 84
Joined: Sun Jan 27, 2019 2:53 am

by AlgaeHater

Thanks Tobin. I'll try the regular aero Q-Rings and return the carbon ones.
2019 Bianchi Oltre XR4 eTap
2019 BMC Timemachine Road 01 Di2
2018 BMC Roadmachine 02 Di2
2018 S-Works CruX 1X Di2

AlgaeHater
Posts: 84
Joined: Sun Jan 27, 2019 2:53 am

by AlgaeHater

OK, after a bit of dremel work to shave off 1mm of thickness on the Q ring (the part that was making contact with the crank arm) we have success!

I was a little worried with the front deraileur shifting but after some fine tuning I'm pleased to report that the Q Rings seem to shift better than the factory rings. On the factory rings, the chain would often ride the tops of the teeth when shifting from small to big before settling into the chainring after a few revolutions. The chain seems to settle in place faster on the Q Rings.

I'm looking forward to spinning up some hills. I have an oval Wolftooth chainring on my gravel bike and like the feeling spinning the cranks when climbing in the saddle.

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2019 Bianchi Oltre XR4 eTap
2019 BMC Timemachine Road 01 Di2
2018 BMC Roadmachine 02 Di2
2018 S-Works CruX 1X Di2

by Weenie


Jugi
Posts: 593
Joined: Sun Jun 24, 2018 8:10 am

by Jugi

AlgaeHater wrote: I was a little worried with the front deraileur shifting but after some fine tuning I'm pleased to report that the Q Rings seem to shift better than the factory rings. On the factory rings, the chain would often ride the tops of the teeth when shifting from small to big before settling into the chainring after a few revolutions. The chain seems to settle in place faster on the Q Rings.
I'd say that was a fine tuning issue you had with the factory rings which most likely stems from FD's attitude. You can consider yourself lucky, if you found a very good FD position for the Q rings without any extra effort or test riding.

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