Author Topic: AbsoluteBLACK sub-compact chainrings  (Read 923 times)

AbsoluteBLACK sub-compact chainrings
« on: December 23, 2018, 05:43:31 pm »
With bigger ranges available from rear derailleurs I've been mulling over the idea of a sub-compact (super-compact) to replace the triple I've used throughout my audax career but they are all seem to be limited in some respects - either lowest gear not low enough, or too expensive, or require a non-standard BB.  I've trialled an ersatz version using inner and middle positions of a triple crankset (the old 130/74BCD kind) and found a 44/28 front 11-32 rear (10speed) was not too far from where I wanted to be in terms of total range, but the chainguard on the outer position wasn't pretty, the chainline was not quite right, and some of the jumps are bit big.
Anyway I was talking gearing with someone at the AUK reunion who mentioned that it is now possible to get a smaller number of teeth on a 110BCD (the newer 4-arm asymmetric kind) by going OVAL :o
So I went out on a limb and used the best of the Black Friday deals to get an R7000 chainset and a set of 46/30 rings to fit it.   What with one thing and another I didn't get to try it out until yesterday, but first impressions are quite positive.  I did one of my regular loops, with a couple of stops to faff, no PBs on any of the hills, but overall time was pretty good (for me) and I formed the (unproveable) impression that the lactic build-up was slightly less pronounced than with similar cadence/similar effort on round rings.

More to come when I've tried them out on longer rides.

Re: AbsoluteBLACK sub-compact chainrings
« Reply #1 on: December 24, 2018, 06:53:23 am »
I use an AbsoluteBlack oval ring on my 1x bike. The biggest thing that struck me when I first started using it was that it felt no different than a round ring. Whether it helps on the steep off-road climbs I wouldn’t be able to tell, but it certainly doesn’t hinder me.

Re: AbsoluteBLACK sub-compact chainrings
« Reply #2 on: December 30, 2018, 09:08:56 am »
Just been for my first ride since fitting absolute black oval sub compact.  Bike is trek domain with Di2.
Removal of the old rings was really easy as was fitting the new rings.  I saw on one website that they had managed to fit the rings without removing the crank.  This is not possible with the subcompact rings. you do need to remove the cranks.

I took the opportunity to fit a new chain.

Rolling out of the drive I felt no difference.  Changing was fine.  Dropped the chain on one up change.  I was in the 11 cog at the back and changing from small to big the chain went too far.  I will adjust the limit screw and maybe drop the derailleur 0.5mm as I was perhaps a little large on my settings.

Climbing my local hill with a reasonable 12% section which i use as a measure the sub compact did what i wanted and gave the equivalent of another gear.  On my way back i had no problems with my limited sprinting!

I have an incline on the way back on which i like to practise keeping the legs turning circles whilst still maintaining a good power.  This definitely felt easier.

The oddest feeling was on spinning backwards when I really felt the ovality of the chainrings.

At the moment I would give them 10/10 and my setting up 9/10.

Re: AbsoluteBLACK sub-compact chainrings
« Reply #3 on: May 15, 2019, 12:55:01 pm »
More to come when I've tried them out on longer rides.

After a frustrating period when a ghastly creaking noise seemed to make an appearance with these (turned out to the BB, not cranks or rings after all), and the tweakage necessary to eliminate overshifting shifting on the up change, I'm now happy enough to take them out on BCM600 this weekend.  Just wish my legs were as well prepared...

More to come.

jiberjaber

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Re: AbsoluteBLACK sub-compact chainrings
« Reply #4 on: May 15, 2019, 02:15:45 pm »
Point of note for anyone searching / viewing in the future.

Absolute Black 46/30 rings fitted to Ultegra crank. After a year of use, creaking on power stroke.

After replacing BB etc finally traced it to symptoms only happening in outer 46t ring, silent in 30t inner ring. 

Remedied by removal of rings and a good clean of the spacers and crank spider holes. 

The way the spacers machined into the rings are constructed is that they allow a void which collects dirt (gravel dust mostly) over time - quite a lot in my case!  Once cleaned and refitted - good as new!
Regards,

Joergen