super slim
Zen MBB Master
Rick
Thanks for copying to the cruzbike site as it is a very good review of bent chainrings!
,I thought as did Marc that this was a very interesting read.
********Below is from the BROL thread - permission given by seemark2 *********
This was posted by me, 3/7/'15 on BROL: (While still on the 1st 1000 mi. MBB learning curve)
http://www.bentrideronline.com/messa...96844#poststop
I have tested extensively the following on my M5 CHR:
1) Rotorcrank RS4X cranks
2) Rotor Q-rings
3) Rotor QXL rings
4) Doval rings
5) Osymentric rings
My criteria was solely which gave the highest speed average with the least exhaustion. Not too scientific, but that was my only concern.
Note: We don't have a lot of rolling hills in South Florida, but the course includes 4 large hwy overpasses, so gradients were included. I regularly ride this course twice a week with a group of roadies.
Note: I am not a "masher" with big powerful legs. I am a "spinner" and keep a higher cadence.
Rankings:
1) Rotorcrank RS4X - gave the best overall speed/performance ratio. Note: The cranks were blueprinted for max efficiency via Airwolf's friction reduction process.
2) Rotor Q-rings- About 90% as efficient as the RS4X, good for a normal/to higher cadence
3) Doval rings- Interestingly no "dead spot" as with the Osymetrics, but not index-able either, but overall gave good performance, almost as good as the Q-rings
4) Rotor QXL- Definitely for mashers or very powerful riders. Tended to be suited for lower cadences but definitely required more effort, I was more exhausted at the end of the ride. Note: Might be good for a MBB (moving bottom bracket) recumbent. I will give these a try again once I'm better on my Vendetta.
5) Osymetrics- The worst of the bunch. They do increase power somewhat, but exaggerate the dead spot, even more than just a round ring. There are riders who have gotten used to them but I found them inferior to any of the other four above
10/10/'15
Having ridden my Vendetta now about the same amount of time as my M5 CHR, I thought I'd post my findings on regular q-rings vs QXL q-rings. (The QXL rings have a more extreme ovalization than the regular ones.) Setting on both types of rings for the test is on the regulation point 2.
The course and conditions are exactly the same as was previously written, my conditioning has remained consistent for the last 8 yrs or so, for clarification purposes.
Note: Rotorcranks cannot be installed on a Vendetta, due to the bottom bracket mounts. So only the Rotor rings have been tested on the V. Doval rings are not indexable, so were not used on this test. The Osymetrics are also not indexable and gave poor performance on the last two rear wheel dr recumbents I tried them on, (Metabike and CHR), so I didn't bother with them either.
Initially I used round rings the 1st 500 miles or so while learning on the V, as I knew I did not have a baseline nor did I ride the M5 since riding the V, so my autonomic responses wouldn't get confused.
At 500 miles I did not feel I could power down hard yet, but had been riding in a paceline for a couple hundered miles.
Switching to the regular q-rings at 500 mi gave immediate smoothness, not so much as usual on the small (44t) crankring as on a rwd, but the large ring (53t) felt real good, better than when on the rear wheel dr. (I have used a 44/53 combo for the last few years, I found it quite suitable for the predominately flat roads we have here.)
For the next 1000 mi I found myself using the 53t gear as much as possible, the compensation is greater the larger the diameter I think. This is opposite of what I used on the CHR, I rarely used the large ring, only going downhills. (I can sprint up to 31 mph in the 44t ring before cadence gets too high) (Running 700c wheels, 11/28 rear cassette on both bikes)
That got me wondering if the Vendetta was just that much more efficient? To me it feels more efficient, mechanically or ergonomically, or maybe both, still not sure and the debate would go on forever no doubt.
I know the 44t QXL ring on the M5 required too much effort, maybe it would be the ticket on the V? So, I installed it about 300 mi ago. Immediately it was WOW! More responsive, smoother, AND more power! Much easier to maintain a higher cadence with less effort. My average speed is up about 1mph, I don't get winded as much going uphill, my legs are not as sore after a ride, nor do they take as long to recuperate. Win, win, and Win! It feels like a new bike!
Anyway, I thought I would share this with you all. Not trying to convince anyone of anything thing, and as always, your mileage my vary.
If anyone feels inclined to post this on the Cruzbike forum please, feel free, I can't log on anymore since they changed it without changing my email address.
Thanks for copying to the cruzbike site as it is a very good review of bent chainrings!
) on my Vendetta with double Q's. They seem to still be going strong, no chain slipped, no broken teeth, etc. I'm not sure how to check wear, but the way I think is; "if it ain't broke don't fix it". I may be wrong, but I don't see why they would not last as long as standard rings - I would imagine to get the most miles out of them, keep the chain in good working order waxed or oiled and replace it before it wears.
