Absolute black a British company with production facilities in Poland sent us an interesting chain-ring to try recently. most chain rings are round, this one is oval. Oval rings have been around for a while with some famous riders being proponents of them. As it takes a while to test components like this we thought we would have a quick look first and then have a more detailed look at the whole oval chain ring subject at a later date once we have had enough time on the rings.
Made out of light weight CNC’d 7075 series aluminium the ring has an oval shape where the peak of the oval is designed to be set at ninety degrees to the peak spot of the pedal stroke. This allows the use of 32 teeth but with the ratio output of 30 teeth in teh smaller part of the stroke, which is ideal for our 1 x 10 set-up that we have first mounted on our Cannondale test bike. The rings are very nicely machined and have been hard anodised black to protect the surface of the rings. They are very slightly offset to allow the chain to pass behind the standard 104 bolt pattern and allow the chain to move behind the spider. The difference with this oval chain ring which made it leap out at us was the fact it uses a drop stop tooth profile instead of straight teeth. This profile is now becoming a standard on the trail when new rings are released. In theory the inherent pulsing and chain movement that can can cause a chain to jump should be mitigated by the use of these teeth profiles when used with a stronger spring on the rear changer mechanism.
On the Trail First Impressions
The idea behind oval rings is to make a system that gives a more constant power output when pedalling and eliminates the power dead spot at 90 degrees to the pedal arm. The first overall impression is that indeed this can be felt. There is less pulsing when standing on the pedals once moving faster than the slowest speed. At the slowest rotational cadence it can be felt back through the pedals that the ring is not completely round but once cadence builds slightly one is able to feel that the rotational movement is more constant in the pedals.
So did it make us pedal better? At this point in time we felt that power was smoother but we cant say it was significantly better, as by the very nature of where we ride when we ride the trails are rough and we have to vary the power input as we go upwards. The bike has to be picked up and moved over objects and rocks upwards, so it was harder to note the improvements, in our opinion at this point in time we thing that there might have been a marginal improvement in traction once moving, but at very slow speeds we feel the jury is still out on the improvement. Downwards we felt no huge difference that we could note made it better.
When on smoother tracks climbing we could feel there was a difference to a pedal force and leg movement, but again this was once the bike was moving somewhat, not at dead slow cadence speeds. This lead us to the conclusion that we need more time on this system to understand it. We know Absolute black as a company likes to push the designs of components to interesting places, in fact when this first arrived we were under the impression that it might be a prototype for us to try as we simply hadn’t seen a ring like this on the market, so we were open minded about trying it, although they are in full production and sold out which tells us that their popularity is taking off.
Drop stop teeth were one of the features that peaked our interest in this ring and made us fit it to the bike, as normally with an oval system some form of chain guide is needed. However when used with a type II x9 dérailleur we found that the chain stayed on with no guide. Despite our best efforts we did not loose the chain even over long descents and rough ground.
The Absolute Black ring is the first oval drop stop ring we have seen, and for that reason it interested us enough to try it. On a second note we had spoken to Fabian Barel some months previously about his use of oval chain rings and this started us thinking about the whole concept more. After the initial period of time on this system we have actually only been left with more questions and are interested in more why the oval system should be of interest and if it is valid off road? Some pro street bikers use them some don’t. There doesn’t seem to be a clear answer to their existence. The main point so far is that surely if they were really that good then every drive train brand would have it as a stable on their systems? This though is not the case. This short test has actually opened up a whole can of worms that we think is probably worth further investigation to see if there is any definitive answer and further time on the oval chain ring system .
Weight: 43 grams