A4 scale = 70%
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A4 scale = 70% |
EGGring Ovals page 3
Nothing. Round rings remain a good choice if you always spin your pedals fast, working flat-out all the time. This is how road racers often ride, keeping on the very edge of their anaerobic thresholds - if you ride like this then stick to round. But most cyclists keep something in reserve and only push their hardest when absolutely necessary, which is when an Oval could help.
Ovals also make it easier to maintain traction on slippery surfaces offroad, because they deliver power to the rear wheel more smoothly, by reducing the stop-go effect which is so pronounced with round chainrings.
Many riders mix round and Oval chainrings on their chainsets (see 'Ovality').
You may notice a difference at first, just like when wearing a new pair of shoes. But after that your pedalling will feel perfectly natural - you may simply notice that it's easier to climb hills.
Several riders have told us they didn't notice any difference until they tried round rings again, and that these felt dead in comparison. That's when they finally realized what Ovals are all about!
The shape of your chainring doesn't alter the mechanical efficiency of your cycle one jot. But Ovals allow you to pedal more effectively by changing the gear ratio, continuously, to match the output of your legs better. You will climb hills easier but are unlikely to be any faster on the flat.
Your rear mech will work normally but you may need a larger front one (see 'Front derailleur capacity').
Ovals are particularly helpful on recumbent cycles since the dead-spots are more noticeable and you can't push harder by standing on the pedals. But an Oval designed for an upright bike won't work on a recumbent as its orientation will be wrong.
Yes, and you won't need a chain-tensioner if the ovality is less than about 15%. But, to be safe, don't exceed 10% with fixed-gears.
Ovals were invented in the 1890's and brands such as Thétic and Elan were used by time-trialists in the 1930's. But Ovals don't lend themselves easily to mass-distribution because of the large number of variations that have to be catered for, so the big manufacturers tend to only make round chainrings.
Unfortunately Highpath can't begin to compete with the advertising budgets of the large manufacturers. Nevertheless we do have many satisfied customers riding our Ovals all over the World - literally!
Shimano gave all Ovals a bad name in the 1980's by orientating their 'Biopace' rings back-to-front. This gave an even higher gear to push through the dead-spots! Today's Osymetric and Q-rings are much better, although only EGGring Ovals are available in the thousands of different sizes, ovalities and orientations to suit every rider. See 'Oval history ' for a summary of Oval rings from the 1890's to today.
Over the years several other devices have been offered in the quest to increase the efficiency of cycle transmissions. Some of them appear to work, some make no difference at all, and others actually make matters worse. Note that any increase in mechanical complexity inevitably reduces the overall mechanical efficiency.
Since the smallest Oval that will fit your cranks will be a few teeth larger than the smallest round ring, you may be tempted to increase the number of teeth. However we would advise reducing the ovality instead, a lower gear taking precedance over ovality. Better still, choose a crank which allows smaller chainrings - these will allow you to specify larger ovalities.
| © Chris Bell, 2007 |
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| HIGHPATH ENGINEERING Cornant, Cribyn, Lampeter, Ceredigion, SA48 7QW, Wales, UK phone / fax: +44 (0)1570 470035 (UK office hours only) email: 
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