Tioga releases ultra-thin axle-less mountain bike pedal
While many mountain bikers like so-called "clipless" pedals, in which cleats on the bottom of their shoes click in and out of a mechanism in the pedal, others prefer the unfettered feeling of platform pedals. Generally speaking, the two types of pedals are about the same thickness. Given that platforms don't need to contain any springs or other cleat-retaining gizmos, however, they could be much thinner ... if only it weren't for that axle running through them. Well, Tioga has done away with the axle, in its new ZEROaxle MT-ZERO pedal. At a maximum thickness of 7 mm, it's being billed as the "world's thinnest dual-concave mountain bike pedal."
The pedal is attached to the crankset via the company's ZEROaxle bolt assembly. Like a traditional axle, the assembly screws into the crank, and contains sealed cartridge bearings that allow the pedal to rotate separately from it. The ZEROaxle's bearings, however, are twice as large as those usually found in traditional pedals, and can reportedly withstand five times the dynamic load. This is a necessity, as the pedaling load is concentrated on the bolt assembly, instead of being spread out along the length of an axle.
The bolt assembly and pedal platform can be separately replaced, as needed.
While the one-piece chromoly steel pedal itself is 7 mm deep at its thickest point, that number goes down to just 4 mm in the middle, as both sides of the platform are concave. This thinness minimizes the chances of pedal strikes against trail objects such as roots and rocks, and is also said to increase pedaling efficiency, as it places the rider's foot closer to the center of the pedal.
Although some riders might question how much abuse such a thin pedal would be able to take, Tioga maintains that its product has been "tested to handle a wide spectrum of off-road applications from XC to all-mountain." Hmm, we'll see ...
As has been pointed out on BikeRadar, a similar product already exists in the form of MomentumBicycle's FlyPaper pedal. It, however, can only be used with the company's own crankset - by contrast, the Tioga pedal's 9/16" thread allows it to be mounted on a bicycle's standard, existing cranks.
ZEROaxle MT-ZERO pedals weigh 450 grams (15.87 oz) per pair, and should be available within the next month-and-a-half at a suggested retail price of US$99.
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Or maybe it\'s a single bearing of the needle roller variety, or even a single sleeve bearing - ceramic or nay - dunno.
It\'s an awful lot of force, on a very great leverage ratio, into a very short bearing......
All my experience, all my engineering, all my designs - everything to me says that his is not a good idea.
That\'s not correct. The load may be gathered by the axle but it still ends up at the bearing either way. All this design is really doing is taking the load on the pedal itself instead of the axle. So the strengthening needs to be in the rectangular part of the pedal not the bearing.
That\'s not to say that it\'s not an improvement over a pedal with an axle. Just saying...
You\'re incorrect. With conventional pedals, the load on the bearings is almost entirely radial (vertical). With this design, there are massive bending loads on the bearings, something that is nonexistent on regular pedals.
It\'s really nothing new anyway. Over 30 years ago, Shimano did something similar with their Dura Ace AX group. It put the bearing inside an oversized threaded stub which would only fit the AX crank, since it needed a far larger hole than normal 9/16\" pedal axle. That and other functional problems made the AX group a failure. But it allowed the AX pedal platform to be below the center of the pedal axle.
This has changed the power transmission from a cantilever beam - with the bearings operating on a beam supported at each end - with NO leverage on the bearings;
A cantilever beam, with the bearings operating under cyclic load reversal, under enormous amounts of leverage or force multiplication.
The bearing (however it is designed) has to both keep the pedal axially aligned along the center, AND not get torn from it\'s socket.
Assuming the bearing has a 1.5cm length - and that the pedal or cantilever beam has a length of 9cm to the center of the load application - of a 120Kg rider pushing hard - giving say a 200N force, then that is a multiplication of 6 - thus making it a 1800N side loading on the bearing.....
I cannot think of a better way or a more self destructive design - for a bearing than this.
Now I am not saying the design is wrong, or that the bearing and mount is incapable of handling the load - but if I wanted to remove a short shell bearing from a casing - with no care for the amount of damage caused - then the use of a strong steel rod and plenty of side leverage - if that is all I had to get the bearing out - then I would absolutely destroy the bearing and damage the casing.
It\'s why crowbars work so well on shifting big rocks or prying things apart or separating things like doors from door frames.
LEVERAGE - and this design has an awful lot of it, on a very high ratio - against every bearing design I have ever known.
It reads, \"Slow motion hand grenade\"