Jump to content

A gadget for the Inertia-conscious


Johan Bornman
 Share

Recommended Posts

Is this a viable concept?

 

Maybe on a flat road or track but not on a normal race.On a hill that's added weight to the wheel and the system isn't very aero either.

Then you have all the noise that will drive you nuts.

Link to comment
Share on other sites

haha. :rolleyes:

This is so funny.

JB, Remember I brought up a topic like this a few months ago?

Along with me thinking that ultra heavy wheels may be quicker along a TT course or something.

 

We had quite a in length debate when we finally came to the conclusion that lighter is always better, but you can in certain cases sacrifice a little bit of weight to be more aero.

Link to comment
Share on other sites

Won't work.

 

Agreed, wont work! If Johan posted this on the 1st of April it might have worked!

Link to comment
Share on other sites

This is what the website claims

 

post-4352-028176300 1280953152.jpg

 

"Riders experience the easy responsiveness of a lighter wheel during climbing" - How can that be, you have just added weight to your wheel? The weight is only centered around the hub at slower speeds, it didn't magically disappear

and yet feel the surge of added momentum when coming out of a downhill" - thats about the only thing of this theory that makes sense

 

Just put on a couple of kg's if you want to go faster downhill.

 

The next problem is that the distribution of the weights is based on the rotational speed of the rim, it does not take into account the actual incline of the hill. To many variables here.

Link to comment
Share on other sites

what about the weight - those are 42g per weight and they recommend 6 per rim (and here is the catch) PER SIDE!

that is 42g x 6 = 252g x 2 = 504g per wheel extra

That is 1.08kg extra

 

and that is why you need to read the fineprint!

post-4352-016189400 1280954789.jpg

Link to comment
Share on other sites

From Wikipedia

Due to the fact that wheels rotate as well as translate (move in a straight line) when a bicycle moves, more force is required to accelerate a unit of mass on the wheel than on the frame. To accelerate a wheel, total wheel mass matters less than the moment of inertia, which describes the inertial effect of the mass resisting acceleration (inertia) based on its location with respect to the axis of rotation (the center of the wheel hub/axle). In wheel design, reducing the rotational inertia has the benefit of more responsive, faster-accelerating wheels. To accomplish this, wheel designs are employing lighter rim materials, moving the spoke nipples to the hub or using lighter nipples such as aluminum. Note however that rotational inertia is only a factor during acceleration (and deceleration/braking). At constant speed, aerodynamics are a significant factor. For climbing, total mass remains important. See Bicycle performance for more detail.

 

So it seems their invention does have some merit, at least it keeps weight closer to the hub.

 

Look here for detailed analysis on bike performance with some maths thrown in. Ill just quote this bit.

 

In other words, a mass on the tire has twice the kinetic energy of a non-rotating mass on the bike. There is a kernel of truth in the old saying that "A pound off the wheels = 2 pounds off the frame."

 

Whether the kinetic energy gain on a decent will cancel out the extra weight on uphills is hard to determine.

Link to comment
Share on other sites

My thinking is, all this does is "absorb" energy/speed on the flats/downhills and "releases" it on the uphills, so you are really getting no gain. As with all systems there will be losses between the "absorbed" energy and the "released" energy(as in less aerodynamics in the wheels with these objects spinning around), so at the end of the day you will actually loose.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

Settings My Forum Content My Followed Content Forum Settings Ad Messages My Ads My Favourites My Saved Alerts My Pay Deals Help Logout