Rockered Chassis or similar

**MDE3** · 02-10-2003, 06:45 PM

It is my understanding that the skate manufacturers for inline hockey decided the inline hockey industry needed something that more closely simulated an ice hockey skate. To this end the "rockered chassis" or it's similar concept - the Mission Vibe - all were supposed to be a quicker turning skate that more closely simulated the feel of ice skating than anything else out there.
Having wrestled with grip, turning and acceleration problems on different surfaces for many years with all different kinds of chassis and wheel combinations, one thing became evident. The more and stickier rubber (or polyurethane variant) that meets the road - the faster you will go and the better you will stop. Whatever gain in the turning radius might be gained by having only 2 or 3 wheels in contact with a skating surface was usually more than offset by slippage from less grip.

Learning to skate for roller has some subtle differences from ice. Keeping your weight over the wheels can be one of the most important elements. When turning hard you may have to project your hip into the turn more while keeping your upper body more over the slates. This accomplishes your "bite" and allows some controled slippage while still keeping the maximum weight on the wheels. The more grip you have, the harder you can push and the faster you can go - whether in a turn or in a straight line. If you lean your entire body into the turn as you can on ice, while still having your "edge" to prevent slippage(again on ice) the average roller player will go down. Watch the elite players skate. The good skaters accomplish their turns by technique, not by some trick of the skate. Rapid turning in inline hockey is accomplished more with the skate in the air, than the one in contact with the surface - as in ice. Look at the hop in the step of the good players in inline hockey.

No matter how close the skate may seem to simulate the feel of ice - it never will, because there is no "edge". The feel is different. Although a good ice skater can become an excellent roller skater and vice versa, they must learn the difference. Many elements are the same in the stride, but the "feel" is definitely different. Time(practicing) not machinery will correct this.

**DannyG** · 02-10-2003, 07:40 PM

Oh, that is the best detail of the situation that I have heard yet...good job, and obviously a ton of thinking about the game...

I would only add what I hope is a "statement of the obvious:" It is the energy transfer from the skate to the playing surface is the difference between the two.

On either surface, you MUST have friction to "push" force backward against, which causes your body to go forward. (Okay, all you guys stay with me here...)

On ice, you must dig in, with a cutting force with at least one force vector perpindicular to the ice surface, in order to create a force transfer vector against the ice (the dig). You must also have a second force vector backward (the push), so you will glide forward.

On wheels, the force of the wheels against the surface already has some friction, so less of the perpindicular vector is needed needed for the propelling motion. In fact, and we call 'em "hippy-hops," you could propel yourself forward by just the force from the toe wheel against the floor, all by itself. No need to turn the blade sideways at all to create the initial force vector to get going. You can't do this on ice. This allows a high economy-of-movement force/energy transfer on wheels that ice can't have...which is really cool.

Now, don't any of you wise guys out there go "Huuuuuh?"

"Because you can push on the floor without diggin in, you can skate more efficiently on wheels," that's all I am proposing here...

Incicentally, because you must both dig and cut on ice, and you don't have to dig on wheels, this is why novice ice skaters coming to wheels at first "tromp" on the floor. We say they "frankenskate" to start with, until they learn they don't have to use so much downward force.

**columbus_RHstar** · 02-10-2003, 08:02 PM

DannyG,

Those are some good points for people just learning to play skate on inline skates, wether they started on ice or this is their first tiem of any skating. But dude to think of all that you must have an awful lot of free time to think that stuff up.

**missionhockey21** · 02-10-2003, 08:06 PM

Either that, or they are a heck of lot more knowledgeble than I am.

**columbus_RHstar** · 02-10-2003, 08:12 PM

Hey I'll admit that all the geometry stuff comes alot easier if I think of it in hockey terms.

**DannyG** · 02-10-2003, 11:33 PM

Yeah, since you asked....

1. Since being an inline hockey facility & program administrator is my job, this is all I do...

2. The subject I got the absolute worst grades in high school is the one that I use the most in my job...(geometry)...either the Math Gods or the Hockey Gods are laughing at me...

**MDE3** · 02-11-2003, 12:44 PM

Lol note... my son was the worst offender in reverse. When he went to ice - you could hear him skate in the parking lot. The reason was that our inline floor - where he learned to skate was so "gripless" that he had developed a habit of driving his wheels down hard on the surface to increase his grip (technically - compressing the wheels to create more contact area between the wheel and the floor) It was a great testing ground for proving which wheels would grip and which would not. I have the healed ribs, nose and thumb to attest to this constant testing of our old floor "envelope" lol

Edited by MDE3 on 02/11/03 11:52 AM.

**MDE3** · 02-11-2003, 01:20 PM

I think just a lot older lol(sorry Danny - I speak for myself) - you get a chance to look at that stuff when you are trying to elevate your hockey programs over a period of years. Note - take 3 strides and coast on inline floor and skates, then do the same thing on ice if you can. See how much farther you glide on one or the other. Inline takes much less energy to travel the same distance as ice, or you will find you go much farther on inline skates than you coast on ice for the same amount of energy. Most of the differential is caused by the "rocker" shape of the ice blade which will penetrate more into into the ice creating "drag". While the rockering of an ice skate allows for a shorter turning radius it will increase skating resistance and can actually reduce speed a little and certainly uses up more energy - in exchange for better manouverability.

Just look at the difference between "speed" skates and hockey skates. Speed skates (ice ) are much flatter and longer blades - flatter for less drag, and longer for greater push(leverage)per stride. Similarily the longer blade used in speed roller skating is used to increase the push, along with the larger wheels used to reduce the rolling resistance and increase the grip. This reduced resistance becomes very critical in energy saved over the longer races in either discipline.

The whole selling of the "rockered" inline skate, is a "come-on" which actually tricks the ice hockey player into feeling that inline skating is more similar to ice skating than it really is. The percieved advantage is only there at the beginning, and once the player becomes familiar with the different dicipline - they will find that the "rockered" chassis, or "Vibe" (same concept) is actually a hindrance not a help.

**DannyG** · 02-11-2003, 03:39 PM

not to go off on too much of a tangent, but I think where this really applies is to goalkeeper skates, and I thnk everybody has it backwards...

on ice, where stability is paramount, the flat skate blades on goalie skates enable to goalie to get more push on side to side movements.

when 'keeper skates came out for inline goalies, the manufacturers attempted to imitate this factor with smaller wheels, five wheels, straight line surface contact.

-however-

I would think that manueverability, NOT stability is the overriding factor for inline goalies! I would think that fewer wheels, and a rockered presentation to the floor surface would increase the ability of the keeper to mauever and turn on the plastic floor.

I have not really seen any evidence of this either way, but that is what my sense tells me...

**MDE3** · 02-11-2003, 11:26 PM

The flat skates on goalies blades are for sliding sideways on ice - and that has more to do with the grind and balance for and aft stability as well as being better able to push back up off their toes. Goalie skates on ice are generally ground fairly dull(shallow radius honed edges)on the flat of the blade and sharper on the small front radius of the blade for push. Ever see an ice goalie go to slide sideways when the new kid in the shop ground his skates? It's pretty funny. (Bye the way speed skaters use a flat blade with an deep ground radius (hollow radius now)to offset the lack of rocker assisted bite.

Wheels on goalie roller skates are typically a much harder compound than used for forwards or defencemen, and the small diameter wheels have less contact area - both factors to insure that they have less grip to permit sliding. Obviously a goalie needs to push off too and needs some grip - making for a variety of different problems than those skating out - like you observed.

With so many goalies using the butterfly - I would assume that more grip is needed to push back up to vertical than used to be true so grip may be even more of an issue and sliding sideways easier may become sacrificed. Your suggestion for using a rockered blade for goalies might have some real merit given these different needs. Maybe just rockered in the front not front and rear with the two front wheels being grippy and the rear wheels being harder for sliding.

**DannyG** · 02-12-2003, 12:14 AM

the above are excellent points...and a good indicator that when Rob Laurie said, "they haven't finished writing the book yet on how to play inline goalie effectively," he was right...