Review: Rollerblade Fusion 84

[azumi]

And wheels determine the length of the frames.^^

[Bebai]

True but the shorter the frames, the more maueverable...Don't get me wrong, Im not complaining abt the RB 10. It's just curiosity. I mean there's a significant difference btw 285mm frames on the RB 10 and 255mm on say seba or fusion 84?.

[azumi]

Bebai, I get your point, those 5mm gaps suck. Better swap the RB 285mm frames with Seba GT 90mm frames (276mm) since you own already 90mm wheels. Or even better Seba deluxe 976 frames (273mm = 4x90mm); although they cost a fortune.

http://bladeville.pl/p/frames/seba/seba ... 4x90-11177

[Bebai]

Lol...Azumi y are u anti 84mm?

[azumi]

I'm not against it. I'm just trying to rationalize here. Evidently 84mm is a poor marketing machine in order to tell the novice skate customers those skates are better and fast merely due to 84mm wheels. I mean, what did they change in the past anyway besides the colors? Not one thing! Since the increase of the ABEC numbers don't do it anymore.
The same applies to cameras. They tell people the more megapixel a camera has the better will be the image quality which is totally bollocks! The only things that really matter are, aperture, lens and the sensor size. End of story.

[Bebai]

Yea....lol. U do hv a point. In reality I'm only tryna justify buying a new pair of skates...il definitely consider frames for a change. I might hv to get it from the US though..Everything seems to b cheaper over there...
http://www.inlinewarehouse.com/Seba_GT_ ... GT276.html

[azumi]

Bebai, if you still want the 255mm frames get them. But don't expect much more speed from plus 2mm PU.
No need to justify yourself. If want new skates just get them. Life is short anyway.

[Bebai]

Lol...if I was looking for more speed, I would be talking abt 100mm. Jus tryna find a balance btw speed and maneuverability. I jus tot 84mm would b the answer. I totally understand what u mean though .

[azumi]

100mm is a killer! Don't get how people can roll with that unless they have huge, and I mean huuuuuuge, feet. xD
Whatever you choose, pls let me know about it. I'd like to know.

[Ozzy]

With skates, rolling resistance is approx. proportional to "surface roughness" divided by wheel-radius (unless the "roughness" gets "big", we're talking about a few mm's here).

This means that 84mm wheels gives around 5% less rolling resistance compared to 80mm wheels. 90mm give around 7% less resistance than 84mm wheels. Not that much, but probably already noticeable over a certain distance. Now from 80mm to 90mm is around 11% less, which should be quite obvious to notice. And 80mm to 100mm is around 20% (which is btw the same factor as moving from four 80mm wheels to five 80mm wheels). Also interesting: Riding on a strong rocker (with only two wheels on the ground) even doubles rolling resistance.

Of course all this ignores air resistance which starts to dominate at around 10-15km/h (depending on body posture and clothing) and goes up quadratically (it quadruples at doubled speed). So while bigger wheels gives you higher speed, the increased air resistance will starting to take its toll (so use tight clothing and deeper posture to reduce wind drag).

Stability is not unimportant, because it also costs energy to stabilize the skates with your feet (how much depends on your technique). That's the reason, fitness skates use longer frames than necessary: Because most people who buy them don't have good technique and need the stability the longer frame gives them.

But the main reason for bigger wheels is the reduced rolling resistance.

[azumi]

Ozzy, that all sounds scientific. What about the gaps between wheels have you considered that in your equation as well? Besides how do you know about rolling resistance? And why is it that I am with a rocked-setup (76-80-80-76) being faster than those with flat 80 to 84mm setups? I just recognized on a few skate nights. They keep pushing, I just roll and still I am faster.

[Ozzy]

Ozzy, that all sounds scientific.

Sure. And?

What about the gaps between wheels have you considered that in your equation as well

That only changes frame size (thus stability), not rolling resistance. So it's primarily important for beginners (or downhill - but I don't think, we're talking about that).

And why is it that I am with a rocked-setup (76-80-80-76) being faster than those with flat 80 to 84mm setups?

Perhaps because of your incredible strength. I also tend to skate with a rocker, but I've lost quite a bit of my speed when going a distance (I traded the speed for the greater fun). Also a rocker certainly feels faster.

I just recognized on a few skate nights. They keep pushing, I just roll and still I am faster.

It's probably your technique. Most people on skate nights in germany can't skate well, so it's easy to drive faster than most of them. You should pick out someone who is about as fast as you and then switch from a rocker to flat and see what happens. Or better: Pick a track, and measure your time both with flat and rocker, driving as fast as you can.

[Bebai]

I totally agree with ozzy Azumi....

[azumi]

What about the gaps between wheels have you considered that in your equation as well

That only changes frame size (thus stability), not rolling resistance.

Proof? Since you are so fond of science.

Bebai, you only say that 'cause you roll flat. Hence your opinion seems quite biased?

[Bebai]

Bebai, you only say that 'cause you roll flat. Hence your opinion seems quite biased?

Lol...I did try rockered once and it wasn't stable enuf. Dunno how one can gain speed with that kinda set up . Different technique I dunno abt?

[Ozzy]

Proof? Since you are so fond of science.

Do you despise science?

First: There are no "proofs" in science, you can only disprove things (by showing the opposite). That's part of the philosophical foundation of modern science.

Now why should frame length change rolling resistance? Rolling resistance only depends on the wheels (their size, material and the pressure on the wheels). Imagine a 1m long frame: Should a frame this long roll easier (or harder) than a frame with only 30cm length if nothing else has changed? Of course not. Now change the wheel-size from 80mm to 2mm. If your pavement has 2mm roughness, the thing wouldn't roll at all, but become stuck in the pavement.

Frame-length only matters if you turn, not as long as you roll straight forward. Turning is of course easier with a shorter frame. That's why people use 4x100mm wheels instead of 5x80mm wheels today: Turning is a bit easier with 4x100mm (30cm compared to 32cm with 5x80mm wheels for "zero gap").

The reason why 4 wheels roll easier than 2 is that the force on each wheel is halved and rolling resistance is also proportional to the downward force on a wheel. Thus rolling resistance is also halved.

It's even more complex, because you also have to consider things like "rebound", "churning work", "wheel profile", "wheel hardness" etc. But those depends on the material of the wheels, and so lets just assume using the same wheels and that those things doesn't change much when going from 80mm to 90mm.

[azumi]

Lol...I did try rockered once and it wasn't stable enuf.

Well, it's a slalom setup. Best maneuverability possible. Certainly, better use a flat setup for downhill and fullspeed (holding on to a car or motorbike).

Ozzy, I'm a believer hence science is witchcraft for me. So basically you are saying, the glass is not half full, but half empty? Whereby I would say, the glass is twice as big as it needs to be. And that's the part where the witchcraft comes into play.

Let's say there is a deep pothole in the street. Its diameter is round 84mm. You roll with a flat 80mm setup. What might happen when you roll over the pothole?
Your toe-wheel get stuck in the pothole? You lose balance, you stumble and you kiss face the concrete?
Now let's assume you roll over the very same pothole and get stuck again but with a rocked setup (76-80-80-76). What might happen here?
Your second wheel after the toe wheel get stuck in the pothole. Due to speed your toe wheel will be forced to touch the ground which subsequently levers out the wheel that got stuck in the pothole and this saves you from kissing the concrete.
..think about it.

[inkh0rn]

I've tried rockering a couple of times, have just rockered my FR2's to try slalom again (with big thanks to dodgy, t@rty & conekicker from Southport for their top tips & enouragement ). I have to say that I find rockered wheels are much 'keener' to roll and gain speed than flat - for example, I often spin stop, and on rockered I find myself spinning way faster than on flat, to the point of where I nearly go flying off .

Riding on a strong rocker (with only two wheels on the ground) even doubles rolling resistance.

Of course all this ignores air resistance which starts to dominate at around 10-15km/h (depending on body posture and clothing) and goes up quadratically (it quadruples at doubled speed). So while bigger wheels gives you higher speed, the increased air resistance will starting to take its toll (so use tight clothing and deeper posture to reduce wind drag).

Sam Tuffnell set off a UK speed camera doing 30mph+ on aggressive skates with an antirocker setup! You''ll have to search that on YouTube, I can't find the link.

Theories, anyone?

[Ozzy]

@inkh0rn:

You probably talk about: http://www.youtube.com/watch?v=W9e-txPOoEw

An anti-rocker on small wheels is very stable. That's the reason aggressive skater use this setup, because for aggressive skating stability is much more important than maneuverability. So it's possible to drive high speed. At those speeds air resistance dominates, so it's more a question of posture than wheels. Also it was downhill and the street seems to be quite smooth.

Rolling resistance depends on the surface. On a smooth surface, wheels doesn't matter as much as on a very rough underground because it's the ratio roughness/wheel-diameter which counts (there are also other factors). For very smooth surface, wheel diameter isn't really important. But most people drive on varying surface which is often quite rough. And there a bigger wheel diameter can make driving easier. If you go from a smooth surface with 0.1mm roughness to a rough surface with 2mm roughness, the rolling resistance increases approx. 20-fold.

That "rockered wheels are much 'keener' to roll and gain speed than flat" is probably because of sub-optimal technique: It's much easier to correct little mistakes with a rocker because turning is easier. So if you hit the street at a slightly wrong angle, it's more easy to just turn the skates a bit during the movement compared to a flat setup. If your stride is correct, this wouldn't matter.

(@azumi: If you don't have anything to say, just don't, instead of always replying compulsively)

[inkh0rn]

An anti-rocker on small wheels is very stable. That's the reason aggressive skater use this setup, because for aggressive skating stability is much more important than maneuverability. So it's possible to drive high speed. At those speeds air resistance dominates, so it's more a question of posture than wheels. Also it was downhill and the street seems to be quite smooth.

Trust me Ozzy, UK streets (especially main roads like that one) are ANYTHING but smooth. The asphalt tends to have bigger chunks of stone in that I find teeth-rattling even on 80mm wheels. I really don't know how he got those speeds up on a UK road, downhill or not - 57mm wheels? Rough asphalt? He's superhuman!

There's another video of the state of his wheels after the attempt - chewed . Mind you, at the roller rink I often skate at, skaters regularly achieve speeds of (so I'm told) 30mph on quad skates with 57mm Belair Hockey wheels, albeit on wooden floor - so size isn't everything, it seems .

That "rockered wheels are much 'keener' to roll and gain speed than flat" is probably because of sub-optimal technique: It's much easier to correct little mistakes with a rocker because turning is easier. So if you hit the street at a slightly wrong angle, it's more easy to just turn the skates a bit during the movement compared to a flat setup. If your stride is correct, this wouldn't matter.

I should have clarified: when transitioning forward/back and spinning/turning etc is what I meant, not so much 'normal' forward or backward skating. My fault. In any case, I find rockered much more unstable for forward/backward skating, and that I need to be much more precise with setdown than on a flat setup - unless my balance is spot on when skating rockered, then it quickly becomes VERY unstable...so I find flat to be much more 'forgiving' in that respect. I find it strange that many skaters on here talk of rockered as more 'forgiving.' Maybe when you're a really good skater with solid balance - not in my just-post-gumbie experience!

However, I find it much easier to roll for a distance on one foot on rocker than flat! Weird.