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| Q&A: McKendry on Speed (1810 Posts)
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slow wheel size
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On 10/12/2005 herbn
wrote in from
United States
(64.12.nnn.nnn)
people seem to win races on every available size of DH wheel, it
's not like the guys who spend the bucks on 100mm wheels win every race.SO if there are races where 76mm wheels or even 70mm wheels beat out the big guns,you're not limited to losing speeds with smaller wheels.If a hill looks to fast don't start at the top,or work on carving techniques ,and sliding turns, and get the speeds down that way,get slow bearings, stand up tall,wear an oversized windbreaker jacket and big parachute pants.
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Wheelsize & going *slower*?
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On 10/11/2005
nathan
wrote in from
Canada
(24.235.nnn.nnn)
This may be an bizarre question but, I'm trying to overcome my ignorance so here goes:
Exactly how much difference will wheel size (for same durometer wheels) make in terms of speed? For some hills beyond a certain steepness, carving, footbraking & other attempts to slow down notwithstanding, I find myself going... too fast for my comfort. (yes I'm going to learn how to slide)
I'm not really into longboarding for the speed aspect -- I just want to enjoy carving around in a controlled fashion. But there's not a huge selection of different steepness hills where I live. If I move down in wheel size (e.g. from 76mm to 70mm), will it make a huge difference in terms of the top end of my velocity? I don't mind going at a decent clip, but sometimes it would be nice if I knew that my top speed was... capped in some way...
Thank you for your response. I hope this question isn't too ridiculous (since it seems to be the opposite of the original forum intention).
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chaputs'trucks
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On 10/10/2005 herbn
wrote in from
United States
(64.12.nnn.nnn)
I think cc has shown a liking for jimz's in the past, not the 10mm axles though, why would he? no biltins in 10mm ,yet.
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56 in the rain past a copper in salem, OR
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On 10/10/2005
david
wrote in from
United States
(192.211.nnn.nnn)
chris the big wheels dominated last saturday at the top speed challange in salem, OR. sean won on the old 101s, dave B who got third was using brand spankin new 97 flys and I managed to keep up with them on gumballs. the green looks so much better in the rain when its all clean and shiny.
check the video here.
http://academic.evergreen.edu/p/pridav25/sk8movies/Top_Speed_Challange_low_res.mov
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Speedtrucks
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On 10/9/2005 Dennis
wrote in from
Sweden
(83.250.nnn.nnn)
Hi Chris!
Which of these 3 trucks would you recommend for speedboarding.
1. Jimz with his own baseplate and 200/10mm axel, 173/8mm axel.
2. Maguns Speedtruck
3. Radikal Dragons Talon
4. Randals comp II (170 or 205mm hanger)
Would really appriciate an answer!
Btw, I just find out the joy of sliding gumballs, I have always thought that those wheels wasn´t for sliding, but the 88a sure is..like the way the wheels kickback after a slide.
Thanks for making such great products.
You don´t happen to know where I could get hold of a set of 74mm/78a flywheels and 101mm/78a flywheels?
Thanks again!
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bearings
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On 10/8/2005 a person with out knowlege
wrote in from
United States
(206.135.nnn.nnn)
what's a good bearing?
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Pairs
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On 10/7/2005
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
We'll sell pairs of any wheel on Abec11.com, but we ship everything to our vendors in packs of four. Even the most slalom-like wheels (ie, Grippins) are packaged that way. If you want to buy from a store, let them know that we'll sell'm by the pair to them.
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ONE MORE THING
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On 10/7/2005 KLUDYMAN
wrote in from
United States
(68.111.nnn.nnn)
60MPH PLUS STAND-UP RULES!!!!!!!!!!!
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I FEEL THE NEED FOR SPEED
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On 10/7/2005 KLUDYMAN
wrote in from
United States
(68.111.nnn.nnn)
HAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAH!! !!!!!!!!!!!!!!!!!!!!!1
LETS DO SOME TESTING AFTER THE HOLIDAYS BRO.
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Gumballs by the pair
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On 10/7/2005
Chris P
wrote in from
United States
(24.10.nnn.nnn)
Chaput, this forum rocks. I'd just like to tell you that before I ask a silly question.
How come Gumballs aren't sold by the pair? I do love Gumballs but can't really justify buying two sets to run split duro.
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Maryhill 2006
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On 10/7/2005
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
I'll keep an Eye out for you. And yes, four very wide wheels. In the mean time, I'll be cookin' up some more speed in the lab.
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rocks
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On 10/7/2005 me again
wrote in from
United States
(67.100.nnn.nnn)
see you again maryhill '06. 4 wheels down this time...
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green crack rocks
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On 10/7/2005
david
wrote in from
United States
(67.100.nnn.nnn)
damn chaput, you always keep coming out with new stuff, you got me hooked on that green like a crack fiend.....i remember the first time i tryed the new flywheels, i was blown away by their traction, speed, etc, can't wait to see what you are up to now....
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Oops
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On 10/7/2005
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
I knew that I shouldn't have said "sluggish". Here's what I meant by that. The Gumballs are a massive wheel. Not in its height (although 76mm is pretty big for a skateboard wheel), but in how much urethane is supported by the hub, and by how much unsupported urethane is hanging off the inside and outside edges. Whenever we're moving boxes of wheels around the shop, the box of Gumballs is always the back-breaker. The hubs are relatively small for a wheel of that size. In a very soft durometer, such as our 75a, the wheel will deform (adapt) to the ground whenever there is a sideload. This means that in Downhill for example, when you are maching into a turn, the wheel will flex and keep the contact patch flat on the ground. You get a boatload of traction, and if you're in a low and stable position, you can control the board when the wheels want to grab. It's not ideal for sliding, but when traction is of paramount importance, they hold. These are faster, longer, and more drawn out turns than you'd experience when pumping your board around as in Slalom.
When doing snappier turns as in Slalom, 75a feels too "blubbery". The wheel will deform so much that speed is actually lost when compared to a firmer wheel with decent traction. Wheels with durometers in the low 80's are firm enough to support themselves when pumping, and are still sticky enough to hold the road. So what I'm saying is that any really soft wheel that has a large wheel-to-hub ratio is going to feel blubbery or sluggish when trying to pump them, comapred to a firmer version of the same.
The 75a Gumballs are very fast for downhill, carving and cruising. Once you've taken a couple of good strong pushes, they roll forever and hold their momentum well. They are like big green balls of stored energy, that smooth out even the roughest roads. Only the 97mm Flywheels have more urethane depth. The 97mm Flywheels have the advantage in being able to roll over junk in the road. They feel more tank-like, and breed a different type of confidence. Most of the guys who race the really big wheels (90mm and 97mm) like the amount of urethane, the centerset bearing seats and the shape. They like the smooth sliding characteristics and mass of the wheel. It's not that their top end is really much more of an advantage, but the way that they handle. People are designing boards and trucks around them. Even though they have comparable amounts of urethane on them, the Flywheels do have a large core, and are not quite as smooth as a Gumball. Compared to a 75a Gumball, just about every wheel feels a little harsh.
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re 75a Gumballs
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On 10/7/2005
brad
wrote in from
United States
(155.229.nnn.nnn)
Chris - "The 75a Gumballs will feel a big "sluggish" at low speeds, but will start pulling away from a 70mm at higher speeds"
higher speeds? above 30mph? above 35mph? above 40mph? ....
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oh yeah
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On 10/7/2005 herbn
wrote in from
United States
(152.163.nnn.nnn)
another question that's been bugging me (just a little) ,when do you use 97mm wheels? I liked the accelleration of 76mm wheels over 83mm wheels and 70's are even quicker, 97a's whould take either a really big hill(how big is big) or maybe a heavier rider,turns? seems like 97mm wheels would be full of problems on turning courses, as if bigger riders don't have enough problems with turns. I might be inclined to thinking that wheels that big might just be a gimmicky marketing thing,but your company is so racing orienting.
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That distortion thing
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On 10/7/2005 herbn
wrote in from
United States
(152.163.nnn.nnn)
I use a set of 78a gumballs too,i have posted before that one session when i was using the 78a in the front they felt grippier while carving really hard,i egotisticly(sort of )took my board set up for cruising around on flats and small hills, onto a hill that would be 50mph in helmet and leathers(47 in baggy jeans and a t shirt)the asphalt is really pretty smooth but kind of wavey. There are some little wheels that are available in triple compound;a very hard core,a hard hollow tyre ,and a 78a "tube" in the tire,to raise resilience. Now , you could apply that to long/slalom board wheels. I think a 80a-84a tube in a 72a tire ,around a 100a (54d whatever) core would be interesting but very critical in the chunking/durability aspect. But perhaps a real hard small core,with a 86a soft(for a core) big core then a 75 or 72a core tire. To bad there isn't a way to make a progressively softer tire in one or two pours.
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Hard vs Soft
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On 10/6/2005
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
Here's my analogy:
Hard wheels are faster than soft wheels when the surface is exceptionally smooth, like polished concrete, plastered pool walls, and wooden ramps. The wheels are like balls and the surface is like the race of a bearing. The less the balls distort from being round and the more polished the surface is, the faster you'll spin. The contact patch (and friction) are often minimized because traction is not the biggest concern. Quick acceleration is. Rebound in a hard wheel can (and does) help in the speed of the wheel, but as the hardness goes up, the rebound goes down. The rebound helps the wheel to return stored energy after running into/over the imperfections in the surface.
Once you get out onto the ashphalt however, things are different. Even the smoothest asphalt is an inherently pourous surface. And it tends to be softer too. Many of the wheels with the fastest roll speed are between 72a and 76a. Psychologically, it's difficult for most people to believe that these duros are that fast, because they feel so smooth. "Smooth" doesn't feel or sound fast, but the wind going through your helmet does. Even if the road is smoother, I resist the tempation of moving up in durometers and take faith in my 75a wheels. If you are pumping a board (like in slalom), you need the firmness and control of a wheel from about 80a to maybe 88a, with 84a being a happy medium. The roll speed is slower, but the traction and control is better in a wheel that doesn't deform too badly in the (many) tight turns. I'm developing a wheel in the 80's with more rebound than we currently have. Initial tests are somewhere between "big smiles" and "oh my god".
I wouldn't be surpised to hear that a 78a Grippin feels quicker than a 75a Gumball at moderate speeds. Especially if you're pumping at all. Gumballs have a lot of massive by comparison, and it takes a bit more to get them up to speed. The 75a Gumballs will feel a big "sluggish" at low speeds, but will start pulling away from a 70mm at higher speeds. People really like 78a - both the duro and the number. It does last a bit longer and doesn't distort as much, but for pure roll speed, 75a is kind of a sweet spot for rebound, and it doesn't go any slower when the asphalt is smooth. If the temparature is about 96 degrees or more, the 72a and 75a compounds start to run into some wear problems. They almost feel "greasy". I'd go with 78a or maybe even 81a when that happens.
Stay tuned though. Our new 81a formula has the rebound and feel of a softer wheel, without the distortion. I think that you're going to like it.
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good surface
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On 10/6/2005 herbn
wrote in from
United States
(205.188.nnn.nnn)
a few posts back you suggested 75a urithane for a "good" surface ,good is a relative term, good in nj may be mediocre when compared to the fine grain asphalt on the frostless,unsalted,streets of cali. harder urithane should be faster on really smooth streets, 78a or 81a ,especially with the new smaller cores.On the old wheels i thought the 75a was definitely the way to go but i'm using a set of 78a grippins and they seem quicker than 75a gumballs on my short local daily hill carves. I'm pretty sure the gumballs will be faster on bigger hills.
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Bob's Burn Quest
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On 10/5/2005
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
I think that Bob is using 90mm Flywheels and going around 100mph. So what is the circumference of a 90mm wheel? Hmmm. Well, 90mm is about 3.5433 inches and C=Pi*D or 2*Pi*r, right? So I get 11.1316 inches every time that the wheel rotates once. There are 5280 feet per mile and 12 inches per foot, so a mile is 63,360 inches. That wheel would rotate 63,360/11.1316 times to travel a mile which is 5691.9 revolutions. 60 miles per hour is 1 mile per minute, which makes 5691.9 revolutions per minute. Therefore:
60 mph = 5,692 rpm
70 mph = 6,641 rpm
80 mph = 7,589 rpm
90 mph = 8,538 rpm
100 mph = 9,487 rpm
105.41 mph = 10,000 rpm
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Tire Sauce
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On 10/5/2005 EBasil
wrote in from
United States
(63.206.nnn.nnn)
Jeez, Bob. Just tell those motorheads to stop using tire sauce and to hose down the track before you run...
Nice looking wheels! yuck
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Fish Oil
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On 10/5/2005
Bob
wrote in from
United States
(132.250.nnn.nnn)
Hmm thanks for the tip on cleaning the wheels.. where you implying I get smaller whels and they will just fling the sludge off? Now just one question for you. Who ever said anything about 83mm wheels?
bob
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Omega
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On 10/5/2005 Skeptic Skater
wrote in from
United States
(207.200.nnn.nnn)
I believe that 10,000 rpm works out to 97.2 mph with an 83mm wheel. My math shows that yours are turning around 9206 @89.5mph. Chris?
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Cleaning Flywheels
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On 10/4/2005
Bob
wrote in from
United States
(69.251.nnn.nnn)
Hey Chris, Here's a question for your Top Secret Chemist and it is not one you will get from many..
What kind of solvent can I use to clean the VHT and burnout rubber from the dragstrip from the Flywheels??? Something that won't attack the magic green mix and turn it into green goo please.
It is some kind of ride with this stuff stuck to the wheels when they are turning over 10,000 rpm. A ten year old spectator suggested that I spray them with PAM before I get on the track.
this is a serious question by the way..
bob
Dragstrip sludged Flywheels
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Spacers for JimZs
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On 10/4/2005
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
If JimZ uses a bearing with a 10mm bore (0.3937"), the axle will a little less than that. McMaster-Carr (McMaster.com) has some 1/2" (12.7mm) OD steel tubing with .049" wall thickness, which could be used to make some spacers. The part number is 89955K26, comes in a 6' length, and is $19.33.
I'd cut .402" (+/- 0.001") spacers. The .012" chamfers are a luxury. You should be able to get two spacers per inch, which is 144 spacers out of a 6' tube. If shipping is less than $10.00, the cost per spacer is under 20 cents. Now try and find some machinist who won't break the bank...
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