wheel coning

Slalom skateboard wheels

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wheel coning

Post by Guest » Sat Apr 08, 2006 7:43 pm

Does wheel coning usaully occur on the boardside half of the wheel or the outside half of the wheel? I have offset wheel hubs. Any info appreciated. THanks

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Eric Brammer
Posts: 324
Joined: Sat Sep 25, 2004 4:48 am

Coning happens...

Post by Eric Brammer » Wed Apr 12, 2006 8:56 pm

In Racing, Coning usually reflects two main occurances, wheel sideload distortion, and axle flex. Those tend to wear the wheels towards the inside. Wheels with greater offset in bearing placement (such as Flashbacks or LaCostas) cone more than 2/3rd (Avalon/Cambria) or Centered (Grippin/N-Gen) bearing types. Centered bearing wheels can be, sometimes, flipped to prolong wear, but user beware of traction differential!

Wheels featuring 2/3rds bearing placement wear in nicely indeed if kept on similar axles, and I feel that they gain traction due to the wear (although there's a loss of rolling speed). Not everyone agrees with that, and coning certainly can reduce the wheel's contact patch. Using differing axles can also wear wheels differently, and I think it's likely unwise to swap worn wheels onto differing styles of trucks.

Coning on the outside of wheels is usually slide or kickturn related wear. I say 'usually' as I've seen luge wheels 'scrub' (not Slide) to an outer-coned profile due to high speeds, tempatures, and sideloads, where the wheels have literally stretched laterally until they wear the sidewall/lips of the wheels. Hence, I'm a fan of ABEC 11's Flywheels for Downhilling/Luging, as they're fat, big cored, and centerset.

Trucks that have split axles (Turner TTC) or Offset axles (Tracker RTS Offset, Radikal Dragon's Tail) will flex at the axles a smidge under pumping loads. This affects wheels in how they wear noticably, and that flex, combined with the Grip that true 8mm axles provide will cause distortion especially on rear wheels. Solid axle trucks (Seismic, MMW Trackers) seem to create less cone angle upon the wheels. Stock 5/16" axles on most "over the counter" trucks have inherent slop between the bearings and axle that can make Slalom wheels wear in a 'scalloped' pattern.

To find if your wheels have that 'scalloped' wear in their coning, roll individual wheels on a smooth, level table (I use a draftingboard). If the wheel rolls straight, it's fresh, or at least unmolested. If it rolls in a smooth curve, it's merely coned. If it curves, but not in a smooth curve (or noticably hops), then it's time to either Lathe that wheel, or retire it from Slalom use. I run coned, but still round, wheels often enough to say I feel they're generally O.K. to use, although they may be slower(?) than fresh wheels. I mention Lathing as a means of correcting wear, even though I realize that may be something that is too 'techie' for most. It does extend wheel life, but it usually dosen't make for a faster wheel. Fresh and round are Fast, slightly worn in may be faster, coned, um, I dunno.

Look at Kenny's wheels sometime... :-) He's a conehead :-D
"Surfin' these Old Hills since back in The Day"

Pat Chewning
Pat C.
Pat C.
Posts: 1400
Joined: Mon Sep 16, 2002 2:00 am
Location: Portland Oregon

Re: Coning happens...

Post by Pat Chewning » Thu Apr 13, 2006 2:11 am

Eric Brammer wrote:In Racing, Coning usually reflects two main occurances, wheel sideload distortion, and axle flex.
Wheels without significant side load or axle flex can still wear in a cone pattern. For example, wheels with sideset bearings will have more contact pressure right under the bearings/hub and wear more there than on the rest of the wheel.

This is very evident in wheels on printers and other media transport devices which do not have huge side loads or enough flexural load on the axle for significant flex of the axle. Yet the wheels still will wear in a cone shape due to uneven force distribution along the axis of the wheel (roller). In some printers/copiers this is significant enough to warrant replacement of the roller after, say 500K pages. Even though the copier can still move the paper fine, the uneven wear tends to skew the paper to the side and cause paper jams.

Which effect is the largest in racing? I don't know. But if you compare how much a wheel deflects under your standing-weight load and how much the axle flexes, I'm pretty sure you will see a much larger wheel deflection/distortion than the axle deflection.....

-- Pat

Paul Howard
Posts: 202
Joined: Sat Dec 27, 2003 7:15 pm
Location: Corvallis, Oregon. USA

Paul's 2 Cents on Wheel Coning

Post by Paul Howard » Sat Apr 15, 2006 5:47 am

I agree with Pat that wheels flex far more than Axles. I'll add this, "standard" offsets that are made by chopping and welding like with trackers and Indy's and Radikal Dragon's Tail(rear Truck) flex more than others because of all that torsion(? I think that's the word, Pat feel free to correct me) on the "wings/brackets/whatever" and thus they cone wheels the most.

Next, TTC's cone almost as much as the above because the stock TTC's are ALL out of alignment as far as I could tell(Wallgren will amply back me up on this), and the wheels try to wear into less pressure on the pressure points caused by the missalighment.

Next, AirFlow OS, and Splitfires cone MUCH less because the alignment is good and the hanger is solid,

Best for least coning is the Rebuilt 8mm straight axle RT-S, 8mm rebuilt straight axle Seismic, or PVD because those have the straightest axles and flex the least. But, wheels will still cone on them. What I like about centerset bearing wheels(Grippins) on these is that they will cone almost symmetrically with the most coning almost smack-dab in the middle. Still they will cone slightly assymetrically due to uneven pressure loading of the inner egde Vs. Outer edge relative to the turning action and uneven loading of the inner verses outer wheel in a turn. If you ride Grippins on any other truck that flex's or isn't TRULY aligned(a quick hanger only spin test with a wheel on one end with the axle nut snugged on), it will cone noticably more assymetrically because of uneven loading and abraision.

I truly believe a coned wheel truly does have more traction than an unconed wheel and less speed, both dependant on how much coning there is.

As far as traction and speed and coned Vs new- in 2002 to 2005-ish, a LOT of pro's and regular racers such as myself swore by the "Use a brand new set of unconed but slightly worn" strategy. It worked for a while. Then as courses got a lot more technical in 2004 to the present, people started to notice that traction throught the turns and making the course clean and not sliding was paying off more than the simple straight roll speed advantage of an unconed wheel on a hard technical course(using the same wheel, same hardness, same width, same brand, etc).

I have even seen more than once, people showing up to races in the last year with brand new, never ridden pre-coned wheels they altered with a lathe or beltsander. They did get more traction, but me personally I'd rather ride my wheels into coned condition, but that's me, plus, heelside Vs toeside wheels cone slightly differently so for that reason I would rather wear(cone) my wheels by riding them so they reach coning "equilibrium" with the trucks and the board and the rider, etc. Although, it you do precone your wheels, I would think it would be best to make them as identically coned to each other as possible to start with.

Hope this is of some use, good luck-Paul
I just dig slalom!

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