Wednesday, August 13, 2008

Rim Jobs

I am not an engineer of any sort. The only college science course I took was earth science—rocks for jocks—and while I did allegedly pass calculus, I can't remember a single thing I allegedly learned. As for physics, I didn't even take that in high school. Combine that with the fact that I've only built one wheel in my life—using the time-tested hold-the-new-rim-next-to-the-old-wheel-and-transfer-the-spokes-over method, and it should be abundantly clear that I am entirely unqualified to criticize a new rim design. Like this one, from éclat:







They look cool, I guess. Nice colors. And as everyone seems to be trying their hands at rim design lately—Animal, Fly, Stolen, Shadow—I suppose that each company needs their own unique design to help them stand out from the ever-growing crowd. Will they be stronger than time-tested designs from Odyssey, Primo and Sun? Damned if I know. Then combine all the new rim designs with new hub designs from (among others) Tree and Simple, and it's enough to drive a simple wheelbuilder crazy. (I'd like to see someone 5-cross crosslace a Tree front hub to a Fly rim without breaking something.) No wonder Pierre Pierros III has been on vacation for months.

It would be interesting to see some sort of independent testing as to which rims are stronger, and which spoke patterns (close to the edges or all in the middle?) and lacing patterns work best. Anyone?

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24 comments:

Anonymous said...

I <3 my greens

Russ said...

Dammit, I knew I should have just posted the Sinisi Lederhosen picture again.

blah said...

bmx parts are on the whole not designed by engineers, just kids and drunks who want something in a different colour

Stephen said...

It's weird to me that anymore, no one really seems to think about things like "is my bike gonna hold up" when getting ready to fire out a banger. Odyssey, Primo and Sun have spoiled us, to an extent.

I am very skeptical when it comes to running stuff like this. Forks, rims and cranks are so critical. Putting holes in something and making it a neat color doesn't pass the smell test with me. But then again, I live with an ex hippie, so my sense of smell is sort of fucked anyways.

Mexican John said...

Its not independant but I'm sure George French has done it to death, the Ribcage on my back wheel has been spinning true for nearly year now..

Russ said...

Anyone who designs a new rim should just give a set to Alex Liiv or Sean Burns and see what happens. Although I don't like to condone the "human crash test dummy" approach to BMX product testing.

Then again, I suppose it's hard to dupicate the effects of a 12-stair 180 in the lab.

Smitty said...

I think that spokes ultimately play a huge role in wheel performance under extreme loads.

Wheels built with different spokes and hubs cannot give you an accurate apples-to-apples comparison of the rims.

Thus I think that any empirical rim testing would need to be done by testing the rims by themselves, and leaving the spokes and hubs out of the equation.

I'm no master wheel builder, but I've built several that seem to be holding up under some good riders. What I've learned from reading Jobst Brandt and Gerd Schraner's books is that as a general rule, keeping your spokes tensioned is key. A properly hand-built wheel - not one from off a wheel building machine - should keep its tension despite heavy use. Replace any damaged spokes. Those damaged ones would be the weak link that could lead to catastrophic rim failure when subjected to an impact, like a 10 stair gap to flat.

Maybe rims/wheels should be rated by a "stair number"?

I.e. - this rim is 15-stair rated, while that litewate one is only rated to 5-stairs.

Granted, that is a whole new ball of worms for manufacturers to deal with, and nobody would do it because spoke tension is the key to wheel longevity (something out of the manu's control after the components leave the manu's hands.)

But hey, car tires are rated for different speeds and conditions.
As riders, we should be smart enough to realize that all rims/wheels are not going to be strong enough to handle all impacts.

Noel said...

Hmmm....Pennywise was (is?) Kevin Robinson's favorite band but I haven't seen him in a video part since "Until Monkeys Fly."

I've gotta admit, Russ - your songs have all had me stumped so far.

Anonymous said...

you've resorted to making posts about things you admittedly know nothing about...somebody's stoked on themselves.

Joe said...

"Ball of worms" hahahaha.

The thing about this blog is that there aren't new and stupid parts coming out every day, but he wants to update it daily. Some days he's just going to have to talk about whatever happens to be out there, and I think he's doing an alright job. I guess he could start talking about stupid parts from the past (if that were the case, the Mongoose triple bolt seatpost clamp would have my vote).

P.s. Wheel building machine? I didn't know those existed, although it is kind of hard for me to imagine a guy sitting in a room building wheel after wheel for shitty department store bikes. Hmm, interesting.

Anonymous said...

"P.s. Wheel building machine? I didn't know those existed, although it is kind of hard for me to imagine a guy sitting in a room building wheel after wheel for shitty department store bikes. Hmm, interesting."

No wheels on any complete bicycle are hand built, and no aftermarket wheelsets are handbuilt (ie: Odyssey wheels etc etc). Not knowing a wheel building machine exists is kind of bizarre.

Forrest said...

you don't want frames to be the same but you don't want rims to be different

Anonymous said...

http://www.youtube.com/watch?v=ArrLTVgq85s

Loop said...

"Then again, I suppose it's hard to dupicate the effects of a 12-stair 180 in the lab."

Depends whose lab it is mate.

Check out the video in the following article on Soletech's (as in Etnies etc.) STI lab.

http://www.crookedtongues.com/editorial/?e=46

I know it's about testing footwear rather than skateboards or bikes themselves but you can see what I'm getting at.

daz. said...

With regard to machine built wheels, I thought that they were laced up by hand and then trued/tensioned by machine. I can't imagine a robot having the dexterity to be able to do crosslaced patterns.

james said...

there is a video on youtube somewhere of a wheel building machine,

it holds the hub and spits all the spokes into the flanges,
then it gets put on another machine which spins the wheel with a different comb templates that space the spokes out and sort the lacing,
then another machine spits in the nipples and then spins and auto trues the wheel

its actually pretty clever,
hand built is better though

the problem with stuff like these new rims is that there used to be alot less choice so people knew quickly what worked and what didnt
now there are so many parts / colours that come out that no one keeps anything long enough to test it out, or you wont know anyone else that has that part who has already tried it out

Russ said...

Were I to re-write this entry, I surely would have mentioned that while my academic qualifications (or lack thereof) may prevent me from critiquing new rims, they wouldn't necessarily prevent me from designing them.

Mark Westlake said...
This comment has been removed by the author.
P Double 3 said...

thanks for the concern Russ, but i'm on sabbatical, not vacation

i should probably get back to work soon. at the rate Parrick is buying HD cameras, we'll be in the red faster than it takes one of those machines to build a wheelookzv

Anonymous said...

why would anybody buy anything other than a Ribcage?

Colby said...

pennywise, maybe schwinn's american muscle? i'm thnking timmy strielecki's part...

Russ said...

I don't think I knew that Sean Burns rode for Éclat? Man, Tunney doesn't tell me anything.

Will they be making a 45t sprocket?

Mark Westlake said...

He doesn't ride for Eclat 'online' yet, apparently. You'll see soon enough, haha...

salty old man said...

Mavic did it all long ago.

The Primo balance rim is just a mavic rip off.

Wide hole pattern? = CHECK

I-beam down the center? = CHECK

Well over 10 years ago.