carlfreddy

Levi riding some prototype Bontragers

Psimet2001 

paired spoke. Boo.

carlfreddy

Bontrager has a non-paired spoke deep section carbon wheel; Aeolus 5.0 ACC.

dmotoguy

he needed them to keep up w/ lance..

Psimet2001 

Yay....in general I don't bother keeping up with Bontrager wheels after whitnessing the multitudes of rims cracking and spoke failures.....IMHO due to paired spoke designs. I would be interested if they could provide a wheel that competes with Zipp, that is cheaper and more durable not using paired spoke then that would be interesting.....

.....maybe interesting is a strong word......meh.

gsteinb

Pretty effing remarkable how many threads we got out of one photo shoot. Nice work folks.

carlfreddy

Just keepin' it real.

kudude

i think i prefer the 3x20s running commentary.

carlfreddy

You've seen spoke failures/rim cracking in their deep section carbon wheels?

Thats a new one. I've not heard or seen anything like that (spectacular crashes aside), and I work at a Trek store.

Bantam

"808s are the new 404s"
~Fabian

cslone

Probably made by Hed anyway. Just skip the paired spokes and buy some proven Stinger/Jet 90's.

WCroadie

Exactly how many have you witnessed? I've put thousands of miles on 2 sets of bontrager race x lites on harsh pennsylvania roads and have had 0 problems. I've also seen problems with several different kinds of wheels including the almighty zipps. All tyoes of wheels can break

That said I probably wouldn't buy a set of paired spoked wheels again, but it's not like seeing cracking bonty's are a common occurance.

botto 

bdcheung

webshots doesn't allow hotlinking, methinks.

Psimet2001 

Not carbon deep section rims, rather just about every bontrager aluminum rim with paired spoking that anyone riding with me has ever had.

I ride with one guy riding their deep section carbons and IIRC he had some problems already (don't rememebr specifics so I'm not saying they fail), but I remember him telling me on more than one occassion the only reason he rides them is because of a "5 year warranty - no questions asked" (not familiar enough with Trekies to know if that is through Trek or through the shop he works with).

One of the guys on the Tuesday Night hammerfest we do (also a part-time bike mechanic when not running his accident investigation company or teaching at Northwestern.....or winning races....I hate him.....anyway) and I tracked the cracks on his ___ race lite wheelset over the summer. We'd mark the ends of the cracks and watch how they spread. When it became evident that they were about to fail he took them in to swap out.

Psimet2001 

Off the top of my head I've seen over 10 sets cracking around the nipples. Fairly common failure with Bonty wheels with paired spoking.

....didn't Contrador have the same spoke failure on his wheel during the Giro this year??....and Bonty turned it into a "Hey look how strong the wheels are....he rode it with a broken spoke....."

Yes, wheels fail. I;ve broken more than one set in my life, but paired spoking, in my direct experience, seems to lead to force concentrations at the rim that have resulted in what I would consider to be a high enough level of failures to cast the entire spoking philosphy aside.

Carbon, having infinite fatigue life, might work great with paired spoking......but I'll let everyone else figure that one out.

bdcheung

carbon has "infinite" fatigue life?

What about the glue holding the carbon together?

BikeIndustryGuy

Well, there are lots of aluminum wheels on 20 year-old bikes still working well, despite the finite fatigue life.

I'll agree that paired spoking was a fad with few fans. Rolf didn't help that.

CB went with a twin-spoke idea for MTB, but evenly spaced on ally.


And CF composites will certainly fatigue if under-engineered:

https://cat.inist.fr/?aModele=afficheN&cpsidt=2909424

Great aeronautics forum discussing CF fatigue, words like "catastrophic" and "explosive". the B2 bomber had issues.

https://www.airliners.net/aviation-fo...ad.main/91016/

Psimet2001 

Sorry about using the term "Infinite"....got wrapped up (pun intended) in the terminology that Trek "engineers" were using to describe carbon frame material properties during the horrid "Modern Factorys" show I watched last night where they demonstrated ho the Madone is the absolute best bike in the world.....because it's made out of carbon and Lance rides it......

The basic idea though is that carbon fiber itself does not yeild to fatigue failures in any way even remotely in the same ballpark as just about any metal alloy....especially aluminum.

Psimet2001 

I'd never argue that....here are my 15 yr old Mavic Open 4 CD rims after the cyclocross race 2 weeks ago...



Here's a poorly designed Ritchey aluminum crank that experienced a fatigue failure during the same race...




I basically just added it because it was in the same photostream....and it dealt with aluminum fatigue.

fad or not...it's just poor design....IMHO.

And CF composites will certainly fatigue if under-engineered:

I like how you picked a site that highlights a "Fluid Mechanics" book on their masthead....which undoubtedly has pages and pages about boundry layer flow and drag....might even talk about dimples...

BikeIndustryGuy

Isn't that the same series that shows how great Harley Davidson's are?

I think Madones are in the top ten CF frames, and I don't understand the bad wrap they get.

flame on!

BikeIndustryGuy

and the appropriate use of dimples for pipe flow for viscous substances.

kudude

psimet, what gloves are those?

Psimet2001 

Gore...with windstopper. Picked them up at Performance maybe 2 or 3 years ago. The used to work great, but I believe repeated washings have broken down the fabric that was responsible for stopping the wind....I now freeze with them on unless I am riding hard...

patentcad

It all breaks sooner or later.