Tandem Cycling - Anyone riding the Velocity Chukker wheel?
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01-31-12, 03:11 PM
I'm shopping around for wheels for our '11 daVinci (one of those itches begging to be scratched). At the top of my list is the Chukker wheel. Anyone hear ride these? I'm looking for specs on how yours are built (spoke count, hub choice, etc.) and reports from the entire Navy (Rear Admiral and Captain) on how they ride. Preferably also what other wheels you've ridden, so we have some sort of comparative reference.
We have a set of Rolf Prima Tandem Disc wheels, and a set of Spinergy TX2 (tandem-specific) wheels. Both are 20/24 spoke, with paired spokes on the Rolf and evenly-spaced on the Spinergy. We liked the crispness of the Rolf, but broke a rear so we were going to set them aside as spare/event wheels. The Spinergy wheels seem mushy (stoker thought we had a flat on Sunday).
01-31-12, 04:19 PM
We have never used them but there are some high mileage folks that do.
01-31-12, 06:02 PM
We have a Chukker rear rim, but I doubt if our experience will be of any use to you. We have 26" wheels and a Rohloff hub. The builder went with the Chukker because the Rohloff hub only comes in 32 hole and he didn't think the Aeroheat rim would be strong enough.
Peter White claims the Chukker builds the strongest wheel he's ever seen.
Which is a funny statement, considering he is a Velocity rim distributor, and there are much stronger Velocity rims.
I scale up the Velocity rims like this:
That covers ground for everything from a superlight weight training wheelset that is marginal for a tandem (in my mind), to more or less the strongest rim being made today, period (48h 700c Psycho).
I really don't know what to do with the "in-between" Velocity rims Cliffhanger/Taipan which is being rolled in 700c (28x25). It doesn't scale up as nicely, being wider than the Dyad and Chukker, but less deep than the Chukker (while being deeper than the Dyad). Maybe that is where it fits, right in between.
For the record some people touring on singles have been having failures with the Chukkers, and are switching to the Psychos. However, the Psycho, while an absolutely epic truly bombproof touring tandem rim, may not be rolled all that much longer. People just aren't buying them. Sadly it may go the way of the Mavic Module 4.
With wheels it is hard to talk about the relative strength of rims, as in reality the skill of your wheelbuilder is so much more critical than the rim. Any 400-600g rim isn't really "strong" and it doesn't take hardly any mass to deform the naked rim under load. A wheel gets its strength from the dynamic tension of the spokes, not the rim. The last point I want to make is that the cycling world is absolutely full of boutique wheelbuilders with name reputations that, in reality, do not build strong reliable and stable wheels. There is a reason that there was a market for machine built wheels, as poorly built as they are. When it comes to tandem wheels I don't think there is any particular reason to EVER have a wheelset built by anyone other than Peter White, unless you are learning to do it yourself.
What really confuses the issue is that not all spokes are created equally. People talk about 14g versue 14/15 or 14/16 or even 14/17 thinking these are homogenous quantities. However, companies like DT vary the quality of the steel wire they are using between their high end spokes and their low end. The specific point I am making is that a DT 14/15 high end spoke can be significantly stronger than a lower end DT 14g straigh gauge. Even more confusing is that almost no one makes a high quality stainless steel 13g spoke, so almost all available straight 13g spokes are made of "weaker" steel than are performance high zoot race spokes.
The only company that isn't varying the quality of their steel from their straight gauge stuff to their double butted is Sapim. Essentially you are getting almost as good a quality of steel with a Sapim Leader straight gauge as you are with their single and double butted spokes. Where this isn't true is with the Sapim X-ray and CX-ray, which aside from being lighter than anything else they are offering (the 13g Sapim Leader, for example) are actually stronger. Difficult to understand.
The best way I try to explain it is that straight gauge spokes are like Harbor Freight tools. They are tools, but a Harbor Freight socket is going to break long before a Stanley, Craftsman, Matco, or Snap-on. So while a 3/4" drive Harbor Freight socket wrench might have some heft to it, it isn't comparable to a higher end 3/8" drive tool. What you really need to compare are similar grades of steel wire across straight guage, single butted, double butted, and bladed spokes, and unfortunately no one (not DT, Sapim, Wheelsmith, no one) is using the same quality steel wire across everything in their spoke product range.
Why the rant? It ain't all about the rims. A lot of time people think particular rims are strong or bombproof, but they just happened to have an evenly tensioned high tensioned wheel built with high quality spokes (regardless of butting or gauge). The last thing that was relevant to such a build was the rim "strength."
Hopefully, I didn't muddy the waters too much.
I keep it simple. Stick with Sapim spokes, and find the Velocity or Mavic rim that fits your needs, and have 'em built by Peter White. Punchline being that Mr. White doesn't use Sapim spokes, but rather Wheelsmith.
02-01-12, 08:01 AM
I have a single wheel built by Peter White and I have been happy with it. I also own hand built wheels from other builders as well with no problems. We are not a big team so we probably don't make a tough test of wheel building. The Peter White wheel does not seem to have more even spoke tension or any other factor that I could ascertain to make it a better wheel. I am sure there are wheel builders out there that don't do a good job, but there are other besides Peter that also do a fine job making an evenly tensioned wheel.
02-01-12, 08:54 AM
"I keep it simple. Stick with Sapim spokes, and find the Velocity or Mavic rim that fits your needs, and have 'em built by Peter White. Punchline being that Mr. White doesn't use Sapim spokes, but rather Wheelsmith."
Sounds like a plan.
FWIW.. I bought a 'machine built' wheel a few yrs back.. needing a wheel asap and having no knowledge of the wheel building game then. Needless to say that wheel went south fast... I'm a heavy load. That LBS shop owner builds wheels for yrs.. went thru and rebuilt with Wheelsmith 14G spokes. LSS.. that rear went to 3000 miles before finally breaking a inbound NDS spoke.. which I road in said cond two more trips before replacment.. no one was open for a repair. Was no need to open the break.. it cleared fine with just a little wobble. Another W head spoke installed and it's running fine today. Understand that wheel took some major abuse.. potholes on some rides.. not by choice. But IMO that wheel has done simply outstanding. Wheelsmith or Sapin.. take your choice.
Mount spoke washers on the 2.0's for closer elbow clearance on the inbound spokes with thinner flanges. Simple effective detail that moves stresses off the elbow.. extending spoke life.
White details why he went to Wheelsmith spokes.. I've learned over the yrs since that's sound rationale.
02-01-12, 12:19 PM
While it certainly is generally true that the spokes/ wheelbuilder are a critical strength determinant, I have been really surprised that when my Rolf Vigors (single bike) fail, a large section of the rim 1" x 1 1/2" where the double spokes attach catastrophically fails but the wheel stays true. It doesn't appear to be a mm out of true and I ride 20 - 30 miles home after wrapping the 2 spokes around others on the rim. It would seem those Rolf rims contribute an awful lot of strength to the wheel. I am 200lb. and get 2 yr./10,000 -12,000 mi. out of the wheels before fatigue failure.
02-01-12, 01:57 PM
The Rolfs hold true when spokes pull out because the sideways forces are balanced rather than staggered and offset.
Big picture, I'm thinking a Chukker 36H on DT Competition double-butted spokes and "premium" aluminum alloy nipples to a Chris King ISO/MTB hub, stainless steel freehub guts, and ceramic bearings; wheel built by a reputable custom wheelbuilder. Continental 4-season 700x28 tires to 120psi, for a 470-pound team plus 38-pound bike, riding 2500 miles/year.
02-03-12, 07:43 AM
We had aeroheats (26") on our touring tandem. After two rim failures (braking surface pulled away) we got a couple of PW built wheels with Chukkers on them for our tour last summer. The first Chukker cracked about four-five weeks out. This split was along the spoke line, and caused an inner tube to fail. The second lasted an additional five or six weeks, and was swelling in one spot, but we managed to ride it the rest of the way.
We were riding with panniers, not a Bob; team weight at the start of the trip 290lb, at the end, 15-20lb less. ~80lb gear. PW suggested we had the tires over-inflated for those rims (Velocity doesn't spec tire pressure, that I could find). By moving to Psychos we were able to run on higher pressure, which my stoker prefers.
Were the rims just a bad pair? They would have been from the same manufacturing lot.
Great thread. Ironically I have been emailing Penny @ PW today about pricing out a set of Clyde worthy Chukkers. She's been very helpful so far.
Right now I'm stuck on what hub to use being that they are going to be for a Trek T200 with 140mm spacing..... and I have no idea how the various spacings affect anything *sigh* (yes. I'm reading about it on Sheldon's sight as we speak)
I have every confidence I will be on a set of Chukkers about 4 weeks after my tax return comes in.
There have been plenty of reported failures on Chukker's of late, but Velocity is moving the manufacturing to the US so I expect that whatever issues may have been out there will be getting resolved.
The most common is of this sort: Chukker failure (http://www.flickr.com/photos/tylerkellen/4265397463/in/photostream/)
Velocity replaced their Chukkers with Psyhos and the difference is galling: Difference between Chukker and Psycho (http://www.flickr.com/photos/tylerkellen/4266138410/)
You can read about their experience with the Chukkers failing on loaded singles (very lightweight cyclist, but heavily loaded here: Chukker failure but Velocity saves the day. (http://journal.goingslowly.com/2010/01/velocity-rims-part-3/)
I'm tempted to go with the Psychos on my touring bike in light of the recent Chukker failures. Peter White has a lot of tandems out there on Dyads that are going just fine. The Psychos aren't light, but when you're on tour the last thing you want is your bike vacation interrupted or ruined because you wanted to save 100g on the rim (or rather 260g being the difference from the Chukker to the Psycho).
Rolf rims are very heavy compared to "traditional" rims and have to be to account for the extremely high tensions paired spokes use in the wheel architecture. The overall wheel is very light, but the rims themselves have to be very stout. I'm not surprised at all that someone was able to ride one with paired spokes having been "blown out." Then again, I'm also not surprised that they blow out with some regularity and consistency. High tension gives you a stronger wheel, but at higher risk of a failure. Which is one of the reasons that I wish Velocity would use eyelets in all of their rims (Dyad doesn't use them for example), to insure against rim failure.
Remember, that you can always go more spoke and less rim. If you are considering a 36h Velocity Chukker why not consider a 40h or 48h Velocity Dyad?
02-06-12, 04:15 PM
In '09 Velocity had many wheels that cracked on the braking surface. The problem was the aluminum that the wheels were built from. I had a rear Aeroheat rim crack with 1000 miles on it and I know of several others with the same problem. I took the wheel with the cracked rim along with the front wheel (rebuilt at the same time) to Velocity in Grand Rapids Michigan and had both rebuilt. Velocity was good about rebuilding the wheels with new rims and assured me that the defective aluminum had been replaced. Of course, rims may have been in the supply chain or in shops with the defective aluminum for several months or years before they are used to build a wheel.
Someone mentioned using 48 spokes on a tandem wheel. Years ago 48 spokes was the standard for a tandem wheel and they have advantages but few are used today. I have 48 spoke tandem wheels and I wonder about the supply of 48 spoke rims in the future.
02-08-12, 08:25 PM
Thanks all for the input (and if anyone else has something to add, please chime in!). I see the logic of the Psycho, but it's too wide for what I want (700x28). I just passed a career certification for my day job, so I'm hoping a little bonus cash will come my way and pay for some new wheels.
An udpate to this topic: Peter White shipped out my Chukkers last Wednesday. They were scheduled to be here tomorrow. I just got an alert from UPS saying they would be delayed due to circumstances beyond their control.
The website says they are in Peru, IL. The agent at UPS said there was a train derailment. I found this on youtube...
according to Google maps, Toluca is about 10 miles from Peru. So it adds up that they were on *this* train. I cringe at the thought of what a train derailment does to a set of bicycle wheels.
Of course, if they survived that.... they really are bomb-proof.
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