Wednesday, May 26, 2010

Equipment - Bokken, or HED Jet 6-9 Wheels

So, the final installment of the series. I had to delay it while I tested the subject matter to just two more tests, but it's all good - I can post now.

In review, I've gone over the Katana, the actual fighting swords. In my world they're my racing wheels for almost all conditions. Only unusual or training races would see me on other wheels.

Next, the much shorter Tanto, which, for me, represent non-fighting swords, used for emergency or difficult conditions, stuff like extreme wind, debris, dirty roads, stuff like that. The trainer could be one such condition since the rear wheel will likely end up used mainly on the trainer.

Finally we get to the "bokken", or wooden practice swords - that's what this installment is going to cover. In the HED world they'd be called the Jet 6 + Jet 9. In my world they're my aero training wheels, used as a substitute for the lighter, more agile katana. I like to call them bokken because the rim profile heights reflect the 60 cm and 90 cm standard bokken sword lengths perfectly, with the wheels measuring in at 60 and 90 mm for the Jet 6 and Jet 9 respectively.

60 mm to the right, 90 mm to the left.

When I first rode the wheels, I noticed a couple things immediately.

First, they're heavy. Compared to the Bastognes, they add about 120 grams up front, 200 grams at the rear, but it's all at the rim. These wheels don't like to accelerate quickly, at least not as quickly as the Bastognes, definitely not like the Stinger 6s.

Second, partially because they're heavy and partially because they're so frickin' aero, when I'm sitting in a paceline on a flat or slight downhill road, I feel like I have an electric motor on the bike. The bike wants to go, and I have to rein it in.

These wheels are fast.

They just want to motor on all day. Not the best match for a jumpy rider like me, but a good one for a time trialing machine.

I have yet to do some more objective testing, but those are my two biggest "take aways" from my first rides on the wheels.

The Jet 6 in front, the Jet 9 in the rear.

You can see the drain holes in the fairing. These help keep the wheels drier than waterlogged - some older aero wheels could hold a few ounces of water in the rim.

Note also the aluminum brake track - they stop just like a normal aluminum wheel. They've been very good, smooth, no oil spots or anything. Very nice.

You should know that these wheels are essentially aluminum, not-very-tall-rim wheels with a carbon fairing. Therefore they will ride like aluminum wheels with a low spoke count and a not-very-tall rim. They are not like a structural carbon wheel, where the rim really is 60 or 90 mm tall. I don't know the rim height, but I'm guessing it's in the 30 mm range. The fairing is a false front.

Jet 9, by itself.

Huge area for logo. I left them on, being a logo kind of guy. If you're not a logo kind of person you can remove them pretty easily. In fact one corner of one of the labels started to peel without any prompting. For stealth riders this is a nice touch.

Find the valve hole. No, I didn't remove the logos, it just happens there isn't one in this area.

With no valve, and a valve too short when I actually mounted up the tire, I had a bit of trouble finding the valve on the Jet 9. A Carpe Diem Racing sticker took care of that.

See how the spokes enter the side of the carbon, and each spoke goes through a large-ish hole? This indicates the carbon is simply a fairing, not a structural part of the wheel. If you squeeze it you'll realize it right away - the carbon is only a little stiffer than an inflated party balloon. The carbon is there simply to guide air around the rim and tire.

Wheel fairings are legal for USAC so this isn't a problem for racing.

The Jet 9 is tall. Both wheels have the same 80 mm size valves, yet the Jet 9 requires an extension. Note sticker on the Jet 9 marking valve location.

It's a bit stunning, how tall the Jet 9 really is. I bought a couple 80 mm valves for the wheels. On the Jet 9 I can barely close the presta nub of the 80 mm valve with my fingers. On the Jet 6 it sticks up way too far.

No bulge - Jet 6. Okay, a hint of one.

One thing I found kind of interesting - no huge bulges out from the sidewall. I was kind of disappointed, to be honest. I thought, after seeing the wicked wide bulges of the Stinger 6s, that the Jet 6 and Jet 9 would be similarly enhanced. No such luck. Although tall, and wide (due to the wider rim), the sides don't bulge out significantly.
No bulge, Jet 9. You can tell it's the 9 because it's the rear wheel.

The rim "peaks" (i.e. where the spokes enter the fairing) are kind of flattened out. This helps the air move sideways over them - someone told me a long time ago that this flow really helps stabilize a wheel in a crosswind. Sharp edges catch more wind.
Various hand-built evidence things. Note FSA rim strips (red things top right corner).
4-5 indicates date, based on when I got the wheels.

I didn't mention this in the other posts but the wheels all arrived with various marks and notes on the rims. These seem to reflect the builder's initials, build date, and other notes. The big "CAMPY" scribble probably means "get a Campy cassette bodied hub". It's reassuring to see all these markings - I feel like someone actually took responsibility for the wheels.

I point out the FSA rim strips because the rims end up coated a bit with a very slick lube, evidently used to lube the spoke nipple on the rim (based on the trails of lube barely visible when the light hits the rim just right). Velox rim tape (my default tape for clincher rims) doesn't stick to the stuff, and it's hard to clean off the grainy metal finish. The guys at Bethel Cycle (where I bought the wheels) like the FSA strips because they just stretch onto the rim, no adhesion necessary. It works well for these wide rimmed, low pressure wheels.

Ginormous profile rim. I never thought I'd have a wheel like this.

After my first ride on the wheels - it was a group ride. Picture taken inside where there were fewer mosquitoes.

I mentioned some extra testing done on these wheels before I did this post. The first distraction was riding on a group ride where, somehow, I managed to hit just about everything on the road. Potholes, 2 inch chunks of loose pavement, random gravel stones, cracks, seams, everything. I was bouncing around for a good hour, the carbon fairings amplifying the noise. At least half a dozen times I hit something, turned around, and saw yet another meteor-fragment-like piece of pavement bouncing off the road.

To my pleasant surprise, the wheels shrugged off everything. They were totally straight, totally round, and didn't seem bothered at all by the impacts.

The low pressure tires (you can go down to 95/105 psi on the 23 mm rims) also shrugged off all the impacts. Some of those rock impacts could have flatted a tire on a regular rim, but nothing happened here.

The next morning, though, I noticed the rear tire was low. Since it had a valve extension, I thought maybe the open valve got "touched" and let out the air. I re-inflated the tire, left for another night.


I re-inflated again, left it another night, but this time I removed the extension and tightened the valve down.

Flat again.

So on the third day I replaced the tube (no, I didn't ride those days so I just left the bike in the same place, leaning against the wall in the kitchen). And lo and behold, a piece of glass had squirmed its way into the tread.

Glass shard. Gear bag underneath.

I tested the wheels another way too. This involved me sprinting to 30 mph, impacting an object going about half that speed, then throwing the bike down onto the pavement.

Surprisingly enough, the wheels held up fine there too. They were straight, round, and made no untoward noises. I don't have pictures because, really, there's nothing to picture. The wheels look exactly the same, with some extra scuff marks on the tires.

Although I'd rather not repeat either of those two tests, they did help show that the wheels are quite durable.

Now to go out and spin the legs a bit.


Anonymous said...

Aki -- you've got years of experience on me, so my gut tells me that you're knowledgeable and sensitive/aware enough to tell the difference between one wheel vs. another. However, for me, I can't tell the difference when I'm riding my Richey wheels vs. the stock wheels, or riding my "race" tires vs. training tires. It makes me wonder whether it is worth the hassle to swap things around, and the $$ required for the variety.

Just curious -- do you know of any quantitative data that clearly demonstrates the differences between various types of wheels and tires? Maybe I'll never actually "feel" the difference, but at least if I could see some hard numbers "proving" the difference, I'd feel more comfortable with the hassle and $$ invested.

Suitcase of Courage said...

You may not have pics of the second test, but I hope you can post a helmet cam!

(not that I'm interested in replicating that particular test)


Aki said...

Dennis - there are some sites with aero data on wheels, listing different wattages required to turn the wheel at certain speeds. I can't think of one off hand, but the differences seem small. I want to do some back to back tests myself, testing at higher speeds, higher wattages, and see what happens.

SOC - I'm debating what to do with the clip - it illustrates my mistake very clearly. That's the good thing. And that's a bad thing too :)