Sunday, April 19, 2009

Delta 7 Ascend road bike review

It's not about the bike, but...

The Delta 7 Ascend is the road version of Delta 7's "IsoTruss" carbon fiber mesh frame. I got to play with it during the Sea Otter Classic 2009.

Delta 7 Arantix Ascend Road Bike

Gary Fisher and the infamous "Bikes Gone Wild" both gave me grief for it, but I just had to try this paen to space age technology. Jeffrey of Delta 7 set me up with the Ascend while Erik hit the trails with the Arantix mountain bike.

The Ascend is a real head turner. I'm a moderately homely middle aged guy with birth control glasses; I rode for a short while with Liz Hatch in her Vanderkitten kit and her Storck Absolutist bicycle. Every male roadie we passed by snapped their necks looking at me, not Liz. If you've seen Liz on a bike, you know that's something.

Built up, the Delta 7 Ascend weighs a hair over 13 lbs without pedals. The light weight combined with a reasonably aggressive road geometry and super stiff rear triangle translates into rocket like acceleration and effortless hill ascents. I popped up to bunny hop over a pothole and nearly launched myself into orbit because the bike is so light. If you want to try for sub 20 minutes on Old La Honda Road, this wouldn't be a bad bike to use.

During my test ride, I caught up with a cyclist on a nice looking Trek wearing Astana kit. He looked strong but tired pushing up a steep hill, so I whipped out my phonecam and took a photo of this guy as I rode no handed on the magic bicycle. Sorry for the lousy phonecam photo -- we had to push through a crowd clanging cowbells and shouting "LEVI." I didn't realize the jeans company had such a big presence at Sea Otter.

Levi Leipheimer Sea Otter

I only put a few short miles on the Ascend so I can't do a full evaluation, but the ride on this bike isn't the least bit jarring in spite of the stiff frame.

Everybody asked me if this bike whistles in the wind. Here's video of my riding the bike on a steep downhill -- no whistling, but the shadow of this mesh bike looks pretty cool against the road surface. The video was shot using GoPro's new Wide Angle HERO Cam strapped to my chest.

According to Delta 7, they performed wind tunnel tests on this frame expecting more wind resistance from all of the surfaces and they wanted to quantify just how bad the turbulence would be. There's indeed more drag because of all the flow through the lattices, but the drag induced by vortices behind the tubes completely disappears, resulting in a net benefit: the IsoTruss design results in less drag than conventional tubes.

In summary, the Delta 7 Ascend road bike is fun, stiff, light, fast, comfortable and very expensive. My buddies at Road Bike Review took delivery of the Ascend so watch for a real, in depth review from them Real Soon Now. Also, "Bikes Gone Wild" promised to provide his own comments on this bike in the comments after I post this review :-)


GhostRider said...

Who cares about the rode with Liz Hatch and didn't get any pictures of that? You stink!!!

Yokota Fritz said...

Here you go, Ghost.

KWC has a better one.

Ron said...

According to Delta 7, they performed wind tunnel tests on this frame expecting more wind resistance from all of the surfaces and they wanted to quantify just how bad the turbulence would be. There's indeed more drag because of all the flow through the lattices, but the drag induced by vortices behind the tubes completely disappears, resulting in a net benefit: the IsoTruss design results in less drag than conventional tubes. Thanks for the cover story. This piece about it being superior over conventional tubes as far as aero drag is concerned is all fluff in so far as they don't publish evidence backing up this claim. I have some hard time believing that a TT bike fitted with an Isotruss frame will outperform a top of the line Cervelo in a timed event.

I wrote extensively about this Isotruss structure and some of its advantages and disadvantages, particularly in the context of building a bike with it.

Intro to Isotruss Open Lattice StructureShortcomings

Yokota Fritz said...

Ron: Regarding aero and TT bikes, that's precisely why I weasled out by mentioning "conventional tubes." Still, this bike is much more comfortable to ride than any TT bike.

Thanks for pointing to your earlier articles about Delta 7's application of iso truss structures to bikes. Yes, the bike is a little over the top and I've been skeptical of the design, but then I hopped on the bike and -- wow, what a bike.

Regarding the 'cheese grater' look -- the surface is smooth. You're not going to lose skin or catch clothing on this bike. Anybody who's looked at this bike knows this right away, so I'm puzzled about the 'cheese grater' claim.

Tyler said...

The Aerodynamic properties of the IsoTruss are directly proportional to the "solidity ratio" of the tube, or the percentage of open space-to-truss. For example, the larger the diameter of an IsoTruss, the less wind drag it has. Also, the distance from peak-to-peak on the IsoTruss will affect the density of the weave, thus affecting the drag coefficient. When you compare the IsoTruss tubes on the road bike to those on the mountain bike, you can see that the mountain tubes were optimized for strength-to-weight without any regard for aerodynamics. The mountain bike has a shorter peak-to-peak distance and some very small diameter IsoTrusses in the rear triangle, while the road bike was designed to strike more of a balance between strength, stiffness, weight, and aerodynamics. The peak-to-peak length is much more elongated and the IsoTruss members are thinner. That's one of the main reasons why the road bike has a "traditional" rear triangle instead of the IsoTruss rear triangle that the mountain bike has. At those small diameters, the IsoTruss would create more drag than the rearward vortex that it eliminates, so no net gain.

The road bike frame was tested at the "A2" wind tunnel in North Carolina, which is a highly respected aerodynamics laboratory both in the cycling industry as well as the NASCAR racing industry. As stated by the author, our hopes were not very high originally. we simply wanted to know how the bike compared to a conventional cylindrical tube frame to see if there was any aerodynamic penalty in the new design. The net result was that the Delta 7 bike had slightly less drag than the classic cylindrical tube frame, but the difference was only by a handfull of grams, so it was a pleasant surprise, but not worthy of a major marketing angle. Surely a frame built with an airfoil shape will be more aerodynamic, but the Delta 7 Ascend is not intended to be a time trial bike, but rather a swift nimble all-around bike with a tilt toward agressive climbing, cornering, and sprinting.

Wirehead said...

IIRC, the Isogrid folks claim that you can take a pickup truck over the frame without breaking it.

IMHO, that's a better feature to sell me the bike on than aerodynamics.... but I don't claim to be a normal cyclist. :D

Yokota Fritz said...

Wirehead: I remember a video about that from one of the titanium frame builders. It would be cool if Delta 7 has something like that :-)

Ron said...

For a road bike, the advantages of iso-truss are moot. For an MTB, this is just a bad application. For the hefty price tag of the bike, it has not bothered to follow the trends in the market. Amateur riders may want to mess around with oil, and dirt all the time. We're in the age of belt drives, trying to slowly rout out the chains. And looks are everything down on the sales floor. Using the Isotruss on a muddy singletrack is going to be a cleaning nightmare. Unless you have your own washman, I don't see how anyone could enjoy wasting time plucking out leaves, flowers and mud from 'trusses', whatever the perceived advantage they may otherwise offer the rider maybe. There are plenty of all-round designs in the market without holes in them that are 'nimble', and aggressive without the price of an arm and a leg. Anything said about the aerodynamics of the bike is to be taken with a pinch of salt unless data is presented showing the effects of air at various angles. Maybe they should supplement their frames with a free cleaning rag and water hose.

Anonymous said...

My brother and I are both former racers. There is a climb near our house that we have done many times, with 6-10 percent grades, and over 2,000 feet of climbing. I got a chance to demo the Ascend today. Despite the fact that we had to ride in the afternoon in 100 degree temps, and didn't have the tail wind we have had lately, I still beat my best time this year by over 1 minute 30 seconds. If I had gone in the morning with cooler temps, I have no doubt I would have gone at least another 30 seconds faster (the heat killed me). This bike is so stiff, it is unbelieveable! You get out of the saddle, and there is a transfer of power to the wheel that is like nothing I have ever felt. After reaching the top, my brother and I switched bikes, and did the last steep sections again. This time I was on his Specialized Rubaix with Dura Ace, and he was on the Ascend. The Rubaix felt like it had a flat tire by comparison. My brother could not believe the difference, and after 2 days of giving me crap for considering upgrading my bike, suddenly was trying to figure out how to afford one too. If you live in the mountains, don't try this bike unless you are ready to buy. It climbs like nothing else. Oh, and my bathroom scale said this incredible stiff bike only weighed 14.5 lbs with water bottle cage :)

Allison said...

Yokota, FYI Delta 7 just launched a Facebook and Twitter account. They posted a link to your review. Feel free to post a few comments on the review or upload the video file. This info is really helpful and interesting for people to get a hold of. Also become a fan and suggest it to some friends to keep the conversation going. Cheers!

Reviews tab:

Yokota Fritz said...

Thank you Allison. Are you with SOAR?

Richard said...

I left the comment a few weeks ago where I mention how much faster I was climbing the hill near my house with my brother on the Delta 7. Since writing that comment, I demoed the Cervelo R3 for a weekend as well. I bought the Delta 7 last week! :) I believe that is what they call putting your money where your mouth is.... LOVE this bike!

Yokota Fritz said...

Hi Rich, and thanks for that update.