I test rode one yesterday in Madison. Great handling bike, nicely spec’d with Di2, TriRig front brake, Zipp 808s. Beautiful bike except for the front of the top tube where it looks like a chunk was cut out of tube and the stem comes up. Anyone else bothered by that gap? I thought there was a snap on part over it missing or something. You can’t really appreciate it in most of the pictures of the bike as they are mainly black in color and the photos taken in mood lighting. The rep says some bike owners have fashioned their own cover for it and they are redoing some of the beams which are interchangeable and may address this. I just thought for a $12,500 bike it looked a bit unfinished there. Did I say it rides like a dream? Even with platform pedals on cranks that were too long and a cockpit that was too short, it rides beautifully.
I test rode one yesterday in Madison. Great handling bike, nicely spec’d with Di2, TriRig front brake, Zipp 808s. Beautiful bike except for the front of the top tube where it looks like a chunk was cut out of tube and the stem comes up. Anyone else bothered by that gap? I thought there was a snap on part over it missing or something. You can’t really appreciate it in most of the pictures of the bike as they are mainly black in color and the photos taken in mood lighting. The rep says some bike owners have fashioned their own cover for it and they are redoing some of the beams which are interchangeable and may address this. I just thought for a $12,500 bike it looked a bit unfinished there. Did I say it rides like a dream? Even with platform pedals on cranks that were too long and a cockpit that was too short, it rides beautifully.
I know the gap. But I’m not concerned. It’s not clear that there is any sort of aerodynamic penalty. Of course, it’s also not clear that there isn’t.
I’d bet that a lot of it is dependent on what aerobars you are running.
I would think that anything that fills in that gap more is going to necessarily restrict some of your choice with aerobars. You could extend the beam out more and have the cables go in the front of the beam rather than down, but do you really gain anything?
Debatable.
My hope is that the Dimond guys don’t tweak it until they can get into a good tunnel to actually see if there is a penalty with the current design.
You’ll be moving too fast on it for anyone to notice.
You’ll be moving too fast on it for anyone to notice.
In reality, is there any reason to think that this bike is any faster than any other high end triathlon bike?
that gap works quite well with my 3T bar setup - although I admit this is a slightly different config to the “standard” Dimond builds that you see
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You’ll be moving too fast on it for anyone to notice.
In reality, is there any reason to think that this bike is any faster than any other high end triathlon bike?
I’m sure the Trek SC is close, P5 probably too, and when Specialized brings out a new Shiv I’m sure it will be quick. They do have wind tunnel data… doesn’t everyone 
But keep an eye on the bike splits you see in races to see how they are doing. eg IMMT - the fast bike splits had Dimond all over.
I was on a Shiv before, and my times on known loops are quite a bit faster on the Dimond, although a big part of that is that I can achieve a more aero position.
If you can get into a better position, that is because of the frame, but you probably could have done that with a $300 aluminum P3. I think these bikes are really cool, I just don’t think they are necessarily faster than other high end bikes. A couple of weeks ago, I was talking to an old friend about his Zipp 2001. I love that bike, but back when it was new, I used to beat him on a round tubed QR Kilo.
Jorden’s bike split margin doesn’t mean much. I think his IM NYC bike margin was probably about the same on a Shiv. You never know who will be at any IM so margins don’t tell you much.
Biggest problem with a bike like the Dimond; if you are passing people, it’s the bike, if they are passing you, you suck!
The problem is that switching to a different bike also usually has you changing positions a little bit, and that throws a wrench in the results. A position change probably has 5x the impact on speed than frame shapes on these high-end bikes. And when you take a great rider, they are going to take the opportunity to change the position for the positive, since they are changing and they know what they are doing.
Think about it as moving houses. When you move, you get rid of a bunch of clutter and crap and set up the new house to be more efficient than your last one. Could you have done it at your last house? Sure, but you didn’t because you were entrenched and had traction with the way things were.
Get a new bike frame desing, and along the way get a different helmet to match, change crank lengths and pull in the aerobars some and maybe drop the front end half a centimeter. You ride your old route half a mile per hour faster. It’s gotta be the bike! Nope, it was everything else.
I test rode one yesterday in Madison. Great handling bike, nicely spec’d with Di2, TriRig front brake, Zipp 808s. Beautiful bike except for the front of the top tube where it looks like a chunk was cut out of tube and the stem comes up. Anyone else bothered by that gap? I thought there was a snap on part over it missing or something. You can’t really appreciate it in most of the pictures of the bike as they are mainly black in color and the photos taken in mood lighting. The rep says some bike owners have fashioned their own cover for it and they are redoing some of the beams which are interchangeable and may address this. I just thought for a $12,500 bike it looked a bit unfinished there. Did I say it rides like a dream? Even with platform pedals on cranks that were too long and a cockpit that was too short, it rides beautifully.
If that’s the only thing that bothers you about the bike I’m pretty sure you can get a 3D printed piece to fill that gap either from Dimond itself or from one of the other Dimond riders who have done it.
I did a couple of reference tests in SolidWorks a few years ago.
Because it’s flat and virtually vertical, you can get a fair amount of air trapped in there depending on your bar setup.
I found virtually no difference when using a traditional horizontal stem and a base bar where the round section is wide enough to mount extensions on. With a wide, round trailing shape on the stem
There was a more measurable impact when using a chopped 3T Ventus. I believe this was because a lot of air was able to stay attached to the shape of the stem (which is narrow), and thus was directed into that relatively wide, flat area. It was on the order of 2W compared to filling in the space.
I did not test with a Zipp/Bonty style Kammback foil bar.
For easy of assembly, I would guess it’s worth it to leave that open and let people toil away on their 3D printers to get it right.
I am curiousl How do these bikes do when compared to a Falco, or to that new one that looks like an old lotis. Are there any studies on that?
I am curiousl How do these bikes do when compared to a Falco, or to that new one that looks like an old lotis. Are there any studies on that?
I’m not sure if anything exists around those comparisons. I looked at the Falco but I really liked the engineering, local production and the whole team at Dimond (and I liked the look of the bike more than the Falco). The handling on the Dimond is also the best I’ve had. The Ventum looks interesting - those Ventum guys have worked hard on the aerodynamics so I’m sure it’s pretty good. I actually like the way it looks too.
PS Jesse Thomas just won his first IM today (wales) on his Dimond - boooyah!
Except that I couldn’t with the “old house” ie the Shiv geometry had too much stack for my body type - my comparisons are using the exact same equipment except the frame, which does indeed allow for a better position, for me. A Trek SC would probably have been just as fast for me, but for me personally its too mainstream.
Jorden’s bike split margin doesn’t mean much. I think his IM NYC bike margin was probably about the same on a Shiv. You never know who will be at any IM so margins don’t tell you much.
I agree with this. He’s an excellent cyclist, and talked up the Shiv a lot. After leaving Specialized, he trashed the bike as if it sucks suddenly, now he’s talking up Dimond. I’m sure once he gets a new sponsor, he’ll be trashing Dimond in favor of the new sponsor’s bike. Leads me to conclude that bikes are basically fungible with someone as fast as he is (and thus likely to the rest of us).
It is their job to promote the bikes of their sponsors. I think Jorden does a good job of that. Funny thing is at IM NYC while riding the Shiv he beat Tollakson on the Dimond by 5 minutes.
I think the Dimond is one of the coolest bikes out there. I’ve had lust for my friend’s Zipp 2001 since it was new. I’m just not so sure that one top end bike is any faster than the other.