When the uci outlawed beam bikes it made it uneconomical to make them. Zipp quit and over time it killed softride as well. Titanflex kept going but it's a small operation.

My take is that on one hand the larger triathlon market and on the other the decreased cost and increased availability of carbon production has made it profitable for other small manufacturers to get into beam bikes again.

Also charging $6,000 makes it profitable (I have no idea what they cost to manufacture...just mad I can't afford one!)

I still do not know why they do not have a seat tube. The seat tube should help aero dynamics by creating a much better leading edge for the wheel than a tire. Even the part that does not shield the tire would create a bunch of lift of low yaw numbers, which is helpful. It made sense when the beam had some suspension in it, but both the Dimond and the Falco are rigid.

I think they are making a comeback because they look really cool. The dimond is also pretty aero, but I think it would be even more aero with a seat tube.

They still have a lot more give than a seat tube equipped bike.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

That is probably true, but you could always just have have the seat tube mounted to the beam with some compliance. Or even design the seat post with some leaf springs for vertical compliance. I would not be shocked if something like the Felt IA with its elastomers in the seat post would be pretty close to the Dimond.

I think part of the reason is that today's tri market no longer gives a damn what the UCI says or does. Once the superbike manufacturers gave the finger to the UCI, the green light was there for beam bikes to make a comeback.

What? No love for the Titanflex? It is a very comfortable ride, good results in the wind tunnel, affordable. If you have a bad back it is the way to go!

Never heard of Titanflex

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Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/

I still do not know why they do not have a seat tube. The seat tube should help aero dynamics by creating a much better leading edge for the wheel than a tire. Even the part that does not shield the tire would create a bunch of lift of low yaw numbers, which is helpful. It made sense when the beam had some suspension in it, but both the Dimond and the Falco are rigid.

I think you might be onto something. I am not an engineer, but I did ride a Softride to some success back in the early 1990's. What I heard back then, was that the exposed rear wheel of the Softride ( and the Zipp) was ONLY better, when you were riding a disc. When riding any other type of wheel with a rim, the bikes tested worse than bikes with a seat tube in front of the wheel.

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Steve Fleck @stevefleck | Blog

Keep in mind there is no seat stay on a beam bike and no seat tube. While the seat tube fairs the rear wheel in a conventional superbike, the seat stay causes drag.

Perhaps the fastest would be a bike with a seat tube, but no seat stays by beefing up the chain stays like on a Dimond. Just draw a line from the BB to the seat on the Dimond and fill in behind it with fairing up to the wheel and that is what i am talking about....just leave the seat stays out.

maybe there is no advantage to a seat tube, if you use the right tire and a disc?

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

every time I ride this bike...it put a smile on my face. so much more comfy that my P3-5 or road bikes. I m old now..i like comfort!!! I would not be interested in a beam bike if it wasn't bouncing..i need the bouncing to be comfy

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Jonathan Caron / Professional Coach / ironman champions / age group world champions
Jonnyo Coaching
Instargram

#legend

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Steve Fleck @stevefleck | Blog

http://www.titanflexbikes.com/

It really is a nice comfortable, fast ride!!!

I did not mention anything about seat stays.

A disk is probably really important on a beam bike. Even then, a seat tube is going to create a much better leading edge than a tire.

Wouldn't that pretty much be a Z frame?

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My Blog - http://leegoocrap.blogspot.com

The old lotus frame?

Yes, a Z frame. The old Lotus like this version, not the other Lotus that Boardman rode in Barcelona that has the "uni-seat/chain stay"

LOL....we both pulled this up a few minutes apart....

I hate to tell you this...but my post was first.

on a more serious note, I would love to see a current manufacture take a stab at this style of frame.

Except a downtube is also good for aero. It is able to treat the flow coming off of the front wheel. A downtube will also work better in yaw than the top tube on that lotus bike. Ideally a bike would have a seat tube and down tube, but a thin top tube is probably worth the small amount of drag for structural reasons.

Also, flat pedals?

I've watched the videos on youtube where the guy makes his own Z frame (actually his wifes...)

I'm a cheap vacuum bag away from trying to make one... (probably failing in epic fashion though.)

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My Blog - http://leegoocrap.blogspot.com

Change the front end shape to mate with the front wheel. I would need a large chainring though.

Hi Chaparral,

The beam on the Dimond has about 5-7 millimeters of flex. As far as I am aware, a seatpost that is able to attain the same range of displacement does not exist outside of suspension seatposts, which are neither aerodynamic or competitively weighted. The beam design does offer a significant comfort advantage (which, I would argue, leads to a performance advantage over IM length races), though we were very particular to make sure that the natural frequency of a rider on the beam was much higher than typical pedaling rpms in order to avoid "pedal bob".

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David Morse

Hello

You want to sponsor a Fat guy with no talent on his quest to reach kona in 5 years?

Hi Jack,

Exactly - an appropriate width clincher tire matched to an aero wheel actually makes a pretty good leading edge, especially at yaw. Furthermore, the added surface area of a seat tube contributes to overall drag caused by viscous shear. Any would-be gains made from fairing the tire with a seat tube would have to be weighed against the frictional losses caused by the added surface area.

Indeed, current traditional TT/Tri bikes have been undergoing constant refinement and optimization using very sophisticated engineering design tools over the past decade. I think it is a great testament to the aerodynamics of the beam design that the Dimond is able to compete with and out perform these highly optimized designs despite being in its first iteration.

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David Morse

GT Superbike, built for the 96 Olympics:

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''Sweeney - you can both crush your AG *and* cruise in dead last!! 😂 '' Murphy's Law

My BP Stealth has noticeable vertical flex/give, which is great, and quite a lot of side to side flex when climbing out of the saddle, which isn't quite so confidence inspiring.

I really recommend them. Although the geometry is road-based, you can get round that with a forward post, they're cheap, weird, turn heads, won't lose value, are really easy to build up, and seem to be fairly fast.



Picture is during the build.


Post build:

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´Get the most aero and light bike you can get. With the aero advantage you can be saving minutes and with the weight advantage you can be saving seconds. In a race against the clock both matter.´

BMANX

Hey David, you're too modest. Your Dimond reflects excellent execution of a beam bike. Plenty of other beam bikes have mucked up design and execution. You've corrected many historic issues, so while this is your first Dimond iteration, you've evolved cutting edge distinctions.

Keep the good work guys! I love what you are doing! I m a big believer in the beam bike concept.

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Jonathan Caron / Professional Coach / ironman champions / age group world champions
Jonnyo Coaching
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I did not know it was that much flex, do you know how much the IA's elastomers deflect? The comfort factor is good, but I am still not convinced that seat tube (or even a vestigial seat tube) would not be even better. I mean the beam does not need to firmly connect to the seat tube. Maybe it could even be used to store spares.

What about:

http://images.worthpoint.com/...ins/spe/4/3575-7.JPG

Is the Dimond bike OK to use on a standard skewer clamped trainer? There are other threads which claim it is not OK for trainer use.

Holy chainring!

Hello beautiful! I know the eye isn't a great wind tunnel but that bike looks FAST!

Re-doing a softride tt7. Will post some pics after the build.

I always wondered how fast this bike was, bought it in 2012 as frame only from a shop in Chiliwack. Brand new but from 1998…..Sitting in his shop for 14 years!!

Had to buy it last minute when I finally realized the P-5 wasn't coming that year, raced it in CDA and IMC. Not sure about aero…but Mike Burrows is a smart guy.

Maurice

I have to agree but for a different reason. If you look at both the P5 and the Speed Concept they maximize the size of the seat tube near where it meets the top tube (in Trek's case, they do this with the draft box). In Cervelo's white paper, the stated reason was to reattach airflow behind the rider sooner and therefore reduce pressure drag.

With that said I think Dimond is on to the right thing with rider comfort. IMO the next generation of UCI illegal superbikes will probably continue and improve upon current storage integration. The only aero improvement I see being made across the board is elimination of the seat stays in favor of larger chain stays ala the QR Illicito. Bikes that don't have integrated front brakes will likely move to straight pull brakes. Otherwise the focus will be on comfort, likely with some sort of dampening built into the seat post similar to 3T's mounting mechanism.

Like this?? Plus or minus disk brakes:

Culprit Legend

The Culprit Legend is still a work in progress and will make it to market next year is the plan. Keep your eyes out for the bike launch again. yes, it will have disc brake option as I believe it takes brands like Culprit to start developing the bikes for the brake makers to jump in. But the bike can also run rim brakes.

Get ride of seat stays = less drag
Disc brakes = more drag

So what's the point?

you painted it???? enjoy the ride!!!!

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Jonathan Caron / Professional Coach / ironman champions / age group world champions
Jonnyo Coaching
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Yes, no seatstays reduces drag, Disc brakes add some drag. However, you choose your option. The beauty of my design is you can have either rim brakes or disc brakes on the same frame. Such as our Croz blade bike. In a race course like Challenge Phuket where you have about 20 km of very technical riding with hay bails out on the turns and often wet rainy conditions. disc brakes have an advantage. on a flat course. go rim brakes. Best of both worlds. With the new shimano flat mount design, disc brake mounts wont come at much an aero dis advantage anymore.

I live in Taiwan full time, it rains in Asia alot. disc brakes on my Croz Blade are something I ride and have no desire to go back to rim brakes personally. The biggest issue with disc brakes are those who have never experienced them on a road bike at speed. Go try the new Shimano ST-785 or ST-685 and they are a game changer. Imagine that kind of control and performance gains on technical courses.

Point here is this, If its a flat course, of course, run rim brakes for a faster build. The bike will have that option. If you are riding a course where confidence and ability to descend at higher speeds with more control gives you an advantage, then disc on that course has its advantages. The frame does not force a rider into rim or disc. It only opens the options to the rider.

Bikes are also about being different and unique. Culprit bikes are all painted to order and this future model and Croz blade lets the buyer have a bike that has more build options and that is something we are proud to offer, versatility. The new design will also be very fast as I am working with a very capable CFD expert in developing the re designed frame.

Bikes are all about the buyers choice. Having a bike with disc brakes is different and some people want that unique bike as well as confidence in the bike increases ones athletic ability.

Not to speak for them, but I think the "point" is innovation, somebody has to be first to try new things so that technology can improve. Like say without Mavic Zap (which was miserable) we might not have Di2. Or without Zipp/Softride we wouldn't have Dimond/Falco, etc.

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My Blog - http://leegoocrap.blogspot.com

It is just frustrating when the better solution is clearly to just use a rim with a better material for braking, which is avoided because it adds weight, so instead they add disc brakes, which also add weight, and drag.

It is just total madness

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

well... some innovation does end with a closed door. :D
Personally I think rim braking is beyond adequate on 99.9% of the roads a triathlete will ever face (and most road riders too) but if somebody found a way to get the caliper integrated then sure, maybe in 10 years we're all riding disc Discs!

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My Blog - http://leegoocrap.blogspot.com

Can I ask why the Dimond engineers chose to leave a gap between the frame and the stock fork? It sticks out visually, and it looks as if it's begging for something like an FK26 to mate better with the frame...

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ZONE3 - We Last Longer

My point for pointing out the bike was that we may soon know what the aero benefit of no seat stays is with this bike...Yes the picture is of the disk brake variety, but as stated it CAN be fitted with rim brakes.

Unfortunately my internet skillzzzzz did not find a culprit picture with rim brakes.

I think the Culprit style design may offer the middle ground between beam and current superbikes (in rim brake configurations)...This is a guess but Im interested to hear what the ST aero experts think a seat stay-less design would do

Wouldn't the only way to see the difference between a frame with and without seat stays be to use the same frame? I would wager that current superbikes are more aero pretty much everywhere so how would you be able to tell if an gains were due to the lack of stays?

Also, will this just follow the beam bike trend of testing faster until you put a rider on the bike?

Well, thats not an apples to apples comparison...

If you took a current superbike, and cut the seat stays off, the bike would have inferior stiffness/handling characteristics (assuming the current designs are at the reasonable limit WITH seat stays)

I think what the culprit style design (not necessarily the culprit) does is trades beefier chainstays that have less aero impact and forgo the seatstays.

It is all speculation on my part, and Ive never ridden a beam bike, but I think the culprit style design is very intriguing.

I will need a day or 2 to find the data. When Culprit Launched the Legend we did wind tunnel testing of the same bike built with Rim brakes to run against the version of the bike for the other brand I shared the molds with originally before moving on, Theirs had seatstays, mine didn't. I will post the drag differences of that frame with and without stays to show the improvement of no stays. Again, that bike had some areas we have further improved on and you will see them on the new version set to release sometime next year. Glad to see Culprit getting some chatter.

I believe in the future the disc will be better integrated into the bike, etc, but until it is mainstream, opening a caliper, design, etc gets expensive for a young innovative brand. Ashima was working on hydraulic levers and calipers with me until some changes in the company occurred and their main engineer/manager pushing the project moved to another company, thus stopping the project in its tracks. But they were beautiful and well designed together. It takes someone to make that leap, as said before for more to follow. When we launched the Croz blade rim/disc frame in 2012, we were among the first in the road disc movement. one of the first race geometry road disc. Many told us we were nuts, but look where that technology has gone since then and continues to improve.

Give tri disc some time, it will eventually get there. til then, brands like Culprit and Ceepo are pushing and pulling to at the forefront. When the big brands follow, it was because the small brands created a small demand and the big brands justified it for shimano , sram, campy, magura to jump in. etc

The biggest benefit I've noticed is handling in cross winds. Kona was very windy this year, and I felt super stable on the Dimond, compared to a few sketchy moments I had on a different bike in 2013 (easier year, less windy). This allowed me to ride with a lot more confidence and therefore faster, especially in the fast sections. As for aero/watts savings, I know it's not very scientific to use race time/effort as a benchmark, but this year I was only 5 mins slower, on lower watts, in tougher conditions.

2013: 4:55 on 236w NP 222 AP (fast year)
2014: 4:59 on 226w NP 204 AP (slow year)

Of course there are other variables (such as body position on new bike) but everything else (clothing etc) was the same. I know you can't read too much into this, but to me, this data is validation that cleaner, more aero bike + better position = better performance for less effort

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Are you ready to do an Ultraman? | How I calculate Ironman race fueling | Strength Training for Athletes |

Don't know about crosswinds as I only ever feel their impact on my front wheel (and I always run a disc). I would think that the higher position I'd be in due to increased stack would play a bigger role in stability in crosswinds. There's also no way I can get as good a position on a beam bike which is the main reason I wouldn't buy one (the second being aesthetics).

wut?

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

I figured that last time I looked. Upon looking again, I could replicate my position but I'd be limited in my choice of bars and would sit a bit higher on the bike (not ideal). I still don't really see the point of beam bikes as the aero credentials don't really seem to be there and I don't suffer from any comfort issues. Different strokes I guess.

Oh, you can't get in a good position on some particular beam bike. That makes more sense.

The Dimond appears to have pretty good aero credentials.

But I agree about comfort, I've never had any issues with that either.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

I think the Dimond has very similar stack/reach to a P5

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Are you ready to do an Ultraman? | How I calculate Ironman race fueling | Strength Training for Athletes |

Perhaps, but not a Plasma 3 TT. My position is good and I'm fairly certain my Crr is pretty low (find out for certain when the weather is good enough for an aero test). Basically if it ain't broke. If it were I'd probably go for a Plasma 5 as the price is competitive and I know I can get the same position without a lot of faffing.

Still not convinced about any aero gains: http://www.rustersports.com/...eport-11.14.2013.pdf

Worth noting the rider position in their test is absolute pants. Seriously, who rides like that?

The goal was to create a position that could be reliably replicated. It is possible that there is some interaction between that unusual head position and frames that could differ a bit between frames but probably not much.

A mannequin would be better but that is not a bad choice when testing with a human.

The P5 is being hurt a bit by the upturned aduro levers though, at least a gigaton of drag! ;)

still I think the Dimond is doing well there, and they have a better fork coming

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

You can get the same position on the Plasma 5 that you have on the Plasma 3 TT? Looking at the stack and reach numbers of the Plasma 5, the frame looks to be pretty short and tall.

Yeah with the zero rise stem (published figures are with the 45mm rise).

Published numbers are WITH 45mm riser stem?

That's my understanding although I could be wrong (in medium the 3 Premium is 545 w/riser stem and 505 with flat stem whereas the 5 shows 540mm). Looking at Svein Tuft's fit from the 3 TT to the 5 there's barely any difference, so it seems easily achievable.

Do you have a photo of Svein on the 5?

He's on the new 5 in the first photo but he's got the flat stem not the riser stem. I wish it weren't the case but I think the published stack/reach numbers do not include the riser stem.

Take a look at the 3rd (Plamsa 5) and 4th photo (Plasma 3). Certainly doesn't look like a 35mm difference in stack...

Maybe you're right. I certainly hope so.

also, disk brakes require crossed spoke patterns; I'd think 3x minimum - yikes! A radial spoked wheel with disks - ouch!

As a triathlete I've never needed more brakes than I have. Disks on my Motorcycle? I'll take 3 Brembos to go please.

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I saw this on a white board in a window box at my daughters middle school...
List of what life owes you:
1. __________
2. __________
3. __________

Here is perhaps a better comparison of fit on the 5 vs. 3, both with TT stems.

One overlooked fact is that the wave of wide rim wheels are eliminating the "advantage" of having a seat tube as a leading edge for the wheel. The wheel/tire combo is becoming a rather decent leading edge itself already. The seat tube which is 8-15mm in front isn't adding anything.

BINNY@FalcoBike

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Yes, it is true for now disc brakes wheels are all laced, but I believe in time, there will be tri spokes and disc wheels with disc brakes cutting that drag down dramatically

Here are the drag differences of the Culprit Legend Run against another brands version of the shared mold with seatstay, then run with disc brakes. Please Note, for the disc brakes, I ran it with a cut out behind the post, and the rim brake version was run with tape over it closing it , which we found to be faster.

I used the Legend with Rim brakes and no seatstay as the starting numbers and show the drag increase for stays and with disc brakes. again, Believe with technology advances those drag numbers will come down, this was done using Ashima mtn bike brake calipers and all bikes were run with the same 55 mm rim from Trigon, Disc build had a disc brake wheel build. Also, round spokes vrs aero spokes. marginal differences, etc

Most beam bikes use a pivot for height adjustment which, aside from the odd result that tall guys will end up w/ a more forward saddle, simply puts a huge load on the pivot -- simple physics of leverage. Pivot v. monocoque makes a world of difference. Softride recommended beam replacement every 5K miles. A monocoque design however, is a completely different matter. There is a lot of carbon at the front and it's ONE PIECE which helps a lot. The pic below shows the size of the structure against our road frame, which passed EFBe's toughest test standard. Our own testing was based on 300lb rider weight, so durability I won't worry about. FYI carbon has superb fatigue characteristics unlike alu, so if it doesn't break in 500 reps under load, it most likely won't break in 100K or 200K reps.

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https://www.facebook.com/falcobikeglobal
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Can anyone tell me how to upload a chart with drag n umbers. I have tried over and over again even uploaded an image to FB but cannot get it to work or show in forum

Here is the link if you need it. Sorry I cant get it working in the forum

https://www.facebook.com/culpritbicycle/photos/a.759280034151598.1073741843.325827290830210/759288114150790/?type=3&theater

if batman rode a pushie...then the falco would surely be his ride. I love the look!

Yes you can use a standard road stem... I rode one like that for weeks at the prototype stage (still remember the looks of the local cycling boys when I showed up for the weekend warrior rides, LOL). The adjustable stem can also get you a "negative" rise which lowers the bars a bit more.

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http://www.falcobike.com
https://www.facebook.com/falcobikeglobal
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Here you go!

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´Get the most aero and light bike you can get. With the aero advantage you can be saving minutes and with the weight advantage you can be saving seconds. In a race against the clock both matter.´

BMANX

Thank you. I appreciate it.
The new Legend under re design will be much faster. Will have to wait til next year to see.

i'm wondering of the shiv fork would work on the dimond? looks like the cutout on both frames are very similar, any idea?

The first TitanFlex was designed in 1991 to enable me to return to cycling after back surgery. The Softride of the day was very heavy and--in my opinion--had too much flex. Using a titanium boom kept the weight down and enabled the amount of deflection to be customized. (US Patent #5,474,317)
I never had ambitions to build a bike empire...only wanted to have fun making and selling them direct--which the dawn of the net afforded. Because I have zero overhead (no advertising expenditures or college tuitions) I can pass on my component costs. How about $1600 for an Ultegra Di2 grouppo which includes everything but pedals. This even covers assembly and ground shipping costs!
Over 20+ years with the help of 600+ owners, the design has been incrementally enhanced--and still made in the USA. I'm in the process of updating the website with new images. Please visit http://www.TitanFlexBikes.com for the full story.

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Tom Piszkin
UCSD Triathlon Coach
@TitanFlexBikes
(619)334-7222
(619)328-1870 FAX

I got my titanflex before my back surgery. I guess I did it backwards.

How does the integration compared to that of the adjustable version?