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Guru frames inefficient?
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Does anyone out there have any experience with riding a Guru (crono) frame vs. a different frame in respect to speed vs. power production? I've had 2 athletes experience the same issues on a Guru crono over the past 3 months in that on the Guru's it is taking much more power (25-30w) to go the same speed. I realize all of the variables that go into this equation (wind, terrain, position, etc...) but we've collected enough data points using their SRMs and similar conditions to suggest that the Guru is just less efficient as demonstrated by needing 8-13% more power to maintain an absolute speed... Anecdotally both athletes reported feeling slower on the bike (despite one being tested at the A&M wind tunnel with Cobb and put in an optimal position) and say they feel like there is just a loss of power transfer with the bike...

Just trying to figure out what could be causing this and if anyone else has experienced it or found a solution for it.


http://www.source-e.net
Last edited by: SE: Jul 8, 08 14:18
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Re: Guru frames inefficient? [SE] [ In reply to ]
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Having witnessed certain posts, over the last little while, asking questions about the quantitative performance credentials of our bikes, we have finally managed to convince our engineering crew to snap out of their understated nature -- they don't like to brag -- and flex a little muscle. Based on popular demand, we are currently running a series of comprehensive performance tests, conducted by actual scientists (i.e. led by an independent PhD specializing in cycling performance) to substantiate what the vast majority of our GURU owners tell us: the Crono is the fastest bike they have ever ridden. What is the definition of "fast"? That is a great question…
  • Is it the most aero bike? That's certainly a part of it, but it’s definitely not the only thing, given that the actual coefficient of drag created by a tri bike is negligible when compared to that created by the rider himself (nothing creates more drag over the course of a long ride than a rider moving around to relieve discomfort). We often hear from first-time Crono owners that the ‘no compromise’, custom fit we delivered allowed them, for the very first time, to complete the bike portion of their race without ever getting out of their aero position. And that they never felt more energized in the legs to attack their run portion.
  • Is it the most stable bike? The smoothest, best-handling machine that allows you to push to the very limit of your speed because you are in complete control (regardless of any change in terrain). 100 mph in a Ferrari and 100 mph in a stock Ford Escort are both possible. Good luck trying to sustain the speed over time in an Escort. Other than the odd exception, you won't find one of our custom Crono's with a ridiculous number of head tube spacers, an off-spec stem or maxed-out saddle position. For us, proper weight distribution on a bike is a key contributor to an efficient power transfer and overall speed (going straight, uphill, downhill and around turns). For some reason, this point is rarely brought up in the industry.
  • Is it the stiffest bike? Our Crono design is based on aerospace parameters and was conceived to take full advantage of carbon fibre’s tensile properties. It is based on extensive FEA modeling and features the very highest carbon-to-fiber ratio (70/30) in the industry to optimize power transfer. That said, if maximizing stiffness as a definitive was the way to go, we’d all be riding I-beams on wheels. There are obvious trade-offs of weight and vertical compliance/comfort to consider. It’s all a question of balance. To quote Desirée Ficker, “the Crono is the purest, smoothest power transfer” she has ever experienced.

We recognize that we probably have not done a very good job communicating the science and technical characteristics that make the Crono such a special bike. It’s time for us to speak up. Results from the aforementioned testing should allow us to start addressing this point moving forward. In the meantime, I submit the following to you: We just recently had one of our athletes, Wolfgang Guembel, win the Muskoka Chase up here in Canada; Joanna Zeiger and Dede Griesbauer finish 1-2 at Eagleman; Gina Kehr beat her PB on the bike by 2 minutes (in her first race after giving birth and first race on a Crono) on her way to victory at the UVAS South Bay Tri; Viktor Zyemtsev finish 2nd at Coeur d’Alene the very first time he rode a Crono. Straight-Up: Every one of these athletes could probably score a bigger endorsement deal with a bigger company. They came to GURU because our bike could make them faster. It did.

Rob
Guru Marketing
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Re: Guru frames inefficient? [Guru Bikes] [ In reply to ]
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...features the very highest carbon-to-fiber ratio (70/30) in the industry...
Do you mind if I ask what "carbon-to-fiber" ratio is? Are you referring to the carbon-fiber to glass-fiber ratio used in the frame?

Other than that, your post is not really an answer to what makes a GURU fast. It is, rather, the stock answer that custom builders always give about what makes a custom bike better than an off the shelf bike. I dislike this argument a great deal, because simply put, custom geometry does not equal comfort. Correct position equals comfort. Just because I have a custom bike, it doesn't mean my position is good. There are a TON of stock bikes out there. It is rare to find someone that doesn't fit pretty darn well on stock bike. Ever wonder why all the CSC guys ride in almost identical positions? Because there is a consistency of positioning. We are not all beautiful and unique snowflakes. Custom does not guarantee a good fit. In fact, I would argue that you are just as likely to see a crap position on a custom bike as you are on a stock bike. Frames are rarely the limiter to a good position. And given that most people will usually fit one of several frames, then the frame itself does matter. So if I can get in the exact same position on a Felt DA as on a Guru Crono, then wouldn't I want whichever of those frames is actually aerodynamically superior? What is perhaps more likely is that if someone buys a GURU, they MUST get fit for it. Whereas I can buy a Felt DA in the mail. So really, that's an argument for FIT, not for custom.

In terms of stability, that's really an issue most often with long legged riders who need more wheelbase. But more and more bikes are being built with plenty of front center. That's really the ONLY issue facing tribikes in terms of handling, and most of the good ones have addressed it. I don't see at all that it is rarely brought up. It is entirely the thinking behind the front end geometry of, most notably, Cannondale's and Specialized's new bikes. Custom is an advantage for short-torsoed/long-legged riders (who are the most likely candidates for custom bikes), but that's a small percentage of riders, and even among those riders, a good fitter can still usually provide several options, though of course you may be slightly restricted on what aerobars you can ride, but that's a relatively small price (and even that is likely debateable given the adjustability of most modern aerobars). I'd honestly be very surprised if the geometry of the bikes you built for any of your pro athletes was not remarkably similar to two or three of the bikes we have in our database. I'd wager that I could fit everyone of those athletes, with less than 10mm of spacers, on a handful of stock bikes that have basically indentical geometry in all aspects that matter.

The last point is also mostly marketing speak. Is Desiree equipped with an internal strain gauge monitor? I'm not too worried about power transfer on most bikes, since I am pretty sure I put out less power than David Millar or Fabian Cancellara or George Hincapie or Alberto Contador, none of whom seem to have too much trouble with their frames wobbling underneath them. What is that optimal point of stiffness/compliance? And how do you find it? I'd argue that's a purely subjective point, where I think you'd be hard pressed to find any company with a distinct advantage (among those that actually invest in carbon fiber development).

So, as semi polished as what you've written here is. It's also remarkably obvious that you are part of the marketing department. Now, even within that understanding, I don't see that you've written too much here on why I'd actually want a Guru. You've given me plenty of reasons to get a custom (sort of), but why wouldn't I just go buy a Parlee (for example)?

"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp
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Re: Guru frames inefficient? [Rappstar] [ In reply to ]
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since I am pretty sure I put out less power than David Millar or Fabian Cancellara or George Hincapie or Alberto Contador, none of whom seem to have too much trouble with their frames wobbling underneath them.

Jordan,

Me to. Great line.

It always amazes me how people obsess over the stiffness of a bike when just about all us will never come close to the power out-puts of the top pro riders who these days are often riding in the same bikes that anyone can buy in a store.



Steve Fleck @stevefleck | Blog
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Re: Guru frames inefficient? [SE] [ In reply to ]
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In Reply To:
Does anyone out there have any experience with riding a Guru (crono) frame vs. a different frame in respect to speed vs. power production? I've had 2 athletes experience the same issues on a Guru crono over the past 3 months in that on the Guru's it is taking much more power (25-30w) to go the same speed. I realize all of the variables that go into this equation (wind, terrain, position, etc...) but we've collected enough data points using their SRMs and similar conditions to suggest that the Guru is just less efficient as demonstrated by needing 8-13% more power to maintain an absolute speed... Anecdotally both athletes reported feeling slower on the bike (despite one being tested at the A&M wind tunnel with Cobb and put in an optimal position) and say they feel like there is just a loss of power transfer with the bike...

Just trying to figure out what could be causing this and if anyone else has experienced it or found a solution for it.


http://www.source-e.net
the number you are mentionning are for yaw of 15+ degress..... at 0 yaw, the crono isnt as bad and will only cost you about 7-9 watts penalty over the top aero frame on the market.

Jonathan Caron / Professional Coach / ironman champions / age group world champions
Jonnyo Coaching
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Re: Guru frames inefficient? [SE] [ In reply to ]
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Two Missing Pieces of Info:

- Did you try doing the analysis on a trainer where drag is not an issue to try and determine if the inefficiency was from drag alone, a combination of drag and mechanical, or mechanical alone?

- Why don't you name the 'different frame'? Is it a CAT? Or a P3C? Or a Giant OCR 3? Kind of important, isn't it?
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Re: Guru frames inefficient? [Rappstar] [ In reply to ]
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It's also remarkably obvious that you are part of the marketing department.

Nice deduction, sherlock. Did you read his sig?

I kid, I kid. You did such a great job tearing into him that he probably will not respond. I wonder if they can just take the lesson and develop a new bike. It's not like Cervelo and Trek have a monopoly on good designers or wind tunnels.

In his defense, you can't get nearly as nice a paint job on a Parlee. Did you see the flowers they put on Des's?



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Re: Guru frames inefficient? [Rappstar] [ In reply to ]
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while the post you replied to definitely could have been from their marketing department (although I have spoken with their head of marketing and this does not appear to be written in the same type of language I would expect him to write), I did work with them when I was at my old company, and I know that Simon (one of their engineers) has already implemented some stiffening of the frames simply through ply manipulation (as you have seen how that can be done with my old software company Jordan). I doubt stiffness has anything to do with losing power, and wondered if it was simply different positioning that can attribute to a 10+% loss of power? That seems to be quite a bit for a frame only.

I have seen people who have lost power and increased overall speed due to better positioning that allowed them to stay aero longer, but there is just no way to attribute this immediately to a frame (as ST likes to also stipulate that a 10% increase is not able to be attributed to frames, powercranks, etc.

:-)

Craig Preston - President / Preston Presentations
Saving the world with more professional, powerful, and persuasive presentations - one audience at a time.
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Re: Guru frames inefficient? [Learn] [ In reply to ]
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It's also remarkably obvious that you are part of the marketing department.

Nice deduction, sherlock. Did you read his sig?

I kid, I kid. You did such a great job tearing into him that he probably will not respond. I wonder if they can just take the lesson and develop a new bike. It's not like Cervelo and Trek have a monopoly on good designers or wind tunnels.

In his defense, you can't get nearly as nice a paint job on a Parlee. Did you see the flowers they put on Des's?


I was amazed he felt the need to indicate that he was part of the marketing department in his signature. I was pretty sure we all figured that out well before we hit the end of the post. ;)

It was funny, after I replied, I realized that I should have added, "if you really want to sell more bikes, talk up the paint jobs. THAT is why I'd buy a GURU (were I to ever do so)."

"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp
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Re: Guru frames inefficient? [Rappstar] [ In reply to ]
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I assume he meant "fiber-to-resin" ratio. He should have run the post by the engineers first.

He should also have enough ST knowledge to know you can't post marketing-babble on ST and expect to get away clean.

That said, I don't really understand the anti-Guru sentiment on ST, which is about as well supported as the marketing-babble.


> why wouldn't I just go buy a Parlee (for example)?


If you're buying a TT bike and you're using your own money, I'll give you about 6000 reasons.
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Re: Guru frames inefficient? [Rappstar] [ In reply to ]
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It was funny, after I replied, I realized that I should have added, "if you really want to sell more bikes, talk up the paint jobs. THAT is why I'd buy a GURU (were I to ever do so)."
Except their paint is crap...looks great but is extremely fragile.
Tracy's Crono is chipping worse than any bike I've ever seen and when I emailed them about it, they offered to send me a paint pen for $20. Oh and by the way, doesn't even match...


Shawn
TORRE Consulting Services, LLC
http://www.TORREcs.com

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Re: Guru frames inefficient? [Rappstar] [ In reply to ]
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...I don't see that you've written too much here on why I'd actually want a Guru...

Custom does not just mean seat tube and head tube length. It also means angles to suit your riding style. It means extra strength where you need it. It means not having to compromise and put an overly long or short stem. It means adding a bit of rake to suit the terrain you ride most.

It also means not having to have a vanilla bike.

If this was any other industry rep posting on slowtwitch you would fall all over yourself because they are using this site to communicate with the people who care most. If you give too many legit posters a hard time then other potential industry reps might think twice about posting here.

The original post named GURU bikes and who best to try and answer the questions than a GURU rep.

This all reminds me of Mac vs. PC.


You just won't get it until you've used a Mac.
You just won't get it until you've ridden a GURU.

__________________________________________________________________________
Bike Centric Art
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Re: Guru frames inefficient? [cupajoe] [ In reply to ]
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In Reply To:

Custom does not just mean seat tube and head tube length. It also means angles to suit your riding style. It means extra strength where you need it. It means not having to compromise and put an overly long or short stem. It means adding a bit of rake to suit the terrain you ride most.

The original post named GURU bikes and who best to try and answer the questions than a GURU rep.


THe HTA and rake values tend to fall within a fairly narrow range and few people are quite as unique as custom brands would have you believe. Most stock bikes are overbuilt for the people who buy them. A triathlete pootling away to a 30kph sub 200w half or IM, or a century rider of similar capabilities is kidding themselves if they think they need a beefed up frame. On our hammer ride the P3Cs and P2Cs are often subject to 1200w plus for crossing sprints and no one has yet complained of flex in the frame. The things you list are part of the package for a frame that is well designed for its intended purpose - a lot of stock frames fail to meet this criteria so custom is a big improvement just by adhering to basic principles. There are stock frames that are well designed for the purpose and they elicit similar rave reviews to custom.

I really like Gurus but as Jordan said - their success is based on fit. Purchases of stock bikes are driven by price, or what such and such race winner rides, or what all my buddies have - if they were selected by "this is the position I need and this is the bike that fills in the dots and has appropriate features for the intended use" - the job of custom builders would be somewhat harder.

Given that the OP was asking why Gurus seemed slow I'm not sure that someone from guru is the best to answer. I'd suggest that someone following the Tom A testing protocol (preferably blinded) would be best to answer the original question.
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Last edited by: lschmidt: Jul 8, 08 19:30
Re: Guru frames inefficient? [Rappstar] [ In reply to ]
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Yeah, he was clearly confusing ST with one of those OTHER triathlon magazines where he is use to the writers blowing cool air on his balls ;)
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Re: Guru frames inefficient? [cyclenutnz] [ In reply to ]
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...On our hammer ride the P3Cs and P2Cs are often subject to 1200w plus for crossing sprints and no one has yet complained of flex in the frame...

This is what happens when someone mentions GURU. They immediately compare them to a Cervelo.

But you would not believe the feel when in the aero position. I tell you it's like you are being pull by an invisible rope. And if I can feel that and take advantage of it then a pro certainly could.

Not everything can be boiled down to watts and tunnel tests.

__________________________________________________________________________
Bike Centric Art
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Re: Guru frames inefficient? [cupajoe] [ In reply to ]
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Before I bought my bike, I was wavering between the Crono and the P3C. I tried out both bikes - back to back a few times, going from one to the other, as the shop I bought from's owners all rode Guru and they had one in my size.

I gotta say - the Guru did *feel* faster. I remember getting that feeling the first time I rode one when I was initially trying about six bikes. I only tried the guru by accident - and it wasn't my size and it didn't have aero bars. It just felt like it had a better power transfer.

I can't quantify that.
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Re: Guru frames inefficient? [Learn] [ In reply to ]
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Here we go...

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Bike Centric Art
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Re: Guru frames inefficient? [cupajoe] [ In reply to ]
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as much as you feel pull by a invisible rope... it will cost you a lot more watts to ride the same speed on that bike that on a aero bike. IT s not a opinion but a fact. It s very simple, just look at the shape of the tubes on the frame, they are square and triangle and sharp edge... airplane would never fly if they were using aerodynamic principale like this....

even more: Tony, the founder of the company say himself in his blog on the guru website that he knows guru dosnt make the most aero bikes out there. They do not beleive it s one of the most important criteria so prefer to focus on other area....

Jonathan Caron / Professional Coach / ironman champions / age group world champions
Jonnyo Coaching
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Re: Guru frames inefficient? [cupajoe] [ In reply to ]
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...On our hammer ride the P3Cs and P2Cs are often subject to 1200w plus for crossing sprints and no one has yet complained of flex in the frame...

This is what happens when someone mentions GURU. They immediately compare them to a Cervelo.

But you would not believe the feel when in the aero position. I tell you it's like you are being pull by an invisible rope. And if I can feel that and take advantage of it then a pro certainly could.

Not everything can be boiled down to watts and tunnel tests.

It sounds like you have a bike that fits you well, which is great. I have a cervelo that fits me well, before that I had 2 cannondales and a giant (just talking about tri bikes) that fit well, none of them had an issue with power transfer and among amateur cyclists I'm as likely to notice as anyone (thanks to being big and powerful). THe fact that I mentioned cervelos is incidental - my point was that riders putting a lot of power down have no issue with the stiffness of most stock frames, nor do they have issues with handling and it is possible to find bikes to suit most positions.

This thread is about efficiency - which means it is all about watts. The OP says that some of them are disappearing on the Gurus, this is bad. When I changed to the P2C my power to drag got much better - that is measurable improved efficiency. I'm sure Jordan had the same when he went from QR to Trek (to use non cervelo examples). The 40s improvement over 10mi felt like an invisible rope to me too - I can quantify how hard that rope was being pulled, for the OP this rope is being pulled in the other direction and he wants to quantify that. So watts and tunnels are germane.
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Re: Guru frames inefficient? [jonnyo] [ In reply to ]
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Never said the bike was aero. Just feels amazing. There are some things you can't measure.

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Bike Centric Art
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Re: Guru frames inefficient? [cupajoe] [ In reply to ]
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i agree with you. And in the end, it s important to be happy and love your bike. All my friend that rode guru said it felt so nice and amazing to ride. I beleive them.

But if speed is what you look for or you want to get to the finish line asap... the crono isnt a good choice ,as good as it feel, it dosnt move as fast as it should. i would recommend the guru mantis that will be a lot more aero and faster or simply go with another company that make fast aero bike.

Jonathan Caron / Professional Coach / ironman champions / age group world champions
Jonnyo Coaching
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Re: Guru frames inefficient? [jonnyo] [ In reply to ]
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I think you guys are missing one important point in this discussion: How do you feel running after you get off your ultra fast bike? The bke is the prelude to the run. If you have a great fit, and feel fresher off a slighly slower bike, and can run just that much faster, then are you not ahead at the final point that really matters (the finish line)?

Maybe a custom frame like a Guru is a tad slower than a Cervelo. But if the bike fits you better, and you run faster as a result, then you are ahead of the game I would think. Just pointing this out....

TT
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Re: Guru frames inefficient? [jonnyo] [ In reply to ]
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the crono isnt a good choice ,as good as it feel, it dosnt move as fast as it should

Complete overstatement. I am in that 10% (or is it 1%) that truly does not fit on stock bikes. Monkey arms, long legs, disproportionately short torso. I did not go in to Transition Cycle to get a Guru. I went in to get a fit and pick a bike based on that. After extensive measuring by a FIST certified fitter and power measurements in various positions, we got my numbers. There wasn't a stock bike out there that would have fitted me without significant alteration. A P3C (my first choice) for example would have been a joke with enough spacers to get it banned from ST. The Argon 18 was the next choice. No go. We got to the Guru Crono after we could not find anything stock that would fit. Regardless of the aerodynamics of the frame, I simply would not have moved as fast on any of those frame as I do on a properly fitted Crono.

I really do not understand the anti-Guru-animus that seems to permiate this site. Life was REALLY rough around here for me when I had my Ergomo on my Guru Crono. Thank gawd I now have an SRM ...

If there are no dogs in Heaven, then when I die I want to go where they went. - Will Rogers

Emery's Third Coast Triathlon | Tri Wisconsin Triathlon Team | Push Endurance | GLWR
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Re: Guru frames inefficient? [Guru Bikes] [ In reply to ]
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"Our Crono design is based on aerospace parameters"

May be it would be faster if it was designed to be ridden on the road.

(sick of bike companies saying aerospace - just because carbon fibe is used in the aerospace industry - the arospace industry also uses steel, titanium and aluminium - do marketing people think we are dumb)

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