Would appreciate feedback on two unconventional frames

[RPS]

I’m asking for and would appreciate your feedback to help determine if one of these bikes “looks” less unconventional than the other. I know these may seem quite radical for purist and traditionalist, but I’d appreciate all feedback nonetheless. For purposes of this comparison, please ignore functional differences caused by the longer upper chainstays which extend to the downtube on one frame and not the other. I’m neither a retailer nor manufacturer and have nothing for sale – I’m just asking for your opinion comparing these two similar frame designs.
Thanks,
Rick

[saab2000]

They both look a bit 'unconventional'.

You don't want an opinion, so I won't give one. But I have one.

What's your opinion?

[swoop]

i just put this all under the header of solving problems that don't exist. i appreciate that craig calfee is willing to search... and if one likes novelty as part of the package...

put if we are talking about functional vertical compliance.... there are a lot of ways to functionally skin the cat and the first way is via tire pressure, the second is via geometry, the third is structural, the fourth is novel.

so this is a novel aproach and pretty far down my personal list.

calfee is a reachable and honest guy. he makes informed choices and i'm sure is only a phone call away.

all written above is subjective atmo-ness.

if you are asking which one looks less g*y... i think it's a dead heat.

[Frustration]

K, so why isn't this considered either structural or geometry?


I like it.


I like anything that's made to promote comfort and it would provide a lower COG.

Gotta wonder how well it resists twist and the stress points have to be a ***** as the tubes are still tubes (unless Craigs got a new way to blow a Monocoque...) Even then the load points would be "special"


But I'm not sure you can brand it "Novel" until you know it doesn't perform...

.

[Jason E]

+1

Not sure why either would be done instead of a more traditional design.

The more traditional design is such for a reason. Stiffer rear, better support.

[Ginger]

Looks like they're waterskiing...

[catulle]

What are the advantages of the design? It sems to me like it is a solution for a problem that doesn't exist. Like change for the sake of change. Maybe not, maybe there is a good reason for the design, in which case, what is it? Note the webbed frame. Seems as if the design puts stress on the critical joints of the frame. Aesthetically, I don't like it.

[Serpico]

put some square wheels on the second one and you're good to go!

[Frustration]

It's pretty obvious that verticle compliance is what this targets... And I for one don't think bikes are as comfortable as they could be.

It doesn't stress any joints... It does side load the hell outta the seat tube though, so it's probably wrapped over a load spreading plate...

[Ozz]

Jeez folks, the OP knows both bikes look unconventional....the question was which one looks least unconventional.

FWIW....the bottom one....atmo.

[christian]

1 looks better, because if I squint, I can pretend it's a full-boinger mountain bike.

- Christian

[Fixed]

it don't do it for me bro, but i'm not buying it ..if you dig it.. cool
cheers

[kbwheels]

bottom bike looks closer to a "conventional" bike, if you need someone to test ride them let me know.

[RPS]

For the record and in fairness to Calfee, this is not his design. The patented design is mine, not Calfee’s. The two bikes shown are Calfees because they are almost identical in color, size, etc. so they lend themselves to appearance comparison. I could just as easily have included pictures of titanium or steel frames manufactured by others.

Since overall function seems to be unavoidable, the reason for the design is enhanced performance by introducing significant rear wheel travel without introducing adverse characteristics. This frame design can be made in any material to have far more rear wheel travel than the combined differences of tires, wheels, carbon seat post, titanium saddle rails, etc...., and far more than conventional frames. Additionally, the model with extended upper chain stays stiffens the BBKT area, makes the frame laterally stiffer, and also makes the main triangle torsionally stiffer. It is not different just to be different -- it was designed and engineered with a purpose in mind. Please keep in mind that even race cars have to have suspension to maximize performance.

[SoCalSteve]

For the record and in fairness to Calfee, this is not his design. The patented design is mine, not Calfee’s. The two bikes shown are Calfees because they are almost identical in color, size, etc. so they lend themselves to appearance comparison. I could just as easily have included pictures of titanium or steel frames manufactured by others.

Since overall function seems to be unavoidable, the reason for the design is enhanced performance by introducing significant rear wheel travel without introducing adverse characteristics. This frame design can be made in any material to have far more rear wheel travel than the combined differences of tires, wheels, carbon seat post, titanium saddle rails, etc...., and far more than conventional frames. Additionally, the model with extended upper chain stays stiffens the BBKT area, makes the frame laterally stiffer, and also makes the main triangle torsionally stiffer. It is not different just to be different -- it was designed and engineered with a purpose in mind. Please keep in mind that even race cars have to have suspension to maximize performance.

We discuss this frequently here.

DKS rear end on the Serotta Hors Categorie

ST rear end on the Serotta Ottrott and Legend

Terraplane rear end on the Kirk road frames

Doesnt Klein-Trek also do a suspension system on a road bike?

Also, Moots....

[harlond]

Jeez folks, the OP knows both bikes look unconventional....the question was which one looks least unconventional.

FWIW....the bottom one....atmo.+1

[JohnS]

For the record and in fairness to Calfee, this is not his design. The patented design is mine, not Calfee’s. The two bikes shown are Calfees because they are almost identical in color, size, etc. so they lend themselves to appearance comparison. I could just as easily have included pictures of titanium or steel frames manufactured by others.

Isn't this advertising?

[ergott]

You lost me with the g-bars. Those are the ugliest bars I've ever seen, bar none.

The top one looks cool to me. If it's going to be different, go all the way. The bottom one doesn't look "conventional and it doesn't look like it does as much to effect vertical compliance. Are the upper stays connected to the seat tube as they pass?

Either way, it's not something I would consider in a bike.

[chrisroph]

The top one looks good, for the reasons you stated. It looks like it will be compliant vertically while having a rigid main triangle and good torsional stiffness. I'd like to ride it and see how it feels.

Funny, I also thought the bars looked awful, like those super ergo ritchey monsters coy just pulled off all of his bikes.

Just because it doesn't look conventional doesn't mean it won't work well.

[Frustration]

We discuss this frequently here.

DKS rear end on the Serotta Hors Categorie

ST rear end on the Serotta Ottrott and Legend

Terraplane rear end on the Kirk road frames

Doesnt Klein-Trek also do a suspension system on a road bike?

Also, Moots....


You might get close to the ravel feel with a soft tail like the moots, but the minimal travel from the ST stays would be nothing like what you could have with a design like this...

I wouldn't worry about BB twist, it would be the rear wheel twisting out of line that would (could) be more of a problem.

[wanderingwheel]

Is this the Grail Bike design of a couple years ago? I was wondering what happened to it.

[djg]

To my eye, the frameset with the little rear triangle looks considerably "less unconventional" (more conventional?) than the one that splits the main triangle.

[RPS]

My intent is not to advertise since I don't have anything to sell, but if it comes across that way, I'll remove the post. I mostly enjoy cycling and hope that I can apply engineering skills to improve it in any small way.

FYI: For those who have question it; optimum rear wheel travel and suspension stiffness were first analytically determined based on riders who will likely spin up to about 120 RPM. The goal is to make the suspension as vertically compliant as possible, but not so much so that the rider will start bouncing due to the pedaling action. Setting the natural frequency of the suspension just above the pedaling-induced forcing frequency prevents bouncing, yet makes it as compliant as possible to better isolate the rider from road-induced vibration and harshness.

This optimum suspension stiffness requires in the order of 1/2-inch of travel, which is significantly more than can be accomplished with conventional frames like those mentioned above. With this design, a qualified manufacturer could easily provide more travel if they wanted, but it would not be advantageous unless the rider was going to limit their maximum cadence to a lower speed (mashers, time-trialist, etc..).

It is true that active-suspension frames (like MTB) can handle this amount of travel, but this frame's lack of friction can better isolate the rider from high-frequency low-amplitude vibration (road buzz). Additionally, the lack of moving parts reduces cost, weight, and maintenance; and in the right embodiment improves lateral and torsional stiffness compared to an otherwise identical frame.

Thanks to all who responded with a comparative preference. I honestly appreciate all the input and feedback.

[nicrump]

the first one looks less conventional, gowd aweful. i think its the bottle boss placement turning me off.

[manet]

if the top frame had straight elongated stays instead of
stays slightly dipping down to the DT i would like it best.

of the frames now, the bottom one pleases my eye
most _ i do like it.

it's not news that manet can be unconventional.

i wonder if in fact there is anything new in this
design other than being executed in CF. it has a
scent of the old english designs that dave kirk's
terraplane emits _ perhaps pewter.

[manet]

get a calfee bar-stem combo on those bikes quick!

[bironi]

Bush: Great President, or the Greatest President in History?

[oracle]

word (http://video.google.com/videoplay?docid=-869183917758574879&q=steven+cobert&hl=en) Bush: Great President, or the Greatest President in History?

[Too Tall]

The bottom frame is more conventional. Two diamonds.
If possible you can enhance a familiar "conventional" feel by matching top tube angle and the quasi-seat stay. Just a thought.

I def. get it as I've seen your design before on ultra bikes and it works well.

[catulle]

word (http://video.google.com/videoplay?docid=-869183917758574879&q=steven+cobert&hl=en)

Thank you so much for the link. I truly enjoyed it.

[dvancleve]

I like the bottom one better looks-wise. On the top one is the suspension flex in the "seat" stays? Are they connected to the seat tube? In the bottom it is flex in the seat tube, correct? Interesting and it seems like it would work with the right engineering and construction, but for me it is probably a solution looking for a problem.

Doug

[sg8357]

What is the goal of the design ?

If it is for ride quality, long reach brakes would be good, fit some decent
sized tires.

Anyway the second looks better, sort of a SoftRide look.

If you are building it for the funk factor, a carbon Flying Gate would cool.

http://www.classicrendezvous.com/British_isles/Baines/baines_47WhirlW.htm

Scott G.

[Archibald]

I’m asking for and would appreciate your feedback to help determine if one of these bikes “looks” less unconventional than the other. I know these may seem quite radical for purist and traditionalist, but I’d appreciate all feedback nonetheless. For purposes of this comparison, please ignore functional differences caused by the longer upper chainstays which extend to the downtube on one frame and not the other. I’m neither a retailer nor manufacturer and have nothing for sale – I’m just asking for your opinion comparing these two similar frame designs.
Thanks,
Rick
I would do it like the pic below. Prestress the "seatstays" so that as they are installed on the bike they would want to curl upward (direction of travel). Have some sort of simple sliding yoke at the seat tube so that you maintain freedom of movement in the stays as they decrease their radius yet limits lateral play so the bike doesn't become a noodle. With some work at the chainstays to bottom bracket joint, you could easily obtain an inch or two of pivotless travel and it would look very cool, atmo.

[92degrees]

Ooh, ooh, or you could attach them like this:

http://img215.imageshack.us/img215/8466/attachmentphpky3.jpg (http://imageshack.us)

Waaaiit a minute...

[RPS]

That's funny guys.

However, if the design had been around for 100 years and someone came along and asked to modify your bike's design by installing two rigid struts that ran from the rear wheel directly to your butt, it wouldn't make much sense or seem funny, would it? I don't know, maybe it would.

I can appreciate that double triangle frames shaped like a vertical truss made perfect sense and were needed 100 years ago when materials were ancient by today's standards, otherwise they couldn't carry the load.

In my humble opinion tweaking the old double triangle has limitations if the goal is more than just reducing weight. To better utilize modern materials that are 10 times stronger requires change.

Thanks for the art.

[cpg]

I think it's an interesting idea. Have you done any fatigue testing? That would be interesting and tricky if these were to be marketed. Tricky because they need to be "tuned" to the rider but riders change and bikes change riders. I'm curious about the amount of actual movement. It seems to me the wheel won't move vertically but travel more in an arc. So on the second picture, the wheel appears quite close to the seat tube. Given the rider induced sag and then wheel movement there doesn't seem like much room for movement before the wheel contacts the back of the seat tube. Am I making sense? Just curious. I'm just asking.

Curt

[swoop]

still not sure what problem you are solving. i mean, i'm not a moron.. i get it.. i just haven't experinced the double triangle as a design or engineering flaw. there are a myriad of ways to address creating vertical compliance and this solution seems to take a rube goldberg approach where okham has made a lovely home.

and running the rear brakd down near the bb is not a real world improvement... maybe for a prolgogue bike but otherwise... yuh, no.

keep it up though... tinkering rules!

[Archibald]

That's funny guys.

However, if the design had been around for 100 years and someone came along and asked to modify your bike's design by installing two rigid struts that ran from the rear wheel directly to your butt, it wouldn't make much sense or seem funny, would it? I don't know, maybe it would.

I can appreciate that double triangle frames shaped like a vertical truss made perfect sense and were needed 100 years ago when materials were ancient by today's standards, otherwise they couldn't carry the load.

In my humble opinion tweaking the old double triangle has limitations if the goal is more than just reducing weight. To better utilize modern materials that are 10 times stronger requires change.

Thanks for the art.
Actually, I was serious and appreciate what you're trying to do. Revisit my suggestion, it's sound. You're not alone in this. Many on the MTB side of the world are trying the same thing. Check out this website (http://www.jonesbikes.com/update/designtech/index.html) when you get a chance and check out his gallery pages. His goals are similar to yours.

[TimD]

Will there be a bamboo version? :D

[oracle]

Thank you so much for the link. I truly enjoyed it.

by all means
my pleasure...

[Too Tall]

You lost me. Say why you asked us which frame appeared most conventional again? Is the unconventional look as perceived by our crowd what you are after or what? Reason I'm confused is that now you did give an opinion, your own, that conventional design is obsolete or irrelevant for your purpose(s). No worries.

[RPS]

Excellent point Too Tall. I got sucked into the technical aspects by trying to answer “technical” questions which seem to interest many.

I still own my first new car, a 73 Mustang Mach I. It is obsolete by today’s standards, but it is far from irrelevant. It meets many purposes, but I wouldn’t want to drive it everyday. Although a classic and irreplaceable to me, it remains incredibly inefficient.

I was a cyclist long before an engineer. I know the design works great when executed properly by a qualified manufacturer. I also expect the main barrier to acceptance for some people is that it looks different; hence my question as to which design may seem more conventional.

Market innovators probably prefer change, and purist won’t consider it anyway, so maybe it’s pointless to ask the question in the first place.

[Too Tall]

Hardly. Clearly the bike design elicit opinions from seasoned riders who are a resource for early adopters and folks with no predilection one way ta udder ;) Feel me? So, your orig. question was market oriented. Purists??? Where??? hehe.

Consensus is that the bottom pic. looks more like a bike. Now what?

[stevep]

i would like to ride one of those rigs.
might be interesting.
has anyone ever built a bike like this before?
in the late 19th century and into the early 20th there was huge innovation in frame design as well as other experiments.
clipless pedals, disc wheels, quad spoke aero wheels, full suspension bikes, multiple saddle designs,
practically every other recent advance was "invented " 100 years ago.
i am curious if this was sparked by old bike literature.

ill bet a dollar* that there are photos of this design from 100 years ago.
*if i lose the bet i will not pay. if i win i expect to collect atmo.

[catulle]

Hardly. Clearly the bike design elicit opinions from seasoned riders who are a resource for early adopters and folks with no predilection one way ta udder ;) Feel me? So, your orig. question was market oriented. Purists??? Where??? hehe.

Consensus is that the bottom pic. looks more like a bike. Now what?

Now this.... (he, he, he...)

[stevep]

are all bike races like that?
i can t figure out why more guys dont race...
hmmmm.

[Too Tall]

Doh! How does the man do that???? Blindsided again.

[chrisroph]

Looks way more spectator friendly than your typical pro 1-2 race.

[RPS]

For a patent to be approved it has to be a new design; and they do searches back to the start of time. And even if someone had tried this design with materials (steel) of 100 years ago when tubes had to be much thicker due to their low strength, the frame would not flex enough to make a significant difference; particularly at that time when tires were larger and ran lower pressure.

The approved patent also covers the natural frequency of the suspension and an “optional and removable” insert that can be easily installed at the base of the seat tube to add stiffness, damping, and/or to serve as a bump stop. I know detailed technical stuff is boring to most people so I won’t get bogged down in details.

For me, understanding the difference between damping and compliance and when they are beneficial and also when they are detrimental makes it easier to see that there is room for improvement – whether with this design or something else doesn't matter. In engineering terms cyclists benefit from a reduction in transmissibility (in this case the ratio of rear wheel movement that reaches the saddle and BBKT), but only if it comes without added weight, inefficiency, cost, or complexity.

I heed Einstein’s excellent advice to “make it as simple as possible -- and no simpler”.

The picture is of my largest and heaviest friend, who normally rides a 62 instead of a 56 CM frame, test riding one of the bikes. And no, it didn’t break.

[Archibald]

For a patent to be approved it has to be a new design; and they do searches back to the start of time. And even if someone had tried this design with materials (steel) of 100 years ago when tubes had to be much thicker due to their low strength, the frame would not flex enough to make a significant difference; particularly at that time when tires were larger and ran lower pressure.

The approved patent also covers the natural frequency of the suspension and an “optional and removable” insert that can be easily installed at the base of the seat tube to add stiffness, damping, and/or to serve as a bump stop. I know detailed technical stuff is boring to most people so I won’t get bogged down in details.

For me, understanding the difference between damping and compliance and when they are beneficial and also when they are detrimental makes it easier to see that there is room for improvement – whether with this design or something else doesn't matter. In engineering terms cyclists benefit from a reduction in transmissibility (in this case the ratio of rear wheel movement that reaches the saddle and BBKT), but only if it comes without added weight, inefficiency, cost, or complexity.

I heed Einstein’s excellent advice to “make it as simple as possible -- and no simpler”.

The picture is of my largest and heaviest friend, who normally rides a 62 instead of a 56 CM frame, test riding one of the bikes. And no, it didn’t break.
Very cool! Don't get discouraged. Many people were negative towards Serotta's DKS rear end but its demise is lamented. IMO, this is a cleaner, if slightly less conventional, design.

[JohnS]

For a patent to be approved it has to be a new design; and they do searches back to the start of time. And even if someone had tried this design with materials (steel) of 100 years ago when tubes had to be much thicker due to their low strength, the frame would not flex enough to make a significant difference; particularly at that time when tires were larger and ran lower pressure.

The approved patent also covers the natural frequency of the suspension and an “optional and removable” insert that can be easily installed at the base of the seat tube to add stiffness, damping, and/or to serve as a bump stop. I know detailed technical stuff is boring to most people so I won’t get bogged down in details.

For me, understanding the difference between damping and compliance and when they are beneficial and also when they are detrimental makes it easier to see that there is room for improvement – whether with this design or something else doesn't matter. In engineering terms cyclists benefit from a reduction in transmissibility (in this case the ratio of rear wheel movement that reaches the saddle and BBKT), but only if it comes without added weight, inefficiency, cost, or complexity.

I heed Einstein’s excellent advice to “make it as simple as possible -- and no simpler”.

The picture is of my largest and heaviest friend, who normally rides a 62 instead of a 56 CM frame, test riding one of the bikes. And no, it didn’t break.
What's the tube running from the seat to the rear axle?

[DfCas]

I think it makes sense and seems like a good use of the characteristics of carbon fiber. Craig Calfee commented on it on the calfee forum and says it works. I'll let he or the inventor decide which design suits my size best.

I plan to order one after Interbike.

[RPS]

John,

The tube only records maximum wheel travel during a ride -- has no other function.

It makes it easier to compare bikes, effect of rider weight, and road surface (like running over pot holes) under actual ride conditions.

Thanks,
Rick

[stevep]

John,

The tube only records maximum wheel travel during a ride -- has no other function.

It makes it easier to compare bikes, effect of rider weight, and road surface (like running over pot holes) under actual ride conditions.

Thanks,
Rick

how much movement does it measure? say under the guy pictured?
compared to a regular calfee?

[swoop]

remember these lil buggers.

[RPS]

Steve,

I haven’t tested a standard Calfee.

Of the standard frames I’ve tested with straight seat stays about 1 MM of vertical compliance was typical. Straight seat stays don’t compress appreciably.

Curved seat stays offer a little more compliance which is noticeable to most riders on rough roads. I’ve seen reports of 2 MM, which is in line with what I’ve seen at the front of a couple of bikes with carbon forks.

Total vertical compliance should be left up to the manufacturers so they can tune the bike as they see fit. I only require the frames have a minimum of 1/2-inch of travel capability. I require this minimum to ensure the benefits are noticeable and far more than seat stays.

The Calfee in the lower picture is about 30 % more compliant, and at 150 lbs I compress it about 9 to 10 MM during normal rides; although I intentionally pushed it beyond normal to 14 MM to confirm the ½-inch requirement.

As I recall my large friend compressed the stiffer bike on the top picture about 8 MM during an easy 40-mile ride. At his size he would need a much larger frame which is easier to design.

The titanium frame I’ve ridden most has been tested to 22 MM, although I normally compress it about 50% of that during most rides.

Please note that to get the best results with this bike design, the very best fork should be used. Because the back end is so plush, you will notice fork and front wheel differences that much more.

Hope this helps,
Rick

[Archibald]

Steve,

I haven’t tested a standard Calfee.

Of the standard frames I’ve tested with straight seat stays about 1 MM of vertical compliance was typical. Straight seat stays don’t compress appreciably.

Curved seat stays offer a little more compliance which is noticeable to most riders on rough roads. I’ve seen reports of 2 MM, which is in line with what I’ve seen at the front of a couple of bikes with carbon forks.

Total vertical compliance should be left up to the manufacturers so they can tune the bike as they see fit. I only require the frames have a minimum of 1/2-inch of travel capability. I require this minimum to ensure the benefits are noticeable and far more than seat stays.

The Calfee in the lower picture is about 30 % more compliant, and at 150 lbs I compress it about 9 to 10 MM during normal rides; although I intentionally pushed it beyond normal to 14 MM to confirm the ½-inch requirement.

As I recall my large friend compressed the stiffer bike on the top picture about 8 MM during an easy 40-mile ride. At his size he would need a much larger frame which is easier to design.

The titanium frame I’ve ridden most has been tested to 22 MM, although I normally compress it about 50% of that during most rides.

Please note that to get the best results with this bike design, the very best fork should be used. Because the back end is so plush, you will notice fork and front wheel differences that much more.

Hope this helps,
Rick
If I may be so bold, were I you I would change the setup on your measuring tube so that you can eliminate the seatpost and the saddle from the variables both of which offer significant amount of flex . You should only be measuring movement of the rear axle by anchoring your measuring device to the top of the seat tube thereby eliminating the seatpost and saddle as contributors.

[RPS]

Archibald,

That’s an impressive observation and you are correct; however, I’m more concerned with the total which is what a rider actually feels. Although measuring your way skews results more in my direction, I feel it would be less indicative of how it affects ride comfort.

I know for a fact that if I clamp the rod to the saddle rail right next to the seat post clamp, I will get less than 1 MM of total travel on a stiff traditional frame. We can then conclude that the seat post and ¼-inch of saddle rail contributes 1 MM or less.

If I clamped it to the frame at the top of the seat tube, I would get 0 MM on that same frame (I’m not guessing, I’ve done it before).

So if I compare my stiffest frame to my most compliant, I would be comparing 0 MM against 21 MM measuring as you suggest.

The same comparison would yield 1 MM against 22 MM the way I’ve been doing it most of the time.

In both cases the difference is about 21 MM, but your way shows a much greater percent frame improvement (which is actually correct).

Anyway, the central difference that matters is how it rides; and that can’t be represented by this number alone since there are other factors involved.

Thanks,
Rick

[R&D]

I have ridden both designs. I probably have more miles on the top original design then even its designer and this includes approximately 500 miles in six days at this years Texas Hellweek, (Hellweek.com) which is held annually in the Texas hill country. The overall stiffness of the frame was quite surprising and made climbing, accelerating, and descending at 50mph+ a very pleasant experience. The lack of soreness in my butt and overall fatigue after the 500 miles was a real surprise and convinced me that there is validity to the design. I am pretty much "old school" and had several preconceived ideas on how the bike would perform. The 500 mile experience dispelled them all.
My name is on top of the list to buy the original bike when and if it is sold.