Kirk Frameworks

[Dave Kirk]

And I was blaming it all on Cannondale :)

I've had the pleasure of owning lots of cool bikes over the years and I got a Cannondale the first year they came out for $150 F, F & hs. It fit OK and handled OK as i recall but it was so brutally stiff that I got rid of it after two weeks. It's the shortest I've ever owned a bike.

So let's blame it all on Cannondale - I'm in.

dave

[HSTFixed]

Best Thread Ever.

[Eric007]

This growth has meant that there are a lot of new folks in cycling that came into the sport very quickly and they have not progressed slowly into the sport, learning over time, like many did back in the day. ............. they don't have enough experience and wisdom from spending years in the saddle ..................... and this is a bit ironic, because the new cyclist is often very fit (lots of ex-runners and soccer players) they can push on the pedals very hard but they have not developed the skill to properly and smoothly spin the pedals.

Darn it, he just described me.

And I think he knew he was describing me too. ;>)

And BTW, my first bike WAS a Cannondale. A CAAD-something, shook my fillings loose on every bump on the Burke-Gilman.

[Steevo]

This is a fantastic thread. Thanks Dave for all the great info and time, and thanks to the Vsalon for being here.

Dave, is there a common element to the ride feel - a Kirkframeworks DNA (for lack of a better term) - that you strive to incorporate into each frame you design and build? Is there a common thread running through a Kirkframeworks JKS and a straight up road bike, and an all-rounder and a tourer, etc...?

[Dave Kirk]

This is a fantastic thread. Thanks Dave for all the great info and time, and thanks to the Vsalon for being here.

Dave, is there a common element to the ride feel - a Kirkframeworks DNA (for lack of a better term) - that you strive to incorporate into each frame you design and build? Is there a common thread running through a Kirkframeworks JKS and a straight up road bike, and an all-rounder and a tourer, etc...?

Hey Mr. Steevo,


There are a few traits I build into every Kirk regardless of the type of bike it is.

* I like a bike that is precise, accurate and intuitive in it's handling. I like quick turn in without any feeling of the bike feeling twitchy.

* I like all my bikes to have snap and life to them. It gives them the feeling that when you push on the pedals that the bike is ready and willing to jump forward - it snaps forward with urgency. I like that a lot.

* A Kirk should also not draw attention to itself while you are on it. It should just be an extension of the rider and not make any special demands of the rider to compensate for it's short comings.

* a Kirk should be fun. Very few of us 'need' bikes like this and we own them because they are fun and enjoyable. I want to be sure that every Kirk is just that way - fun. A bit hoky but there you go.


Thanks for the question.

Dave

[72gmc]

Dave, I said a while ago that every time you speak up online is another reason to buy one of your bikes. If you're wondering, this thread is pure ride-a-Kirk.

Re your question about my screen name: I joined the old forum under that moniker because it seems unassuming. At the time I was noticing a lot of people touting bikes, cars, bling, and big ring climbing abilities in their screen names and posts. I don't feel the need to do that. I also tend to change what I'm trying with bikes on a fairly regular schedule, so a sexy component didn't fit. That left my real name or the yard truck, and the yard truck seems to fit as well as anything else. I asked about your routines because I suspected that you're a clean tools, "taking care of what takes care of you" kind of guy. I was taught the same things, so the truck says something about me that I like. I keep it in good shape mechanically and I'm hoping I can restore it cosmetically someday down the road. My wife likes to say that I married her for that truck; I did inherit it from my mother-in-law so I remain silent on the topic.

[Dave Kirk]

Good Morning,

Thanks for your kind comments.

I like the story behind your avatar. Avatars can be like custom license plate in that sometimes you see them and stare and wonder whatever could that mean? Mine is boring and leaves little room for interpretation and wondering what it means.

Thanks again,

Dave

[msurch]

Hi Dave,

First, I want to thank you for being so generous with your time here. Your replies are thoughtful, insightful, and gracious.

Your words about the manner in which road bikes have changed, in terms of ride quality/feel, over the last few decades, really resonates with me. Sure, its the unpopular view, but that doesn't matter; as you say, those who 'feel it' nod in silence. Well, I'm nodding and then some.

Coming from a mtb backgound, beginning in the early 1990s, stiffness has always been talked about alongside frame quality in my bike life. Fortunately, suspension entered the mix with mtbs, and travel started to focus on the the wheels' paths. Meanwhile, pedaling efficiency became a question of suspension actuation, i.e., less bobbing under pedaling load = good. I have never, ever, encountered an argument for beneficial flex for pedaling efficiency in the context of mtbs. Only riding road bikes of differing tubing specs has afforded me the data points to discern beneficial flex, that which syncs with my effort: planing in Jan Heine's terminology. I appreciate how my 853 29er planes, and don't want a stiffer hardtail at all.

Back to road bikes, I have ideas about tubing diameters and profiles, mostly based on my riding experience and the writing of bright minds like yourself, Padraig at RKP, and without a doubt, a lot from Jan Heine. I wholeheartedly believe in (passive) suspension for road bikes, your Terraplane being the best execution I can think of. Chalk this up to my mtb background, which is the basis of my all-road tendencies on my road bikes. Fast and loose. I've found that the bikes that pedal the best in the saddle also feel really good on the rough stuff. My Nemo tubed Pinarello 'cross bike is a great example. I've surmised that its 25.4 top tube helps afford the front end some additional suspension. My newer custom all-road frame uses a 28.6 TT, and the bike is definitely a bit stiffer in the front end. The latter bike (31.8DT, 28.6ST) is good in the saddle, but not the best for all out sprints. In contrast another OS bike I have with a 34.9 ST, even bigger DT (!), and 31.8 TT is great out of the saddle, but does not sync well with me at all on seated climbs. I have to stand a lot to stay on top. I've noticed lots of PROs do this too....

Ok, so blah blah aside, here is my question: If you were able to build with any tubing diameters and profiles available in steel, how would you go about deciding which tubes to choose for a given rider? Or, in other words, would you agree that a bike for a fairly strong rider getting into 'cross, for example, should be constructed out of different tubing than another rider of the same size and weight, but higher power and greater fitness? My rationale is that less strong riders will tend to ride most of their race in the saddle, thus requiring plenty of flex for pedaling efficiency, while the stronger rider will attack out of the saddle much more and desire more torsional stiffness. If this sounds reasonable, would you be likely to run a 25.4 TT for the more flexy bike? I know some feel 25.4 TTs lead to shimmy, but I'm not so sure that's true. Along the same lines, contra the position that a 'bike' is a 'race bike' if its raced, I wonder what your thoughts are with regard to flex for an all-day ride sort of bike versus a shorter, more spirited club ride/weeknight World Championship sort of bike? I can attest that my steel fixed gear with standard diameter tubes gets pretty squirrely at 60kph downhill in a 44x16!

[Dave Kirk]

Hi Dave,

First, I want to thank you for being so generous with your time here. Your replies are thoughtful, insightful, and gracious. ...............................

Ok, so blah blah aside, here is my question: If you were able to build with any tubing diameters and profiles available in steel, how would you go about deciding which tubes to choose for a given rider? Or, in other words, would you agree that a bike for a fairly strong rider getting into 'cross, for example, should be constructed out of different tubing than another rider of the same size and weight, but higher power and greater fitness? My rationale is that less strong riders will tend to ride most of their race in the saddle, thus requiring plenty of flex for pedaling efficiency, while the stronger rider will attack out of the saddle much more and desire more torsional stiffness. If this sounds reasonable, would you be likely to run a 25.4 TT for the more flexy bike? I know some feel 25.4 TTs lead to shimmy, but I'm not so sure that's true. Along the same lines, contra the position that a 'bike' is a 'race bike' if its raced, I wonder what your thoughts are with regard to flex for an all-day ride sort of bike versus a shorter, more spirited club ride/weeknight World Championship sort of bike? I can attest that my steel fixed gear with standard diameter tubes gets pretty squirrely at 60kph downhill in a 44x16!

Good Morning and thanks for the question. I'm sorry about the slow reply - I tried to reply yesterday but each time I tried the reply the site locked up on me. Seems to be fine now.

I feel that tubing is best chosen with the rider in mind - and by that I mean the size, weight, skill level, and riding style of the rider in question. You are right - a strong, skilled rider who tends to stand to put the power down will benefit from different tubes as compared the a rider of the same size and weight who has less skill and can generate less power. Another huge factor in choosing tubes is how the bike is to be used.

A 1" top tube will certainly give a smoother ride and more comfort and in the case of a cross bike can help keep the bike stuck to the floor but it can come at the expense of torsional rigidity and handling accuracy. This lessening of torsional rigidity can lead to shimmy at speed for some riders depending on size and how the bike is to be used.

I do design around a 1" top tube (along with a 1 1/8" DT) for lighter and smaller riders when they can benefit from the smaller size. I'm just stating a bike for a woman who is 5'3", 125 lbs, and the last thing she will need for her all-day road bike is OS tubes.

In the end all design comes down to the "C" word - Compromise. I know compromise sounds like a dirty word but it's the reality and not every bike can have everything at the same time so priorities need to be established and then the bike needs to address those while letting the smaller things slide. Compromise seems to have a negative connotation but I don't see it that way. I see it as being realistic and honest about what can be done and what can't and then designing for the most good.

I hope that is what you were looking for.

Dave

[Tim Porter]

I'd be remiss if I didn't add something to this thread from a recent customer viewpoint. By "recent", I mean that I received my fillet-brazed complete bike from Dave last Weds. My story's a little different from Dave's typical customer because I bought the spec frame that he built for NAHBS, so I didn't go through the fitting regimen with Dave. I sorta regret that, but not really; we'll get to that in a minute. When Dave blogged about this frame being available in January, the spec sheet he published was like a siren song because the dimensions are EXACTLY what I ride (saddle height, reach, setback, you name it). The only dimension that varied was that the headtube was 1 cm longer than the great fitting Ottrott I was comparing it to. So fit wasn't a problem.

Dave emailed me 31 times with updates, questions, lots of photos, etc. I'm a pretty low-maintenance customer ATMO; we never even spoke on the phone (kind of sick, eh?). When the time came to specify the paint and components, I spoke with Joe Bell a few times and Dave emailed the quotes for the build kit. I didn't need another set of wheels (imagine that), but Dave had me send the new Joe Young rear wheel I had made for this bike so the drive train adjustments would be perfect.

I've only done one 40 mile ride on this bike so far, but if you look a few posts up from here you'll see the aims that Dave has for his bikes. He really expresses perfectly what he tries to get from each frame and I think he nailed it with this one. You know when you reach a little hump in the road that maybe you should shift down for but you decide to just power up and over? Well on the first handfull of pedal strokes the Kirk surges forward beautifully. When you sit up to take off your arm warmers or stretch your back, it tracks perfectly. When you look down at the workmanship on the frame and the beautiful JB paint, you get a big smile on your face, thinking, "how cool is that." When you put it in the 53-12 and use your Clydesdalian might to hit 45 mph down a hill that isn't all that steep or long the stability is perfect. Out of the saddle, I feel really balanced between the wheels, which doesn't happen with every bike atmo. There'll be many, many miles and longer rides on this bike and I want to express to Dave how great it's been to work with him. The level of discussion on this thread has truly been inspiring.

Maybe Dave can address this one question. Clearly, I bought a spec frame and the fit turned out to be as perfect as I could hope for after seeing the initial graphics and specifications. So I'm the beneficiary of some good luck in being in the right place at the right time on the world wide intertubes. Sometimes I think that it's better to have found a bike that the builder must be thinking "This is how I want one of my bikes to look and perform," rather than one where there are Compromises (see above) to adapt the "ideal" Kirk to the customer. Is it more difficult for you to make some of the frames adhere to your expectations or retain the common elements mentioned above. Would you be better off having a whole table of specs, perhaps in 1/2 cm increments and just make that bike for everyone? Or am I just lucky to be an approx. 55 or 56 cm off the rack rider?

One last thing: Dave can really pack a bike; his attention to detail is mind-boggling. He even included a huge black trash bag for the stuffing/wrapping/bubble wrap.

Great bike! Tim

[Tom Kellogg]

Hello,

... Cycling as a sport has grown in a big way over the past 20 years and it's now cool to ride. Back then real men played golf ... virtue of an appropriately stiff bike would be seen again and the bikes with 3" down tubes would go away.
Dave

Thank you, thank you. And as I recall, Cannondale started all this hooie when they were forced to make super stiff bikes to keep them from breaking. They make much better bikes than that now, but back before they started using stronger materials, they needed to make bricks. If you have to make bricks, then it is best to convince folks that bricks are best.

This allowed the use of bikes that had a sweeter ride and ones whose flex the rider could use and exploit to his advantage and at the same time ride/race all day.

I had always thought that most riders could tell that a bit of "snap" helped the body work with a bicycle. Dave here points out the obvious to me. Those who are new to the sport simply don't have the experience or finesse to perceive or make use of what a good frame can be. Dave; thank you. You are one smart dude. Keep up the education.

[suhacycles]

My newer custom all-road frame uses a 28.6 TT, and the bike is definitely a bit stiffer in the front end. The latter bike (31.8DT, 28.6ST) is good in the saddle, but not the best for all out sprints. In contrast another OS bike I have with a 34.9 ST, even bigger DT (!), and 31.8 TT is great out of the saddle, but does not sync well with me at all on seated climbs. I have to stand a lot to stay on top. I've noticed lots of PROs do this too....

I think I know what you mean but let's clarify... you've noticed that the less rigid frame seems to move with you rather than resist each stroke while climbing in the saddle? I'm wondering if this is related to the analogy of jumping up and down on concrete versus a trampoline. Clearly, all that 'flex' in the trampoline is not inefficient at all...

[Dave Kirk]

I'd be remiss if I didn't add something to this thread from a recent customer viewpoint. By "recent", I mean that I received my fillet-brazed complete bike .................................

Maybe Dave can address this one question. Clearly, I bought a spec frame and the fit turned out to be as perfect as I could hope for after seeing the initial graphics and specifications. So I'm the beneficiary of some good luck in being in the right place at the right time on the world wide intertubes. Sometimes I think that it's better to have found a bike that the builder must be thinking "This is how I want one of my bikes to look and perform," rather than one where there are Compromises (see above) to adapt the "ideal" Kirk to the customer. Is it more difficult for you to make some of the frames adhere to your expectations or retain the common elements mentioned above. Would you be better off having a whole table of specs, perhaps in 1/2 cm increments and just make that bike for everyone? Or am I just lucky to be an approx. 55 or 56 cm off the rack rider?

One last thing: Dave can really pack a bike; his attention to detail is mind-boggling. He even included a huge black trash bag for the stuffing/wrapping/bubble wrap.

Great bike! Tim

Hey Tim,

Thanks for the comments and questions.

I think in the end you are fortunate to be a 56ish average rider. Being 6'4" I envy 'average' sized people. I can never buy anything that fits - from bikes to clothes nothing fits. I have to mess with everything including my cars to get them to fit right. But in the end it's worth it.

There are times when the fitting needs of the rider and my want to make the frame ride, handle, and look a certain are at odds. This is where the 'C' word comes in and one must prioritize the needs and address them as best possible. The first compromise for me is looks. If the bike will fit, handle and ride best with a stem or spacer count that is not approved by the Fonz, so be it. The rider will be loving life on the bike and that is the most important part. But in the end it's getting the bike to work as good as it can, in as many areas as possible, for the rider all the while knowing that very few can have everything............ except for the perfect 56 sized person!

I have toyed with having an extensive set of 'stock' specs but I've been there and done that in the past and there is always room to improve on any stock chart so it would all be for nought. I'd end up changing something and no time would be saved and the rider might feel that their design was compromised to make a stock size fit them. So I have no stock anything and every design and build starts with a clean sheet of paper.

I'm glad you liked the packing job. I learned the hard way a long time ago that any time saved in packing will come at a cost later on when there is inevitably an issue with shipping damage. I'd much rather everything goes out 'overpacked' so that I 'waste' my time there than the alternative of spending my time to repair a bike after a quicker packing job.

Enjoy the Putz Green bike and send photos.

Dave

[Dave Kirk]

Thank you, thank you. And as I recall, Cannondale started all this hooie when they were forced to make super stiff bikes to keep them from breaking. They make much better bikes than that now, but back before they started using stronger materials, they needed to make bricks. If you have to make bricks, then it is best to convince folks that bricks are best.



I had always thought that most riders could tell that a bit of "snap" helped the body work with a bicycle. Dave here points out the obvious to me. Those who are new to the sport simply don't have the experience or finesse to perceive or make use of what a good frame can be. Dave; thank you. You are one smart dude. Keep up the education.

Thanks for the note and the support. You are one smart dude yourself despite your choice of footware and you just put a smile on my face.

Dave



P.S. The '.......bricks are best' thing is damn funny.

[edoz]

What do you check on the alignment table, and what are your standards?

[Dave Kirk]

What do you check on the alignment table, and what are your standards?

Good Morning and thanks for the question.

I suspect you will get similar answers from all the builders you have asked this question. I just read Carl's answer and I could almost cut and paste his answer in here and get the job done. But I do a few things differently if for no other reason that I build with different joining techniques.

I build frames in a two step process - I build and complete the front triangle and when that is done I add the rear. So in my little world I braze the front triangle, face the BB, and then put it on the plate and check that the seat tube and head tubes are at the proper elevation and that the head tube has no twist. I find that it's easier to control overall alignment if I'm adding the rear to an already straight front. Once that is done it makes sense to invest the time into doing the finish work (as an aside I always do alignment checks before investing time into aesthetics - IMO it makes no sense to put the time into making it pretty if it's headed to the dumpster - RE "The Goal") before adding the rear triangle. I do the finish work on the front before adding the rear just for the ease of being able to reach in and around the smaller piece in the vice.

With the front end complete and the rear added I chase/face the BB and head tube so that I can do a 'final alignment' to the completed frame. It goes on the plate and I check seat tube, head tube and drop out elevations - I check that the seat stays are equidistant from the bike centerline - and I check for head tube twist. I aim for a +- .005" tolerance overall using a height gauge measured to the plate. Once everything is checked the bike comes off the plate and then goes right back on and rechecked to be sure that the BB hasn't shifted on the post giving me false numbers. Once this is done it comes off the plate and the rear dropouts are H tooled and the reference wheel is installed to check for centering between the stays.

I suspect that most pro builders do something similar to what I do. It makes sense that we'd all do something similar as we are all trying to solve the same problem and the solution is clear.

One note on alignment - it is of course important and I work very hard to get it just right but the numbers can be misleading. I shoot for a plus/minus .005". This might make some think that a bike with a +- .003" would be better and I suppose it would be even though I think we are far past the point of diminishing returns. Industry standard for most the the big guys is +- .120" and one doesn't need to be a rocket surgeon to see that .120" is a lot bigger than .005" and yet we don't see too many mass produced high end bikes going down the road sideways. I think most of us align to such a tight tolerance as a point of pride and for the challenge not because we need to to make the bike ride well.

Is that what you were looking for?

Dave

[msurch]

In the end all design comes down to the "C" word - Compromise. I know compromise sounds like a dirty word but it's the reality and not every bike can have everything at the same time so priorities need to be established and then the bike needs to address those while letting the smaller things slide. Compromise seems to have a negative connotation but I don't see it that way. I see it as being realistic and honest about what can be done and what can't and then designing for the most good.

I hope that is what you were looking for.

Dave

Thanks Dave, this did indeed answer my question. I think 'compromise' is absolutely appropriate. When everything comes together, and the bike sings, life is good.

Thanks for your time Dave.

[msurch]

I think I know what you mean but let's clarify... you've noticed that the less rigid frame seems to move with you rather than resist each stroke while climbing in the saddle? I'm wondering if this is related to the analogy of jumping up and down on concrete versus a trampoline. Clearly, all that 'flex' in the trampoline is not inefficient at all...

Yes, exactly. I like the analogy! While pedaling either in or out of the saddle, force is exerted toward the center of the bike as well as vertically (i.e. inwards, nor just down, back, forward, up). So in the saddle, when you really groove on a bike that syncs well, you are consciously rocking the bike a bit side to side, working the flex to sync up and give you a nice return for each subsequent pedal stroke. On a stiffer bike, you have to rock it further over to get it to flex as much as you might want, so you can push inward more as the bike is leaned over. At least, this is how I experience it. On a too-stiff bike, this flex cannot be felt much if at all, and the bike tends to bog down as effort increases on climbs. It becomes necessary to stand in order to feel like you are keeping the speed up. When riding out of the saddle, you can exert more pressure on the bb, and get some flex going to help you out. If the material of the bike takes the flex, but damps instead of returning it with a 'snap,' I suspect most would find it craptastic. I have an old Peugeot like that; it flexes a lot, but doesn't return it fast enough. It feels like a barn door on wheels. So I think the amount of flex the frame can produce, coupled with the speed at which it returns that stored energy, is what we are looking to get dialled in a custom frame.

[edoz]

Is that what you were looking for?

Dave

Yes, and thanks for the detail. I remember Carl S saying somewhere that he felt .040" was unacceptable, and I figured most here would have similar standards but wondered where they stood in relation to the big companies.

[Dave Kirk]

Thanks Dave, this did indeed answer my question. I think 'compromise' is absolutely appropriate. When everything comes together, and the bike sings, life is good.

Thanks for your time Dave.

Maybe the word 'compromise', with all it's negative connotations, could be replaced by 'optimization'. Same thing, sounds better.

Dave