Kirk Frameworks

[Dave Kirk]

Dave,

Some questions I don't think have been asked:

Looking at the framebuilders' collective website, the public can see the vision. Are there strategies, goals and tactics which inform this vision? For example, it appears to my very novice eye that Smoked Out is one such way the Collective is working to achieve its vision. If we are truly seeing the golden era of handbuilt bicycle frames, how will all of this knowledge, business acument and technical skills be codified? As leaders in your respective field, does the Collective have a duty to make sure the torch is passed, much in the same way, competent leaders in business, gov't and academia create a pipeline of talent to keep their organizations humming along? I state that knowing the Collective is comprised of one man shops, and that doing so could eventually eat into your margins and new business. I realize you are but one voice there, but if you could offer perspective it would be appreciated.

Also, I have ridden on the track 2x in my life and absolutely love it. However, there really are few tracks here in the U.S., none where I live (Wash, DC). From what I can tell these aren't huge moneymakers for the ones that do exist. There have been lot of grassroots efforts to build tracks across towns in the USA, with varying levels of success. Considering huge interest in sport in the first quarter of the 20th century, can track cycling ever make a comeback? DO you think social media, crowdsourcing, etc. provides a new mechanism by which to raise $ for such a grassroots effort? I would love to be part of something like this in Wash, DC, although not sure it exists.

Lastly, have you ever been approached to sponsor a professional road cycling (domestic or int'l) team for a portion of a season or the entire season? Would that be realistic for a one man shop or just too much craziness? It seems that would go a long way into rightsizing the carbon / alu / steel ratio in race bikes, should one have that top level goal.

Thanks again for your time.

Scott

Hey Scott,

Thanks for the well thought out questions. I’ll do my best to give you answers that are as well considered.

The Framebuilders’ Collective is truly a group of individuals and while we inevitably speak for the group by virtue of our being members I can only speak for myself. While Smoked out room isn’t an official TFC action it certainly helps the group in its mission. Smoked out is a great place for one and all to ask questions of those in the hot seat and to learn a good bit about how the builders build and conduct their businesses. I’ve been a bit surprised that more new builders aren’t asking questions. I like to think that if I were in their shoes I’d be bothering the shit out of every builder who puts themselves out for all to see.

I personally feel no duty to make sure the torch is passed on. I realize that sounds cold but the way I see it is that it is market driven. If there is market need for the type of work that I do there will be others that want to meet that need and they will (and do) come to me for advice. If on the other hand the market is fine with my craft dying with me then that is fine too. Passing on the torch only to have the receiver stand at a bench with nothing to build is pointless. I think of it this way. The reason Mr. Sachs has a 6 (?) year wait isn’t because there is a lack of supply of well crafted lugs bikes – it’s because there is a shortage of “Sachs” bikes. Regardless of how many other builders the torch is passed onto none of them will be Richard so very few of them will get work. In other words they don’t want a lugged bike – they want a Sachs and there is no substitute. So if the market demands the passing on of the torch I feel it will happen. IMO the Collective is there to encourage that and help it along. I don’t really see TFC passing on knowledge will in anyway impact any of the builder’s bottom lines for the reason stated above. People that want a Kirk will know where to go and my phone will ring.

---------------------------------------------------------------------

I wish we would have tracks in every community but I don’t see that happening. In my mind it all comes down to money and even if one can use modern social media to raise the funding needed to build a velodrome that same social media won’t fill the track for a weekly race series. The energy needs to be sustained over years to keep the money rolling in to cover costs.

Being a skateboarder I understand the lack of places to play. What is happening now with skateboard parks might be a good model for track cyclists to follow and that it the city owned public park idea. Here in Bozeman we have a small but nice public skateboard park for all to use at no cost. There is no liability release to sign and no safety gear is required. Use it at your own risk (falls under the ‘extreme sport’ law) and respect others and life is good. The skaters raised money through a variety of means to build the park and the city donated the land. It’s doing so well that a second park will be built soon. If tracks were the same way I think they might stand a chance. But if they are closed and locked and a ‘pay to play’ deal then I don’t see it working regardless of how nice the track is. Have you heard of any of the DC cycling clubs approaching local government with the public track idea?

---------------------------------------------------------------------

I have never been approached to support a professional team and doubt I ever will. The reason is simple – I don’t have enough money. Times have changed since I was building Serottas for the Coors Light Pro team and I’m sure the numbers have gotten bigger but they will do a good job at illustrating the issue. When Serotta supplied the Coors team with bikes the contract was for all the bikes they could use, money, and the lining up of co-sponsors. So Serotta gave the team a good 40 bikes a year, about $100,000 and had to line up component/tire/pedal…etc sponsors. This is of course the mid 1990’s and the dollar was worth less then. As you can see this was a big nut to crack and the bikes were the small part of the equation. What a bike company does really is give bikes to the team and then pay them very large money to get them to use them. As an aside – bikes are not chosen by the team because they are the best, fastest bikes. They are chosen because the company can pay the most to have the team use the bikes and the quality of the bikes is for the most part irrelevant. So anytime you read online that a certain bike must be good because a certain team has ‘chosen’ them you are reading BS. The team chose the money and the bikes were just part of the deal. But back on task – even if a pro team wanted to use my bikes and not charge me money to use them it still wouldn’t make sense unless I wanted to grow the brand beyond me – which I do not. If the team racing my bikes generated lots of interest in my bikes and it got me a lot of deposits it would not mean more money in my pocket and therefore would not be worth the trouble. My income is based on how many bikes I put into boxes and not how many I sell. As long as I have a backlog it will be this way. I can only build as many as I can build and more sales just make the wait longer which does no one any good. One could argue that it would allow me to raise my prices due to increased demand but that price increase would need to pay for all the bikes I gave to the team and I doubt regular paying customers would want to pay $10K for a frameset just because some powerbar team is riding my bikes. So in my mind it just doesn’t add up.

--------------------------------------------------------------------

Thanks again for the questions – I hope I answered them!

Dave

[YiPsan]

Dave,

Thank you for such honest and straight up answers. I really respect your skills and attitude.

Since you just mentioned price and wait time, do you adjust your price accordingly now that you have a good backlog and momentum of your brand? Or when and how do you determine the time to raise your price?

Thanks,

[Tonger]

Dave,

Wonderful, informative, and incredibly practical thread. Referring back to the simple and light design philosophy of Colin Chapman, sometimes he erred on the side of 'too light' and critical design components failed resulting in driver injury (e.g. Lotus Type 49 rear wing).

Obviously this would not work for a modern frameset producer in this legal climate but it brings to mind a question from the reformed engineer in me - how much 'headroom' do you engineer into your designs. Is it 50% overbuilt, 100%, or 200%, 500%?

For a lugged or fillet bike using modern materials, what is the weakest link or most likely site of failure when the frameset is generally overstressed? You see builders cutting lugs to make aesthetically beautiful designs (e.g. TDF lug) and using thinner walled tubes - is there a practical limit? What do you have to overbuild the most? Is the rider weight limit of a lighter JKS frameset the same as for one of your other lugged bikes?

Finally, is there a 'most critical' subsystem of the bike that has the most impact on the ride? Aside from geometry which I assume has the biggest influence on ride, if a tube in xyz location isn't 'right' the ride of the bike suffers most?

Thanks!

Frank

[Dave Kirk]

Dave,

Thank you for such honest and straight up answers. I really respect your skills and attitude.

Since you just mentioned price and wait time, do you adjust your price accordingly now that you have a good backlog and momentum of your brand? Or when and how do you determine the time to raise your price?

Thanks,

Good Morning Renold,

Thanks for taking the time to write. I've enjoyed this thread and the opportunity it's given me to speak my mind and share my opinions. It's not often in life one is given a soapbox of their own and I appreciate it. Hats off to Too Tall and Richard again for the opportunity.

Setting prices must be one of the more difficult things to do and to justify. For the most part my lead time has not factored in to my pricing. I think if it were to explode to a number of years it might but at this point it has not. I work very hard to keep my lead time to a minimum despite the fact that it looks cool to have it be long. As a slight aside - having a long lead time is expensive and time consuming and it presents it's own negative feedback loop - meaning that the longer the backlog, the more time is spent managing the backlog and the less time that can be spent filling the backlog at the bench. If the builder has a 3 year backlog (40 bikes a year - 120 orders in the queue) and each of those customers sends and email or makes a phone call to the builder every few months that can mean a whole pile of emails and calls that need to be returned and less time at the bench. So the builder makes fewer bikes in a year and needs to raise the price on each one he does build to keep the bottom line stable................ A bit ironic in a way.

But I digress - I base my pricing on the cost of materials, shipping, paint, what I feel my work is worth, what the market will bear. I pay little attention to what other stuff out there costs as it really doesn't factor in that much in my mind. I had a rather large price increase a few years ago when I realized that I had been negligent in keeping track of my material, shipping and paint costs and saw that I wasn't being fair to myself. I'm sure that I scared a few people away and that's just how it goes. If I don't charge enough I won't be able to continue to do this and I may as well work for someone else and lower my risk.

I hope that helps.

dave

[Craig Ryan]

Hey Scott,
Smoked out is a great place for one and all to ask questions of those in the hot seat and to learn a good bit about how the builders build and conduct their businesses. I’ve been a bit surprised that more new builders aren’t asking questions. I like to think that if I were in their shoes I’d be bothering the shit out of every builder who puts themselves out for all to see.
Dave

OK Dave, I think I have one for you. I've read the many online discussions, and realize there may be no definitive answer you can provide, but maybe you can speak about how you personally handle this issue. As a lugged builder what strategy do you employ to compensate for, and deal with BB thread alignment. I'm talking about the discrepancy between the two threaded faces and their desire to close in toward the top. Do you stick with the left side measurement, or somehow measure off the center? Or, is this so minor it should be considered a non issue. As a new builder striving for perfection, these are the kinds of things that go through my head at night (actually, not at night, I conk out and dream). What method and tools would you recommend to ensure the best predictable results? For reference I have been building off one face and referencing from it throughout the build.

Thanks in advance! Also, I just finished reading The Goal and found it insightful. I only wonder when that poor guy cut his grass.

Craig

[Dave Kirk]

Dave,

Wonderful, informative, and incredibly practical thread. Referring back to the simple and light design philosophy of Colin Chapman, sometimes he erred on the side of 'too light' and critical design components failed resulting in driver injury (e.g. Lotus Type 49 rear wing).

Obviously this would not work for a modern frameset producer in this legal climate but it brings to mind a question from the reformed engineer in me - how much 'headroom' do you engineer into your designs. Is it 50% overbuilt, 100%, or 200%, 500%?

For a lugged or fillet bike using modern materials, what is the weakest link or most likely site of failure when the frameset is generally overstressed? You see builders cutting lugs to make aesthetically beautiful designs (e.g. TDF lug) and using thinner walled tubes - is there a practical limit? What do you have to overbuild the most? Is the rider weight limit of a lighter JKS frameset the same as for one of your other lugged bikes?

Finally, is there a 'most critical' subsystem of the bike that has the most impact on the ride? Aside from geometry which I assume has the biggest influence on ride, if a tube in xyz location isn't 'right' the ride of the bike suffers most?

Thanks!

Frank

Good Morning and thanks for the question.

I completely agree that Chapman often crossed over the line from cutting edge to fragile and the problems, and in some cases the loss of life, must have been impossible to deal with. I'm not made of the right stuff to take those chances. It's interesting to read reports from racers back in the day that said that they were openly scared at times driving a Lotus due to it fragility and at the same time they were the favorite cars to race. Odd but I can understand it in a way.

The hard part is of course knowing when you've gone too far with a design and it's no longer safe or practical. There is always the temptation to take off just a bit more and push the limit and for the most part you won't know you've crossed the line until you are on the other side of it. This, I think, it at the core of your question. How do you know when you are approaching that line.

I don't have a firm and clear answer for you. I've had the pleasure of touring some of the most advanced testing rooms in the industry and in almost every case the testing is comparison based. Meaning that the loads on a frame or component are not determined ahead of time and then tested to that value but instead the new component is tested in comparison to one that has been on the market for some time and that has shown an acceptable level of failure. Take stems for instance - back in the day the Cinelli 1A was the standard and very few broke - so they would be tested to see at what loads they would fail and then if a new design would equal or surpass the 1A's numbers it was considered to be safe. When I designed Ti stems and carbon forks years ago this is what was done. It's a very safe way to go and almost always results in a design that is as overbuilt as the part it was being compared to. If one were to further optimize the design you could usually pull a few grams off here and there with no ill effects. What is interesting is that if you look at designs from one man shops to the largest 'high tech' factories we all pretty much do it the same way. The big factories won't admit this and will fill their ads with FEA images but in the end if it lasts longer than a Cinelli 1A it's good.

I think from the above you might gather that no one, myself included, really knows how overbuilt their designs are and how much cushion they have before failure. Hard to believe I know but there you go. We are all doing what Chapman did and using our experience, our real world observations and our gut to develop a design and then test it. As crude as this method might sound I have no real issue with it. The issue, if there is one, is of the engineer getting cocky and thinking that his numbers don't lie and that the design will be safe because the numbers say it will be. I think we all saw the results of this on some of the early carbon bikes that gave the wrong impression that a carbon bike explodes without warning. A poorly designed and constructed carbon bike can and will explode without warning but a good one will not.

As to what part of the bike is most prone to failure. Typically the downtube/head tube joint is the highest stressed area of the bike and we used to see a lot of failures there. But in time designers realized this was an issue and beefed up the area and now it's pretty rare to see a failure there. This of course means that the weak link is elsewhere in the frame and the next weakest thing will break instead. On some handbuilt bikes the lug cutting and dropout sculpting/design will make the bike more prone to failure. Less so in lug cutting if the bike is properly brazed. Even the most cut-back lugs still have plenty of surface area to hook the two pipes together so they rarely fail. Dropouts are another matter. Many dropout designs have placed the form far ahead of the function and we see those dropouts break. Not all of them of course but too many for my taste. I think even the most uncritical mind can look at some of the designs being offered and think - "really? is that enough material to do the job?" Well it often isn't and your gut feeling was right. Keeping in mind what the typical testing process is for a small builder it is easy to see how this happens.Tthey build one for themselves, they ride it hard for a month and it seems fine so they sell it. This is a good way to find yourself replacing a lot of dropouts 5 years down the road. For some small builders it could mean that they can not afford to do the repairs with the repaint costs and, if on the financial edge, it could put them under. All because they wanted a big logo or window cut into their dropout. Now will all that doomsday talk I just put out there this isn't that big a deal. Most bikes that fail will be repaired under warrantee and life is good for the consumer. The part I really hate is when risks are taken with headtubes, forks or stems. If your fancy rear dropout breaks your friends laugh at you and you call the wife and get a ride home. If, on the other hand, your stem fails you can end up spitting out your teeth like a mouthful of bloody chicklets. Not much fun and no reason for it IMO.

I do not have a rider weight limit on any of my bikes. That said if you call and tell me you wright 275 pounds and want a JKS I won't sell it to you. Not because I fear it will break but because it won't be stiff enough for you to enjoy. I turn down a reasonable number of sales this way and while I'd like the money I'd rather sleep well knowing that the guy who just put out real money for one of my bikes really loves it and will tell his friends so.

I'll sound a bit like a broken record on this one and I won't go into detail here about it as I've done so in so many places over the years but................ the most overlooked and underbuilt tubes on a metal frame are almost always the chainstays. You see plenty of huge down tubes out there that are meant to make the ass end of the bike stiff but last I checked the BB was hooked to the rear wheel with the chainstays and not the down tube. Chainstays are compromised in a big way because we want them to be short and to fit between chainrings and ever fatter tires and something has to give and in many cases that is the stiffness of the chainstay. I have my own OS chainstays made for me so that I can control the drivetrain stiffness without making the bike harsh with a 3" downtube. So much can be done with so many of the tubes but if the c-stays aren't stiff enough the bike won't have that jump and snap that a real performance bike should have IMO.

I hope that is what you were looking for. I need to get to the bench and heat up some pipe.

Dave

[Dave Kirk]

OK Dave, I think I have one for you. I've read the many online discussions, and realize there may be no definitive answer you can provide, but maybe you can speak about how you personally handle this issue. As a lugged builder what strategy do you employ to compensate for, and deal with BB thread alignment. I'm talking about the discrepancy between the two threaded faces and their desire to close in toward the top. Do you stick with the left side measurement, or somehow measure off the center? Or, is this so minor it should be considered a non issue. As a new builder striving for perfection, these are the kinds of things that go through my head at night (actually, not at night, I conk out and dream). What method and tools would you recommend to ensure the best predictable results? For reference I have been building off one face and referencing from it throughout the build.

Thanks in advance! Also, I just finished reading The Goal and found it insightful. I only wonder when that poor guy cut his grass.

Craig

Hey Craig,

Thanks for the question and a good one it is. Lunch time finally came and I can attempt and answer for you.

I do two things to minimize the issue.

* the first thing is to minimize the pulling in on the top side of the shell. This shrinkage results from two things. The first being that many builders check the shell to see that it's got parallel faces and then they start doing shaping work on it by putting it in a vice and clamping it down good and snug so it won't move while it's being carved. Well with a solid bottom and a top full of huge holes it's no wonder that the BB shell gets squished in on the top side during this work. You can test this very easily - measure the face-face width of the shell and then clamp it in the vice and then remeasure. In many cases it will have pulled in a good bit. And this is before any heat was put to it.

* then you put heat to the shell in a very asymmetric way. All the tubes are on the top side where all the brazing and heat goes on and the bottom side stays cool. This means that when the shell cools the top side will shrink and voila! you have an issue. So the thing to do it put some heat to the bottom of the shell too. I braze the ST & DT into the shell and then before moving on heat the underside of the shell for a minute or two. Just saturate it with heat and use flux as a temperature indicator. This will cause the bottom of the shell to shrink a bit and will minimize the difference between the top and bottom. It won't eliminate the issue but if you do it well it will easily cut the difference in half.


So with the above in mind I move on. I use and Anvil jig and it references the non-driveside of the shell so I face that one side before I add the rear end to the front. I don't touch the driveside. Since I've only had to skim about .003" off the one side I'm not worried about it in the big scheme of things. Once the rear is added I chase and face the BB and all is good. My alignment plate references the drive side and I do a final alignment based on that face.

Does that make sense?

Dave


P.S. - I'm glad you read the book. Good stuff in there and if you open your mind to the ideas you can use them in many areas.

[Craig Ryan]

Hey Craig,

Thanks for the question and a good one it is. Lunch time finally came and I can attempt and answer for you.

I do two things to minimize the issue.

* the first thing is to minimize the pulling in on the top side of the shell. This shrinkage results from two things. The first being that many builders check the shell to see that it's got parallel faces and then they start doing shaping work on it by putting it in a vice and clamping it down good and snug so it won't move while it's being carved. Well with a solid bottom and a top full of huge holes it's no wonder that the BB shell gets squished in on the top side during this work. You can test this very easily - measure the face-face width of the shell and then clamp it in the vice and then remeasure. In many cases it will have pulled in a good bit. And this is before any heat was put to it.

* then you put heat to the shell in a very asymmetric way. All the tubes are on the top side where all the brazing and heat goes on and the bottom side stays cool. This means that when the shell cools the top side will shrink and voila! you have an issue. So the thing to do it put some heat to the bottom of the shell too. I braze the ST & DT into the shell and then before moving on heat the underside of the shell for a minute or two. Just saturate it with heat and use flux as a temperature indicator. This will cause the bottom of the shell to shrink a bit and will minimize the difference between the top and bottom. It won't eliminate the issue but if you do it well it will easily cut the difference in half.


So with the above in mind I move on. I use and Anvil jig and it references the non-driveside of the shell so I face that one side before I add the rear end to the front. I don't touch the driveside. Since I've only had to skim about .003" off the one side I'm not worried about it in the big scheme of things. Once the rear is added I chase and face the BB and all is good. My alignment plate references the drive side and I do a final alignment based on that face.

Does that make sense?

Dave


P.S. - I'm glad you read the book. Good stuff in there and if you open your mind to the ideas you can use them in many areas.

Yes! Thank you, next time around I'll watch and see if I can detect a difference. The vise pressure and heat cycle make a lot of sense. Seems simple and easy to measure progress with.
Thanks, Craig

[Dazza]

"So much can be done with so many of the tubes but if the c-stays aren't stiff enough the bike won't have that jump and snap that a real performance bike should have" IMO

hear hear!

[Tom Kellogg]

+1! That is why we had custom chain stays made as well. In our case, Reynolds 531. Dave is one smart fella'.

[Tonger]

"I hope that is what you were looking for. I need to get to the bench and heat up some pipe."

Thank you for your thoughtful and educational insight Professor Kirk!

Appreciatively,
Frank

[Dave Kirk]

+1! That is why we had custom chain stays made as well. In our case, Reynolds 531. Dave is one smart fella'.

Right back at you.

dave

[merlinmurph]

Dave,

Not a question but a statement: this is, by far, the most interesting thread I've read on any forum, anywhere, anytime. Thanks for taking the time to share your experience with us.

+100 'Nuff said for my first post ever here ;-)

[Dave Kirk]

+100 'Nuff said for my first post ever here ;-)

Yo,

Thanks so much. I'm glad you have enjoyed the conversation. I know I have very much enjoyed the interaction and the thought required to come up with answers - it's good mental exercise. I'm certainly open to any more questions anyone might have and thank you all for all that have come in so far.

dave

[big shanty]

Hi Dave,

I have really enjoyed the discussion as well. A couple more questions.......why does the straight-stayed JK road model have fastback seatstay attachment vs. the JK cross model w/ semi-wrap seatstay caps? Signature style and/or weight and/or strength and/or other technical reasons? And I may have missed this, but are the new dropouts now standard issue on both JK road and cross models? I ask b/c I saw a recent JK road frame on your blog with the hooded drops w/ fillet attachment. Will the new dropouts work w/ the Terraplane design or w/ straight stays only?

Thanks,

Noah

[Dave Kirk]

Hi Dave,

I have really enjoyed the discussion as well. A couple more questions.......why does the straight-stayed JK road model have fastback seatstay attachment vs. the JK cross model w/ semi-wrap seatstay caps? Signature style and/or weight and/or strength and/or other technical reasons? And I may have missed this, but are the new dropouts now standard issue on both JK road and cross models? I ask b/c I saw a recent JK road frame on your blog with the hooded drops w/ fillet attachment. Will the new dropouts work w/ the Terraplane design or w/ straight stays only?

Thanks,

Noah

Hey Noah,

Great to hear from you. I hope you are still enjoying that cool bike of yours. I have to find the cool photos of it you sent me awhile back. Very clean or as we BMX kids used to say - it's 'sano'.

The difference in stay attachment between the JK Special and the JK Cross is purely pragmatic. On the JKS I like the super narrow and aero fastback for it's lack of weight and it's simple elegance. On the JKC I use side take stays with fabricated hollow caps because they allow for a good bit more tire clearance while at the same time making it easier to set up canti brakes on the stays without having to offset the studs to the outside (canti studs need to be a certain distance from one another and a fastback set up puts them too close together). The side tacks on the JKC make for a very clean package as it meets all the needs at once.

The new Triple F dropouts will be on most every Kirk as soon as I have them and they are designed to work with either straight or Terraplane seat stays. There has been a delay with getting the drops unfortunately - I got the first batch in and neither the machinist or I were totally happy with them and since they are worth getting just right another batch will be cut to get them to be what we both want them to be. I'm pretty damn excited to get them and start putting them into bikes. They will of course be available to other builders with proof of insurance once I have a stock of them.

Thanks for the question.

Dave

[Dave Kirk]

Here's a bit of a cross post link-a-mundo from the classifieds just in case people didn't see the ad there -



Your Name Here.

This might be of interest to someone here. What color would you like it to be?

Kirk Frameworks Custom Bicycles - Blog


dave

Picture 1.pngs20.jpg

[edoz]

So the thing to do it put some heat to the bottom of the shell too. I braze the ST & DT into the shell and then before moving on heat the underside of the shell for a minute or two. Just saturate it with heat and use flux as a temperature indicator. This will cause the bottom of the shell to shrink a bit and will minimize the difference between the top and bottom. It won't eliminate the issue but if you do it well it will easily cut the difference in half.

Thanks for this bit of wisdom. I've been wondering about doing that, but hadn't tried it yet.

[Dave Kirk]

Thanks for this bit of wisdom. I've been wondering about doing that, but hadn't tried it yet.

Let me know how it works for you.

dave

[Craig Ryan]

I employed it on my last build and saw a marked difference. Thanks tons! I think I can take it further now that I'm aware.
Craig

Let me know how it works for you.

dave