New Landshark Tandem with WAY too much Flex?!
#76
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To be fair to Landshark, custom builds are challenging. I'm on my 3rd tandem and countless single bikes (aluminum, steel, ti, and carbon). Practically every build required tweaking (eg. custom stoker stem) after taking delivery. I also know a few factory-sponsored riders who test new bikes. It's unusual for a high-end bike to go from the drawing board (or CAD program) to production model without changes to the prototypes.
The good news is that carbon is the ideal material for custom builds and tweaks. I'm confident that this Landshark can be easily modified to provide a dream ride for the new owners.
The good news is that carbon is the ideal material for custom builds and tweaks. I'm confident that this Landshark can be easily modified to provide a dream ride for the new owners.
I believe that one problem with a carbon custom frame is the difficulty predicting the amount of flex the frame will have. A benefit of carbon is that in theory the builder to design any degree of flex and strength desired. I think that in practice this design flexibility results in preventing the builder from designing a one off-frame and knowing exactly what the results will be in terms of frame flexibility. Avoiding variability would begin with controlling the type of tubes used but also include construction and fabrication details of the frame. Examples that come to mind are: joint wrap material, number of wraps, the adhesive used, and how cured. Viewing photos of carbon tandem construction over the years it appears to me that the hand-work involved in bonding the tubes for a custom tandem would make it difficult to control all of the variables. Even if the builder carefully logged each frame, its tubing and construction details then measured the flex is an objective repeatable way, the low number of frames built makes it difficult for the builder to build a database from which to predict future one-off builds. The time and effort required would dramatically reduce the profitability of building these frames. I have not seen any evidence this is being done and that is to be expected since the builders have to make a living just like everyone else.
Aircraft and other large-scale manufacturers using carbon can control the variables while low volume tandem frame hand builders probably do not have the resources. As mentioned this can be offset by the ability of adding material to the frame to add stiffness. I am not sure what could be done to make a too stiff frame less stiff.
Metal frames have the advantage of the long history and consistent flexibility of metal tubing and lack of variability in welded and brazed joints. The design flexibility given up by using metal yields consistent results. We ordered our custom tandem frame designed the frame's stiffness relative to the bikes we have by using tubing specifications publically available for metal tubes and adjusting for any differences in tube length. The frame acts exactly as expected because it was designed to do so. With metal it boils down to math because the builder can only choose the tubes and does not change how the tube will act by wrapping more material and glue around it or changing how it is connected to other tubes.
Last edited by waynesulak; 08-09-18 at 12:40 PM.
#77
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Within the composites industry, often, in jest, but also in truth, we state that paint hides a multitude of sins.
This should not be the case ! the only layer of paint capable of "Hiding" is the primer and that is only if you use high build primer / filler or spray filler.
The typical build up of layers for a paint system are :-Etch Primer 10-15 microns, Primer filler 30-40 microns, basecoat (depending on colour) 10-18 microns and Clearcoat 30-45 microns.
At these thicknesses, paint will hide virtually nothing, if anything it will only highlight defects.
Even at the top end specification at 118 microns, on a tandem you will add around a kilo of weight.
It is a miss conception that the thicker the paint the better, the actual opposite is true, the thinner the paint system is (as long as specification is met), the better it will perform in both mechanically and durability testing.
The above is applicable to steel, aluminium and the majority of composite materials. Good quality Carbon Fibre also falls into this category. However, some carbon can be very porous and requires excessive use of primer / filler, this followed by the subsequent layers will add significant weight to the finished product.
A manufacturer of lightweight sports cars I dealt with in the past, boasted, this is the lightest body we have ever made, the carbon fibre was soooo bad, it took 16kg of spray filler to "hide" the defects - not so light now
If teams are conscientious of weight on carbon, go with a nude finish, this will also show the quality of craftmanship in the finished frame.
This should not be the case ! the only layer of paint capable of "Hiding" is the primer and that is only if you use high build primer / filler or spray filler.
The typical build up of layers for a paint system are :-Etch Primer 10-15 microns, Primer filler 30-40 microns, basecoat (depending on colour) 10-18 microns and Clearcoat 30-45 microns.
At these thicknesses, paint will hide virtually nothing, if anything it will only highlight defects.
Even at the top end specification at 118 microns, on a tandem you will add around a kilo of weight.
It is a miss conception that the thicker the paint the better, the actual opposite is true, the thinner the paint system is (as long as specification is met), the better it will perform in both mechanically and durability testing.
The above is applicable to steel, aluminium and the majority of composite materials. Good quality Carbon Fibre also falls into this category. However, some carbon can be very porous and requires excessive use of primer / filler, this followed by the subsequent layers will add significant weight to the finished product.
A manufacturer of lightweight sports cars I dealt with in the past, boasted, this is the lightest body we have ever made, the carbon fibre was soooo bad, it took 16kg of spray filler to "hide" the defects - not so light now
If teams are conscientious of weight on carbon, go with a nude finish, this will also show the quality of craftmanship in the finished frame.
In order to obtain aerodynamic smoothness, repair aspect ratios are one of my main focuses to minimize filler and paint thickness. Ultimately though, after epoxy primer, a fill primer is used, followed by conductive primer, then top coat.
Improper paint thickness, being too thick, can result in lightning skips on the paint surface as it can not disipate correctly.
So, in some ways, paint hides a multitude of sins...FWIW, when I accomplish carbon repairs on bicycles, I tell them up front, if it does get painted, it will be low cost spray can. As for the repairs, most can be designed well enough and accomplished to need very little after final blending of the repair edge.
#78
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You are still assuming that the frame needs less lateral flex. Classic first post bias. Not your fault, I see it time and time again. The first person to get their truth out there is the one that gets all the credibility and support and the other side simply can't win. Another team might not think the bike too flexy. Mel knows that. From his calculation it might make better sense to save that beautiful paint job for a team that appreciates it (and its weight). It can't be sold as 'custom' again, but it won't be a total loss either.
I don't know Mel and can't comment on what he "knows". I do know that he gave Woocycl a full refund (and go quiet) rather than offer the modification option. The latter would probably make Woodcycl happy, and be less expensive than selling the Landshark at a significant discount (and create unfavorable impressions about the brand). Even after so much has been said, I would like to hear from Mel directly because he represents Landshark.
#79
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I won't claim to know much about carbon fiber construction. However, it seems a bit counter-productive to add layers, wraps, gussets, etc. to compensate for a frame with fundamentally inadequate geometry. The genius of carbon fiber is high strength-to-weight ratio. To add in a bunch more material to make the frame stiff enough rapidly adds weight that could have been applied elsewhere with greater benefit.
#80
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I won't claim to know much about carbon fiber construction. However, it seems a bit counter-productive to add layers, wraps, gussets, etc. to compensate for a frame with fundamentally inadequate geometry. The genius of carbon fiber is high strength-to-weight ratio. To add in a bunch more material to make the frame stiff enough rapidly adds weight that could have been applied elsewhere with greater benefit.
#81
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I won't claim to know much about carbon fiber construction. However, it seems a bit counter-productive to add layers, wraps, gussets, etc. to compensate for a frame with fundamentally inadequate geometry. The genius of carbon fiber is high strength-to-weight ratio. To add in a bunch more material to make the frame stiff enough rapidly adds weight that could have been applied elsewhere with greater benefit.
Sad to read about not only the customers not being satisfied, but also the customer service to offer the refund. Hopefully, in the end, all those involved will be content and move on.
#82
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Essentially true. With that said, I referr back to my comment regarding the construction technique. I do not know if Landshark uses a mitered tube with wraps like Calfee does, or if the utilize partial or complete molded sections.
Sad to read about not only the customers not being satisfied, but also the customer service to offer the refund. Hopefully, in the end, all those involved will be content and move on.
#83
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I agree and yet disagree. Calfee has shown photos of lug style single and tandems on their website. Calfee also has instruction video on building the DIY Bamboo bike. It seems when a manufacturer utilizes lugs, they tend to let the lugs show. This seems common on Calfees website. However, if you notice some of the bikes, the joints are clearly wrapped. Typically, those designs are not lugged and are mitered, bonded and wrapped, as somewhat explained in the Bamboo DIY video. If Calfee is building all frame by using lugs, even if wrapped, I admit being wrong, but this just does not seem to be the case.
#84
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I have to plead ignorance here. Our Calfee Tetra has round tubes. Where a tube has a junction with another tube, the junction is wrapped with a smooth wrap. If there is a lug, it is not visible from the outside.
#85
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Every Calfee tandem we have ever seen has wrapped joints. Our original frame went back for a few modifications as component technology changes occured and we tend to be early adopters and they were able to make changes quite easily and affordable for us. BTW one tandem and both singles are nude and the carbon tubes and wraps are flawless but the forks on the other hand, have filler (Enve and Whisky). Calfee's workmanship is amazing with out paint to cover anything. 30 plus years of carbon experience is worth something and Craig Calfee has a 25 year warranty on his frames
Last edited by akexpress; 08-10-18 at 12:15 PM. Reason: added
#86
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We own two Calfee tandems and two Calfee Dragonfly singles and had a previous Calfee tandem frame To the best of my knowledge only the Dragonfly, Luna and Mantra singles use lugs.
Every Calfee tandem we have ever seen has wrapped joints. Our original frame went back for a few modifications as component technology changes occured and we tend to be early adopters and they were able to make changes quite easily and affordable for us. BTW one tandem and both singles are nude and the carbon tubes and wraps are flawless but the forks on the other hand, have filler (Enve and Whisky). Calfee's workmanship is amazing with out paint to cover anything. 30 plus years of carbon experience is worth something and Craig Calfee has a 25 year warranty on his frames
Every Calfee tandem we have ever seen has wrapped joints. Our original frame went back for a few modifications as component technology changes occured and we tend to be early adopters and they were able to make changes quite easily and affordable for us. BTW one tandem and both singles are nude and the carbon tubes and wraps are flawless but the forks on the other hand, have filler (Enve and Whisky). Calfee's workmanship is amazing with out paint to cover anything. 30 plus years of carbon experience is worth something and Craig Calfee has a 25 year warranty on his frames
We spent the week riding around Santa Cruz Ca area and just rode up to the Calfee building (no appointment) and a nice guy named Patrick (I think he said he was the general manager) came out and gave us an extensive and informative tour. By the way, rode up on our approx. 14 year old steel Land Shark tandem which we like a lot. If you're interested you can buy from Calfee for $1,500 all the parts you need to build your own bamboo single bike frame.
#87
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Seriously? What else could the dealer/builder do in the case of a customer unhappy with a custom bike with a one of a kind paint job??? It is exactly what I would have done. Once the bloom is off the rose there is no getting it back. Trying to make that tandem into something the original purchasers would be happy with 'might' have been possible. But odds are better than even that it would not, could not be, short of building them a completely new tandem. On the house. Mel has way more experience with tandem customers than you or I will ever have and I have no doubt he is good with the call he made and that this is already behind him.
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Seriously? What else could the dealer/builder do in the case of a customer unhappy with a custom bike with a one of a kind paint job??? It is exactly what I would have done. Once the bloom is off the rose there is no getting it back. Trying to make that tandem into something the original purchasers would be happy with 'might' have been possible. But odds are better than even that it would not, could not be, short of building them a completely new tandem. On the house. Mel has way more experience with tandem customers than you or I will ever have and I have no doubt he is good with the call he made and that this is already behind him.
I do not recall that I ever suggested modifying the existing frame to make it work, that is the other guy...
#89
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I agree and yet disagree. Calfee has shown photos of lug style single and tandems on their website. Calfee also has instruction video on building the DIY Bamboo bike. It seems when a manufacturer utilizes lugs, they tend to let the lugs show. This seems common on Calfees website. However, if you notice some of the bikes, the joints are clearly wrapped. Typically, those designs are not lugged and are mitered, bonded and wrapped, as somewhat explained in the Bamboo DIY video. If Calfee is building all frame by using lugs, even if wrapped, I admit being wrong, but this just does not seem to be the case.
My stock Dragonfly has lugs at all three junctions.
Beloved stoker's custom 43cm Tetra is hand-wrapped at the headtube and seat cluster, but the botton bracket is lugged.
Historically, all Calfee tandems have been hand-wrapped, but in the last 18 months they have offered lugged versions for an upcharge. Not sure if these are true or "faux" lugs (I've seen at least one lugged Calfee tandem).
#90
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Our now 3 year old Calfee Dragonfly is unpainted, so you can see the wrapped construction:
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#91
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2018 Landshark Zero flex issues
Pictured is our 2018 Landshark Tandem. Rides like a dream! No flex. Handles great with a very smooth ride. I don’t know what is going on with your frame flexing. But, why don’t you go ahead and post a video of you riding for all to see. Maybe, we can help figure out what the problem is.
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If you read the rest of this thread you may agree that this one has been flogged enough.
Brent
Brent
#93
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FWIW I completely agree that it is more likely the case than not that it was riding style/technique that made the other Landshark owners unhappy with their machine. That and their failure to realize that a 5 coat one of a kind paint job would completely obliterate whatever weight savings a carbon fiber construction might otherwise represent.
Last edited by StanSeven; 09-17-18 at 01:43 PM. Reason: Removed reference to prior post insult
#94
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What happened to to the post(er) that called our bike “ beat with an ugly stick ugly” ? I thought that was quit amusing. I think he or she was upset that I posted our bike and asked for a video to help the unhappy Landshark owners after they already returned the bike. Maybe the moderator took it down?
Anyway, in the end, I hope nobody shys away from a Landshark because of one unhappy customer. John Slawta is a true craftsman,artist, and gentleman. Easy to work with. We told him what we wanted the bike to look like, what ride quality we wanted, and he made it happen to perfection. My wife and I feel privileged to have one of his bikes. John won’t be building bikes forever. And when he retires , there will not be a replacement.
#95
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I see. More time had passed than I realized since last I read the post.
What happened to to the post(er) that called our bike “ beat with an ugly stick ugly” ? I thought that was quit amusing. I think he or she was upset that I posted our bike and asked for a video to help the unhappy Landshark owners after they already returned the bike. Maybe the moderator took it down?
Anyway, in the end, I hope nobody shys away from a Landshark because of one unhappy customer. John Slawta is a true craftsman,artist, and gentleman. Easy to work with. We told him what we wanted the bike to look like, what ride quality we wanted, and he made it happen to perfection. My wife and I feel privileged to have one of his bikes. John won’t be building bikes forever. And when he retires , there will not be a replacement.
#96
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We stole the setup from Dave and Terry at Paketa. They have a single coupled tandem that breaks down and fits into a “Biknd” case that is airline friendly.
#97
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What is a 'single coupled tandem'? Are you saying this is a tandem that can convert to a single by swapping out the rear end?
#98
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No. Sorry, I should have been more specific. What I mean is the bike only has one set of couplers. It only breaks down into two pieces. Most tandems have two sets of couplers and break down into more than two pieces.
#99
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i'm curious about those HED Wheels. I'd be concerned using 24 spoke HED rims where, to my understanding the carbon portion is a fairing and not structural, for all but the lightest tandem teams.
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You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.