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New Landshark Tandem with WAY too much Flex?!

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New Landshark Tandem with WAY too much Flex?!

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Old 08-09-18, 12:36 PM
  #76  
waynesulak
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Originally Posted by mtseymour View Post
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.

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.

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Old 08-09-18, 12:48 PM
  #77  
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Originally Posted by Juke41 View Post
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.
Beyond pretty, and structural, plus compliance conformity, aerodynamic smoothness is paramount for many high performance carbon composites. In those situations, many factors are incorporated in delivering the best final product.

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.
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Old 08-09-18, 12:51 PM
  #78  
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Originally Posted by Leisesturm View Post
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 think that I had any "first post bias". I actually made the effort to talk to Woodcycl and John Slatwa, and look closely at the team's body size and frame geometry. My impression is that Woodcycl fairly described the ride characteristics, and had no ulterior motives. If you look at the photos and read my post #58 , you might agree that the frame may be too flexy for THIS TEAM. I also said that this Landshark may be "a dream ride" for ANOTHER team (preferably with a smaller stoker).

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.
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Old 08-09-18, 03:04 PM
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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.
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Old 08-09-18, 03:17 PM
  #80  
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Originally Posted by oldacura View Post
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.
That is a good point and may have entered into Landshark's decision not to modify the bike into something which does not represent Landshark well. As it is, a low power team might find that bike to be a dream ride.
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Old 08-10-18, 06:37 AM
  #81  
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Originally Posted by oldacura View Post
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.
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.
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Old 08-10-18, 08:02 AM
  #82  
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Originally Posted by PMK View Post


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.
Sorry Calfee doesn't use metered tube techniques, per Calfee's site "The lugs are created around metal mandrels, and it takes about 10 hours to create a set of lugs. During assembly, the carbon frame tubes bonded in."
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Old 08-10-18, 08:24 AM
  #83  
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Originally Posted by Bad1 View Post

Sorry Calfee doesn't use metered tube techniques, per Calfee's site "The lugs are created around metal mandrels, and it takes about 10 hours to create a set of lugs. During assembly, the carbon frame tubes bonded in."
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.
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Old 08-10-18, 09:17 AM
  #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.
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Old 08-10-18, 12:11 PM
  #85  
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Originally Posted by Bad1 View Post
W
oSrry Calfee doesn't use metered tube techniques, per Calfee's site "The lugs are created around metal mandrels, and it takes about 10 hours to create a set of lugs. During assembly, the carbon frame tubes bonded in."
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

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Old 08-10-18, 01:19 PM
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Originally Posted by akexpress View Post
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
We had a tour last week of the Calfee facility. The guy making a tandem frame was sort of sculpting or carving "fake" thin lugs on the wrapped joints because that's the appearance the customer wanted on the custom tandem frame.

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.
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Old 08-11-18, 12:20 AM
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Originally Posted by PMK View Post
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.
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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Old 08-11-18, 07:03 AM
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Originally Posted by Leisesturm View Post
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.
Read the words I wrote and the intended meaning. You are reading far too much into what was written. Sad to read, meaning bummer the customer was not happy with the bike and bummer the customer service had to refund the the money. Nothing more, nothing less.

I do not recall that I ever suggested modifying the existing frame to make it work, that is the other guy...
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Old 08-13-18, 08:47 AM
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Originally Posted by PMK View Post
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.
If Calfee doesn't have a lug in the proper dimensions (tube diameter & angles), they will hand-wrap the joint.

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).
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Old 08-13-18, 09:30 AM
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Our now 3 year old Calfee Dragonfly is unpainted, so you can see the wrapped construction:


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