Berk PROTO-TYPE Composites

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Klaster_1
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Location: Paphos, Cyprus

by Klaster_1

ms6073 wrote:
Tue Dec 28, 2021 5:40 pm
Wouldn't this kind of aft mouting on the saddle rails suggest that (A) a seatpost with greater setback is required
Agree that a setback seatpost would be more optimal. But this is WW, people push the components to their limit. Expecting for parts to hold beyond designed limits sure is unreasonable, but when the limits are vague, you can either play safe or hope for the better.
ms6073 wrote:
Tue Dec 28, 2021 5:40 pm
the weight limit might need to be variable based on how the saddle is mounted?
Depends on where the weight limit is measured, it's a range, a function of the saddle fore/aft position. I suppose the manufacturers are free to list the lowest value to play safe. That's what my question was about.
I would also think that the length of the saddle clamp would come into play as wouldn't a longer clamp distribute the load better along the length of the rails?
Good point. The original carbon fibre T1 yokes had a convex surface, so the T1 Dyneema loops seem to have a large surface area.

Aryeh
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Joined: Tue Oct 08, 2019 3:07 am

by Aryeh

Klaster_1 wrote:
ms6073 wrote:
Tue Dec 28, 2021 5:40 pm
Wouldn't this kind of aft mouting on the saddle rails suggest that (A) a seatpost with greater setback is required
Agree that a setback seatpost would be more optimal. But this is WW, people push the components to their limit. Expecting for parts to hold beyond designed limits sure is unreasonable, but when the limits are vague, you can either play safe or hope for the better.
ms6073 wrote:
Tue Dec 28, 2021 5:40 pm
the weight limit might need to be variable based on how the saddle is mounted?
Depends on where the weight limit is measured, it's a range, a function of the saddle fore/aft position. I suppose the manufacturers are free to list the lowest value to play safe. That's what my question was about.
I would also think that the length of the saddle clamp would come into play as wouldn't a longer clamp distribute the load better along the length of the rails?
Good point. The original carbon fibre T1 yokes had a convex surface, so the T1 Dyneema loops seem to have a large surface area.
I would use setback if I could but Darimo does not make a setback seatpost for my bike.
Gotta make some sacrifices to save 150g


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ms6073
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by ms6073

Aryeh wrote:
Tue Dec 28, 2021 7:20 pm
I would use setback if I could but Darimo does not make a setback seatpost for my bike.
Gotta make some sacrifices to save 150g
I must be getting old as I would much rather have a slightly heavier seat post that assures good fore/aft saddle position, thus helping to ensure the saddle rails don't crack when I wind up on less than optimal road surfaces. :beerchug:
- Michael
"Solving problems you didn't know you had in ways you probably won't understand"

RyanH
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by RyanH

Huh? Am I missing something? OP clamped the saddle on the flat part of the rails. There is nowhere in the instructions or markings on the saddle to suggest to only clamp in a certain range. Now, he's being criticized for not using a setback post???

Aryeh
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by Aryeh

Here's another picture from when it was on the seatpostImage

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Klaster_1
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by Klaster_1

RyanH wrote:
Tue Dec 28, 2021 11:31 pm
Huh? Am I missing something? OP clamped the saddle on the flat part of the rails. There is nowhere in the instructions or markings on the saddle to suggest to only clamp in a certain range. Now, he's being criticized for not using a setback post???
No criticizing OP on my part, I just saw an opportunity to ask Jure about the subject.

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ms6073
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by ms6073

RyanH wrote:
Tue Dec 28, 2021 11:31 pm
Now, he's being criticized for not using a setback post???
Sorry, I was not intending any criticism, simply pointing out that the 'bite' marks on the saddle rails would be marginally ahead of what company's like Selle Italia annote on the saddle rails as the max forward position:

Image
Aryeh wrote:
Wed Dec 29, 2021 12:16 am
Here's another picture from when it was on the seatpost
Image
Given this latest image, I don't think the saddle postion is that overly agressive for a seatpost with a more traditional clamp. but looking at the design of the Darimo seatpost clamp, I think the cradle is relatively small when compared to the span of the clamping mechanism. In the image above it does not look like an optimal design for preventing the kind of deformation of the rails in that image.
- Michael
"Solving problems you didn't know you had in ways you probably won't understand"

Aryeh
Posts: 230
Joined: Tue Oct 08, 2019 3:07 am

by Aryeh

ms6073 wrote:
RyanH wrote:
Tue Dec 28, 2021 11:31 pm
Now, he's being criticized for not using a setback post???
Sorry, I was not intending any criticism, simply pointing out that the 'bite' marks on the saddle rails would be marginally ahead of what company's like Selle Italia annote on the saddle rails as the max forward position:

Image
Aryeh wrote:
Wed Dec 29, 2021 12:16 am
Here's another picture from when it was on the seatpost
Image
Given this latest image, I don't think the saddle postion is that overly agressive for a seatpost with a more traditional clamp. but looking at the design of the Darimo seatpost clamp, I think the cradle is relatively small when compared to the span of the clamping mechanism. In the image above it does not look like an optimal design for preventing the kind of deformation of the rails in that image.
The clamp is carbon and Dyneema, its interesting that the saddle rails were deformed by a carbon cradle. Its not like its was aluminum or steel.

RyanH
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by RyanH

At the end of the day, this is a Berk issue. There are multiple reports of rails breaking. Berk needs to work on improving the design of the products so that they're actually engineered for the intended uses rather than some form of experimental end user R&D.

I've broken 3 of 5 of my Berk saddles for one reason or another (the 4th was broken by the 2nd owner). There's a certain point where we should expect accountability.

basilic
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by basilic

Ryan, I understand your annoyance if several of your saddles broke, but Berk does ususally take care of his customers. It would be unreasonable to expect an 80g saddle to last the same as a saddle that weighs 2x or 3x as much.

re design, I'm more surprised at the Darimo system. The upward pressure from the post is in the middle of the rails, but the downward pressure of the cords is way off. The rails are being bent like an arch. Plus the cords cut into the rails. This cannot be optimal.

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Berk
Carbon Cowboy
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Location: Slovenia

by Berk

Hi to all, first of all we give our best and take care, so please drop us an email info(a)berk-composites.com and we'll answer as soon as possible. Please mention that in some cases it can take a few days and some patience is much appreciated, but we won't dissapear anywhere and we do take care of it.

Unfortunately we are not the only company that of course also faces with problems. It of course also all depends from the clamping system, such damage can happen because the small area of the lower cradle (which is in some cases only 1-2mm thick) needs to support the complete rider weight, and after some use it can damage the carbon surface, you tighten it again, and it goes like that untill the failure. Who to blame? We replace such saddles since there is nothing to do here, we only put a note where we recommend max. 5Nm, mainly because such seatpost designs which can cut the saddle rails. If the clamp compresses the saddle rail from both sides at the same area it is no problem to go up to 16Nm (like Specialized, Ritchey etc. seatposts).

Of course as any other product also our won't last a lifetime. We give our best and try to improve it during all the years, we already did quite a few changes which can't be seen, but it is all to improve such things. In 2014 we used to produce the Lupina saddle for max. 85kg and round saddle rails. Till today we decided to produce it for max. 100kg and have the ISO4210 standards for it. As we all know the cycling market grows a lot and also the definition of a customer (also for weightweenie parts) is slightly different like it used to be, and today we are asking ourself at the company if we should go for up to 120kg rider weight, but then such saddle won't be good for a 60kg rider and it is a completely different product. Every season there are some improvements which maybe can't be seen, but we are giving our best. There are more than 10.000 Lupina saddles worldwide and of course there are also warranty cases or any other problems. There is traveling with poor bike bags, crashes, bad or no maintence etc.,..and we give our best to find a solution, I dare to say that we didn't let anyone down or without a solutions.
Last edited by Berk on Thu Dec 30, 2021 10:43 am, edited 1 time in total.

Kumppa
Posts: 462
Joined: Mon Oct 13, 2014 10:05 am

by Kumppa

I have so far broken only 1 of my 3 Lupinas becouse of broken rail (3-4 years old/less than 10k km/Enve seatpost). Discount offer for old test saddle wasn't that great, something like 25-30 %. People like me who have 5 month cycling season, 2 years warranty is frustrating when you same some expectension how long some item should last.

Agree with RyanH. Last of 2 saddles are with 100 kg limit so fingers crossed these are going to last. Still love the shape.

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Berk
Carbon Cowboy
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Location: Slovenia

by Berk

Thanks, yes the first saddles (round rails) were for only max. 85kg. They were lighter of course, but later we decided to produce only 7x9mm saddle rails which hold up to 100kg rider.

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Juanmoretime
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Joined: Sat Jun 19, 2004 11:08 am

by Juanmoretime

Anyone using a Lupina with a Darimo T1 Loop seatpost? I bought the post and plan on installing iit in the next day or so.

Aryeh
Posts: 230
Joined: Tue Oct 08, 2019 3:07 am

by Aryeh

Juanmoretime wrote:Anyone using a Lupina with a Darimo T1 Loop seatpost? I bought the post and plan on installing iit in the next day or so.
Me


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