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No Fear
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1,372 Posts
Discussion Starter · #1 · (Edited)
I bent it at last .:madman: :madman: :madman:
I didn’t know why Kona had filled in the rocker arm rear holes till when I read a thread in the Kona forum about the 06 rockers been bent . I got worried from the second I saw the pictures of bent rockers as I havnt access to a near Kona dealer . Today I opened my rockers and saw the right one is bent slightly just above the middle hole. And CRACKED:madman: :madman: ( Ahhhhhh) at the same point but in the under part I mean the bottom beam of the rocker. Friends in MTBR and on the trail told me I wouldn’t have an issue with mine due to my low weight ( 130 Ibs ) and balls ( Biggest drop i did was 6 feet) . But it bent and Cracked it.
Now I have some choices
1: Call Kona and ask them to send me the rockers according to my one year guarantee
2: Call the dealer which I got the rig ( 12 /000 km away in Singapore ) post my rockers for them and ask them to send me the new ones.

I designed a prototype of the 06 hollow rockers in SOLID WORKS and tested it . Very obviously it was stressed form the exact point . Working farther on it I realized the problem is solved even by filling the middle hole .I draw the bention torque and cutting force graph’s ( I thought the central pivot of the rocker is fixed and then considered the rear part of the rocker as a cantilever beam ) The cutting point and the maximum point in the bend torque graph ( both a same point ) were exactly the point where all Stinky’s rockers were bent . 95 mm behind the central pivot . Approximately in the middle of the middle hole.
I don’t know what were engineers doing in Kona . If the rockers are made out of 7005 aluminum with the density of (0.0027 g/ mm^2) a pair of hollow rockers would wight 464.5 grams ( with out the cartridges and bushings ). Then I calculated then weigh of the new 07 solid rockers .They contain 6395.2 cubic millimeters more volume . So a pair of new solid rockers would weigh 500.4 grams
All that problems and worried for 36 grams . Is 36 grams that important for a freerider . Half the weight of your wallet .
I really don’t know what was the idea when they were designing the hollow 06 rockers :skep: .
 

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Equal opportunity meanie
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2,781 Posts
I don't think Kona has weight savings on the mind as a priority. I'm sure that cut was made for cosmetics. If it's a widespread enough problem they could do away with that middle slot altogether and save themselves some CNC time as well.

If you have a local Kona dealer just see if they would go to bat for you. Chances are they will if you explain to them that the place you got it from is that far away. Kona usually takes care of people, particularly with newer bikes.
 

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Just roll it......
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7,621 Posts
SABER_MTB said:
And a more clear photo from the crack.
Option C: Take it to the nearest Kona dealer and they'll get replacement rockers from Kona right away. Doesn't need to be from the dealer you bought it from. If you don't have any Kona dealers near you, email Kona directly (don't use this forum as they never check it) and have Ed or Joe send you new rockers.

EB
 

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Yay! Bikes !
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1,761 Posts
btw: Saber lives in Iran. I don't know if there are "local Kona dealers" that he can count on for help.

Good luck man. I have a friend that had the same crack and Kona did not warranty the parts.
 

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Meh.
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17,508 Posts
Nick. said:
btw: Saber lives in Iran. I don't know if there are "local Kona dealers" that he can count on for help.

Good luck man. I have a friend that had the same crack and Kona did not warranty the parts.
Was he the original owner? There is no warranty for later owners. Even so, Kona is very good about these sort of things. Did he go through a Kona dealer? And was that Kona dealer a reputable one?
 

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Just roll it......
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Nick. said:
btw: Saber lives in Iran. I don't know if there are "local Kona dealers" that he can count on for help.

Good luck man. I have a friend that had the same crack and Kona did not warranty the parts.
Ahh, that's right.....I forgot about that. Saber, email Joe at konaworld dot com and ed at konaworld dot com and they should be able to help you out with new rockers. Include your pics.

Nick, are you saying that your buddy cracked an '06 rocker (that's what saber's showing) and they didn't warranty it? That's very unusual from the dealings I've had with Kona and what others who've had the issue with the '06 rockers.

EB
 

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Yay! Bikes !
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1,761 Posts
EB:
Yes. As I understand it; the frame WAS bought new, but off eBay. I have no idea if the seller was an authorized dealer not, and my post was not slamming Kona, just stating fact. They denied him warranty coverage but offered him a crash replacement deal that was not cost effective to take advantage of. He is now riding a different brand frame.

I understand their warranty guidelines but considering the faulty design and known failures I think Kona should have taken better care of the situation. When a company puts out a component that fails WELL within the expected usage, they should stand behind it.

I hope Saber has MUCH better luck with his frame.
 

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Meh.
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17,508 Posts
Nick. said:
EB:
Yes. As I understand it; the frame WAS bought new, but off eBay. I have no idea if the seller was an authorized dealer not, and my post was not slamming Kona, just stating fact. They denied him warranty coverage but offered him a crash replacement deal that was not cost effective to take advantage of. He is now riding a different brand frame.

I understand their warranty guidelines but considering the faulty design and known failures I think Kona should have taken better care of the situation. When a company puts out a component that fails WELL within the expected usage, they should stand behind it.

I hope Saber has MUCH better luck with his frame.
If I remember correctly, new rocker plates were only something like 80 or 100 bucks. I wanted the newer style plates for my o4 Coiler.
 

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No Fear
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1,372 Posts
Discussion Starter · #19 ·
I was looking on the rockers today and found out why the right one has been cracked .
The sidewalls of the holes had different thicknesses .
On the left one the sidewall is 2.5 mm thick and on the right ( cracked) its 1.5 mm.
When they were machining the holes the milling machine had cut out 1 mm of extra aluminum in the right rocker arm.
Take a look at the pic
 

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