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Ambush
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26 Posts
Discussion Starter · #1 ·
Call me impatient, but Niner represents the Jet9 as a race bike, I bought it to race and this is race season. Its my first Niner bike, its been two weeks and no warm fuzzies from Niner yet so I have my own solution until they figure out theirs.

Tire Bicycle tire Wheel Bicycle frame Bicycle wheel


I had Jeff at Action Machining in Lorton VA (703-339-7232) fabricate me replacement rockers out of 6600 T-6 aluminum. It only took him a couple of hours. Strong, not pretty and not much difference in weight (no I didn't weigh them) Cost $200. I chose not to curve them inwards and used spacers instead. It required a 6mm cap head bolt w/ 66mm length which I got from Fastenal. I had to buy a box of 50 for $25. So a total cost of $225. I had Jeff measure the lower rockers just in case there is a problem with those as well.

Green Bicycle part Bicycle drivetrain part Auto part Motorcycle accessories


As for the bike it weighs 28.1 lbs with a large frame.

Specs

Rider 195 lbs, 5' 11" 33 " inseam

FOX F29 Fork I started with a Reba race fork but I weigh 195 and the flex was unacceptable so I replaced it with a Fox.
XTR Crankset
XTR Cassette
Juicy 7 Brakes
SRAM X9 Shifters
Salsa Pro Motobar
Moots Seat tube
Crappy and heavy Bontrager seat
old pair of Time pedals

Wheels by Dave's Speed Dreams

Stans ZTR Rims with rear axle bolts instead of a skewer
Chris King Hubs
Revolution Spokes
Bontrager Jones ACX Dry Tires running tubeless

Kudos to The Bike Lane in Burke Va for assembly. They are the shop in VA/DC for 29rs

Need to change the seat, new pedals and probably change the tires. Lets go racing.
 

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Superflying on Haven
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638 Posts
No need of chrome because polished aluminium looks almost the same. A bike is for riding not showing off. I think you solved a big big part of the design problem by choosing not to curve the rockers inwards and use spacers and by filling up the empty spaces, at least filling up the front section of the rockers that is weaker.
 

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Registered
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24,083 Posts
Can't believe someone took this long to do this :thumbsup: Not sure you didn't get ripped for it though :skep: $200 seems a lot for a little water cutting of alu and not even polishing - actually to me it looks like it was hand cut or something with those cut marks showing; maybe a bandsaw. If it were me I'd take them off and polish them up using some 600, 800 & 1000 grit water paper. Look good though and should be strong as hell.
 

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Ambush
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26 Posts
Discussion Starter · #7 ·
Yeah, I probably wouldn't have bother if it was a Schwinn but the Jet9 is a pretty amazing bike when you get it dialed in.

$200 is a fair price around here for the first ones as there was a bit of work required to fabricate them and they were done same day. The insides need to be sunk to accommodate the bearing points and the pivot holes need to be exact for the rockers to work smoothly. When you take yours off and look at the inside you will see what I mean.

I had the edges ground so nothing was sharp hence the primitive look.. Doesn't need to be pretty as it is a temporary solution. I figured it would take Niner about 6 weeks to analyze, redesign and fabricate the rockers correctly and it looks like I was right.
 

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Derailleurless
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9,122 Posts
Ambush, great solution. Unless the machinist was your Uncle or a close friend, I think you were charged appropriately, considering what machinists are charging for labor these days.

Just a word of advice, the caps on your spacer ought to extend all the way to the shock. These prevent the shock from moving side-to-side and out of alignment with the stroke of the suspension. I don't know how "real" the problem is as I've only heard talk of oddball wear on the shock, never seen anything in person or in photos / posts online. Anyhow, keep an eye on it. Maybe as a short term solution it won't be a problem. I believe Cane Creek can cut down extended caps for you, to fill these gaps.
 

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Ambush
Joined
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26 Posts
Discussion Starter · #9 ·
Thanks Nate.

The angle of the pic doesn't show it but the spacers are machined with tight tolerances. Action Machining does a lot of custom work on cycles and the rectangle formed is extremely rigid, much more than the originals.
 

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Banned
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16,457 Posts
creekchubb said:
good job, I guess I dont understand what is taking niner so long to do the same thing. how long does it take to make a stronger rocker?
Manufacting in Taiwan= many visits to Taiwan when there's a problem=huge lead times when there's a big problem.
 

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Sugary Exoskeleton
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4,657 Posts
Speedub.Nate said:
Just a word of advice, the caps on your spacer ought to extend all the way to the shock. These prevent the shock from moving side-to-side and out of alignment with the stroke of the suspension.
I may be incorrect, but it looks like his spacers are outside the shock bushings and are simply sandwiching the whole assembly together. No movement possible.

JMH
 

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Ambush
Joined
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26 Posts
Discussion Starter · #18 ·
OK,
Just some clarifications for the queries I have been getting...

I copied the tooling (sizing and threading) that Niner used. However I didn't think it was worth it to curve the rockers in and used spacers to make a "square" design. Much more simple and it required minimal tooling.

The center hole on the outside of the rockers are sunk to allow the red Niner supplied bolts to fit. The rear hole on each rocker are threaded for the red Niner bolts. The front hole of the left rocker is threaded and requires with the spacers a 6mm bolt 66 mm in width.

Take your bike to a machine shop and let them measure the parts on the bike and then remove them so they can gauge the holes and threading. The spacers are simple with just a bolt hole. You could have them tig welded to the rockers but I didn't think it necessary. I did not use a stainless bolt, regular ones are cheaper and much stronger. I used a SHCS M6 -1.0 x 65 Socket head bolt available from fastenal www.fastenal.com It should only take a few hours of work and you can be riding your Jet again. The design is extremely stiff and my Jet9 rides like it is on rails.

Pedal Dammit !!!
 

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Registered
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14 Posts
You can get the bolts at McMaster Carr (Mcmaster.com) also. For spacers try www.misumiusa.com - go to "automation tooling". I design and build custom industrial machines and we use Misumi all the time for semi-custom parts. You can find the right spacer, and order it in the right length (usually any length in increments of .001") for, probably, under $10.

If enough people are interested in this fix, they should pool together and get Ambush to talk to his machinist. $200 for 2 of those links sounds like a deal from my perspective working at a custom machining place. Ordering 10 or 20 at a time should drop the price a little.

I could certainly have the parts made at my shop also in quantity for anyone that wants them. I don't have a JET (I have a RIP), so someone would need to send me a link arm to measure. If enough people order in one batch, anodizing get's cost effective too (usually a batch cost, so $50 for 1 part or 20 parts).
 
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