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Discussion Starter · #1 ·
I am thinking about building up a kona unit 2-9, but I'm not sure what fork to go with. I know I want it to be rigid, but I'm not sure what would be a good crown-axle length. Kona lists the head angle as 71 and bb height as 12.4, based on a sagged 100mm fork with crown-axle of 486mm. I would like a steeper HA and wouldn't mind a lower bb as well, as i will be riding it mostly in tight twisty new england singletrack. Also, I just came off of a rigid 26" wheeled bike with a 71.5 degree HA and while it was a little steep for rocky Colorado riding, I thought it was perfect for new england.

So, will a suspension corrected fork like a KM with a crown-axle of 468 and 43mm rake make the bike quick enough? If not, what other forks are there out there for 29er with lower crown-axle heights? How about an instigator fork with a c-a of 447mm?
 

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I think that the KM fork is sus corrected for an 80mm fork. If the Unit 2-9 is designed around a 100mm sus fork, that should steepen the HA by about a degree. It should also lessen the excessive trail that 29"ers seem to have with sus forks originally designed for 26" bikes. I'm sure the more experienced members of the forum should know if I'm right about the KM fork being sus corrected for an 80mm sus fork.
 

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HIKE!
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Kona will have a steel fork...

..... for the Unit 29er soon! With a complete Unit 2-9 on the horizon, a steel fork surely must be in the works. Anyone have suggestions for axel-crown height and offset (rake) to nail the head angle and trail figures for the Unit 2-9? POST THEM HERE! Surely some worker bee at Kona will pay attention to suggestions and bring them to their designer's attention!

The Reba (80mm travel) I put on mine seems to work well. I noticed the handling to be a bit twitchy, reactive, fast steering. Sure hope they do a rigid fork that could slow down it's manners a bit.
 

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Ride 'Til Your Knees Hurt
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Reba Race 100mm

sparrow said:
..... for the Unit 29er soon! With a complete Unit 2-9 on the horizon, a steel fork surely must be in the works. Anyone have suggestions for axel-crown height and offset (rake) to nail the head angle and trail figures for the Unit 2-9? POST THEM HERE! Surely some worker bee at Kona will pay attention to suggestions and bring them to their designer's attention!

The Reba (80mm travel) I put on mine seems to work well. I noticed the handling to be a bit twitchy, reactive, fast steering. Sure hope they do a rigid fork that could slow down it's manners a bit.
I'm running a Reba Race @ 100mm and the bike handles beautifully. The only deal for me is trying to keep a .5" or so drop from the saddle to the bars. Right now I have a Thomson 110x5 stem flipped up side down but I'm switching to 31.8 bars so I picked up a new Thomson X4 110x0 stem amd Titec Hell Bent XC's. I'm on a 20" frame (a little big for me @ 6') but it feels purty nice!
 

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Discussion Starter · #5 ·
I am surprised that the kona feels twitchy. With a 80mm fork i suppose that would change the HA to around 72. It seems kona usually specs their bikes with slacker HAs than most other companies, at least for their xc bikes. Could you measure the bb height with the unsagged 80mm fork on there?

I know the 26" unit rigid fork c-a is 410mm, or about 15mm lower than an 'average' suspension corrected 26" fork, but still makes for a 71 HA so i will be interested to see what they spec on the 2-9. Any word on when that is coming out?
 

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Bryn Mawr Borracho
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I just built up a 19" Unit 2-9

I used a Vicious Cycles fork, but it only has a 438mm axle-to-crown, w/a 1.5" rake. The head angle looks ridiculously steep just sitting there, but the ride felt fine. I switched to an 80mm Reba and it seems to jack the front end up quite a bit. I haven't had a chance to ride it yet, as we've received a foot of snow today (and still coming down!) However, I was told that the frame was drawn around a 460mm a-c, and I ordered a custom Spot fork yesterday. It will be interesting to see how that turns out. Kevin Noble at Kona tells me he has used a Reba 100mm, a Karate Monkey fork (which is 80mm corrected, btw), and a custom 440mm DeSalvo fork, and said he likes all three. He's been involved in the prototype testing of this bike since day one. Personally, I need more saddle time before I can make any judgements, but if Spot can pull off this 460mm fork in 10 days as promised, (really!) then I'll have more nooze right after the holladaze.
 

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Discussion Starter · #8 ·
geared unit 2-9

Sorry if this as been discussed elsewhere, but i notice you are running gears there. My LBS got some of the unit 2-9s with the housing stops and I was planning to build mine up geared as well. Did you just buy a different dropout from kona or what?
 

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taylor123 said:
Sorry if this as been discussed elsewhere, but i notice you are running gears there. My LBS got some of the unit 2-9s with the housing stops and I was planning to build mine up geared as well. Did you just buy a different dropout from kona or what?
I spoke to an my LBS about why some come with and without cable routing for running gears. They didn't know for sure and are guessing that the early batches were single speed specific and the later ones now are set up for both.
 

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Recovering couch patato
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Understand that if you use a shorter fork to steepen the angles, you'll be adding half an inch of toptube for ever 20mm or so that you shorten the fork. After all, the seat goes where yóu want it, and with the bike tilted forward, you'll just correct and slide it back, away from the handlebars.
 

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If you want rigid....

Both Van Dessel and niner bikes make rigid forks that are suspension-corrected for 100mm forks. They are both disc-only. The Niner bikes fork is steel, and the van dessel is aluminum.
 

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taylor123 said:
Sorry if this as been discussed elsewhere, but i notice you are running gears there. My LBS got some of the unit 2-9s with the housing stops and I was planning to build mine up geared as well. Did you just buy a different dropout from kona or what?
The shop I go to, stocks both dropouts. It is the same drop out that is on the Explosif. If your shop has an Explosif, they can switch it, or you can order one from Kona.
 
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