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PostPosted: Fri Aug 30, 2013 7:29 pm 
Dirt Disciple

Joined: Mon Jun 03, 2013 7:09 pm
Posts: 35
Hey all!

I`m about buying a Kona P2. I want it to be mounted on an 1993 Explosif. I found one, but i don`t know if it`s triple butted. The seller told me the following:
"They weigh 945g.
They are marked on the steerer as follows:
- 183F366
- 1990 J2
- CR-MO 25.4 x 30
- SPINNER
Although marked 1990, they came off a 1991 Lava Dome - a 19" if I recall correctly.
I don't think the Joe Murray Project Twos were butted, although I know some of the later Kona Project 2s were.
The 1991 Kona catalogue describes them as having 'taper guage' cromoly blades."


Thanks guys!


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PostPosted: Fri Aug 30, 2013 8:01 pm 
Old School Grand Master
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Joined: Sun Sep 05, 2010 1:10 am
Posts: 4756
Location: Heathfield, East Sussex
If it was a Lavadome then they won't be triple butted...

...or were they? :?

Can't remember the weights but the standard P2 has straight edged drop outs whereas the TB fork has nice curved drop outs; I think :facepalm:

I hate these early starts!

This should help...

Anthony wrote:
I'm sure you can forget about triple-butted high tensile, there's no such thing. It will simply be the use of thicker, but still triple-butted, tubes to withstand the greater forces near to the axle imposed by disc brakes.

The specifications for the 1997 t-b P2 said "High quality triple butted blades with internal wall thickness decreasing from top down (1.3/0.8/0.5mm). By having the thinnest tubing in an un-raked area at the bottom of the blade, the fork provides shock absorption at the wheel and stiffness at the crown."

A 1997 P2 weighs 835g, and even that is heavier than the 1995 version (785g), so already there had been strengthening. Steel rigid forks can be built lighter than that, but it all depends how stiff you want them for accurate steering.

When they first brought out P2s with disc tabs it was only on the plain-gauge version, which was presumably a sign that the 0.5mm part of the tb fork wouldn't be strong enough. Just guessing, but say the current tb P2s are made of 1.3/1.0/0.8, that would probably take the weight to 1,000g rather than 835. Still cromoly, still triple-butted, but stronger.

Also, I wouldn't rule out that they have put extra weight in the steerer. My P2 has a 1mm thick steerer. A steel Z2 steerer is 2mm thick (and weighs 270g). That's quite a difference.


Looking at the weights quoted there I'd say yours is probably not TB?


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PostPosted: Fri Aug 30, 2013 10:35 pm 
Special Retro Guru
Special Retro Guru
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Joined: Mon Sep 29, 2008 11:34 am
Posts: 5663
Location: Don't mess with monkeys, man
SinDirección wrote:
Hey all!

I`m about buying a Kona P2. I want it to be mounted on an 1993 Explosif. I found one, but i don`t know if it`s triple butted. The seller told me the following:
"They weigh 945g.
They are marked on the steerer as follows:
- 183F366
- 1990 J2
- CR-MO 25.4 x 30
- SPINNER
Although marked 1990, they came off a 1991 Lava Dome - a 19" if I recall correctly.
I don't think the Joe Murray Project Twos were butted, although I know some of the later Kona Project 2s were.
The 1991 Kona catalogue describes them as having 'taper guage' cromoly blades."


Thanks guys!

I've got a few pairs of P2s, and the ones at roughly that weight, aren't TB - I think mine are stamped as single butted.


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PostPosted: Sat Aug 31, 2013 12:47 am 
P.o.T.M. Winner / MacRetro Rider
P.o.T.M. Winner / MacRetro Rider
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Joined: Fri Jan 23, 2009 1:03 am
Posts: 5502
Location: In the foothills of the foothills of The Cairngorm Massif :D
If TB it should have a "TB" stamp on the steerer. Insteda of the CR MO.
My 1992 Explosif came with TB forks so not at all unusual.


Think mine were around the 850g mark but can't recall for sure
:xmas-big-grin:


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PostPosted: Sat Aug 31, 2013 9:49 am 
retrobike rider
retrobike rider

Joined: Sun Sep 23, 2007 11:22 pm
Posts: 7306
Location: Hove
The triple-butted P2 came out in 1992. Prior to that, the top models used the Track Two, which is quite different. The 1991 Lava Dome and Cinder Cone used what they called taper gauge blades and you can roughly tell from the weight how that tube profile compared - 945g is about half way between plain gauge and triple-butted weights. Geometry-wise, a 1991 Lava Dome should be suitable for a 1993 frame.


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PostPosted: Sat Aug 31, 2013 5:06 pm 
Dirt Disciple

Joined: Mon Jun 03, 2013 7:09 pm
Posts: 35
Hey!
Thanks to We_are_Stevo, Neil, Mr Panda & Anthony. I really appreciate your help.

I have one more question. Due to the fact that it`s easier to find 410mm TB P2 -specially when you need them to be mounted on a 20" frame and the steerers available are very often too short-, do you think it`s a bad idea to mount the 410mm P2 forks in a 1993 frame? Anthony, what about the geometry? I don`t want to kill the essence of that lovely frame.

Thanks again!


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PostPosted: Sat Aug 31, 2013 6:55 pm 
Devout Dirtbag
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Joined: Thu Dec 30, 2010 6:53 pm
Posts: 122
Location: Dallas, TX
Just grabbed my P2's that came of my 1994 explosif. The codes on mine are:

Lg3j402

1p95

Cm/tb

Some may be wrong, some of the stamping was hard to read, but pretty darn close. Hope this helps.


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PostPosted: Sat Aug 31, 2013 6:59 pm 
Devout Dirtbag
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Joined: Thu Dec 30, 2010 6:53 pm
Posts: 122
Location: Dallas, TX
The dropouts are marked spinner and maybe 'jbi' or something .


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PostPosted: Sat Aug 31, 2013 7:51 pm 
Dirt Disciple

Joined: Mon Jun 03, 2013 7:09 pm
Posts: 35
Thank you, voodoorider.

Now I`m sure that the P2 I was planning to buy are not TB. I`ve found a couple TB on ebay Germany this afternoon, but the steerer is too short...

:cry: :cry: :cry: :cry: Patience...


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PostPosted: Sat Aug 31, 2013 7:53 pm 
Devout Dirtbag

Joined: Sun May 09, 2010 12:53 pm
Posts: 137
Location: Great Britain
Fitting a 410 a-c fork will alter your head angle by around one degree, slackening the steering noticably.


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