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Compulsive Bike Builder
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Discussion Starter · #1 ·
I am considering tweaking my pseudo CX/29er once again. It is currently sporting a CX carbon fork with a 400mm Axle to Crown and a 71 degree head angle. While I like the idea of toying with a suspension fork in there, 29er axle to crown measurements seem to hover around 500mm, see here:

http://www.sram.com/_media/pdf/rockshox/dealers/AxletoCrownandTorqueSpecs.pdf
http://www.marzocchi.it/System/2604/2004-bomber-en.pdf

If you figure these are 80mm travel forks and you would go with 20mm sag, you are still kicking the front of the bike up 80mm. I don't mind a little more of a slack head angle, but I think this would go to far. It looks like this is just one of those differences between CX and 29er geometry. Is there some minimal travel 29er fork with a shorter axle to crown length?

I suppose I could put a 26" wheel up front - a 26" Reba and wheel might put the front of the bike right where I want it. But a 26" front and 29er rear would be just too wierd. Or would it? Am I doing the math correctly?
 

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This place needs an enema
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Bigwheel said:
Probably this one, 432mm.
Bob, it does my heart good to see that fork in your garage, and NOT in mine anymore...

Hee hee...

DirtDad, that ManiOne's a very tunable fork, and if you're less than 150lbs it could make for a really good ride. Don't be afraid to experiment with different combos of elastomers and coil springs, and don't limit yourself to Manitou's guts--try anything.

MC
 

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128 Posts
make a BW 8 a 65mm fork, heres how...

to make it 65mm you just need some skills. you take a piece of 3/4'' pvc pipe, a make a slightly longer top out spacer (yep, pvc, just like the top out spacer in the fork) this will effectively shorten the travel and length. you need to play with the air setting a bit, and no, it won't feel like an 80mm fork, but it still really take the edge off and still feels pretty good. also, i do not have any pics to show how i did it, but it is very simple.

rick
 

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Squalor
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1,573 Posts
Yep - its gonna be wierd with just about any suspension fork on a cross bike built around a 400mm a-c fork.

Are you sure you can get a 29er tire in the rear of the frame? I have not seen many cross bikes that will fit an actual 29er tire in the rear. Some of the early generation CrossChecks, but that is about it.

Anyway, I think the best you can do is to forget the suspension idea and get a suspension corrected 26er fork with a disc mount (say the 1x1 or dimension) and put that on the front with the 29er tire and a disc brake. That will keep your geo pretty close and let you try out the 29er thing.

Good luck

LP
 

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giddy up!
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3,249 Posts
Yep, I'm afraid Lanpope is correct....putting a suspension fork on the Airborne will most likely produce unfavorable results.

If I were in your shoes I would find the shortest fork that still fits a true 29" tire. Then I would find a reputable frame builder to check out the rear triangle. It's highly likely that you can get it to fit at least a Mutano Raptor or a Ritchey zed.

That would leave you with a really fun bike for long days in the saddle over mellow terrain or mixed pavement/dirt rides.

By the way DirtDad....I put 2 and 2 together and figured out that I met you a while back in the Snow Summit parking lot. I was driving a Honda Element and lent you a tube or a tire lever or something tire related anyway:) We talked Control Tech(to jog your memory).

B
 

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Compulsive Bike Builder
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Discussion Starter · #8 ·
Hi Donkey!

donkey said:
It's highly likely that you can get it to fit at least a Mutano Raptor or a Ritchey zed.
That would leave you with a really fun bike for long days in the saddle over mellow terrain or mixed pavement/dirt rides.
By the way DirtDad....I put 2 and 2 together and figured out that I met you a while back in the Snow Summit parking lot. I was driving a Honda Element and lent you a tube or a tire lever or something tire related anyway:) We talked Control Tech(to jog your memory).
B
I can get away with a 35c rear and 44c front. Getting a 44c in the rear would be nice. I have a carbon CX fork in the front, and it and a 50 psi 44c provide some amount of compliance. I am going to see about expanding the rear at some point in the future.

B, your math is correct, it is I! In case you did not already know, J from CTech has also moved on. I am endlessly playing with bikes. I am finally getting a custom steel, but I went with DeSalvo rather than Strong, because I opted for a sand/snow (i.e., Pugsley type) of project, and all other custom builders pointed me back to DeSalvo
 

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giddy up!
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3,249 Posts
DirtDad said:
I can get away with a 35c rear and 44c front. Getting a 44c in the rear would be nice. I have a carbon CX fork in the front, and it and a 50 psi 44c provide some amount of compliance. I am going to see about expanding the rear at some point in the future.

B, your math is correct, it is I! In case you did not already know, J from CTech has also moved on. I am endlessly playing with bikes. I am finally getting a custom steel, but I went with DeSalvo rather than Strong, because I opted for a sand/snow (i.e., Pugsley type) of project, and all other custom builders pointed me back to DeSalvo
Yup, I just talked to J the other day....this'll be the first time he's been out of the bike industry in a loooong time.

B
 
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