[project] FOX F100X with DUAL AIR from reba

Discuss light weight issues concerning mountain bikes & parts.

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tehan
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by tehan

Hi all,
I did today smething new i think:)

I upgraded my terralogic fox F100X with Dual air chamber from reba race.
It wasn't soo easy, soo I wiil explain few things.

Uppers from fox have inner diameter 28mm and in reba is 27mm. So I had to shwitch main cap from air chamber to original from fox.
With "-" chamber in reba i had to do something with seal (oryginaly was adapted for 27mm). On the and I had to cut about 4cm from main air tube to have 100mm stroke (originaly it was 138mm after puting all together without tuning).

Some facts - now I have 2 chambers:) 15g lighter fork and 98mm pure piston stroke!!! (oryginaly was not more than 87mm)
And btw - i put to this fork uppers from Genesis2 fork - I will be riding on supercaliber in this season.

fork weights now 1649g with polar sensor, soo without it's about 1630g. I also plan to strip lowers from paint- the goal is to go under 1600g.

I tried this fork only "inside" because of the weather, and have to tell it works suprisingly well:) after few rides I'll write something more.

enjoy the photos.
Attachments
fox.jpg
IMG_1014.jpg
IMG_1006.jpg
IMG_1005.jpg
IMG_1002.jpg

by Weenie


Ole
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by Ole

That's just fantastic! Great work!

In my opinion, the Fox oil damper is superior to anything else out there. But unfortunately, thecoil negative spring just doesn't work for my 80kg weight and agressive riding style. I get too much fork dive during braking and hard cornering and front wheel lift on steep climbs. I'm currently on a SID 2009, but the damper is pretty pathetic stuff compared to Fox (I get crazy damper fading on the SID 15 minutes into a XC race - I have to start the race with extremely slow rebund), so my dream fork is a SID chassis, SID air spring and Fox oil damper. TFTuned Shox recommends a better oil in the SID to alleviate some of the damper fade, I'll try that come spring.


Ole.

s1ned
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by s1ned

how does everything go so far?

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yourdaguy
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by yourdaguy

I have a Fox RL29 and a Reba XX 29er and I know everyone raves about the Fox shocks but I find the Reba way more tunable and feel that it has better overall dampening. Since I only weigh 170, I have not experienced the fading problem. Both forks are 100mm 29er and the axle to crown is a few mm less on the Reba which is better for handling. As set up, I am generally using about 3.5 inches of travel on either fork on an average ride. I think you are going to be very happy with the results of your experiment unless there are some unforeseen reliability problems.
For certain parts stiffer is more important than lighter.

blueyes
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by blueyes

fantastic project, tehan :thumbup:

hope everything turns out great
Tahoe!

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scooter916
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by scooter916

FYI the FOX lowers are magnesium and I wouldn't strip the paint off them even to repaint them. they will corrode and could eventually fail.

fox uses a breathable paint to allow the magnesium to off-gas, if you repaint them they will start to bubble

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yourdaguy
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by yourdaguy

The Reba XX lowers are magnesium also as are the Sid.
For certain parts stiffer is more important than lighter.

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Lateralus
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by Lateralus

I think it`s wrong to clarify a change from the terralogic (brain) system to a dual air setup as an upgrade. The terralogic is kind of "intelligent", the dual air is just a regular suspension fork. And i don`t see why you`re doing so. A new Reba isn`t heavier, it isn`t expensive...what`s the deal?

pieterp
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by pieterp

Lateralus, you are mixing the damper part of the fork (right hand chamber) with the spring part (left hand chamber).

The OP only changed the spring part and left the damper part (with the terralogic) as it is. He now has more tuning capabilities because of 2 air chambers in the spring part in stead of 1.

@ Tehan: How did you make the 27mm reba part fit in the 28mm tube?

therapy
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by therapy

pieterp wrote:@ Tehan: How did you make the 27mm reba part fit in the 28mm tube?


tehan wrote:Uppers from fox have inner diameter 28mm and in reba is 27mm. So I had to shwitch main cap from air chamber to original from fox.

Its all up there :wink:

by Weenie


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tehan
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by tehan

Still working perfect 8)

It was the best move i could do with this fork. There is no air loss, i have pure 100mm usable stroke and it's almost linear. I have also noticed that terralogic system is more precise now - it turns on faster and is more sensible for smaller obstacles. But it might be just my feeling.

Still love it and recommend to everyone who has a bit of skills in the art. I even wrote to Fox to tell them how brilliant is my fork now, but the were a bit ignorant and respond me to *f##k* off between the words, if you know what i mean.


forgot:
As to painting magnesium lowers- i haven't had a time to do that buy i've seen few such projects and these users claim no problems.
Besides i wasn't going to paint it but anodize - like aluminum. But this process is more complicated than alu one. By doing this you can drop 50g at least from lowers (fox, rock shox...)

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