[ritche]

We all know the backward compatibility of the fox 40 fork.

I have converted my 2010ish white fox 40 to newer fit RC2 with kashima stanchions and right side internals (HSC and LSC on the top and the rebound at the bottom) with the help of a friend who works at fox for the parts.

now I ask him if he can get me the 650b lowers, to upgrade the fork. and if it is compatible.

He advised me not to because i still got the older crowns. he said If i want it, it must be with the newer crown set of the float 40. He said it can be converted, but it will feel/ride funny, or awkward, and adds that's why nobody is doing it.

I said Ok, i did not argue, maybe next time. We ended the topic asking him if he could find me a new fox float 36 RC2 650b with a straight steerer tube, for my old trail bike, luckily he has one and he will send it in a month.

 

[S.K.C.]

Wait a sec... so this guy told you that you couldn't run the 650b lowers with the pre-2014 crowns?

This is odd because I replaced the older version crowns on my 2012 FOX 40 coil with the new weight optimized 2014 40 FLOAT crowns, and everything fits/works together perfectly. The new (2014) and old (pre-2014) crowns are identical except for the machining/forging process used. What I'm saying is: if the new crowns work fine with the old 26" lowers, then the old crowns should work just fine with the new 650b lowers - unless there is something I'm missing here...

 

[ritche]

also new location for the clamp bolts on the float crowns.

1. I'll ask again my friend to confirm if the float crowns were also "optimized" for the 650b lower's offset, or it's not
really that significant.

2. i'll ask also what to do to with "air release buttons" if it will be installed on old coil fit 40s.

will post later.

 

[kickstand]

also new location for the clamp bolts on the float crowns.

1. I'll ask again my friend to confirm if the float crowns were also "optimized" for the 650b lower's offset, or it's not
really that significant.

2. i'll ask also what to do to with "air release buttons" if it will be installed on old coil fit 40s.

will post later.

1. What SKC is saying is that the "geometry" of the older crowns and newer crowns is essentially the same and putting a 650b lower on older crowns should not affect the functionality of anything.

2. They will do the same thing they do on the float 40's, allow you to release any air pressure that builds up outside of the damping/spring assembly. I have a 2015 27.5 Coil 40 that came on a complete V-10 I bought for my wife and it has the air release valves as they use the same lowers for all forks due to ease of manufacturing.

The 40 lowers are backwards compatible whether 26 or 27.5.

Now, if Fox didn't take forever and my lowers would arrive some day this year that would be great.

 

[ritche]

The fox 40 float was released in 26 and later the 650b version,
*the 650b crowns have different rake, may friend said.

He recommends, If upgrading an old fit 40 to 650 b, the 650b lowers must be paired with the 650b crowns.

as for the air release buttons, no mod needed, leave it as is.

as soon as parts (lowers and crowns) are available, i will upgrade my 40.

 

[kickstand]

The fox 40 float was released in 26 and later the 650b version,
*the 650b crowns have different rake, may friend said.

He recommends, If upgrading an old fit 40 to 650 b, the 650b lowers must be paired with the 650b crowns.

as for the air release buttons, no mod needed, leave it as is.

as soon as parts (lowers and crowns) are available, i will upgrade my 40.

I have 2 2014 fox 40 float 26" forks laying right next to a 2015 Fox 27.5 40. I see zero difference in anything other than the lowers.

Can you ask your friend for specific details on what is different. I have them laying side by side and can not see one difference. Please ask him specifically what measurements are different and where, I've looked at them and measured them from every angle imaginable.

 

[CraigS]

1. What SKC is saying is that the "geometry" of the older crowns and newer crowns is essentially the same and putting a 650b lower on older crowns should not affect the functionality of anything.

2. They will do the same thing they do on the float 40's, allow you to release any air pressure that builds up outside of the damping/spring assembly. I have a 2015 27.5 Coil 40 that came on a complete V-10 I bought for my wife and it has the air release valves as they use the same lowers for all forks due to ease of manufacturing.

The 40 lowers are backwards compatible whether 26 or 27.5.

Now, if Fox didn't take forever and my lowers would arrive some day this year that would be great.

Just received my 650b lowers. Came with seals installed and a sticker kit.
Looks like it will be a pretty simple, straight forward conversion.

 

[kickstand]

Just received my 650b lowers. Came with seals installed and a sticker kit.
Looks like it will be a pretty simple, straight forward conversion.

Yup, picked mine up last night. I'll be swapping both of our forks over to the new 27.5 Lowers tonight/tomorrow.

I'm still curious about @ritche 's friends claims that the crowns are different. My 26 float crowns look and measure Identical to my 27.5 crowns, and it's been said the 26 float crowns are backwards compatible and essentially the same from a dimensional standpoint as the previous 26" crowns.

 

[kickstand]

All of that said, does anyone have a quick link to the tuning of the "volume" spacers for the fox float 40? I want to do some reading and swap things around while i have the fork apart.


*edit*

That was easy enough to google.

http://www.ridefox.com/help.php?m=bike&id=152

 

[kickstand]

One fork down, one to go, even went the whole extra step of changing my volume spacers to add a slight bit of progressiveness to the fork. I'm just a regular @kidwoo and @Udi now with all my knowledge of swapping out super easy shock parts and understanding none of the cool stuff involved.

 

[blindboxx2334]

dawg, im in the same boat. if i can get the lowers off, seals changed, and manage to make it not leak oil by the time im done, you best bet your sweet ass i like to feel like i accomplished something big.

gold star for you today.

 

[CraigS]

Can't imagine the crowns being different.
From what I have gathered the difference is in the lowers, which makes sense.

 

[kickstand]

dawg, im in the same boat. if i can get the lowers off, seals changed, and manage to make it not leak oil by the time im done, you best bet your sweet ass i like to feel like i accomplished something big.

gold star for you today.

just finished the wife's. Made hers a click more linear since she's a lightweight and struggles to use full travel on her 40 coil, easy enough to switch if she doesn't like it.

Can't imagine the crowns being different.
From what I have gathered the difference is in the lowers, which makes sense.

yeah I can't see any way the crowns are different .

The lowers are clearly different both in length and axle offset.

 

[blindboxx2334]

sweet, i really dug my coil 40. but i really liked the linear/progressive feature that the air had, wouldnt mind trying that out one day.

 

[kickstand]

FYI for anyone interested I've got two 26" lowers for sale, both off a float, and I have a complete fox 40 o/b r 27.5 new never mounted off a 2015 v-10

 

[kidwoo]

All right hell, I'll bite.

What's involved in getting a 2013(?) coil 40 into the air spring club? Assuming of course these lowers are part of it. Might as well go full frankenfork and send the anti-air spring crowd into a tizzy.

 

[kickstand]

I am under the impression that you would need a new lower, and a new left stanchion and air spring assembly. The damper side (externally) appears unchanged from my 2011/2012 fit r2d2 star wars whatever dampers.

 

[kidwoo]

So........new fork

Lemme see what I can track down in garages belonging to friends stanchion-wise. I might buy some lowers from you.

With greg herbold as my witness, I will not be laying a finger on the damper side of my fork.

 

[kickstand]

They both sold already! Didn't expect that to happen.

The damper side looks identical, I mean I didn't tear into it, but the stuff sticking out of the stanchion with the lowers off looks the same as the previous fit 40's.

As for the left stanchion, it "looks" like it has been machined more than the coil version to allow the air side assembly to seal up better.

As for the lowers, I don't see why you couldn't run the coil lower, you just wouldn't have the pressure relief valves. I forget to even use mine on most days, and when I do very little air sounds as if its coming out, so I don't know if I just am not sensitive enough to that stuff, or what.

 

[kidwoo]

I haven't geeked out on this enough to look into it but just stanchion and springs: what's the weight difference? Do you know?

 

[CraigS]

"kickstand, post: 4037305, member: 36563"] They both sold already! Didn't expect that to happen.






Where did you put them up for sale, and how much did you get?
I will be wanting to sell mine

 

[kickstand]

I haven't geeked out on this enough to look into it but just stanchion and springs: what's the weight difference? Do you know?

I don't geek out on weights.

I have "read"

that the 40 float lowers are lighter.

That air is lighter than a coil

That the 40 float crowns are lighter.

Sorry, I honestly have sucked at this part.

 

[kickstand]

"kickstand, post: 4037305, member: 36563"] They both sold already! Didn't expect that to happen.






Where did you put them up for sale, and how much did you get?
I will be wanting to sell mine

Pinkbike.

I listed my 40 float lowers at 150.

New 26" lowers to my best estimation had to be near the $275 that 27.5 lowers run......

I had a lot of guys offering $100.

 

[kidwoo]

I have "read"



That air is lighter than a coil

Someone should tell PUSH!

 

[kickstand]

Push = More knobs to turn

 

[kidwoo]

Oh trust me. Those knobs will turn up.





Credit cards in hand.

 

[CraigS]

Pinkbike.

I listed my 40 float lowers at 150.

New 26" lowers to my best estimation had to be near the $275 that 27.5 lowers run......

I had a lot of guys offering $100.

Thanks!

 

[yd35]

Pinkbike.

I listed my 40 float lowers at 150.

New 26" lowers to my best estimation had to be near the $275 that 27.5 lowers run......

I had a lot of guys offering $100.

I sell most of my stuff on PB, so it works, but man, sometimes I gotta give myself a power facepalm after the lowball offers I get.

 

[kickstand]

 

[CraigS]

Yeah, just listed mine.
Cant wait, let the games begin.

 

[Udi]

For those asking about weight, I have a super cool infographic:

 

[kidwoo]

So 300 grams with the lowers and air spring. Maybe a little more with a honed stanchion.

 

[Staktup]

Thanks for this resource everyone! Wow, 4 years later and I just attempted this reverse mullet experiment on my 2012 V10 and 40 Fit RC2. I took a 650b Roval DH wheel and slapped a WTB Convict 2.4 on it and it has ample clearance from the fork arch. I removed the coil, compressed the stanchions all the way into the lowers, and no issue that I can discern.

However, the shorter offset of the 26er lowers made for my 203mm rotor to smash up into the caliper. My choices are:

1) Replace the lowers with a 650b set (which I just bought second-hand)

2) use the 26er lowers but add spacers between the brake mount and caliper mounting holes

3) use the 26er lowers and swap the 203mm rotors with a 180mm rotor

Option #1 seems to make the most sense, so I'll have my shop swap everything out when it's time for a fork service...

 

[englertracing]

Ummm, your rotor should not be hitting the caliper because of the offset..... That's not right...
Also the 45mm of offset is moe better feeling than the 52mm offset of the 650b

 

[Olly]

However, the shorter offset of the 26er lowers made for my 203mm rotor to smash up into the caliper.

Are you sure you haven’t forgotten an adapter or fitted a bigger rotor? If you’ve got a bigger rotor you’ll need a brake mount adapter. The offset would make absolutely no difference to the brake mount.

 

[Electric_City]

Is the rotor a 203mm and the mount is meant for a 200mm?

Ps. That's your problem. The 40 (my 2015 at least) is designed for a 200mm rotor. Use 2 small washers to space the caliper back. Just make sure the washers don't touch the disc.

 

[jonKranked]

bump again.... found out over the weekend that my 2010 dh frame can apparently fit a 27.5 wheel, and it sounds like older 26" 40's can as well? it's hella old, i wanna the chassis/lowers are 2008 or 09?

 

[kidwoo]

I've got a 26" fork with the old castings and they definitely fit a 20mm wide rim with a 27.5 2.5 dh tire.

Lots of people here have done it. You get the bigger wheel if you want it without the dumb fox offset.

 

[jonKranked]

i figured i was OK but just wanted to double check.

 

[HAB]

dumb fox offset.

For real. They figured out that shorter offsets were a good idea on the 36, why the hell haven't they fixed that shit? I'm running a 650b wheel in a 26" 40 and I'd STILL like less offset.