[kidwoo]

I just got the thing last night son!

I kneed some knowledge: Does anyone know the thread pitch and diameter (as in M20x0.5 type nomenclature) of the top cap threads on both a fox 40 and a newer Boxxer? I gotta buy some threadin' tools for an adapter.

sorry to take over the thread but just to keep it relevant

Fox40 chassis with charger damper! Final answer!

 

[blindboxx2334]

damn, thats a big tap.

 

[Dirk77]

sorry to take over the thread but just to keep it relevant

Fox40 chassis with charger damper! Final answer!

Hot Damn ! I can't even afford one of them, now i gotta buy both of them and frankenfork, just to keep up..

Definitely keep us updated, love to see the final results.

 

[Steve M]

I just got the thing last night son!

I kneed some knowledge: Does anyone know the thread pitch and diameter (as in M20x0.5 type nomenclature) of the top cap threads on both a fox 40 and a newer Boxxer? I gotta buy some threadin' tools for an adapter.

sorry to take over the thread but just to keep it relevant

Fox40 chassis with charger damper! Final answer!

Neither of them are standard sizes, ie you aren't going to find taps/dies that work for them. Should be easy enough to cut on a lathe though. Boxxers are 32.40mm actual (probably 32.50mm nominal) OD by 1.00mm thread. Don't have a 40 top cap lying around unfortunately.

 

[Lelandjt]

Are't FIT and charger dampers almost identical? I mean they might be tuned differently but are't they both sealed dampers with rubber bladder compensators that use a spring preloaded shim stack over the piston for high speed damping and adjustment and a needle and port for low speed? What makes the charger better?

 

[kidwoo]

Boxxers are 32.40mm actual (probably 32.50mm nominal) OD by 1.00mm thread.

Booyah! I got the diameter measured but confirmation on the pitch is greatly appreciated. Halfway there. Thanks man! Now get your damn dh bike running!

Are't FIT and charger dampers almost identical? I mean they might be tuned differently but are't they both sealed dampers

Like duh....hence the whole idea. I'm not one of the people that thinks the charger is the only thing that makes the new boxxers so good, but it is a really nice riding damper. I already own the 40 which after riding two boxxers for 5 years makes me really want to hold onto that stiff chassis. But that whole rapid recovery thing that RS has going on really does feel pretty badass. The 40 just damps evenly across the entire rebound stroke like forks always have. There's something about the RS damper that's different. Maybe SteveM could elaborate (or just tell me I'm on crack). But between a few of the new boxxers I've ridden and my pike, there's just something more refined feeling about it.

The biggest problem is just that the topcaps are different (and I have to use the RS topcap because it's blatantly an RS topcap and that's funny), and the FIT dampers are longer. Spacers. That's all I need to get. I think I got the bottom figured out. I just need to have some thread specs when I visit ye ole local machine shop. I'm just going to get a short sleeve machined with the RS topcap thread on the inside, and the 40 stanchion thread on the outside. Should work.

edit: just measured my 40 cap. 37.3something so 37.5 bore. Oh yeah......this should be easy.

 

[Steve M]

If you're making adaptors for the 40, you'll want to machine the OD of the thread to exactly match the OD of the thread in your existing topcap. The thread pitch for the 40 is 0.80mm - couldn't measure diameter as I only have a stanchion on hand, not a top cap.

 

[kidwoo]

0.80.......thanks again!

I've never seen a lathe chase threads when a tap/die aren't available. How tough of a process is that?

 

[Steve M]

Chasing threads or cutting them? Cutting them on a lathe is no problem, chasing them would involve a skillful operator setting things up extremely carefully, would be a very slow process especially with such a fine thread. All the threads in stanchions/damper topcaps are cut on lathes usually. Assuming you're just trying to make a plug-in adaptor to fit the Charger into a 40 stanchion, that can be done on any lathe that's set up to cut metric threads (although 0.80mm is 31.75TPI, if the thread is shorter than 20mm then you could use a 32TPI pitch and it'd work fine).

 

[kidwoo]

Cutting for sure, not chasing. The threads are pretty short in length/span along each top cap as you know so yeah, might be able to get away with a 32tpi which must be easier because it's big and round the way American things should be.

What do you think of uhmw vs aluminum for the bottom spacer? The spacer block I'm envisioning for the bottom is about a one inch cylinder that encases about half an inch of the damper rod from the charger. The center is bored out for the M6 or whatever it is but with a lip inside the top to catch the edge of the damper rod. I figure that should hold it pretty securely.

The hole in the bottom of the 40 lowers is larger than the boxxers so I'm thinking of just cutting a circular lip into the same cylinder protruding out the bottom to sit in the bigger hole. Thinner than the wall thickness of the lowers by just a tad. Then a vented bolt with a washer on the bottom to pull it snug. I want to still be able to hit the rebound damper from the outside. Even if it s with a hex wrench.

Edit: actually hell, what was all that fun stuff sitting in the back of your shop? You want a fun project?

 

[blindboxx2334]

woo-

maybe this is a biz calling for you. You can cater to the guys with the old (exploding) FiT carts

please post pics! i love frankenstein bike sh!t

 

[jackalope]

This sounds like a nice idea, but the real question is if he can get a charger damper in an Avalanche MTN of DHF fork.

 

[Steve M]

Cutting for sure, not chasing. The threads are pretty short in length/span along each top cap as you know so yeah, might be able to get away with a 32tpi which must be easier because it's big and round the way American things should be.

What do you think of uhmw vs aluminum for the bottom spacer? The spacer block I'm envisioning for the bottom is about a one inch cylinder that encases about half an inch of the damper rod from the charger. The center is bored out for the M6 or whatever it is but with a lip inside the top to catch the edge of the damper rod. I figure that should hold it pretty securely.

The hole in the bottom of the 40 lowers is larger than the boxxers so I'm thinking of just cutting a circular lip into the same cylinder protruding out the bottom to sit in the bigger hole. Thinner than the wall thickness of the lowers by just a tad. Then a vented bolt with a washer on the bottom to pull it snug. I want to still be able to hit the rebound damper from the outside. Even if it s with a hex wrench.

Edit: actually hell, what was all that fun stuff sitting in the back of your shop? You want a fun project?

Have to double check that my lathe can actually hold something that big, think chuck capacity is 1.5" which is 38.1mm... have some material here though. If you can measure the dimensions of the hole in the 40 lowers as well as the thickness, I can have a crack at it. Oh and also confirm the charger damper shaft diameter too, I think it's 10mm from memory.

 

[kidwoo]

We should talk. I'll shoot you an email. I just got a quote from a local machinist who wants $350 for the threaded sleeve. This can't be tough.

Hell maybe this could lead to some vorsprung conversion kits!

 

[troy]

We should talk. I'll shoot you an email. I just got a quote from a local machinist who wants $350 for the threaded sleeve. This can't be tough.

Hell maybe this could lead to some vorsprung conversion kits!

Say whaaat? Last year i did a threaded alu sleve to fit modified tpc+ cart to 888and it cost me like 25$. They were charging around 35$ per/h on lathe (non cnc). Unless You desighned some fancy adaptor that pricetag is ridiculous.

 

[kidwoo]

Yeah that's what I said.

I bitched and the guy changed his tune to $90

Imma get steve on this one. He knows the application and that's a much better knowledge base for whatever he decides to charge me.

 

[tacubaya]

$350? WTF, did you ask for a sleeve made from Inconel or what?

 

[Da Peach]

Just get a RUX, way easier.

 

[kidwoo]

$350? WTF, did you ask for a sleeve made from Inconel or what?

Nanotube diamond fiber, gold-plated.

Why, what were you guys thinking material-wise?

 

[Nick]

subscribed for black magic damplificator updates ....

 

[Udi]

I thought you were joking, but that sounds like a lot of work for something you could likely achieve by just revalving the rebound stack on the invert FIT cartridge. Which year 40 do you have?

Rapid Recovery to me just sounds like faster LSR / heavier HSR proportional to each other - although from reading the application list it probably just came out of the oven feeling like that and they decided to market it as a feature. I'd say it's more of a valving configuration on a conventional piston than an actual new technology. I've just revalved my shock to behave like that, mostly to get a little more pop without bucking

I don't personally think it's the best setup for a fork, as it results in a tendency for the fork to spring back mid corner in moderate to large radius corners in a way that makes it difficult to maintain traction. Also, faster return from the deeper stroke isn't dangerous like it is on a shock so the faster response there is generally welcome on a fork. But regardless, I'm pretty sure firmer valving on the FIT rebound piston (with less clicks of LSR) would achieve the same thing if you actually wanted it.

Just get a RUX, way easier.

I enjoy these posts.

 

[Da Peach]

is the RUX really so unworthy of consideration?

 

[Udi]

Looks decent to me, Pinkbike say nice things about it: http://www.pinkbike.com/news/Suntour-RUX-Review-2014.html

 

[StiHacka]

is the RUX really so unworthy of consideration?

Get a new 888CR for $600 and be happy. It is tons better than my old Boxxer.

 

[slimshady]

Vital gave it a good review too, especially for the second review. A friend ordered one, it should arrive in a month por so.

 

[kidwoo]

I thought you were joking, but that sounds like a lot of work for something you could likely achieve by just revalving the rebound stack on the invert FIT cartridge..

Me: hey man you still have an extra charger damper sitting around?
Buddy of me: yeah you want it?
Me: yeah be right over.

And it's simple simple lathe stuff. You should see what I do to snowmobiles
Sum total = not that much work

It's a 2013MY, literally the last production run of the coils RC2

Rapid Recovery to me just sounds like faster LSR / heavier HSR proportional to each other - although from reading the application list it probably just came out of the oven feeling like that and they decided to market it as a feature. I'd say it's more of a valving configuration on a conventional piston than an actual new technology.

That's my take too.
I don't really think it's new 'technology' ya know. Just position sensitive damping done right. (finally) I'm half kidding about the rapid recovery thing. That's just about the only special claim those dampers have. But they do work well.

I don't personally think it's the best setup for a fork, as it results in a tendency for the fork to spring back mid corner in moderate to large radius corners in a way that makes it difficult to maintain traction. Also, faster return from the deeper stroke isn't dangerous like it is on a shock so the faster response there is generally welcome on a fork. But regardless, I'm pretty sure firmer valving on the FIT rebound piston (with less clicks of LSR) would achieve the same thing if you actually wanted it.
I enjoy these posts.

I hear ya on the concept. But I've put about a zillion miles on my pike and enough runs riding with tweak time on a new boxxer to know that I've never felt any fox product that I can get to feel like this, corners included. And a loaded corner is a loaded corner. It's not coming back until the pressure/g-forces let up. If that's not the kind of cornering you're talking about, then I can also say that bumpy, less loaded turns are a dream on these things. Actually that's where I think it really stands out. Love the pike, love the boxxer. And it's not because of the air springs.......those are nothing special.Have you spent any time on any of the RS stuff with this special, super duper proprietary special secret sauce? It ain't bad.

Mostly I just want to ride with an acquaintance of mine who works with fox and let him see the obvious 'charger' knob on the top of my 40.
So I'm doin it! You can't stop me!

If it's worse or no better, I'll just take it out.

 

[Udi]

I've never felt any fox product that I can get to feel like this, corners included.

I know reading isn't your strong point, but I clearly stated that it involved running the HSR valving firmer (i.e. moar shims). You could extrapolate from that that you probably haven't ridden any Fox products that are tuned the way I described.

Put a bit of ride time on the new Pike and also the 2015 Boxxer WC (charger/air) recently, wasn't blown away by either but I'm not a huge fan of air springs and I think that let the Boxxer down. The Pike felt good for a non-DH fork though. I think the coil Boxxer with the same damper would be a solid choice.

But fair enough on the knob swapping shenanigans.

If it's worse or no better, I'll just take it out.

Of course it'll be better, after all that effort it has no choice.
Seriously though, at the very least the Charger (I presume) has a proper seal in the sealhead, unlike the Fox "Rapid Retardation" seal head which features no seals whatsoever and relies on hopes and dreams to hold oil in. If it also uses standard 8mm shims then it's probably easier to revalve than the FIT too. The only step backwards to me is the lack of a HS preload adjuster which I do find myself using occasionally, but it's not a huge deal.

 

[kidwoo]

I know reading isn't your strong point,

I'm not even a fan of pineapple in rum, so I find your suggestions really offensive.

Oh come on, I read just fine. I just don't care because what you're describing doesn't reflect from what I've experienced riding the things. If you want to elaborate on what you meant, I'm down for the geekery. But I can think about 20 completely different scenarios for maintaining 'traction in corners'. I just responded to the first one I thought of.

But anyway, I'm not popping one open to switch around teh shimzor when all I have to do is a get a few adapters cut. As I understand their whole rapid recovery nonsense it's exactly that. Less damping at the top of the stroke (you say potato, I say the shlt works better though chatter, even on a fork). I just want to try it out. I'm fully willing to believe it's a waste of time. It's not like you can feel any difference with the charger assembly just holding it your hand.....it feels just like a fox damper, damping evenly across the entire rebound stroke. We'll see.

 

[Udi]

Just pulling your chain, and like I edited in - I think the charger probably offers a few benefits (aside from the alternate valving) anyway.

PS, if you love the new setup and want to sell the inferior Fox junk cheap, you know who to PM!

 

[no skid marks]

Is there any difference between the 40s and Boxxers air springs ramping?

 

[kidwoo]

Just pulling your chain, and like I edited in - I think the charger probably offers a few benefits (aside from the alternate valving) anyway.

PS, if you love the new setup and want to sell the inferior Fox junk cheap, you know who to PM!

My chain is easy to yank when I'm on bleed number 300 for a brake I don't want to admit is faulty and my elbow is the size of a golfball.

I'd rather just get you to show me how to further tune one if anything. I mean I'm not going to sell the 40 with a charger in it when I get rid of the fork. All I've ever done with a FIT cartridge is change the oil and yell at it.


NSM: boxxers have tokens. Pretty red tokens that you can trade with your friends. Obviously superior. The 40 uses a coil for a negative spring right?

 

[no skid marks]

NSM: boxxers have tokens. Pretty red tokens that you can trade with your friends. Obviously superior. The 40 uses a coil for a negative spring right?

Tokens aren't for negative spring. They're for main spring, to make it ramp up differently.
I was just wondering if the 40 ramped less and needed different shim stack to use Boxxer cart anyway.
I'm sure there's little to nothing in it. It was late, I'd had a few.

 

[kidwoo]

Yes I know exactly what the red tokens are for. Losing behind a work bench.

The fox question was completely separate. It does though right?

 

[Lelandjt]

Yes. Unswappable coil negative springs (as in Fox won't sell them to you). You have to send your fork in to have the spring changed. At 170lb I feel the coil's rate is perfect for me though. For 2016 I guess they're going to a "new Fox 36 style" self adjusting air negative spring.

 

[kidwoo]

Yes. Unswappable coil negative springs (as in Fox won't sell them to you). You have to send your fork in to have the spring changed. At 170lb I feel the coil's rate is perfect for me though. For 2016 I guess they're going to a "new Fox 36 style" self adjusting air negative spring.

Well, this is fox's first attempt at an air spring ever. You know. Gotta give'em time to figure it out.

 

[Josef]

Kidwoo did you ever complete this project?

 

[kidwoo]

Still in the CAD phase........

But working on it.

 

[jstuhlman]

try it now

 

[Steve M]

That's my take too.
I don't really think it's new 'technology' ya know. Just position sensitive damping done right. (finally) I'm half kidding about the rapid recovery thing. That's just about the only special claim those dampers have. But they do work well.

Rapid Recovery is just shimmed rebound damping. There's nothing special about it from a conceptual standpoint.

I know reading isn't your strong point, but I clearly stated that it involved running the HSR valving firmer (i.e. moar shims). You could extrapolate from that that you probably haven't ridden any Fox products that are tuned the way I described.



Of course it'll be better, after all that effort it has no choice.
Seriously though, at the very least the Charger (I presume) has a proper seal in the sealhead, unlike the Fox "Rapid Retardation" seal head which features no seals whatsoever and relies on hopes and dreams to hold oil in. If it also uses standard 8mm shims then it's probably easier to revalve than the FIT too. The only step backwards to me is the lack of a HS preload adjuster which I do find myself using occasionally, but it's not a huge deal.

Actually it's quite the opposite of that. Revalving a rebound shim stack doesn't really change the shape of the curve substantially, but it does alter the range of rebound damping available. The Charger dampers use a much bigger rebound piston with way larger ports than the Fox. Up until a certain velocity, they're both pretty much linear, but above that, the Charger stays linear while the Fox's small ports begin to choke and create a more progressive curve.

Also the Charger damper unit just uses a single wiper seal, in principle pretty similar to the Fox system. In the Boxxer, they use a 2nd identical wiper that's mounted in a plate that's circlipped into the stanchion underneath the seal head of the damper itself. From observation in the workshop, it isn't much better or worse than anything else except in one fundamental way - it's really, really low friction.

Is there any difference between the 40s and Boxxers air springs ramping?

Both are highly adustable to the point where there's no reason to compare them - the differences lie in the negative spring and therefore the initial stroke. If you're in a very specific weight, and therefore pressure, range (ie suited to the particular rate of the coil negative spring in the 40), the 40 is more linear initially and works a little better. If you're outside that weight range then the Solo Air system works better. I believe this is why Fox are moving towards the new 3-moving-seal solo-air-esque system as found in the new 36. Funny after all the effort they put into marketing the new Talas system as better than the old one because it only has 1 moving seal instead of 3, now they've gone the other way with the Float and taken it from 1 moving seal to having 3 instead.

Kidwoo did you ever complete this project?

I'm in the process of getting the adaptors machined up. If you're interested in trying it yourself, let me know - enough interest and I'll make a few of the adaptor kits.

 

[kidwoo]

try it now

Oh damn! Look at that! It's in.

Just took 238 laps.

Best thing ever.

Everyone should do it.