[Sandwich]

I always thought the OG BOS fork would be a good way to go. Triple clamps that were fully integrated couldn't twist, and you could use SHIMZ to assemble the whole thing tightly over the head tube. Must be expensive as fuck to machine though.

 

[jonKranked]

Intend makes some really nice USD single and dual crown forks:

https://www.pinkbike.com/news/intend-suspension-bike-festival-riva-2017.html

It is the company of the dude behind the Trickstuff brakes.

do they intend to sell them at a reasonable price?

 

[Jm_]

Pardon for the slight offtopic - Would a 2012 onwards (assuming good condition) 888 RC3 Evo V2 be a decent budget upgrade?There's a good few on the used market here and I'm told that's when marzo got 'good again' after the 08-09 production issues. For now my 32mm boxxer is trucking along fine, but with enduro exploding with popularity in Ireland there's loads of DH parts gathering dust that I could grab once I get some cash again.

Those are solid in terms of damping tech IMO:

 

[Udi]

And for the love of god, would You please stop spreading Your another BS theory? The force due to friction is independent of the contact area between the two surfaces.

Actually, that's based on a low-level understanding of friction.

Using Ff = μN as you imply here, is to assume that μ holds constant over an array of dynamic variables (normal force, velocity, time), and also assumes that μ holds constant over the entire bushing surface area.

Once you factor in hydrodynamic lubrication (quite inconsistent in MTB forks with low bath volumes), you'll find that μ sees substantial variation at different points of the bushing. If you require more oil to cover/reach the area, you add more weight - and the invert is already lagging behind in stiffness/weight ratio.

Due to manufacturing tolerances - applied force will also vary over the entire bushing surface area (even before any dynamic loading), and the more bushing surface you have, the more difficult it is to minimise static contact hotspots.

This of course varies with implementation, but my point is: there's a reason companies don't just run the entire available length of the fork outer as bushing surface area.

So, what you're saying is, Dorado and the Emerald are shit, is that it? And this new inverted Bos is going to join them???

Sub-optimal might be the better term for all the semantics fans out there.

What toodles said.
I don't think any current products are terrible, just that there is always a "best" way to do things given a specific application and use-case. Doesn't mean the other ways are bad, but for a new fork buyer... why not make the best choice?

 

[jonKranked]

Actually, that's based on a low-level understanding of friction.

Using Ff = μN as you imply here, is to assume that μ holds constant over an array of dynamic variables (normal force, velocity, time), and also assumes that μ holds constant over the entire bushing surface area.

Once you factor in hydrodynamic lubrication (quite inconsistent in MTB forks with low bath volumes), you'll find that μ sees substantial variation at different points of the bushing. If you require more oil to cover/reach the area, you add more weight - and the invert is already lagging behind in stiffness/weight ratio.

In my experience, if you have a large surface area differential (eg. double/triple the area), you'll often see an increase in the static/breakaway μ value when averaged over the entire contact area. In something like a fork this will present itself each time the travel changes direction.

This of course varies with implementation, but my point is: there's a reason companies don't just run the entire available length of the fork outer as bushing surface area.



What toodles said.
These posts always offend someone using the product, and they will always use an extreme example to make the facts sound ridiculous.

The reality is, depending (heavily) on the specific application, there is almost always a "best" way to do things. Beyond that there will be other "sufficient" ways that achieve varying percentages of success compared to the "best" way.

 

[jonKranked]

https://www.pinkbike.com/news/mystery-downhill-fork-spotted-in-the-devinci-pits-2017.html

 

[TrumbullHucker]

RUX - I haven't ridden it but we all know this is the most awesome.

BOS video
lol they just keep searching for barcodes to scan

 

[troy]

Actually, that's based on a low-level understanding of friction.

Using Ff = μN as you imply here, is to assume that μ holds constant over an array of dynamic variables (normal force, velocity, time), and also assumes that μ holds constant over the entire bushing surface area.

Once you factor in hydrodynamic lubrication (quite inconsistent in MTB forks with low bath volumes), you'll find that μ sees substantial variation at different points of the bushing. If you require more oil to cover/reach the area, you add more weight - and the invert is already lagging behind in stiffness/weight ratio.

Due to manufacturing tolerances - applied force will also vary over the entire bushing surface area (even before any dynamic loading), and the more bushing surface you have, the more difficult it is to minimise static contact hotspots.

This of course varies with implementation, but my point is: there's a reason companies don't just run the entire available length of the fork outer as bushing surface area.



What toodles said.
I don't think any current products are terrible, just that there is always a "best" way to do things given a specific application and use-case. Doesn't mean the other ways are bad, but for a new fork buyer... why not make the best choice?

Well this is just a perfect example of the Dunning-Kruger effect.

1st of all the formula to calculate both kinetic and static friction is the same, the only thing that changes is the friction coefficient μ. And guess what, dynamic/kinematic friction coefficients are usually much smaller than the static ones, especially while both surfaces are lubricated.

All Your "arguments" just prove my point. The reason why forks/shocks are "sticky" is due to tolerances and fitment between the bushings, lowers and stanchions, and not because the bushing length. That's why You see some fuckin foam rings under the seals, because they can't figure out how to lube it with 20ml of oil, that they are shipping those forks with.

Since 2000' basically nothing has changed in terms of stanchion coatings and bushing construction.They are still hard anodized tubes with steel/alu backed bushings with PTFE/polymer/brass coating. And the reason why they do not run through the entire fork is the weight and the fact that back of the bushing has to be supported, thence the lowers would have to be much beefier.

Perfect example of light and stiff fork is... Lefty. And before You will get butthurt again and call me or Woo an USD fanboiz or whatever - I am not saying that it is a better fork than anything else. All I'm saying is that it is possible to make it both light and stiff.

 

[Udi]

@troy You obviously didn't read my post, because I pointed out where/why μ changes, and I also pointed out why static μ is important - because it comes into play EVERY time the fork changes direction. This would matter far less in a linear application where the direction of movement was constant - eg. a shaft rotating in a bushing.

Your condescending graph doesn't change the facts - like I said, there are many reasons no current manufacturer is using maximum possible bushing area (or anywhere near it).

Perfect example of light and stiff fork is... Lefty.

That's a completely different implementation to any DH USD fork.
Why? Because it uses a roller-bearing interface, which means we can use flat surfaces to generate stiffness (an effectively rectangle rather than circular stanchion) in a way that heavily minimises friction.

I think the Lefty is an awesome concept. I would support a DH implementation.
I think the DVO Emerald and Manitou Dorado referenced here are not awesome, having ridden both extensively.

 

[jonKranked]

while we're arguing about forks, marzocchi is having their stuff 40-60% off.

did they discontinue the 350? i don't see it on their site

 

[troy]

@troy You obviously didn't read my post, because I pointed out where/why μ changes, and I also pointed out why static μ is important - because it comes into play EVERY time the fork changes direction. This would matter far less in a linear application where the direction of movement was constant - eg. a shaft rotating in a bushing.

Yeah man, Manitou Swinger 6way and Fox RC4 uses the same bushing size which are both installed in the same way in a sealhead. Kinda hard to blame the lubrication in a shock. Something doesn't add up here Udi

 

[Udi]

Yeah man, Manitou Swinger 6way and Fox RC4 uses the same bushing size which are both installed in the same way in a sealhead. Kinda hard to blame the lubrication in a shock. Something doesn't add up here Udi

Not even sure what you're suggesting there, but I'm sure you can also guarantee that the clearances, bushing material, shaft material, and seal forces are identical in both shocks. For what it's worth, the fat-shaft RC4 definitely has more friction than thin-shaft, but I suspect that's driven by seal area, not bushing area. Rubber has a heavily digressive coefficient vs. normal force (more area does = more friction), so classic friction calculations do not apply.

Come on - you are better than these straw-man / multi-variable arguments. Let's take our shaft stroking to PMs, I'm sure no one else cares. I honestly think we just prioritise different things in bikes.

 

[jonKranked]

Looks like they're brought back the bomber name for the 380 as well, 'new collection' too. Maybe they're gonna do the same for the 350?

i just found an article on bicycle retailer that interviewed someone with fox/marz, all product on the market under the marz name through 2017 was developed prior to fox buying marz. 2018 will be the first model year where marz product developed under fox will be released.

when considered in this light, it makes sense that they're blowing out the existing inventory.

 

[konastab01]

Intend makes some really nice USD single and dual crown forks:

https://www.pinkbike.com/news/intend-suspension-bike-festival-riva-2017.html

It is the company of the dude behind the Trickstuff brakes.

Have you seen the price of the brakes? I dont think they will be cheap at all.

 

[mykel]

Anybody have any thoughts on where Fox is going to position Zoke in the marketplace?

 

[jonKranked]

Anybody have any thoughts on where Fox is going to position Zoke in the marketplace?

from what i've read more on the OEM side of things.

 

[kidwoo]

strictly reserved for the breaky stanchions division

http://theteamrobot.blogspot.com/2012/10/shaving-weight-on-stanchions-is-cool.html

 

[norbar]

Not even sure what you're suggesting there, but I'm sure you can also guarantee that the clearances, bushing material, shaft material, and seal forces are identical in both shocks. For what it's worth, the fat-shaft RC4 definitely has more friction than thin-shaft, but I suspect that's driven by seal area, not bushing area. Rubber has a heavily digressive coefficient vs. normal force (more area does = more friction), so classic friction calculations do not apply.

Come on - you are better than these straw-man / multi-variable arguments. Let's take our shaft stroking to PMs, I'm sure no one else cares. I honestly think we just prioritise different things in bikes.

I do care because it reminds me to my talks with troy on a shitty little polish forum where everyone thought you spell damper with a u instead of an a.

 

[kidwoo]

compreshun dumpers go in the stankshuns

 

[jonKranked]

compreshun dumpers go in the stankshuns

forks.

 

[troy]

Make dampening great again.

 

[William42]

Look, maybe BoS was good back when Remy rode one a few years ago, but the fact is, it hasn't won a world cup this year and the RuX has

 

[Udi]

https://www.pinkbike.com/news/bos-teases-new-obsys-inverted-dh-fork-video.html

Lol at 45s.

Good riding video otherwise though.

 

[slimshady]

I think the Lefty is an awesome concept. I would support a DH implementation.

Wasn't the X-fusion inverted fork supposed to be like this, or similar?

while we're arguing about forks, marzocchi is having their stuff 40-60% off.

Linky pleasy? EDIT: Nevermind. I just saw the 350s were out of the picture.

 

['size]

strictly reserved for the breaky stanchions division

http://theteamrobot.blogspot.com/2012/10/shaving-weight-on-stanchions-is-cool.html

bars look ok though...could have been worse.

 

[djjohnr]

Wasn't the X-fusion inverted fork supposed to be like this, or similar?



Linky pleasy? EDIT: Nevermind. I just saw the 350s were out of the picture.

The X-Fusion inverted fork uses a key system. The Lefty uses a square rod and needle bearings.

I can't find a pic of the X-Fusion internals, but it sounds similar to this Wren -

 

[slimshady]

Got it. I thought I had read they were trying polygonal stanchions in the early development stages, but now you mentioned the keyed style ones I remember the entry at Vital noting it.

 

[troy]

X fusion Delta 8 fork had 40mm stanchions and 30mm axle with custom hub and 4 bolt rotor (fork was 6.5 lbs).

With all those new "standards" I am wondering: why da F* they didn't go with 25mm or even 30mm axle, which would stiffen up the chassis tremendously. Whoever will but that thing, would not mind a hub change and 4 bolt rotor (IMHO ofc).

 

[iRider]

Have you seen the price of the brakes? I dont think they will be cheap at all.

Nope, but reasonable if compared to Fox and Rock Shox:

1699 € for the SC
1899 € for the DC

https://www.intend-bc.com/

 

[konastab01]

Nope, but reasonable if compared to Fox and Rock Shox:

1699 € for the SC
1899 € for the DC

https://www.intend-bc.com/

Not as expensive as id have guessed at all.

 

[Udi]

Fun factz from 2012:

You will most likely find that say a 40 is quite seriously more than 10 times stiffer torsionally than say a Shiver.

 

[kidwoo]

Holding my front wheel in place with two grilled asparagus is torsionally stiffer than a shiver.

 

[Nick]

strictly reserved for the breaky stanchions division

http://theteamrobot.blogspot.com/2012/10/shaving-weight-on-stanchions-is-cool.html

Ugh.

 

[kidwoo]

Bonus for only one side!

 

[jonKranked]

Ugh.

That's not the Boxxer L-Turn

 

['size]

With all those new "standards" I am wondering: why da F* they didn't go with 25mm or even 30mm axle, which would stiffen up the chassis tremendously. Whoever will but that thing, would not mind a hub change and 4 bolt rotor (IMHO ofc).

i only run 3 bolts on my rotors so i guess i already win?

 

[norbar]

Make dampening great again.

We need to register than "funpage" (yes that is also used. Nothing better than polish english)

 

[Mo(n)arch]

Ugh.

Remy Morton's bike after the crash at the Loosefest in Belgium. Overshot the last landing. Both his lungs are punctured, dislocated hip and a lot of broken bones. Yikes.
Heal up young fella!
https://www.pinkbike.com/news/remy-mortan-injured-at-loosefest-2017.html

 

[iRider]

Fun factz from 2012:

Facts from 2014 (caution, metric units):

Dorado:
26"
Fore/aft bending stiffness: 412,9 Nm/°
twisting stiffness: 14,5 Nm/°

BOS Idylle RaRe:
26''
Fore/aft bending stiffness: 289,0 Nm/°
twisting stiffness: 31,0 Nm/°

Fox 40 Float:
26''
Fore/aft bending stiffness: 343,6 Nm/°
twisting stiffness: 30,2 Nm/°

Boxxer WC:
26''
Fore/aft bending stiffness: 310,2 Nm/°
twisting stiffness: 31,0 Nm/°

RUX:
26''
Fore/aft bending stiffness: 376,0 Nm/°
twisting stiffness: 41,1 Nm/°

Looking at these measurements, when are you going RUX @Udi ?

Source: http://www.freeride-magazine.com/test/6-doppelbrueckengabeln-im-vergleich/a23001.html

 

[Mo(n)arch]

Et voilá!