[OGRipper]

From Velonews:

http://www.velonews.com/tech/report/articles/9586.0.html


"On the RockShox side, we spied three new longer-travel forks. SRAM representatives wouldn't provide any details on the record, but we were able to scrape up a few hints. Domain is a new value freeride fork and features a 20mm Maxle and oversized stanchions. Lyric is a new light freeride fork, with a new damper system called Mission Control that offers external high- and low-speed compression damping. Finally, Totem is the new top-end freeride fork for '07. First seen at Interbike, the platform appears to have stanchions in the neighborhood of 40mm. Both high- and low-speed compression feature external adjustments, and the new lowers seem to be triple butted externally."

 

[zedro]

From Velonews:

"...and the new lowers seem to be triple butted externally."

someone should tell them you cant butt aluminum castings

 

[CBJ]

Not that I am an aluminum specialist but I noticed when I read it that I had never heard about triple butting externally.

 

[zedro]

Not that I am an aluminum specialist but I noticed when I read it that I had never heard about triple butting externally.

butting is a mechanical process done on tubes (or rods) where you basically form the material to be thicker at the ends through pressure; it can be done on any malleable material really. But people mistake 'butting' for the shape, which is incorrect. In this case the tubes are tapered, simply because they were shapped that way by the mold, not butted.

You can butt externally, internally, or both, and have multiple thicknesses (double, triple....) on any formable metal

Thats my nerding for the day....

 

[Transcend]

Velonews journalists aren't exactly tech specialists...

I thought they weren't supposed to report new products from taipei?

 

[manhattanprjkt83]

I think the totem is going to be pretty dope...All those single crown monster geeks from back in the day will be happy.

They should give it the same internals as the new boxxer wc

 

[zedro]

...All those single crown monster geeks from back in the day will be happy.

heh, thats true, everyone used to laugh at the photochopped pics of the SC Monster....

 

[manhattanprjkt83]

heh, thats true, everyone used to laugh at the photochopped pics of the SC Monster....

i know, i always sorta like the idea...not to derail the thread but frickin fox needs to release a 20mm lower for the vanilla series so i can get rid of my pike :mumble:

 

[skinny mike]

i know, i always sorta like the idea...not to derail the thread but frickin fox needs to release a 20mm lower for the vanilla series so i can get rid of my pike :mumble:

wouldnt that be a 36?

 

[manhattanprjkt83]

wouldnt that be a 36?

NOOOOOOOO! why do people keep saying that. Im talking about a sick solid 20mm 32mm stanchion dj/park/all mountain fork, with basic spring/oil internals...

that would be perfect for the DOC.

 

[no skid marks]

Do they look like 1.5 steerers to anyone else. Wonder if they'll do a 1 1/8th. Not that I care,big single crowns suck.

 

[OGRipper]

NOOOOOOOO! why do people keep saying that. Im talking about a sick solid 20mm 32mm stanchion dj/park/all mountain fork, with basic spring/oil internals...

that would be perfect for the DOC.

That's a pike - what's wrong with yours?

 

[bballe336]

Do they look like 1.5 steerers to anyone else. Wonder if they'll do a 1 1/8th. Not that I care,big single crowns suck.

how do big single crowns suck? They are lighter, have the same performance as DC's, won't smash up your toptube, and have better turning radiuses. If one of those fork's has the same internals as a Boxxer WC I would buy one.

 

[no skid marks]

Might be in my head but I don't think they'll offer the same stiff feel as tripples and I don't think the longevity will be there. I am a stubourn old man but it just don't ad up. Marketing? Built in fuse,three years they'll all be wrecked and ya'll be suckered into buying the next thing.
I'd love to be wrong but they just don't sit well with me,then there's the headset taking the abuse issue.
Oh and for a given stiffness I think you'll find they're not lighter(66/888).

 

[Transcend]

Might be in my head but I don't think they'll offer the same stiff feel as tripples and I don't think the longevity will be there. I am a stubourn old man but it just don't ad up. Marketing? Built in fuse,three years they'll all be wrecked and ya'll be suckered into buying the next thing.
I'd love to be wrong but they just don't sit well with me,then there's the headset taking the abuse issue.
Oh and for a given stiffness I think you'll find they're not lighter(66/888).

Ya, I mean, they obviously didn't put in any sort of research. Clearly no FEA went into them. They just built it and marketed it!

 

[no skid marks]

Time will tell and I'd be happy to be wrong.
So they will have thier DHillers on them next year hey?
Wonder why Marz and Manit aren't using them for DH yet either. Nah not marketing or letting the masses aclimatise,it's RnD.

 

[Cave Dweller]

Im in, where can i buy one. That thing would go so sweet on my DHR.

 

[OGRipper]

Time will tell and I'd be happy to be wrong.
So they will have thier DHillers on them next year hey?
Wonder why Marz and Manit aren't using them for DH yet either. Nah not marketing or letting the masses aclimatise,it's RnD.

Well, I personally don't think they will replace DCs for racing anytime soon, but for the many freehuckers and longer-travel trail riders out there currently riding DC forks, the big travel SCs have some advantages...and don't forget that Marz and Manitou (and Fox, and RS) also have DCs to market as well, so your argument about racers using them isn't that strong to me. Meh, whatever, don't get one.

 

[no skid marks]

Don't get me wrong I'm all for technoligy/advancements it's just the logic is not there yet I don't think,every company has /is trying it even Foes but i'm just instigating some feedback on my parranoia and stating what it is. I'm sure I'll happilly be ridding them too in time to come if they prove to be the answer.I should have origonally said,does anybody doubt the stiffness or longevity of these big single crowns comparred to tripple clamps?
I never said they didn't design them well I just said they market them well.

 

[Cave Dweller]

I would place a bet that a 40mm single crown fork with a 1.5 steerer would be as stiff as a 32mm 1 1/8 boxxer.

 

[no skid marks]

I wouldn't bet against that.What about 66 vs 888?
The headset I scream,the poor headsets.Not sure about frames flaring easier,seems logical.
Hey they can build it to achieve a similer affect but what about hight,weight,stiffness,longevity,frmae,headset life/

 

[zedro]

I would place a bet that a 40mm single crown fork with a 1.5 steerer would be as stiff as a 32mm 1 1/8 boxxer.

dont forget theres a crown that bridges those big tubes...

 

[OGRipper]

The headset I scream,the poor headsets.Not sure about frames flaring easier,seems logical.
Hey they can build it to achieve a similer affect but what about hight,weight,stiffness,longevity,frmae,headset life/

Valid questions, a lot which will be covered if in fact it's 1.5.

As for longevity, I don't know too many people that keep forks (or frames, for that matter) for more than a few years these days anyway.

 

[Cave Dweller]

I wouldn't bet against that.What about 66 vs 888?
The headset I scream,the poor headsets.Not sure about frames flaring easier,seems logical.
Hey they can build it to achieve a similer affect but what about hight,weight,stiffness,longevity,frmae,headset life/

I wouldn't use a 7inch single crown fork with a 1 1/8 steerer. I have seen a few bent 66's, i would only use a 1.5 single crown and this solves any bearing issues as well.

dont forget theres a crown that bridges those big tubes...

I don't understand what your saying? That crown would be massivily stiff with a 1.5 steerer and 40mm legs.

 

[no skid marks]

I may be wrong but I think Zedro is saying that the steerer and staunchion is not the issue but the crown and it's purchase on either the staunchions or steerer,or just it's twisting stiffness perhaps.
I'll speak for myself though and say yeah what about that^?

 

[zedro]

I don't understand what your saying? That crown would be massivily stiff with a 1.5 steerer and 40mm legs.

not necessarily, and certainly not as stiff as two crowns placed a distance apart. Think of the effective cross section of a dual crown...you could make the SC crown twice as thick (like the dual crowns glued together) but still wont be anywhere as stiff. You can beef those tubes up, but the crown is still the achillies heel. Stand on one leg or on two spread apart; that is the mechanism at work, much morethan just the size of your legs.

 

[zedro]

I may be wrong but I think Zedro is saying that the steerer and staunchion is not the issue but the crown and it's purchase on either the staunchions or steerer,or just it's twisting stiffness perhaps.
I'll speak for myself though and say yeah what about that^?

its not just twisting but it effects in every direction, especially fore-aft. Its fairly easy to deflect a lone crown, you have to give it a tall cross-section, which is what the dual crowns effectively does.

 

[Cave Dweller]

not necessarily, and certainly not as stiff as two crowns placed a distance apart. Think of the effective cross section of a dual crown...you could make the SC crown twice as thick (like the dual crowns glued together) but still wont be anywhere as stiff. You can beef those tubes up, but the crown is still the achillies heel. Stand on one leg or on two spread apart; that is the mechanism at work, much morethan just the size of your legs.

I was comparing it to a 32mm boxxer. If i was comparing it to a 40mm monster or fox 40 then sure, it is going to flex more, but that’s not what my comparison was.

A 40mm leg has more surface area/interface then a 32mm leg (obviously) so the crown would be less then 2 times as thick to get the same "purchase" area.

It will flex far less then the current crop of single crowns thats for sure.

 

[OGRipper]

I was comparing it to a 32mm boxxer. If i was comparing it to a 40mm monster or fox 40 then sure, it is going to flex more, but that’s not what my comparison was.

A 40mm leg has more surface area/interface then a 32mm leg (obviously) so the crown would be less then 2 times as thick to get the same "purchase" area.

It will flex far less then the current crop of single crowns thats for sure.

Yeah but still, the 5 inches or so between the crowns adds a tremendous amount of stiffness for probably less weight than a single crown burly enough to come close to matching it, even with 40 mm legs. It's not just the total purchase area, it's where the purchase occurs.

I'm no engineer but it's a leverage thing. Think of a wooden ladder with only one fat rung as compared to a ladder with two thinner rungs set some distance apart...or something like that.

 

[manhattanprjkt83]

That's a pike - what's wrong with yours?

nothing the pike is great fork...fox is just about 8 million times better quality, both construction and travel...I have ridden both quite a bit.

 

[manhattanprjkt83]

oh god i go away for a few hours and we are now talking about flex :nonono:

 

[zedro]

A 40mm leg has more surface area/interface then a 32mm leg (obviously) so the crown would be less then 2 times as thick to get the same "purchase" area.

you are ignoring the fact that the dual crown has a greater mechanical advantage, even if the crowns are half the size. Also you can build a greater width in the crown regardless of slider/steerer size (ie. Marz. M-crowns), but its about the height of the crown; ie. a dual crown gives a massive effective height over the single, thus a much greater cross-section. I am not talking about the effect of the clamping area, but rather the effective beam cross-section between the sliders and the steerer that keeps the sliders from deflecting from the steerers axis.

 

[beaverbiker]

go buy a strength of materials book and read about area moments of inertia and beam loading. it'll explain everything. a single crown is acting like a cantilever beam. a dual crown is acting like a cantilever beam with another reaction in all 3 dimensions placed a distance (headtube plus spacers) apart. thankfully zedro has the patience to explain everything all the time.

 

[SuspectDevice]

No one mentioned that tribal graphics are SOOO 2002 yet?

 

[no skid marks]

its not just twisting but it effects in every direction, especially fore-aft. QUOTE]
Yeah sorry I meant flex as in accross the crown between steerer and stanchions,so meaning for/aft.
I even wonder weather 32mm staunchions with a bit of give(flex) would be stronger,would take the load off the crown a bit, but it would not feel as stiff.(edit)No forget that,the 40mm would be grabbed better by the crown,maybee externally butted stanchions(joke).
I just think if you don't do X-ups or bar spins then there's no point to it. People say it's better for tight stuff but I've never had a problem with tripples in tight stuff and they could just move the stanchions further appart to solve that.
I must say I have no problem as yet with my 36ers but I'm a lightweight.

 

[Cave Dweller]

go buy a strength of materials book and read about area moments of inertia and beam loading. it'll explain everything. a single crown is acting like a cantilever beam. a dual crown is acting like a cantilever beam with another reaction in all 3 dimensions placed a distance (headtube plus spacers) apart. thankfully zedro has the patience to explain everything all the time.

Jeezzzz.........mate, please don't talk to me like im a little kid. I have already completed my mechanical engineering degree thanks.

OK, i can see where Zerdo is coming from now, i was refering to side to side, rotational, "hit a rock and wheel deflects sideways" motion.

For the fork to flex for and aft would require the crown to rotate between the steerer and the legs. The simple fact of the crown having to wrap around a 40mm leg and a 1.5 steerer is going to result in a crown that is at least 25% wider, and it would also have to be deeper as its a single crown, says it is 40% deeper then a boxxer lower crown. That is a chuncky crown no matter how you look at it. How much do you think that would flex over 10cm, not alot. It would probably crack before it flexed a great deal.

Another thing to consider is the top crown doesn't add to the stiffness in a pure for/aft movement, it just provides a place to apply the reaction force. The extra stiffness gained by triiple clamps come from the resistance to euler buckling of the section of leg inbetween the 2 crowns. I can't be bothered doing the calculations, but there would be a point where the extra stiffness of the section of legs between the crowns could be replaced by an increased cross sectional area of lower crown. Im not sure what the point would be, but all i know is that single crown RS will be stiff. That would probably be the chunkiest crown on any mountain bike fork to date.

 

[Bicyclist]

OK. Here's the big question:

Will a tiny bit more flex even matter at all?

 

[dante]

think Decline has to step up to the plate and build a multi-million dollar testing facility instead of blowing their cash on coke parties. if they followed the Germans and started talking about Nm and torque loads we'd finally have something more definitive than "all other things being equal, a DC will be stiffer than a SC." But no, they want to show pretty pictures of rooster tail. braaaaaaaaap! ink:






btw, it looks flexy...

 

[beaverbiker]

OK. Here's the big question:

Will a tiny bit more flex even matter at all?

oh yes, it will. it makes a big difference.

 

[beaverbiker]

Jeezzzz.........mate, please don't talk to me like im a little kid. I have already completed my mechanical engineering degree thanks.

OK, i can see where Zerdo is coming from now, i was refering to side to side, rotational, "hit a rock and wheel deflects sideways" motion.

For the fork to flex for and aft would require the crown to rotate between the steerer and the legs. The simple fact of the crown having to wrap around a 40mm leg and a 1.5 steerer is going to result in a crown that is at least 25% wider, and it would also have to be deeper as its a single crown, says it is 40% deeper then a boxxer lower crown. That is a chuncky crown no matter how you look at it. How much do you think that would flex over 10cm, not alot. It would probably crack before it flexed a great deal.

Another thing to consider is the top crown doesn't add to the stiffness in a pure for/aft movement, it just provides a place to apply the reaction force. The extra stiffness gained by triiple clamps come from the resistance to euler buckling of the section of leg inbetween the 2 crowns. I can't be bothered doing the calculations, but there would be a point where the extra stiffness of the section of legs between the crowns could be replaced by an increased cross sectional area of lower crown. Im not sure what the point would be, but all i know is that single crown RS will be stiff. That would probably be the chunkiest crown on any mountain bike fork to date.

i was obviously talking to the people that hadn't studied it. euler buckling is huuuuuuuuuuge when it comes to designing for stiffness. if you have a long slender column (dual crown fork legs) and you put it in compression, it will want to buckle. if it's clamped on both ends (just like a dual crown fork) the buckling curvature goes from a half-wavelength sine to a full-wavelength cosine. say, if you clamp it in the middle and prevent rotation (like if your head tube height was half the distance from the ends of the fork) then the buckling length gets cut in half and the critical load quadruples.