[DirtEveryDay]

please everyone,put all known forks aside and just look at the facts and theories. You can't do an experiment without the same factors,we do not have any examples with the same factors so there is no statistics that or experience from current forks that really support any argument completely.
Logic and facts,keep it too logic and facts.
Lets start a list of facts.

What I'm judging this all on is that I've seen 888s and 66s broken in the same places. Thus I'd say both are adequately equipped to handle the task, on is obviously going to be stronger in various areas, never said it wouldn't, just feel that singlecrowns are possibly being avoided for silly reasons, urban legend, rumor, and past experiences with equipment being used beyond it's means.
I do not doubt that there are many 66s with trashed crowns/steerertubes, but I've got 3 videos alone saved with snapped stanchions on dual crowns, which were actually an instigator to this post... If somethings gonna go, it's gonna go, and it's only as strong as its weakest link. I just wanna know how FAR it will go before it does that!

 

[Dogboy]

And didn't the 1.5" FRAME arrive before a 1.5" fork ever existed? My understanding, or atleast my perception, was to allow for the use of zerostack headsets, reducing ride height.

Nope. They were designed and arrived at approximately the same time. The original idea was to house the bigger steerer. The zero-stack headsets came after.

 

[DirtyMike]

Hey, how'd that Boxxer Team feel compared to your 66? I can either order one of those along with my ED frame pretty cheap or I can demo a WC for the season. Even if I do think that the SC fork is easily adequate for 90% of the places I'll ride, there's that 10 % that I'll not be needing any other fear factors contributing to the ones already in place...

For Myself, I like the feel of the 66 alot better. Given it was an 03 boxxer vs the 07 66. Are the boxxers available to you the new 08 model??? I havent yet had a chance to play withthose ones on the trail yet.



Oh also, I always felt the boxxer, even with heavy springs, was undersprung but at teh same time ramped up to fast for me at 250.

 

[DirtyMike]

And didn't the 1.5" FRAME arrive before a 1.5" fork ever existed? My understanding, or atleast my perception, was to allow for the use of zerostack headsets, reducing ride height.

Yeah they came out about the same time, remember back whenthe longer SC forks came out, thats how they were getting any stiffness, nowadays its not as critical, seeing how most company's have run with the technology to make it better.

 

[kuksul08]

OH! Actually, I HAVE twisted the stanchions on an 888 when I nosed a boulder and taco'd a wheel at the same time! I ordered the Risse crowns at that point out of fear and a little ignorance, but I knew it dropped the ride height too(and my static leverage ratio...), so win-win. No issues on the 66, but it IS a reason to be concerned. The stanchion/crown interface is the hot spot I'm worried about, not the steerer tube.

Haha yes actually the double crowns should allow the stanchions to twist in them in case of a hard crash. It prevents things from breaking whereas you don't have that option with single crown.

 

[kuksul08]

Just as a side note, MX bikes have 1" steerer tubes with up to 52mm fork legs and 13" of travel.

The tubes are also steel and have a special tapered design specifically for each bike

 

[ChrisKring]

10 years ago there wasn't a 7 inch travel single crown fork.

Has Engineering or Physics changed much in 10 years?

I like your "some things are the way they are". Good thing Thomas Edison did not accept that premise.

No, but what has changed is that most of the companies that are still producing suspension are using engineering to design thier products and testing them in house as opposed to the previous method used 10 years ago of cnc'ing up some parts and testing them on consumers. Tools such as FEA have allowed designers to get the weight down on a SC fork while maintaining the strength.

10 years ago there were not very many good DC forks. My point was that people should not assume that the industry conspires to hold back technology. As pointed out in another reply, a 7" SC fork will be as tall as an 8" DC fork. That is because the designer needs to add material to the crown to provide a good union between the tubes and the crown to handle the additional bending stress. The tradeoff needs to be made between the mass of the additional crown and stantion length of the DC and the extra cross section of the SC. It's all possible. The Totem is an excellent example of a well built 7" SC fork. Like I said, I would own one if I had to pedal up hill to get DH runs.

There are also some DC forks that are not as strong as a SC. I watched a kid break his neck when the lower crown broke on his DC fork when he went off a 1 foot tall jump to grass. There was an obvious design flaw in it.

 

[DirtEveryDay]

Actually, the Totem is an 8" travel fork and, in my opinion only...if you're going to run that much fork... run a dual crown. It will be lighter and still not as bulky! Unless I guess you just HAVE to X-up across the finish... :=
I would be perfectly happy with a 6" travel single crown of identical burliness as my current 66 as long as it ramped up enough to prevent smackin parts that aren't supposed to touch. However, I am 100% satisfied with the geo my 66 provides, which is my main concern, 2nd would be the lack of the knee-knockers for trail riding, 3rd would be for the weight.
And it's not because I can't afford two bikes(which I really can't, but I DO have a really nice street hardtail that may just need to get converted to training duty), it's just that I would prefer to have two of the exact same bikes, just set up a little differently. And I certainly can't afford two ECDs...

 

[no skid marks]

I thought that the 1.5 frame was well before the fork. Giant, Canaondale and I'm sure others used 1.5 headtubes to make a larger surface area to but large tubes to.
Don't forget Chris King tried to make the standard 1 1/4 when 1 18th was just introduced.
Perahaps a single crown with a crown that goes up into the frame to add some support to the steerer with a even larger bearing around that is the future. 2.5" steerer anyone.

 

[DirtyMike]

...Snip...

There are also some DC forks that are not as strong as a SC. I watched a kid break his neck when the lower crown broke on his DC fork when he went off a 1 foot tall jump to grass. There was an obvious design flaw in it.

The first part of this statement is absolutly true, just curious though, are you sure it was a design flaw? Or could it possibly that this "JRA" situation actually came about due to hack riding and abuse? Possibly someone not checking there equipment before riding?



Just making a point on the last part of your post there, "Obviously"

Is a bit misleading.




Edit...... If I missed the Sarcasm My bad, Ive been tossing a few back tonight

 

[ChrisKring]

the crack occured at a stress riser that didn't need to be there at all. If they had chamfered an edge, then the stress wouldn't have been so high. I am going from memory here but I think the pinch bolts were in about the worst location too. It was 5-6 years ago that this happened. That should give you a hint what it was since it had pinch bolts holding the lower crown to the steerer rather than it being pressed in.

 

[DirtyMike]

That makes more sense

 

[WODIE]

Think about how beefy a 1.5 steer tube looks and then check this out:

(mx) just crazy looking but it works.

but... then this could also happen:

 

[Rover Nick]

I like DC's because I like to pretend I'm riding a moto. I even make the brapping out sounds as I leave the start gates
.

 

[-C-]

Single crowns have a higher height for the same travel. They are heavier for the safe strength.They're flexier.They do not stop forks spinning in a crash or whilst riding. They WILL NOT LAST AS LONG. They heve less room for internals. I am talking theory here,not comparing forks,sure a Totem would be stiffer than an old RST Hi 5.
Don't confuse less travel as the topic discussed here.

If you had spend any time on a Totem & a Boxxer, you would soon realise that the Totem is WAY stiffer than the Boxxer.

In fact, its comparable to my Fox 40's in 1.5" guise. And weighs a pound less, for 20mm less travel.

The A-C of a Totem isn't too bad either, same as a Boxxer in 203mm travel mode.

 

[DirtEveryDay]

the crack occured at a stress riser that didn't need to be there at all. If they had chamfered an edge, then the stress wouldn't have been so high. I am going from memory here but I think the pinch bolts were in about the worst location too. It was 5-6 years ago that this happened. That should give you a hint what it was since it had pinch bolts holding the lower crown to the steerer rather than it being pressed in.

Sorry, but that has no relevance here. There are reasons that all changed and we all know old forks sucked and companies highly underestimated the abuse we'd put them through.
But it seems as if you're the only one here still fighting the singlecrown movement, and you're only using the facts and figures from forks in the 4-6 years old range to defend you're case. Get with the program!

 

[dhkid]

you guys are still missing one thing out. a single crown has a higher axle to crown height. a fox 36 has roughly the same axle to crown height as a fox 40 at 7.5 inches of travel.

not that it will bother me that much, if i had the cash i would have a spare 36 lying around so i could use it on smoother courses. the only thing that would stop me using it as my main dh fork is its slight lack of travel and axle to crown height. it adds about an inch.(but thats just being picky)

then again if i had the cash i would rock a 6 and 6 in bike or maybe a 5 and 5 in bike with dh geo. so much more fun then a full on dh bike on loads of dh courses.

 

[ChrisKring]

Sorry, but that has no relevance here. There are reasons that all changed and we all know old forks sucked and companies highly underestimated the abuse we'd put them through.
But it seems as if you're the only one here still fighting the singlecrown movement, and you're only using the facts and figures from forks in the 4-6 years old range to defend you're case. Get with the program!

Do you have a reading problem? I was citing a case of a DC fork with a bad design.

Anyway, why did you even ask the original question if you already had your mind made up. Seems to me that you just want to justify your decision to run a SC. I am done commenting on your post. Do you even ride or race?

 

[FCLinder]

I have to say I have been loving my Totem this year. I have had Boxxers and 40's in the past. The Totem feels like it’s just in between both of them being a little better than the Boxxer and a little off from being as good as the 40.

Differences:
Totem is stiffer than the Boxxer and has a little better feel in its travel.
Boxxer has 1" more but the way the Totem feels makes up for that 1". Plus 6 years ago most DC forks only had 7" of travel. We were all fine on 7"s then and the suspension was nowhere as nice...

Totem is not as stiff as a 40 but damn close. Feels that way to me. Yes in the bigger rocks you do tend to feel the bars moving a little more side to side than with the 40. You can easily fix this with a Steering Dampener or adjusting your riding style a little.

I will have to say I have been on the fence whether I want to go back to a DC over a SC for DH, but every time I look at the Pros and Cons I stick with the SC. Understand I have a DH bike that only has just over 7" of rear travel now. It works great for everything I ride. If I had a full on DH bike with 8" of rear travel I would have a 8" DC fork for it.

 

[DirtEveryDay]

Huh...for some reason I had it in my brain that you can't run a damper with a singlecrown...that's an option worth some serious looking into...
And my DH rig is at 8.5 in the rear..but pedals like a hardtail, so I don't really wanna ruin that with a sloppy fork. Again, it IS only an inch of difference, just depends on WHICH dc fork I'd get. Most likely an 08 Boxxer WC... But I bet it just sits in the corner all season...

And no CK, I don't ride...I just sit and look for useless Wikipedia pages to shove into peoples threads all day. Oh wait....
You weren't offereing any USEFUL input anyway, just more crap that WE all call leverage ratios and fully understand. Talk to ya in the next thread where you'll be doin the same thing...again.

 

[OGRipper]

Actually, the Totem is an 8" travel fork and, in my opinion only...if you're going to run that much fork... run a dual crown.

Um no, the Totem is not an 8" travel fork.

180 millimeters = 7.08661417 inches

 

[Wobbler]

Um no, the Totem is not an 8" travel fork.

80 millimeters = 7.08661417 inches

You might want to double check your maths on that one

 

[Dogboy]

^^I'm sure he meant to say 180mm.

 

[sriracha]

the biggest difference i notice between my 66 and my 888 is that the 66 is much more progressive. this is a result of air volume in the stanchion tubes.

888, with it's longer stanchions, has more air volume and therefore is more linear feeling thru out the travel. i like this better for mobbing thru big rocks and such. it just feels nicer for hardcore DH.

that, and the 888 does feel stiffer under for/aft loads.

the 888 feels more solid to me.

 

[FCLinder]

Huh...for some reason I had it in my brain that you can't run a damper with a singlecrown...that's an option worth some serious looking into...

Yes you can do this. I know a few that run them on their XC bikes. Funny you would think, but they say it really helps with climbing. They say it helps them with the side to side movement when climbing.

I may pick one up for my Totem soon. Just don't want to pay $220 for one just yet.

 

[ChrisKring]

A steering damper is a good addition for any bike. If you give it a chance, it will reduce arm fatigue quite a bit. Some people take them off before they get used to them though. I currently run mine cranked all the way down.

 

[DirtEveryDay]

I thought you were out of this post, there budday?


FCLinder- The fork would retain it's full 360* rotation then, right? Just not as freely? That would solve like MOST of my little issues with a single crown, such as the fear of the bars stabbing me in the gut(DC forks don't allow the bars to rotate all the way inline with top tube in the case of a nose stack or something, so no fears of castration or naval penatration...?)as it would slow everything down enough to work with it. And for the same reasons it might allow the bike to bounce a few more times on the bars rather than just spinning them around ripping cables and hoses out.
What about useless stuff like X-ups, etc? If I felt the need to style it out mid-race(can't think of a dumber thing to do when haulin) on a photo-op launcher, can I still get the bars around quickly enough, or would it have to be set pretty loosely for that?

 

[DirtEveryDay]

the biggest difference i notice between my 66 and my 888 is that the 66 is much more progressive. this is a result of air volume in the stanchion tubes.

Interesting point...perhaps this is why I like my 66 more than my 888 and also why I feel I would like an even shorter fork-reaction time. I think I like being able to "feel" the terrain a little more than most. I also run my 66 a little faster and slower(haha) than most around here.
I tried the mini DH thing(5.5" with an Avalanche rear) for a little while and DID love it, but I was just starting to feel the bottom of the shock a little too much, so I chose to go with a little more bike this time around, should pick up some time and have a smoother go at it.
Still undecided. I don't think I'll buy a DC just yet. If my boy comes through with the WC for me I'll give that a few turns, but I think I'll prob hang onto my 66. That and an 08 ECD with a SC's gonna look pretty tight...

 

[FCLinder]

I thought you were out of this post, there budday?


FCLinder- The fork would retain it's full 360* rotation then, right? Just not as freely? That would solve like MOST of my little issues with a single crown, such as the fear of the bars stabbing me in the gut(DC forks don't allow the bars to rotate all the way inline with top tube in the case of a nose stack or something, so no fears of castration or naval penatration...?)as it would slow everything down enough to work with it. And for the same reasons it might allow the bike to bounce a few more times on the bars rather than just spinning them around ripping cables and hoses out.
What about useless stuff like X-ups, etc? If I felt the need to style it out mid-race(can't think of a dumber thing to do when haulin) on a photo-op launcher, can I still get the bars around quickly enough, or would it have to be set pretty loosely for that?

I don't know about the 360* rotation..... I will have to look into that.

 

[Bulldog]

Actually, the Totem is an 8" travel fork

Not. 180mm = under 7.1" The only 8" SC ever made was the now-extinct Travis "Single 203" made for a couple years.

With all the guessing and theorizing going on year after year I'd really love to see someone put a Boxxer and Totem through some quantitative testing to settle the debate once and for all.

 

[Jm_]

Not. 180mm = under 7.1" The only 8" SC ever made was the now-extinct Travis "Single 203" made for a couple years.

With all the guessing and theorizing going on year after year I'd really love to see someone put a Boxxer and Totem through some quantitative testing to settle the debate once and for all.

Bad example, as RS has neglected the boxxer chassi for a while. How long have they been using 32mm stanchions?

 

[DirtEveryDay]

Not. 180mm = under 7.1"

Yeah, that's been covered already! And now I think the Totem is an even dumberer fork. That's just too much...stuff...when other companies are ALREADY overbuilding them. Well, perhaps not overbuilding, but just enough to make me question getting a DC fork...
And it doesn't sound like the Boxxers will have 32mm stanchions much longer... Don't know why, haven't heard of any more catostrophic failures than any other company's. I only like the Boxxer cuz it's a tiny, tight little dc fork...

 

[Jm_]

Mmm...no, I replaced my 888 with Risse flats for the 06 66 I have on now and dropped an inch. Right now, with 2.5"s, a 66RC2X, an E13 Zerostack headset, zero-rise stem and 1.5" risers, I'm right at a39.5 inch bar height.

Nice, but with a DC fork you can often lower the crowns until your tire just barely clears. You can't do that with a SC fork of any kind.

The DC design has better strength to weight, period. That doesn't mean that an 888 is ligher, but it does mean that it's better suited for situations where you count on strength. Look at mavericks DUC32 fork, it's 3.7lbs for 6" of travel, it's the ultimate in strength to weight. Look at a fox 40, it's a monster 8" travel fork with 40mm stanchions. It weighs the same as your 66. Have you ever looked up inside the 66 at it's steerer? That thing is absolutely massive and a huge source of weight. Go look at most DC fork's steerer tubes, they are much lighter and use material much more efficiently. You'll probably never see DC forks go away for these reasons. Why use an SC fork when you can make a more rigid DC fork that has higher strength? There's just not enough bushing overlap for 8" single crown forks, they'd flex all over the place. In the end what is the point?

BTW, I use a 66, I do some uphill switchbacks where I actually go past where a DC fork would stop (yeah, that tight), and I like the versatility of the design. I'd go with a true DH DC fork if I was going to be doing that type of riding though.

One way to think of it is the fact that my current 7" travel 66 weighs as much as my old 6" and 7" boxxer forks from years ago, but if the same type of engineering was applied to a DC fork you'd end up with something like a fox 40.

 

[FCLinder]

I'd really love to see someone put a Boxxer and Totem through some quantitative testing to settle the debate once and for all.

I think if you read above you will see where I gave this info and many have done this already on Ridemonkey. Ran a 06 Boxxer Team in 06. No change to the Boxxer till this year. They say the 08 is a little stiffer than the 06 and 07. Everything else is the same. If this is so then the new Boxxer should be just as stiff or maybe a little stiffer as the Totem. By the way my Totem Air is a 1 1/8", not a 1.5" which they say is 20% stiffer than the 1 1/8". The travel on the Totem feels better (My Opinion) than the Boxxer. The Adjustability is better on the Totem. You have a LSC and HSC witch works great. The Motion Control on the Boxxer really didn't work that great. I think the next Fork RS needs to come out with is the Totem in a DC with 7" to 8" of travel. It would give the Fox 40 a run for the $$.

 

[DirtEveryDay]

Hey look...all those intelligent, well thought-out words and no links to online encyclopedias! Nice...
The only thing I've got to add to that is that I, personally, am not after a mega travel singlecrown fork, just been curious to know if I'm being a 'tard for fairly heavily DH'ing my 66, or if I'm pretty much on par with others, which it seems I am.
But that would best describe the purpose of a DC fork: unbeatable strength-to-weight ratio. If a 66 was a pound-plus lighter than it is and still rode like it does(not an air fork)while not surrendering any strength, it would be a much closer fight.
Here's two more questions: Having never having ridden one...what's the take on current air forks? My bud's got a 66SL and seems to love it, DH's the crap out of it, but it's only a few races old right now. And I believe the 08 WC I'm trying to get is an air...right? I know I need to try it to know for sure, but will I like it, or am I spoiled by the buttery feel of my 66?
And props, JM, for bringing some common sense into this chaos!

 

[DirtEveryDay]

I think the next Fork RS needs to come out with is the Totem in a DC with 7" to 8" of travel. It would give the Fox 40 a run for the $$.

Now that's odd...I've heard nearly all the Fox fanatics bitchin cuz they want a SC 40.... Ha!

 

[FCLinder]

Hey look...all those intelligent, well thought-out words and no links to online encyclopedias! Nice...
The only thing I've got to add to that is that I, personally, am not after a mega travel singlecrown fork, just been curious to know if I'm being a 'tard for fairly heavily DH'ing my 66, or if I'm pretty much on par with others, which it seems I am.
But that would best describe the purpose of a DC fork: unbeatable strength-to-weight ratio. If a 66 was a pound-plus lighter than it is and still rode like it does(not an air fork)while not surrendering any strength, it would be a much closer fight.
Here's two more questions: Having never having ridden one...what's the take on current air forks? My bud's got a 66SL and seems to love it, DH's the crap out of it, but it's only a few races old right now. And I believe the 08 WC I'm trying to get is an air...right? I know I need to try it to know for sure, but will I like it, or am I spoiled by the buttery feel of my 66?
And props, JM, for bringing some common sense into this chaos!

Many have told me the Boxxer WC Air is better than the 888 SL Air. Plus RS knows their SHT when it comes to Air Forks.... You will be fine with the WC. Its a great Fork!!!! Its not a 40, but very close in many ways. Guys understand I am not trying to sell the idea of the SC over the DC, just giving my experiences I have had with the Boxxer, 40, and Totem. I wanted to build a 7"x7" monster this year and that is one of my main reasons for getting the Totem. So far the bike rocks. I loved it a Windrock TN this past year and that place will give any big bike 8" and up plenty of abuse......

 

[ChrisKring]

Thrillseeka

I am only giving you links so you can learn about engineering and how it applies to bicycle parts. I also belive that I pointed out most of the topics discussed already with the exception of being able to adjust the head angle with the DC.

.

...a dual crown fork eliminates the bending moment on the steerer tube and puts the stress into nearly pure shear stress. The SC fork has bending stress on the steeerer tube. That is the reason for 1.5" head tubes. While 1.5" HT are a great solution, they should be heavier than a DC fork that has the same safety factor on breaking. Therefore, the engineering side of me decides to use a Boxxer for DH.

Tools such as FEA have allowed designers to get the weight down on a SC fork while maintaining the strength.
... As pointed out in another reply, a 7" SC fork will be as tall as an 8" DC fork. That is because the designer needs to add material to the crown to provide a good union between the tubes and the crown to handle the additional bending stress. The tradeoff needs to be made between the mass of the additional crown and stantion length of the DC and the extra cross section of the SC. It's all possible. The Totem is an excellent example of a well built 7" SC fork. Like I said, I would own one if I had to pedal up hill to get DH runs.

The info the Cecil is giving you on the Totem matches everything that I have heard with regards to it's stiffness. There are several guys that are riding them at Windrock with all positive reports on stiffness. That place is pobbably the roughest place around besides Mount Snow or Pkill. The 40mm tubes are a great change that I look forward to seeing next year on the Boxxer.

 

[BMXman]

wow there's a whole lot of E-engineering going on in this thread...D

 

[DirtEveryDay]

"I am only giving you links so you can learn about engineering and how it applies to bicycle parts. I also belive that I pointed out most of the topics discussed already with the exception of being able to adjust the head angle with the DC."

It's all E-crap. We all know about "bending moments"... except here it's popularily called WHY EVERYONE'S LEARY OF SINGLE CROWNS FOR DH!
There's statistics against and for everything. I seriously could give a **** less about that crap. And I knew as soon as you posted that you'd be back with loads of it. And like others have told you in other threads as well, no one wants that ****. It doesn't help anyone. You're one of those guys who crushes ice before putting it in the blender because you've over analized the sheer factors on the blade shaft while everyone else is already enjoying their Vodka smoothy.
While most of the others on here all gave real-world input, I think JM gets the prize for most useful post.
My post title wasn't "Engineering aspects of single crown steerer tubes versus dual crowns." I already stated what I was after. And NO, I didn't get on here with my mind made up, in fact, I'm leaning towards a Boxxer, which is exactly the opposite of what this thread is kinda saying.
Go drink a smoothy and chill, man...it's only bicycle parts after all!