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mob 831 collision

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samtaleterapi

Chimp
Jul 29, 2009
59
0
hi

i have just fitted a fox 831 fork onto my BLKMRKT small 09 mob

everything is fine when i turn the bars to the left (more than 90 degrees), but when i do the same to the right, the lockout ring/knob collides with the frame down tube

(i can see from the scratches under the frame that my 36 talas fork did the same)

im using the headset that BLKMRKT suggested: FSA “Impact” Integrated headset

what can i do?
crashes could be catastraphic for both the frame and forks as it is

thanks
rasmus
 
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mattt

Monkey
Jul 21, 2009
126
0
texas
The price you pay for spending more money...

no it doesnt make sense that many companies put big pointless bling knobs that wont clear the downtube. One would think Fox would have considered this given its meant as a DJ fork. But its gotta have big, expensive, colorful knobs that you turn once a year... looks way cooler than air caps.

Your option is remove the knob(s) with an allen wrench. If thats not possible get an angle grinder with a flap wheel and make the knobs flatter.
 
demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
I have had this issue, the first was a 1.5 HT banshee, i had to get a bigger lower cup. (36 talas) I did not have it with the superco, but, and i do not know your bike/options, i would look for a bigger bottom cup or a taller one, no reason to mess with an incredibly nice fork, to those who say fox sucks making big knobs, i guess your entitled to your opinion, as retarded as it is. I turn mine relatively often, the lockout is 1 of the best features of that fork.

OP, check into a taller headset, and if not, try to find a headset with a taller race (or possibly stack them?)
 
S

samtaleterapi

Chimp
Jul 29, 2009
59
0
a bigger lower cup sounds like a good idea to me
i have never thought about that piece of equipment before
is there a collection of sizes available?

but wont a bigger lower cup affect ride height? (or is that so little nobody will notice?)
im already running 100 mm instead of the recommended 80 mm on the mob
can the 831 be cut down so 80 mm is the first option - with 90 and 100 mm as longer options by removing spacers? and cutting down actually affecting ride height? but removing spacers doesnt affect ride height does it?

thanks
rasmus
 
demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
You can lower the 831 from 120 to 65, (and probably smaller if you wanted to) You have to purchase extra spacers (in whatever mm you decide) than lower the fork, call fox, its not easy to explain. (in a nutshell, you move the spacers to the negative part) The cup wont be terribly bigger, get a cup that will work with the amount you need, if you only need 2-3 mm, find something thats 5mm bigger than you have. I am not sure what headset you have, but on my cane creek, i was able to just get a new cup, and use the same bearings. You do NOT want to get an enormus headset, at least without lowering it, but i would increase your cup size. (lol)
 
Mr Tiles

Mr Tiles

I'm a beer snob
Nov 10, 2003
3,469
0
L-town ya'll
my 08 and 11 36 talas hit the DT on my 06 rfx. I don't like running the king spacer but I do it 'cause I have to...sucks.
 
Tetreault

Tetreault

Monkey
Nov 23, 2005
877
0
SoMeWhErE NoWhErE
demo 9 said:
i would look for a bigger bottom cup or a taller one, no reason to mess with an incredibly nice fork
Click to expand...
your can't get a bigger lower up, as the mob uses an integrated headset, so no way this can happen and no need to mess around withe the amount of fork travel. I've had the same problem with with fox forks for a long time, depending on how bad its hitting, just take of the knobs and hand file them down a bit = problem solved
 
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mattt

Monkey
Jul 21, 2009
126
0
texas
i guess your entitled to your opinion, as retarded as it is.

As retarded as designing a fork, supposedly for dirt jumping, that doesn't have clearance for many dirt jumping frames?

Fact: the higher on the headtube that a downtube is welded, the more torque is applied to the DT/TT weld area. This creates a weaker frame.

These manufacturers that put large knobs are trying to dictate how much clearance frames "need" instead of using the correct design method: Take measurements of existing frames and design according to measurements.
 
demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
mattt said:
i guess your entitled to your opinion, as retarded as it is.

As retarded as designing a fork, supposedly for dirt jumping, that doesn't have clearance for many dirt jumping frames?

Fact: the higher on the headtube that a downtube is welded, the more torque is applied to the DT/TT weld area. This creates a weaker frame.

These manufacturers that put large knobs are trying to dictate how much clearance frames "need" instead of using the correct design method: Take measurements of existing frames and design according to measurements.
Click to expand...
its not only for dirt jumping :rolleyes: its mainly for gated events and dual slalom. I agree they should be smaller, but who is to say the headtube shouldnt be bigger, look at the new demo 8 DH bike, it cant properly fit a fox 40, arguably the most popular fork for DH
 
IH8Rice

IH8Rice

I'm Mr. Negative! I Fail!
Aug 2, 2008
24,524
494
Im over here now
mattt said:
As retarded as designing a fork, supposedly for dirt jumping, that doesn't have clearance for many dirt jumping frames?

Take measurements of existing frames and design according to measurements.
Click to expand...
do you expect Fox to cater to every single frame out there?? cause that totally makes sense.
maybe small bike companies should cater to a much larger company's product :lighten:
 
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boostindoubles

boostindoubles

Nacho Libre
Mar 16, 2004
7,890
6,182
Yakistan
I've ground the knobs down on more than one fox fork to run on dj bikes. Grind the knobs, never think about it again and knobs still work fine just some color is missing. This sort of thing is inevitable sometimes...
 
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mattt

Monkey
Jul 21, 2009
126
0
texas
do you expect Fox to cater to every single frame out there?? cause that totally makes sense.

YES.

Im not just referring to FoxRacing. The higher end Argyle, Pike, Manitou circus... All have huge knobs that only a fraction of users actually need.

They could have easily designed a slightly flatter knob. I've seen how much material needs to be removed, it isn't that much. Some clicks of the mouse on a computer model... soooo difficult.

I hate that MTB hardtail frames are being pushed to look like this:

http://www.norco.com/archives/2009/?id=48a31c95019a2
 
IH8Rice

IH8Rice

I'm Mr. Negative! I Fail!
Aug 2, 2008
24,524
494
Im over here now
mattt said:
do you expect Fox to cater to every single frame out there?? cause that totally makes sense.

YES.

Im not just referring to FoxRacing. The higher end Argyle, Pike, Manitou circus... All have huge knobs that only a fraction of users actually need.

Some clicks of the mouse on a computer model... soooo difficult.
Click to expand...
well judging by your comments, it seems all fork manufacturers are doing it and some frame companies arent catering to the majority of forks out there. it totally makes sense for a large company like Fox to cater to small companies that sell a handful of frames.

if it was sooo easy, then i guess you know a thing or two or cnc work?


that "quote" button does wonders too
 
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M

mattt

Monkey
Jul 21, 2009
126
0
texas
if it was sooo easy, then i guess you know a thing or two or cnc work?


YES, i do

Is 4X actually popular in other states? Im a Texan now, but even in mountainous Arizona the sport is unheard of. I heard the scene is in decline everywhere...

http://www.vitalmtb.com/forums/The-Hub,2/Is-4X-dying,5416

totally makes sense for a large company like Fox to cater to small companies that sell a handful of frames.


Fox can go nuts with their racing suspension... they're name is Fox Racing Suspension... cool. The others have no excuse for pooping out these giant knobbed "dirt jump/urban" forks.

Are you saying Blk Mrkt is selling a handful of frames? Its no Spec. P. in popularity but its probably top five. NS' frames have about the same clearance as a Mob... Atomlab's crown clearance is even less than the Mob's. Is this the handful of frames your referring to? Even the chromo P. series has very little crown clearance, compared to... an Intense Tazer (the only frame I can think of that is specifically for racing) I'm sure there are others, but I see only a "handful" of racing specific frames among a sea of dirt/street frames.
 
demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
You do realize that fox is not only an international company, but have bigger priorities than black market bikes (which like them or not, doesnt sell much) 4X isnt thriving like DH, but what true dirt jumper, is going to spend 831 on a fork, i did, but i am not the norm, these arent sold to most guys on fancy hardtails, it costs more than 2 Marz DJ forks, for things you really dont use outside of racing. This is the dumbest argument ever, also agreeing with Ih8Rice, use the quote feature please
 
N

nwd_26

Monkey
Nov 29, 2007
184
0
Toronto, Onterrible
Pardon me for a second while I offer a bit of help....

Another option I've seen friends with Dartmoors do is take a steerer spacers, file down the inside some, and pop it on under the crown race. Resale on the fork and **** stays intact. a2c gets a bit longer, you can remedy this by further lowering the fork or HTFUing...

And while we're counting, it's lame as **** that all these companies are pumping out so-called dirt jump forks that don't fit frames. Like, come on, the Mob is one of the most common DJ frames out, how your fork ain't gonna fit that? I already knew the 831 was a joke, but come on!
 
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mattt

Monkey
Jul 21, 2009
126
0
texas
You do realize that fox is not only an international company, but have bigger priorities than black market bikes (which like them or not, doesnt sell much) 4X isnt thriving like DH, but what true dirt jumper, is going to spend 831 on a fork, i did, but i am not the norm, these arent sold to most guys on fancy hardtails, it costs more than 2 Marz DJ forks, for things you really dont use outside of racing. This is the dumbest argument ever, also agreeing with Ih8Rice, use the quote feature please


Again: "Fox can go nuts with their racing suspension... they're name is Fox Racing Suspension... cool. The others have no excuse for pooping out these giant knobbed "dirt jump/urban" forks." (me two seconds ago)

(by others I meant RS, Manitou)

Did I not just make a convincing argument about poor design choices on the part of these manufacturers? My list of other frame manufacturers (NS, Atomlab, Spec.) that have the same clearance as BlkMrkt was to illustrate that your opinion "handful of frames" is incorrect.

Try looking at the DJ/park bikes on Pinkbike sometime. These DJ frames are probably the most common, with racing specific being least.

You seem pretty intent on arguing in "the dumbest argument ever".
 
M

mattt

Monkey
Jul 21, 2009
126
0
texas
take a steerer spacers, file down the inside some, and pop it on under the crown race.

Seems dodgy, but if it works without the race wiggling...
 
IH8Rice

IH8Rice

I'm Mr. Negative! I Fail!
Aug 2, 2008
24,524
494
Im over here now
mattt said:
Again: "Fox can go nuts with their racing suspension... they're name is Fox Racing Suspension... cool. The others have no excuse for pooping out these giant knobbed "dirt jump/urban" forks." (me two seconds ago)

(by others I meant RS, Manitou)

Did I not just make a convincing argument about poor design choices on the part of these manufacturers? My list of other frame manufacturers (NS, Atomlab, Spec.)
Click to expand...
so again, to reiterate what you are saying, the 3 major fork companies should cater to the small companies such as NS, Atomlab and BM who cant design a DT junction properly?
by the sounds of that Marzocchi, should be rolling in the cash like Scrooge McDuck from all the business they should be receiving


almost 2 years and you dont know how to quote? really?
 
demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
^ to even compound the problem, many of the companies are using bmx style headsets, the ones you know, designed for a fork with no dials, knobs, or suspension. Stick a normal threadless headset in there, it will work fine. I had the problem on my banshee with a 1.5, i got a bigger lower cup, unfortunately the OP cant do that, but, i dont blame fox, who has 2 choices, improve the A2C to raise the crown and make every DJ biker pissed off, or dump the dials and tech, and make a fork like the A-lab G.I
 
M

mattt

Monkey
Jul 21, 2009
126
0
texas
Im pretty sure Marzocchi bankruptcy/ transition to Teneco was due to misappropriation of funds...

But they're are doing quite well still IMO considering the fork is a stock component on many completes.
 
Tetreault

Tetreault

Monkey
Nov 23, 2005
877
0
SoMeWhErE NoWhErE
mattt said:
take a steerer spacers, file down the inside some, and pop it on under the crown race.

Seems dodgy, but if it works without the race wiggling...
Click to expand...
it is i would HIGHLY recommend not installing anything between a race or the bottom cup

demo 9 said:
^ to even compound the problem, many of the companies are using bmx style headsets, the ones you know, designed for a fork with no dials, knobs, or suspension. Stick a normal threadless headset in there, it will work fine.
Click to expand...
this is true, and honestly how hard is it to take of the lock out knob (thats the one that always hits) its 1 small allen key, put it down on a bench and use a hand file to shave down the 3mm that just nicks the frame, 10 minutes, nothing is lost, no more clearance issues. No need to complain about who should manufacture what which way, there are more rediculous things that people run into with builds, tire clearance, chainring clearance, $3000 dh frames that cant clear a dual crown properly.
 
demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
May not work on a p, but here is a list of bikes that it does fit on;
yeti
intense tazer
superco
trek ticket
giant
banshee
dobermann
transition TOP
Brooklyn hardtail
SC jackal (at least old)
NS majesty/suburban
Diamondback
Kona

Based on a search of "831" on pinkbike, many repeats, so im going to venture a guess it fits all sizes of those bikes. I only listed hardtails
 
Tetreault

Tetreault

Monkey
Nov 23, 2005
877
0
SoMeWhErE NoWhErE
another thing is, it isnt just the 831 that will have clearance issues with these such frames, its any 32rlc fork. The problem is only a problem on frames with steep head angles and integrated headsets. Sorry but its a compatibility issue that just exists, frame makers don't want it move the down tube up for structural reasons, fork makers don't want to change the knobs that they have been making for 8 years now.

a taller race such as the king may work, those press in extenders, that someone else's call but there is no f'in way im putting that on my ride
 
SuspectDevice

SuspectDevice

Turbo Monkey
Aug 23, 2002
4,173
380
Roanoke, VA
One of the reasons that we are seeing a curve at the headtube on new aluminum bikes is too rectify this problem. It's actually become a major problem on most bikes these days as stanchions get larger since the crowns have to be wider to suit.
It's pretty darn infuriating! The super steels that the good bikes use are pretty much impossible to bend in the right radius and even then they require a different butting profile and a fairly thick wall.
There is a benefit to the curved downtube thogh. It's actually considerably stronger than a straight downtube. Close your eyes and think about the stresses from a frontal impact and you'll see why.
The curved tubes look pretty ghey on steel bikes IMO.
The Xfusion forks have much better clearance, FYI
 
FR4life.

FR4life.

Monkey
Nov 2, 2004
606
0
The Bay
Tetreault said:
a taller race such as the king may work, those press in extenders, that someone else's call but there is no f'in way im putting that on my ride
Click to expand...
Real talk. Just take the knobs off.. I had to do this with my argyle on my old eastern frame, I would sacrifice a bit of luxury for reliability any day.
 
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