Go Back  Bike Forums > Bike Forums > Mountain Biking
Reload this Page >

Extra stupid question about fork travel.

Mountain Biking Mountain biking is one of the fastest growing sports in the world. Check out this forum to discuss the latest tips, tricks, gear and equipment in the world of mountain biking.

Extra stupid question about fork travel.

Reply

Old 02-18-06, 07:52 PM
  #1  
vw addict
Senior Member
Thread Starter
 
vw addict's Avatar
 
Join Date: Jan 2006
Location: East coast
Posts: 2,671

Bikes: Specialized Tarmac Expert, Cannondale R700, Specialized Langster, Iron Horse Hollowpoint Team, Schwinn Homegrown

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Extra stupid question about fork travel.

So say I have a fork that should have 130mm of travel. Now say i wrap a zip tie around the stanchion of the fork. Then say I compress the fork until it bottoms out thus "all of the travel". On a whim say I then measure from the zip tie to the leg seal. Now correct me if I'm wrong but that should measure 130mm right?
vw addict is offline  
Reply With Quote
Old 02-18-06, 07:53 PM
  #2  
mtnbiker66
Old School Rad
 
mtnbiker66's Avatar
 
Join Date: Sep 2004
Location: The old Mountains
Posts: 8,212

Bikes: Blur LT

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Well yeah, that shhould give you your travel.
__________________
Like a circus monkey on a stolen Harley......
mtnbiker66 is offline  
Reply With Quote
Old 02-18-06, 07:53 PM
  #3  
blue_neon
Elite Rep
 
Join Date: Aug 2004
Location: Melbourne - Australia
Posts: 2,096
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Close to I would say.
blue_neon is offline  
Reply With Quote
Old 02-18-06, 08:00 PM
  #4  
Svr
Senior Member
 
Svr's Avatar
 
Join Date: Dec 2005
Location: Atlanta, GA
Posts: 1,223
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
You'd think so..... many fork makers stretch the truth a bit in that area.
Svr is offline  
Reply With Quote
Old 02-18-06, 08:18 PM
  #5  
vw addict
Senior Member
Thread Starter
 
vw addict's Avatar
 
Join Date: Jan 2006
Location: East coast
Posts: 2,671

Bikes: Specialized Tarmac Expert, Cannondale R700, Specialized Langster, Iron Horse Hollowpoint Team, Schwinn Homegrown

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by Svr
You'd think so..... many fork makers stretch the truth a bit in that area.
would you say by an inch?
vw addict is offline  
Reply With Quote
Old 02-18-06, 08:27 PM
  #6  
FF 6800
Senior Member
 
Join Date: Aug 2005
Location: Long Beach, California
Posts: 594

Bikes: 2005 Specialized hardrock pro... pike426, e.13 drs, fsa gap crank, formula k24's, and some more/2006 Scattante R-660 easton circuit wheels.

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
i bottom out my fork once in a while, it is actually about 80mm of travel as opposed to 100mm of travel that marzocchi claimed it had

Last edited by FF 6800; 02-18-06 at 08:28 PM. Reason: i forgot my comma!
FF 6800 is offline  
Reply With Quote
Old 02-18-06, 08:35 PM
  #7  
blue_neon
Elite Rep
 
Join Date: Aug 2004
Location: Melbourne - Australia
Posts: 2,096
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
There is a differn'ce between the 'effective' travel i think, but thats what advertised on the fork anyway. Yeh I wouldn't say my 80mm fork is 80mm, but it would be very close, within 5mm i would say. I guess it also depends on how old the fork is and if its worn out or somethign maybe.
blue_neon is offline  
Reply With Quote
Old 02-18-06, 08:38 PM
  #8  
mx_599
Lost in the Black Hills
 
mx_599's Avatar
 
Join Date: May 2005
Posts: 5,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by vw addict
would you say by an inch?
not an inch...are you sure it is not internally adjusted shorter than 130mm? maybe there is a spacer to be removed.

some forks may have a stiff bottoming elastomer...maybe? that tricks you into thinking you traveled al the way...but only the hardest of hits would go a little further.

but not an inch...that's not right. were they fully extended or was there static sag factored into your measures??
mx_599 is offline  
Reply With Quote
Old 02-18-06, 09:00 PM
  #9  
MattP.
Obeying Gravity
 
Join Date: Oct 2004
Location: Bellingham, WA
Posts: 2,962
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by mx_599
not an inch...are you sure it is not internally adjusted shorter than 130mm? maybe there is a spacer to be removed.

some forks may have a stiff bottoming elastomer...maybe? that tricks you into thinking you traveled al the way...but only the hardest of hits would go a little further.

but not an inch...that's not right. were they fully extended or was there static sag factored into your measures??
Yeah, an inch is deff. a little much.
MattP. is offline  
Reply With Quote
Old 02-18-06, 10:36 PM
  #10  
Dannihilator
User Title
 
Dannihilator's Avatar
 
Join Date: Oct 2002
Location: Annandale, New Jersey
Posts: 19,607

Bikes: 2008 Trek Portland, 1989 Nishiki Altron

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
You're just measuring sag there. Measure the stanctions from the bottom of the crown to the seals and make sure it is in millimeters. 25.4 mm =1"

5"=127mm

130 is: 5.12"

With sag set 104mm of stanction should be shown.

104=4.09"

An inch of sag is perfectly fine.
__________________
Appreciate the old bikes more than the new.
Dannihilator is offline  
Reply With Quote
Old 02-18-06, 10:50 PM
  #11  
Pheard
Banned
 
Join Date: Sep 2005
Location: South City, Ca
Posts: 3,348
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Because of the grease on my fork I can see exactly how deep the tubes go. It only travels about a third of the fork, I dont know why even on the hardest rockiest terrain is never goes in more than a third of the supposed travel.(excuse me for not knowing what anything is called)
Pheard is offline  
Reply With Quote
Old 02-18-06, 11:03 PM
  #12  
mx_599
Lost in the Black Hills
 
mx_599's Avatar
 
Join Date: May 2005
Posts: 5,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by KonaRider24
You're just measuring sag there.
no he wasn't
mx_599 is offline  
Reply With Quote
Old 02-18-06, 11:17 PM
  #13  
Dannihilator
User Title
 
Dannihilator's Avatar
 
Join Date: Oct 2002
Location: Annandale, New Jersey
Posts: 19,607

Bikes: 2008 Trek Portland, 1989 Nishiki Altron

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Originally Posted by mx_599
no he wasn't
You should only use a ziptie to measure the sag. Look in any fork manual, when a manufacturer say it has that much travel, it has to have that much travel if not it's false advertising.

A 130mm fork should have about 6" of exposed stanction when unweighted 5" of which is useable. When weighted down if the spring and adjustments are correct to rider weight there will be 5" of stanction showing, 4 of which is useable. Yes there is unseen overlap
past the seals and bushings, that is there for security purposes and is useless otherwise. Basically saying, you only need a ruler and know metric conversions. The way you guys are telling him is really innaccurate. That right there is why I included the numbers. I even gave to where the sag should be.

If you can compress the fork to where it bottoms out, you need a stiffer setting to start with, I can't even bottom my pike out from a stand still when it's set to only 95 mm let alone 140mm, I only get it half way. It's got to be either a marzocchi, manitou or fox. Rock Shox does not make a fork that steadily tops out at 130mm. With those three, it all depends on spring set up.

Been setting, and rebuilding my suspension forks 7 years now.

Oh, and to correct myself, there is another ~1.5" hiding under the crown.
__________________
Appreciate the old bikes more than the new.
Dannihilator is offline  
Reply With Quote
Old 02-18-06, 11:18 PM
  #14  
MattP.
Obeying Gravity
 
Join Date: Oct 2004
Location: Bellingham, WA
Posts: 2,962
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by KonaRider24
You're just measuring sag there. Measure the stanctions from the bottom of the crown to the seals and make sure it is in millimeters. 25.4 mm =1"

5"=127mm

130 is: 5.12"

With sag set 104mm of stanction should be shown.

104=4.09"

An inch of sag is perfectly fine.
Sag is just you sitting on the bike. Not you compressing it as for as it will go...
MattP. is offline  
Reply With Quote
Old 02-18-06, 11:32 PM
  #15  
cryptid01
one less horse
 
cryptid01's Avatar
 
Join Date: Aug 2003
Location: East Jesus NY
Posts: 5,600

Bikes: are better than yours

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by KonaRider24
You should only use a ziptie to measure the sag. Look in any fork manual, when a manufacturer say it has that much travel, it has to have that much travel if not it's false advertising.
Or not. My 05 66 when brand new got only about 120 mm out of the advertised 150 mm. I dropped the oil level a bit and guess what? 150mm. Measured with a ziptie, btw.
cryptid01 is offline  
Reply With Quote
Old 02-18-06, 11:37 PM
  #16  
mx_599
Lost in the Black Hills
 
mx_599's Avatar
 
Join Date: May 2005
Posts: 5,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by KonaRider24
You should only use a ziptie to measure the sag.
you can use a zip tie to measure travel. even better is to install a large o-ring when you have the fork tubes apart. then you always have an evaluation of travel when you ride and it does not look tacky

The way you guys are telling him is really innaccurate.
i didn't see where any of us said anything inaccurate...but okay

If you can compress the fork to where it bottoms out, you need a stiffer setting to start with
probably true... i couldn't do my Reba like that either
mx_599 is offline  
Reply With Quote
Old 02-18-06, 11:39 PM
  #17  
Dannihilator
User Title
 
Dannihilator's Avatar
 
Join Date: Oct 2002
Location: Annandale, New Jersey
Posts: 19,607

Bikes: 2008 Trek Portland, 1989 Nishiki Altron

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Originally Posted by gastro
Or not. My 05 66 when brand new got only about 120 mm out of the advertised 150 mm. I dropped the oil level a bit and guess what? 150mm. Measured with a ziptie, btw.
That's marzocchi's QC for you though, they always come with too much or too little oil. I had to do a rebuild on my pike right out of the box, had too much stanction showing, when set properly a fork will show the full amount of travel.

Just measure it what ever way is easier for you.
__________________
Appreciate the old bikes more than the new.
Dannihilator is offline  
Reply With Quote
Old 02-18-06, 11:41 PM
  #18  
mx_599
Lost in the Black Hills
 
mx_599's Avatar
 
Join Date: May 2005
Posts: 5,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by KonaRider24
I had to do a rebuild on my pike right out of the box, had too much stanction showing
what did you do???? oil height not going to effect it out of the box...what are you talking about?
mx_599 is offline  
Reply With Quote
Old 02-18-06, 11:50 PM
  #19  
Dannihilator
User Title
 
Dannihilator's Avatar
 
Join Date: Oct 2002
Location: Annandale, New Jersey
Posts: 19,607

Bikes: 2008 Trek Portland, 1989 Nishiki Altron

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Originally Posted by mx_599
you can use a zip tie to measure travel. even better is to install a large o-ring when you have the fork tubes apart. then you always have an evaluation of travel when you ride and it does not look tacky


i didn't see where any of us said anything inaccurate...but okay


probably true... i couldn't do my Reba like that either

I'll have to remember that.

Nothing saying innacurate, just using a ruler can be a challenge and requires a sharp eye, I guess I'm just getting lazy with the provided numbers on the U-turn side, or my vision is slowly starting to fail.


If using the zip tie method, it's best to use it while you are on the bike and in motion put your weight as far forward as possible weighting the fork through the travel.
__________________
Appreciate the old bikes more than the new.
Dannihilator is offline  
Reply With Quote
Old 02-18-06, 11:56 PM
  #20  
Dannihilator
User Title
 
Dannihilator's Avatar
 
Join Date: Oct 2002
Location: Annandale, New Jersey
Posts: 19,607

Bikes: 2008 Trek Portland, 1989 Nishiki Altron

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Originally Posted by mx_599
what did you do???? oil height not going to effect it out of the box...what are you talking about?
Had to add oil. The less oil, the more travel is shown, more oil, less travel. It was sitting at 148 mm out of the box. Besides I was going to rebuild it right out of the box anyways, I never use the stock seals or oil on any fork, plus I needed to do a spring change to get the spring rate correct.
__________________
Appreciate the old bikes more than the new.
Dannihilator is offline  
Reply With Quote
Old 02-19-06, 12:05 AM
  #21  
mx_599
Lost in the Black Hills
 
mx_599's Avatar
 
Join Date: May 2005
Posts: 5,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by KonaRider24
Had to add oil. The less oil, the more travel is shown, more oil, less travel. It was sitting at 148 mm out of the box. Besides I was going to rebuild it right out of the box anyways, I never use the stock seals or oil on any fork, plus I needed to do a spring change to get the spring rate correct.
i don't doubt you know what you're doing, but i don't understand why the oil height would affect an unloaded, coil sprung fork?

Kona...you crazy what is wrong with stock seals!!! what the hell do you put in them...teflon impregnated ones or something??

yeah, i totally agree about the oil. i try to ride it first, then change it. however, its less work to just do it right away
mx_599 is offline  
Reply With Quote
Old 02-19-06, 12:23 AM
  #22  
Dannihilator
User Title
 
Dannihilator's Avatar
 
Join Date: Oct 2002
Location: Annandale, New Jersey
Posts: 19,607

Bikes: 2008 Trek Portland, 1989 Nishiki Altron

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Originally Posted by mx_599
i don't doubt you know what you're doing, but i don't understand why the oil height would affect an unloaded, coil sprung fork?

Kona...you crazy what is wrong with stock seals!!! what the hell do you put in them...teflon impregnated ones or something??

yeah, i totally agree about the oil. i try to ride it first, then change it. however, its less work to just do it right away

Oil pressure in a ways. Less oil puts less force on the sprung side providing full travel and quicker rebound and compression, more oil is more pressure, which slows rebound and compression. To put it in a ways that won't take me two hours to describe.

The oil has to be balanced, too much and the oil weights the fork down too little and it sits too high and you burn the seals and bushings out.

Use Enduro seals, they last longer than the stock ones, rock shox isn't exactly known for their seals in their coil forks.
__________________
Appreciate the old bikes more than the new.
Dannihilator is offline  
Reply With Quote
Old 02-19-06, 12:25 AM
  #23  
mx_599
Lost in the Black Hills
 
mx_599's Avatar
 
Join Date: May 2005
Posts: 5,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by KonaRider24
Oil pressure in a ways. Less oil puts less force on the sprung side providing full travel and quicker rebound and compression, more oil is more pressure, which slows rebound and compression. To put it in a ways that won't take me two hours to describe.

The oil has to be balanced, too much and the oil weights the fork down too little and it sits too high and you burn the seals and bushings out.
oh


Use Enduro seals, they last longer than the stock ones, rock shox isn't exactly known for their seals in their coil forks.
yeah...but can't you wait till they leak
mx_599 is offline  
Reply With Quote
Old 02-19-06, 12:27 AM
  #24  
Dannihilator
User Title
 
Dannihilator's Avatar
 
Join Date: Oct 2002
Location: Annandale, New Jersey
Posts: 19,607

Bikes: 2008 Trek Portland, 1989 Nishiki Altron

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Originally Posted by mx_599
yeah...but can't you wait till they leak
I call it preventative maitenance.


__________________
Appreciate the old bikes more than the new.
Dannihilator is offline  
Reply With Quote
Old 02-19-06, 12:34 AM
  #25  
MattP.
Obeying Gravity
 
Join Date: Oct 2004
Location: Bellingham, WA
Posts: 2,962
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Originally Posted by KonaRider24
Use Enduro seals, they last longer than the stock ones, rock shox isn't exactly known for their seals in their coil forks.
Sweet, I just put some Enduro seals on my fork

Kind of bummed they only came in the lame blue color though
MattP. is offline  
Reply With Quote

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service