Fork oil weight

PB Forum :: Mechanics' Lounge
Fork oil weight
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flag konafarker
O+
Posted: Dec 22, 2008 at 12:22 Quote
Again more info here >
http://www.peterverdonedesigns.com/bikesuspension.htm

Be careful not to overfill the fork leg... It will go hard as dry shit on a summers day and can damage your main oil seals as well.
Too little oil and again, possible damage and it might suck air and give SH performance.

My advice is Go for a 7.5 - 10 wt Oil or 125/150 in koto speak, with High Viscosity and Check the Manafacturers website (MarZ)for Oil heights/volumes...Also, you can play with the oil volume by about 10% each way from manafaturers sugested volume. Nothing more.
Redline Oil is my pick of the easy to find crop...

And Don't ever trust that the fork had the right amount of fork oil in it from factory or previous owner...

Enjoy this info as it is accurate... I can assure you.
flag andyjacko123
Posted: Dec 22, 2008 at 12:24 Quote
konafarker wrote:
Again more info here >
http://www.peterverdonedesigns.com/bikesuspension.htm

Be careful not to overfill the fork leg... It will go hard as dry shit on a summers day and can damage your main oil seals as well.
Too little oil and again, possible damage and it might suck air and give SH performance.

My advice is Go for a 7.5 - 10 wt Oil or 125/150 in koto speak, with High Viscosity and Check the Manafacturers website (MarZ)for Oil heights/volumes...Also, you can play with the oil volume by about 10% each way from manafaturers sugested volume. Nothing more.
Redline Oil is my pick of the easy to find crop...

And Don't ever trust that the fork had the right amount of fork oil in it from factory or previous owner...

Enjoy this info as it is accurate... I can assure you.

stripped a few forks in your time Razz
flag rkuhn
Posted: Jun 16, 2009 at 15:55 Quote
BikeDaug40 wrote:
Yea ok, i need 5wt moto oil so i guess autozone would be a good bet.

Attention This reply is late but DON'T use motor/engine oil! Even if its a synthetic! Attention


also wrote:
Also, do i just pour out the old stuff and dump the new stuff in??

Pretty much. What I recommend is that you measure the amount of oil in each leg as a reference for future tuning.
flag jonbikes
Posted: Jun 16, 2009 at 17:41 Quote
rkuhn wrote:
BikeDaug40 wrote:
Yea ok, i need 5wt moto oil so i guess autozone would be a good bet.

Attention This reply is late but DON'T use motor/engine oil! Even if its a synthetic! Attention


also wrote:
Also, do i just pour out the old stuff and dump the new stuff in??

Pretty much. What I recommend is that you measure the amount of oil in each leg as a reference for future tuning.

Quite a bit late. I do believe he meant moto oil as in motorcross fork oil, however I could be wrong.

And measuring the amount of oil in each leg is pretty much useless. It will ALWAYS be off. For one, a large amount of oil will be stuck to the internals of your fork, and it will be a surprising amount, more than enough to throw off your measurement. Second off, Marzocchi for one is horrible for putting the wrong amount of oil in their forks from the factory, and other companies probably follow close behind, so that's out the door as well. The only safe bet is going with what is posted on the manufacturers website.
flag rkuhn
Posted: Jun 16, 2009 at 18:32 Quote
jonbikes wrote:
Quite a bit late. I do believe he meant moto oil as in motorcross fork oil, however I could be wrong.

I wasn't going to reply at first but just in case someone did a search in the forum and came across it I didn't want them to assume. Smile

also wrote:
And measuring the amount of oil in each leg is pretty much useless. It will ALWAYS be off.

Maybe, but if prior to the oil removal and the fork felt good and they refilled their fork and found that it didn't feel or ride the way they'd hope they can reference back to when it did feel right and go from there.

This happened to me with a fork that I bought and didn't change the oil for about 2 years. When I did finally change the oil I assumed that it was filled as per the manual or there abouts. When I filled it per the specs the fork rode like crap Blank Stare

Once I did get the oil level to where I liked it I made a note of it so when I did the fork oil R/R again I knew how much to put in. 2 cents

also wrote:
Second off, Marzocchi for one is horrible for putting the wrong amount of oil in their forks from the factory, and other companies probably follow close behind, so that's out the door as well. The only safe bet is going with what is posted on the manufacturers website.

I've found that true as well. The amount they spec in their manual seems to be off but I'm told that I'm suppose to take that as a "general starting point" and "tweak as needed". Razz Makes sense... Book
flag jonbikes
Posted: Jun 16, 2009 at 18:38 Quote
Yup, it is recommended that for the Marzocchi open bath systems you go in increments of 10cc at a time for adjustments. New oil will feel heavier than old oil as well, over time the viscosity of oil breaks down, which is one of the main reasons you do an oil change, the old stuff is getting worn out.
flag rkuhn
Posted: Jun 16, 2009 at 18:55 Quote
Sort of off topic here but I have a friend who does everything by the book - he sets his bike (and the components) up exactly as the specs state and he doesn't deviate from it.

Perhaps the only thing he deviates from is the tire PSI. Smile

For the most part you do have to get it to spec or close to it but for other things I sort of use what is in the specs as a starting point and go from there - tweak as needed; far from an exact science. Beer

How many of us have set up their forks or rear shock as described in the specs and left it as-is and not touch it? Even noobs tweak their stuff a little. Cool

Not to further digress but I encourage people to tweak and adjust but to always try and record what they did so they can get back to their starting point if needed. Razz
flag jonbikes
Posted: Jun 16, 2009 at 19:01 Quote
I like that method as well. The only thing I follow to a T is staying within min/max pressure on a shock. If you fall below the min pressure cavitation WILL occur, in which case your shock is done for depending on how long you ride it like that for, or if you go over an explosion is going to happen at some point. Other than that, I find things out when I get to them.
flag kqmtb2006
Posted: Jun 16, 2009 at 19:28 Quote
jonbikes wrote:
I like that method as well. The only thing I follow to a T is staying within min/max pressure on a shock. If you fall below the min pressure cavitation WILL occur, in which case your shock is done for depending on how long you ride it like that for, or if you go over an explosion is going to happen at some point. Other than that, I find things out when I get to them.
Uh oh I accidentally rode my shock at like 0 or 7 or something psi for probably around half a year haha that could be a problem...
flag kqmtb2006
Posted: Jun 16, 2009 at 19:38 Quote
also wrote:
Second off, Marzocchi for one is horrible for putting the wrong amount of oil in their forks from the factory, and other companies probably follow close behind, so that's out the door as well. The only safe bet is going with what is posted on the manufacturers website.

rkuhn wrote:
I've found that true as well. The amount they spec in their manual seems to be off but I'm told that I'm suppose to take that as a "general starting point" and "tweak as needed". Razz Makes sense... Book

I know for a fact that fox checks to make sure the fork has the right amount of oil. But like you said, it's kind of meant to be tweaked a bit. I mean if your fork doesn't have the sort adjustments like compression or rebound the doesn't really get to that "extreme" rebound that maybe some would want, and you actually wanted to change these more than it allows, then that would be a case for different weight oil.
flag rangemaster
Posted: Nov 29, 2011 at 18:57 Quote
so i'm reviving this thread with a question. im building a set of super t's. marzocchi says to put 7.5, the guy i bought it from says 5w and some place on the internet says to go 10w. how would each of these affect performance? it's going on a dh sled btw, very light freeride (if any).
thanks
flag blueeyedbiker68
Posted: Nov 29, 2011 at 19:45 Quote
rangemaster wrote:
so i'm reviving this thread with a question. im building a set of super t's. marzocchi says to put 7.5, the guy i bought it from says 5w and some place on the internet says to go 10w. how would each of these affect performance? it's going on a dh sled btw, very light freeride (if any).
thanks
Good question fella. I would go with the 10W since it willl last longer as it takes longer for the oil to lose its viscocity. A forks seals will hold heavier weight oil better as well. It also tends to make the rebound vavling more responsive over the life of the oil. I also treat the internals with a super flouro-polymer too. My Trek outside sales Rep. came in once and was squishin' on a fork of one of my bikes and exclaimed,..."Keith,.WOW! *What* did you do to this fork? Ive felt forks set up by suspension engineers that dont feel this great!! What's your secret,.seriously?"

The flouro-polymer is a Finish Line product and has a lower slip co-effecient than Teflon. Look into it and treat the stanchions and glides inside the fork before you grease anything. There is even a flouro-polymer grease that I'm getting soon for my for rebuilds. Anyone that rides my bikes say my forks feel buttery smooth and above are the reasons why. tup I hope this info helps.
flag rangemaster
Posted: Nov 29, 2011 at 23:00 Quote
blueeyedbiker68 wrote:
rangemaster wrote:
so i'm reviving this thread with a question. im building a set of super t's. marzocchi says to put 7.5, the guy i bought it from says 5w and some place on the internet says to go 10w. how would each of these affect performance? it's going on a dh sled btw, very light freeride (if any).
thanks
Good question fella. I would go with the 10W since it willl last longer as it takes longer for the oil to lose its viscocity. A forks seals will hold heavier weight oil better as well. It also tends to make the rebound vavling more responsive over the life of the oil. I also treat the internals with a super flouro-polymer too. My Trek outside sales Rep. came in once and was squishin' on a fork of one of my bikes and exclaimed,..."Keith,.WOW! *What* did you do to this fork? Ive felt forks set up by suspension engineers that dont feel this great!! What's your secret,.seriously?"

The flouro-polymer is a Finish Line product and has a lower slip co-effecient than Teflon. Look into it and treat the stanchions and glides inside the fork before you grease anything. There is even a flouro-polymer grease that I'm getting soon for my for rebuilds. Anyone that rides my bikes say my forks feel buttery smooth and above are the reasons why. tup I hope this info helps.
thanks will do. i think i saw some of this flouro-polymer and was like huh? now i know. thanks heaps Salute
flag blueeyedbiker68
Posted: Nov 30, 2011 at 5:50 Quote
rangemaster wrote:
blueeyedbiker68 wrote:
rangemaster wrote:
so i'm reviving this thread with a question. im building a set of super t's. marzocchi says to put 7.5, the guy i bought it from says 5w and some place on the internet says to go 10w. how would each of these affect performance? it's going on a dh sled btw, very light freeride (if any).
thanks
Good question fella. I would go with the 10W since it willl last longer as it takes longer for the oil to lose its viscocity. A forks seals will hold heavier weight oil better as well. It also tends to make the rebound vavling more responsive over the life of the oil. I also treat the internals with a super flouro-polymer too. My Trek outside sales Rep. came in once and was squishin' on a fork of one of my bikes and exclaimed,..."Keith,.WOW! *What* did you do to this fork? Ive felt forks set up by suspension engineers that dont feel this great!! What's your secret,.seriously?"

The flouro-polymer is a Finish Line product and has a lower slip co-effecient than Teflon. Look into it and treat the stanchions and glides inside the fork before you grease anything. There is even a flouro-polymer grease that I'm getting soon for my for rebuilds. Anyone that rides my bikes say my forks feel buttery smooth and above are the reasons why. tup I hope this info helps.
thanks will do. i think i saw some of this flouro-polymer and was like huh? now i know. thanks heaps Salute
ya it's a lil bitty baby sized drip bottle for like 7$-9$ USD. The grease retails for like $15 and its a 20Gr syringe!! Eek

EDIT: Oh and you prob know bout the wooden dowell/sock(or rag) method of cleaning the inside of the sliders right? If you cant get the rag out,.I also use a cut plastic hanger. I cut it in a manner that it *retains* both hook ends,.got me? Make sure you dont use *rubbing* alchohol to clean it since it contains Glycerine,.which *is* a lubricant,.but it will hang around and lead to breakdown of the grease you put in, I use Isopropyl Alch 90% or higher.If you cant get on the Super Killer Fire Flouro-Polymer grease ,.use a waterproof grease like Phil's or something like that. It's a clear type. There's another brand I use but I cant think of it right now,..have to get back at ya when I go to the shop and eyeball it!! tup


EDIT-EDIT: if you can,.go to a pharmaceutical/medical supply store and get a 60cc syringe or plastic graduated cylinder for measuring proper oil volume,.works GREAT!
flag rangemaster
Posted: Nov 30, 2011 at 9:42 Quote
blueeyedbiker68 wrote:
rangemaster wrote:
blueeyedbiker68 wrote:
Good question fella. I would go with the 10W since it willl last longer as it takes longer for the oil to lose its viscocity. A forks seals will hold heavier weight oil better as well. It also tends to make the rebound vavling more responsive over the life of the oil. I also treat the internals with a super flouro-polymer too. My Trek outside sales Rep. came in once and was squishin' on a fork of one of my bikes and exclaimed,..."Keith,.WOW! *What* did you do to this fork? Ive felt forks set up by suspension engineers that dont feel this great!! What's your secret,.seriously?"

The flouro-polymer is a Finish Line product and has a lower slip co-effecient than Teflon. Look into it and treat the stanchions and glides inside the fork before you grease anything. There is even a flouro-polymer grease that I'm getting soon for my for rebuilds. Anyone that rides my bikes say my forks feel buttery smooth and above are the reasons why. tup I hope this info helps.
thanks will do. i think i saw some of this flouro-polymer and was like huh? now i know. thanks heaps Salute
ya it's a lil bitty baby sized drip bottle for like 7$-9$ USD. The grease retails for like $15 and its a 20Gr syringe!! Eek

EDIT: Oh and you prob know bout the wooden dowell/sock(or rag) method of cleaning the inside of the sliders right? If you cant get the rag out,.I also use a cut plastic hanger. I cut it in a manner that it *retains* both hook ends,.got me? Make sure you dont use *rubbing* alchohol to clean it since it contains Glycerine,.which *is* a lubricant,.but it will hang around and lead to breakdown of the grease you put in, I use Isopropyl Alch 90% or higher.If you cant get on the Super Killer Fire Flouro-Polymer grease ,.use a waterproof grease like Phil's or something like that. It's a clear type. There's another brand I use but I cant think of it right now,..have to get back at ya when I go to the shop and eyeball it!! tup


EDIT-EDIT: if you can,.go to a pharmaceutical/medical supply store and get a 60cc syringe or plastic graduated cylinder for measuring proper oil volume,.works GREAT!

yea i just picked up some phil's yesterday. i think i still have a 60 cc syringe from brake bleeding. thanks for all the advice!

ps btw what company makes your oil? because apparently the weights mean nothing. it's about the viscosity index that one should really look at.

 


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