Thanks so much for the video. You are the only person sharing how to service a brain fork. Would you be so kind as to tell me how to take the damper out of the lower leg? Thanks again.
Looking at the bottom of the lower leg from below, use a 10mm (it might be 12mm, I forget) DEEP socket to loosen the oddly long nut down the threaded rod. Unscrew the nut 5 or six full turns. Then with the socket still on the nut, tap upward on the end of the socket with a rubber mallet to loosen the dampers from the lower legs.
Hi, great video, I'm not a mechanic, but I'm interested in how to setup the shims you mention to reduce pressure threshold. Would this setup increase sensitivity over small bumps? How is this setup done? Reduce shims to reduce pressure threshold?
stock is 4 shims behind the ring. cut it back to 1 or 2 if and the small bump compliance get WAY better. The fork becomes a dream to ride compared to other dampers.
I can see this system working quite well when tuned to the rider and terrain but terrible if not. The inertia valve i suppose controls 'low speed' oil flow which when in more closed state transferres oil pressure much sooner into the ports closed by the shim stack. If you would have the right shims and a reasonably light spring/low preload pushing the shims onto the port the whole system should be quite active. Making this system work well for a wide range of weights i would think would be quite hard. The threshold pressure keeping those ports closed would have to be quite high though though otherwise when the inertia valve is closed the oil pressure would simply flow past the shims. I find this concept of the inertia valve kind if weird as in choppy terrain the valve would be opening and closing very quickly as the weight rattles back and forth.
You are correct on all accounts. Stock the inertia valve-bypass valving is awful. I finally settled at about 1/4 the stack stiffness. It was stiff enough to prevent bobbing when sprinting but provided a bit of bleed on sharp hits that would try to move the suspension before the inertia valve could open to dump oil.
Hi Integral physics, I hope you can help me, I have a sid brain with hydraulics identical to the one in the video, I wanted to ask you, please, if you can show me the correct procedure and the type and quantity of oil to insert to restore it. I lost all the oil inside and I don't know how to fix it. A thousand thanks
Hi, fellow bike rider. Does this cartridge needs any seals kit during bike usage? Any seals kits like the Fox ones for the micro brain, but for the front fork. I have 2014 Epic Comp with Reba, could not find anything beside rear brain/air chamber.
I have the same bike. The seals are proprietary and bike shops will not sell them to you... HOWEVER. The seal kits can be found on ebay. My advice... Remove 3 of the 4 shims preloading the ring shim on the blowoff valve. It turns that damper into an absolute miracle.
@@INTEGRALPHYSICS i am not a mechanic and i dont have tools/skill to disassemble, but i will tell my mechanic about your advice. Any ideas about name of the seal kit? I only found this one: Specialized Brain RockShox SID Fork Service Kit Part# 11.4418.009.004
Hi, INTEGRALPHYSICS, im from mexico. I saw your video and read all your answers, this day tried to service a specialized s90 fork, when i tried to dissasemble the fork, i didn't se the circlip that retains the bottom blue cap, so i put a hex key in the little socket, and i heared some of air lossing from it, inmediatly screw it again, i think i remove some of the air from the cartridge and i read in one answers that it haves a 100-110 psi and i will need a needle to fill it. I saw that the bottom screw haves a little black dot, and i wanna put the correctly amount of air, how can i do that? Just making a special tool to fill air with a neddle of a syringe and inserting throught the black dot? I will apreciate so much if you can help me
Using a syringe needle is very difficult and VERY dangerous. There are needle filling tools that can be purchased but they can be a bit pricey ($100). I have not had problems drilling out the plug seat that held the black plug and epoxying in a presta stem and valve. I have never had a s90 apart so I don't know if a similar solution would work for you.
I will do a tutorial on the rear shock next time I have it apart. The only substantial difference is your bladder vs my ifp. I will also do a vid on my vaccum bleeder as that is needed to bleed most shocks.
Crank the rebound all the way slow. Push the bike down hard. If the bike comes back up quick then you have lost IFP pressure and need to recharge the chamber. If when cycling the shock you hear a squelching sound, typically at the top of the travel, you have air in the fluid and need to replace a seal. Good Luck...
Was that an IFP at the beginning of the disassembly? You were talking about a rubber pellet being there so there must have been pressure inside, right?
@@lukedinkel1007 I use Fox Green (10wt) which i believe is what was in there stock. IFP depth is 30mm but they added a nylon glide ring to the IFP in later years which changed the ifp depth. Basically you want the ifp within 2-3 mm of the plate which sits behind it.
Hi! Thanks for the video! Sorry for my english, im from Uruguay 🇺🇾 I want to know in what part of the system works nytrogen, how can i fill up and what is the correct pressure en PSI. Best regards
Nitrogen goes in the the chamber that sits at the bottom of the damper. The chamber requires a small needle to inflate and can be quite a challenge. It takes 110psi. Air works just fine in the place of nitrogen.
@@valentinbarreto9332 You'll bleed and fill the cartridge, and set the piston roughly 3-5mm from bottomed out, with the shaft fully extended. Most fluids with a viscosity 22-35Cst will work well. They say to use "Rockshox 7.5" in the manual, but they mean 7wt.
Great explanation, can you do a video showing how to Charge the ifp valve please ?
Thanks so much for the video. You are the only person sharing how to service a brain fork. Would you be so kind as to tell me how to take the damper out of the lower leg? Thanks again.
Looking at the bottom of the lower leg from below, use a 10mm (it might be 12mm, I forget) DEEP socket to loosen the oddly long nut down the threaded rod. Unscrew the nut 5 or six full turns. Then with the socket still on the nut, tap upward on the end of the socket with a rubber mallet to loosen the dampers from the lower legs.
That's the chicken leg frog leg tadpole one spunk, messiah situation was a ball as the spunk, sperm cell 😭😂
@@INTEGRALPHYSICSwhat happened to the ET pictogram pirate long tentacles? With the Albanian seed deployment 😭
great video！
Hi, great video, I'm not a mechanic, but I'm interested in how to setup the shims you mention to reduce pressure threshold. Would this setup increase sensitivity over small bumps? How is this setup done? Reduce shims to reduce pressure threshold?
stock is 4 shims behind the ring. cut it back to 1 or 2 if and the small bump compliance get WAY better. The fork becomes a dream to ride compared to other dampers.
I can see this system working quite well when tuned to the rider and terrain but terrible if not. The inertia valve i suppose controls 'low speed' oil flow which when in more closed state transferres oil pressure much sooner into the ports closed by the shim stack. If you would have the right shims and a reasonably light spring/low preload pushing the shims onto the port the whole system should be quite active. Making this system work well for a wide range of weights i would think would be quite hard. The threshold pressure keeping those ports closed would have to be quite high though though otherwise when the inertia valve is closed the oil pressure would simply flow past the shims. I find this concept of the inertia valve kind if weird as in choppy terrain the valve would be opening and closing very quickly as the weight rattles back and forth.
You are correct on all accounts. Stock the inertia valve-bypass valving is awful. I finally settled at about 1/4 the stack stiffness. It was stiff enough to prevent bobbing when sprinting but provided a bit of bleed on sharp hits that would try to move the suspension before the inertia valve could open to dump oil.
@@INTEGRALPHYSICS Excellent explainer! Is this too firm of a shim stack why it feels like "clunk" when the system opens?
Thank you for the video, what kind of oil use this brain?
Fox Green
Hi Integral physics, I hope you can help me, I have a sid brain with hydraulics identical to the one in the video, I wanted to ask you, please, if you can show me the correct procedure and the type and quantity of oil to insert to restore it. I lost all the oil inside and I don't know how to fix it. A thousand thanks
Getting the oil in and the cartridge bled is not particularly hard. Charging the IFP chamber takes some specialized equipment. (a fill needle)
Would you mind to tell me the pressure for the nitrogen chamber? 2014 Sid brain many thanks
Hi, fellow bike rider. Does this cartridge needs any seals kit during bike usage? Any seals kits like the Fox ones for the micro brain, but for the front fork. I have 2014 Epic Comp with Reba, could not find anything beside rear brain/air chamber.
I have the same bike. The seals are proprietary and bike shops will not sell them to you... HOWEVER. The seal kits can be found on ebay.
My advice... Remove 3 of the 4 shims preloading the ring shim on the blowoff valve. It turns that damper into an absolute miracle.
@@INTEGRALPHYSICS i am not a mechanic and i dont have tools/skill to disassemble, but i will tell my mechanic about your advice.
Any ideas about name of the seal kit? I only found this one: Specialized Brain RockShox SID Fork Service Kit Part# 11.4418.009.004
Hi, INTEGRALPHYSICS, im from mexico. I saw your video and read all your answers, this day tried to service a specialized s90 fork, when i tried to dissasemble the fork, i didn't se the circlip that retains the bottom blue cap, so i put a hex key in the little socket, and i heared some of air lossing from it, inmediatly screw it again, i think i remove some of the air from the cartridge and i read in one answers that it haves a 100-110 psi and i will need a needle to fill it. I saw that the bottom screw haves a little black dot, and i wanna put the correctly amount of air, how can i do that? Just making a special tool to fill air with a neddle of a syringe and inserting throught the black dot?
I will apreciate so much if you can help me
Using a syringe needle is very difficult and VERY dangerous. There are needle filling tools that can be purchased but they can be a bit pricey ($100). I have not had problems drilling out the plug seat that held the black plug and epoxying in a presta stem and valve. I have never had a s90 apart so I don't know if a similar solution would work for you.
please do Rockshox Brain 2.0 rear shock service video tutorials
I will do a tutorial on the rear shock next time I have it apart. The only substantial difference is your bladder vs my ifp. I will also do a vid on my vaccum bleeder as that is needed to bleed most shocks.
@@INTEGRALPHYSICS done subscribe
@@INTEGRALPHYSICS Do you NEED a vacuum bleeder or can you use the standard rockshox suspension bleed kit that looks like a brake bleed kit?
My brain stopped locking out rider pedal bobbing but it still absorbs shocks. Any suggestions to get the brain to start doing its job?
Crank the rebound all the way slow. Push the bike down hard. If the bike comes back up quick then you have lost IFP pressure and need to recharge the chamber.
If when cycling the shock you hear a squelching sound, typically at the top of the travel, you have air in the fluid and need to replace a seal.
Good Luck...
Was that an IFP at the beginning of the disassembly? You were talking about a rubber pellet being there so there must have been pressure inside, right?
Yes. There is an IFP sitting on 100-110psi
@@INTEGRALPHYSICS Any tips for IFP depth? Oil weight?
@@lukedinkel1007 I use Fox Green (10wt) which i believe is what was in there stock. IFP depth is 30mm but they added a nylon glide ring to the IFP in later years which changed the ifp depth. Basically you want the ifp within 2-3 mm of the plate which sits behind it.
@@INTEGRALPHYSICS what a champ💪 Really appreciate the help man, thank you.
@@INTEGRALPHYSICS What's the purpose of the IFP?
Hi! Thanks for the video!
Sorry for my english, im from Uruguay 🇺🇾
I want to know in what part of the system works nytrogen, how can i fill up and what is the correct pressure en PSI.
Best regards
Nitrogen goes in the the chamber that sits at the bottom of the damper. The chamber requires a small needle to inflate and can be quite a challenge. It takes 110psi. Air works just fine in the place of nitrogen.
Thank you very much for your answer, is very helpfull for me. Last question, how much oil i will need to refil and wich oil should i have to use?
@@valentinbarreto9332 You'll bleed and fill the cartridge, and set the piston roughly 3-5mm from bottomed out, with the shaft fully extended. Most fluids with a viscosity 22-35Cst will work well. They say to use "Rockshox 7.5" in the manual, but they mean 7wt.
@@seitenryu6844 thank you very much for your answer, is very helpfully for me! 👏🏻💪🏻
@@valentinbarreto9332 If you do it, please make a post about it on mtbr shock and suspension forum. Cheers
Do u have IG? I have to ask u a question via Dm
Not sure what IG is.
Rango beard Altair? 😭