Mountain Bike Reviews Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
254 Posts
Discussion Starter · #1 ·
I bought a push hc97 and the directions say to use 5wt oil in the damper, I'm gonna use maxima plush. Anyways the rockshox directions say to use 3wt, so I am wondering why push is saying 5wt, is that for more damping since its a heavier weight oil? Also I'm wondering why push would put 20ml of maxima plush 10wt in the lowers
Instead of 10ml of 0w-30 like rockshox recommends. Is it only 20ml if you have their coil springs? They aren't responding to email or phone and I would really like to get this done. Thanks for any insight.
 

·
Read Only
Joined
·
2,101 Posts
Darren answered this in another thread, but they use the motorex 5wt because it has better lubricity. Basically as long as you use a good quality oil the viscosity doesn't make much noticeable difference.

20ml of oil is fine in the damper leg, will just last a little longer but I would stick to 10ml in the spring leg
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #3 ·
Thanks thats exactly what I needed to know, guess I will just stick to the rockshox recomendations for 3wt maxima plush and 10ml of 0w-30 per leg. I thought they used a 5wt maybe because of their shimless compression damper. So the only real difference is its temperature rating for the oil, a 3wt vs 5wt will have basically the same viscosity?
 

·
Read Only
Joined
·
2,101 Posts
Thanks thats exactly what I needed to know, guess I will just stick to the rockshox recomendations for 3wt maxima plush and 10ml of 0w-30 per leg. I thought they used a 5wt maybe because of their shimless compression damper. So the only real difference is its temperature rating for the oil, a 3wt vs 5wt will have basically the same viscosity?
Not exactly, remember the wt classification doesn't actually mean a lot in terms of viscosity, it's just used to compare oils within the same brand/spec. Centistokes (cSt) is the common measurement of viscosity, usually measured at 40*c

A 2.5/3 "wt" can be anywhere from about 8cSt to 16, while a 5wt can be from 15 to 22cSt. 15-21 is where the majority fall. But most high-end dampers (fork and shock) aren't very sensitive to viscosity because they work on the pressure over the valves rather than the damping effect of pushing fluid through and orifice. So you won't notice any difference from a change of a few cSt, as it only effects the low speed/bleed mostly. Even then it might be a case of 1 click on the adjuster.
 

·
Registered
Joined
·
11,629 Posts
SAE WT ratings are all over the place. But 5wt is a fork oil classification and 3wt is a damper fluid classification.

Full series here: https://www.shockcraft.co.nz/technical-support/suspension-fluids-series

The summary is fork oils will lubricate better and resist foaming better. Damper fluids generally handle heat better with less viscosity change.

BUT. You've gotta check out specific fluids as the 5wt (and 2.5 and 7.5 wt etc) category is so broad it's almost meaningless.

10wt is a fork oil classification. 0W30 is a motor oil classification. Generally speaking motor oils cling better than fork oils and work better as dedicated lubricants. But again you've gotta check out specific fluids as many motor oils suck as lubricants and some fork oils are quite good.
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #7 ·
SAE WT ratings are all over the place. But 5wt is a fork oil classification and 3wt is a damper fluid classification.

Full series here: https://www.shockcraft.co.nz/technical-support/suspension-fluids-series

The summary is fork oils will lubricate better and resist foaming better. Damper fluids generally handle heat better with less viscosity change.

BUT. You've gotta check out specific fluids as the 5wt (and 2.5 and 7.5 wt etc) category is so broad it's almost meaningless.

10wt is a fork oil classification. 0W30 is a motor oil classification. Generally speaking motor oils cling better than fork oils and work better as dedicated lubricants. But again you've gotta check out specific fluids as many motor oils suck as lubricants and some fork oils are quite good.
Thankyou dougal, I will def stick with rockshox brand 0w30 for the lowers then and I will read up on that link you posted but most likely will stick with 3wt maxima plush since that is what rockshox recommends as well and also since you said its damper fluid.
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #8 ·
Dougal, I read your website and you said rockshox fluid is 15cSt, the maxima plush 3wt rockshox is recomending now for all dampers is 14cSt and push says 5wt motorex which has a viscosity of 200 so not as big of a temp range as the recomended 3wt plush that is 228 viscosity and since i ride in the mtns temps change quick. I talked to push this morning and they said running the rockshox oil recommendations is fine for the hc97 which i think i will do. Atleast i have a better understanding of fluids now. Guess I have 5wt maxima plush i will be returning.
 

·
Registered
Joined
·
11,629 Posts
Dougal, I read your website and you said rockshox fluid is 15cSt, the maxima plush 3wt rockshox is recomending now for all dampers is 14cSt and push says 5wt motorex which has a viscosity of 200 so not as big of a temp range as the recomended 3wt plush that is 228 viscosity and since i ride in the mtns temps change quick. I talked to push this morning and they said running the rockshox oil recommendations is fine for the hc97 which i think i will do. Atleast i have a better understanding of fluids now. Guess I have 5wt maxima plush i will be returning.
Motorex 5wt has a VI of 287 now. They changed the mix in 2015.
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #10 ·
Motorex 5wt has a VI of 287 now. They changed the mix in 2015.
I just decided to got motorex 5wt, dougal I believe you know alot about motorex. Is the 5wt dirt bike shock oil the exact same as the mtb specific 5wt they have listed on their website? I don't read swiss but it seems like both 5wt oils are the same for the new 3d version listed on their site.
 

·
Registered
Joined
·
11,629 Posts
I just decided to got motorex 5wt, dougal I believe you know alot about motorex. Is the 5wt dirt bike shock oil the exact same as the mtb specific 5wt they have listed on their website? I don't read swiss but it seems like both 5wt oils are the same for the new 3d version listed on their site.
Yes Motorex sell the same fluids in Moto and Bike applications. Same part numbers, same packaging, same stuff.

I would however recommend the Motorex 2.5wt over 5wt for this damper application. The 5wt is basically for open bath forks which use a thicker oil for bushing lubrication.
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #12 ·
Yes Motorex sell the same fluids in Moto and Bike applications. Same part numbers, same packaging, same stuff.

I would however recommend the Motorex 2.5wt over 5wt for this damper application. The 5wt is basically for open bath forks which use a thicker oil for bushing lubrication.
Thanks, push said they use motorex 5wt for all their testing and settings, I was gonna use maxima plush 3wt but then decided once push comes out with their new rebound shim tune settings for the damper 2.1 I would go to motorex 5wt like they use apparently in all their shocks and recommendations in the hc97. I guess I could just pull the rebound stack and rebleed without dumping most of the oil. I got oil 153944, the new 3d stuff.
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top