Difference in fork oil weight?

PB Forum :: Mechanics' Lounge
Difference in fork oil weight?
Previous Page |
Author Message
Posted: May 6, 2019 at 2:15 Quote
I'm looking to service my Rockshox Pikes.

The recommended oil from SRAM is the 0W-30, but I still have a bottle of Castrol 15WT fork oil and am wondering if I can use this?

The 15WT rating on the Castol oil refers to the weight of the oil. How does the rating of 0W-30 on the SRAM oil compare to this, or what exactly does the SRAM rating refer to?

Posted: May 6, 2019 at 6:36 Quote
Peter Verdone has a thorough, albeit dated, page on suspension fluids. The most important message is that the "weight" ratings are inconsistent. It will be a little different from stock; don't know how much or whether the change will be a good or bad thing.

If that 0W-30 corresponds to the SAE motor oil ratings, it should be about 10 - 14 cSt at 100°C. This appears to correspond fluids rated around 10 - 20wt ... so yeah, your 15wt should be close.

Posted: May 7, 2019 at 8:06 Quote
Excellent answer! Thank you very much.

Posted: May 7, 2019 at 13:48 Quote
To add to your question and the answer, I use full synthetic 0w-30 motor oil in my pike. Cheaper and easy to find.

Cheers

Posted: May 7, 2019 at 15:38 Quote
CP-Bike wrote:
To add to your question and the answer, I use full synthetic 0w-30 motor oil in my pike. Cheaper and easy to find.

Cheers

If you're willing to spend presumably thousands of dollars on a bike, it's worth spending an extra ten bucks for the proper suspension fluid. A litre is enough for years of fork overhauls.

Posted: May 7, 2019 at 17:25 Quote
[/Quote]If you're willing to spend presumably thousands of dollars on a bike, it's worth spending an extra ten bucks for the proper suspension fluid. A litre is enough for years of fork overhauls.[/Quote]


But when you can't get your hands on any when you need it, the option I used works.

Posted: May 7, 2019 at 17:45 Quote
CP-Bike wrote:
If you're willing to spend presumably thousands of dollars on a bike, it's worth spending an extra ten bucks for the proper suspension fluid. A litre is enough for years of fork overhauls.[/Quote]

But when you can't get your hands on any when you need it, the option I used works.[/Quote]

Are you certain, for example, the formulation of your motor oil has the right balance of ingredients that swell or shrink nitrile rubber fork seals?

It's questionable, even as an emergency measure. It doesn't warrant a recommendation of doing so.

Posted: May 7, 2019 at 18:21 Quote
R-M-R wrote:
CP-Bike wrote:
If you're willing to spend presumably thousands of dollars on a bike, it's worth spending an extra ten bucks for the proper suspension fluid. A litre is enough for years of fork overhauls.

But when you can't get your hands on any when you need it, the option I used works.[/Quote]

Are you certain, for example, the formulation of your motor oil has the right balance of ingredients that swell or shrink nitrile rubber fork seals?

It's questionable, even as an emergency measure. It doesn't warrant a recommendation of doing so.[/Quote]

While I don't disagree that you should probably just use the oil that was specificity formulated for the application.....Motor oil is generally fine in any suspension application where the oil is used for lubrication, Its generally not effective when the oil is required for damping.

Some applications can even use ATF. Older MTB suspension, and plenty of moto applications actually refer to motor oil use in suspension for lubrication.

Its a far from questionable. there is abundance of discussion on this topic on plenty of forums dating back quite some time. Enduro seals even used recommend motor oil for some of their applications (although I cont find the reference document)

..... (Like seriosuly, in Ottawa, our national capital, you cant find a shop MTB or moto that doesnt have suspension fluid on hand???) .

Posted: May 8, 2019 at 16:53 Quote
I know that motor oil and transmission oil use very different "weight" numbers to describe the same values in centistokes. I'm not sure if the same is true for suspension fluids, but you may be far better off by using suspension-specific oil in the correct weight just in case.

Also, with regard to the "multi-weight" oils, the "W" stands for "winter." It is to remind you that the 0W-30 behaves like a zero weight oil when cold and like a 30 weight oil when at operating temperature. It suffers less reduction in viscosity due to heat than a single-weight oil would.

Posted: May 8, 2019 at 17:00 Quote
Falcon991 wrote:
I know that motor oil and transmission oil use very different "weight" numbers to describe the same values in centistokes. I'm not sure if the same is true for suspension fluids, but you may be far better off by using suspension-specific oil in the correct weight just in case.

Also, with regard to the "multi-weight" oils, the "W" stands for "winter." It is to remind you that the 0W-30 behaves like a zero weight oil when cold and like a 30 weight oil when at operating temperature. It suffers less reduction in viscosity due to heat than a single-weight oil would.

Keep in mind, though, forks run a lot cooler than the roughly 250°C operating temperature of motor oils! Thermal effects are negligible for forks and rarely a problem for shocks.

Posted: May 9, 2019 at 17:53 Quote
Fox 20wt gold in lyrics/pikes if you want butter smooth.

Posted: May 10, 2019 at 18:54 Quote
For availability you could try a motocross or a atv dealer because Fox is OEM on a lot of manufacturers and probably use similar oils to RS

Posted: May 13, 2019 at 17:27 Quote
R-M-R wrote:
Falcon991 wrote:
I know that motor oil and transmission oil use very different "weight" numbers to describe the same values in centistokes. I'm not sure if the same is true for suspension fluids, but you may be far better off by using suspension-specific oil in the correct weight just in case.

Also, with regard to the "multi-weight" oils, the "W" stands for "winter." It is to remind you that the 0W-30 behaves like a zero weight oil when cold and like a 30 weight oil when at operating temperature. It suffers less reduction in viscosity due to heat than a single-weight oil would.

Keep in mind, though, forks run a lot cooler than the roughly 250°C operating temperature of motor oils! Thermal effects are negligible for forks and rarely a problem for shocks.

True, but what I meant was this: An 85W transmission fluid is roughly equivalent to a 40W engine oil. I'm not sure if a typical 01W or 20W fork oil is the same as an 0W-20 or 20W-50 engine oil. Suspension oils "seem" much thinner to me, although I've never measured the centistokes personally.

The thermal breakdown really wouldn't be a problem with MTB forks; you're right.

Posted: May 13, 2019 at 17:43 Quote
Falcon991 wrote:
True, but what I meant was this: An 85W transmission fluid is roughly equivalent to a 40W engine oil. I'm not sure if a typical 01W or 20W fork oil is the same as an 0W-20 or 20W-50 engine oil. Suspension oils "seem" much thinner to me, although I've never measured the centistokes personally.

The thermal breakdown really wouldn't be a problem with MTB forks; you're right.

Agree that "weight" is a terrible measurement of fluids. Wish we could switch to cSt as the primary designation.

Posted: Jan 29, 2020 at 5:26 Quote
Hi all, I have a question. How can I clean old oil? Can I use Cleaner/Degreaser or better gasoline solvent?

Previous Page |

 
Copyright © 2000 - 2021. Pinkbike.com. All rights reserved.
dv65 0.006145
Mobile Version of Website