|   Fork Oil or ATF? | kmltick
Jan 9, 2003 12:40 AM | | Hi,
I just purchased two 2001 Rock Shox Judys (SL & XC) used. One will be used on the girlfriend's bike, the other will be used on my beater/loaner bike.
I'm about to do an overhaul on both of them this winter and read that I could use Automatic Transmission Fluid (ATF) as a substitute. (I know that they can't have seal swellers, and that synthetic would probably be better)
I know that Rock Shox normally uses 5wt fork oil (as per the manual) and ATF fluid is around 7wt but that's fine with me.
Just wondering if there's any other concerns, after all some people seem to be swearing by Fork oil (after all how can you go wrong?), and others have had no problems with ATF.
Thanks in advance. |
| ATF is much heavier than that... | zedro
Jan 9, 2003 11:20 AM | | its considered to be about 12-15wt, although there is one brand (which eludes me right now), which people claim feels more like a 7.5wt.
Theres also some concern (brought to you by Marzocchi) that ATF can do some long term harm as some swelling persists.
I used to be a fan of ATF, and if its the right weight, it does perform better than alot of the fork oils out there. However the current oil i use (Motul Synthetic) has topped it in my books, and Marzocchis warnings have made me timid of further use. |
| ATF is much heavier than that... | kmltick
Jan 9, 2003 6:29 PM | | I saw some of the Marzocchi warnings saying that it'll swell the seals which increases stiction and decreases performance, but I'm assuming that's using a petroleum based ATF (could or could not have seal swellers). But if I use a fully synthetic ATF w/o any seal swellers such as Mobil 1 ATF, should I have any concerns?
Since either forks aren't going on my main bike (i.e. beater/loaner & the girlfriend's bike) and I'm a cheap bastid =), I doubt I'd splurge on getting a really good Fork Oil for them. (Besides they were bought used)
I don't know how Zoke internals are, could they be more complicated than the Judys? |
| there are really only two main types of ATF... | zedro
Jan 9, 2003 7:13 PM | | because ATF fluids are standardised, the only difference will come from the transmission type. The ATF used is assumed to be Delron, the other type is TypeF. So Mobil 1 will be the same as Brand X anyways.
Both internals are fairly simple, although they vary between models. |
| there are really only two main types of ATF... | kmltick
Jan 14, 2003 1:12 PM | | Thanks for the replies Zedro, I bought a bottle of the Mobil 1 Synthetic ATF (Dexron Type, although I don't think it comes in the Ford Type) and overhauled both forks.
Found a site that lists the properties of a bunch of suspension fluids (http://home.att.net/~dirt.tech/susp-oil.htm) and you were right, Mobil 1 Synthetic ATF is around a 10wt fork oil. (at least that's what the properties hover around)
Everything's good now, thanks for the help though. It was a good thing I did the overhaul anyways, one of the forks didn't have ANY oil in it! Now I gotta wait until it gets warmer to test them both out...
Thanks again. |
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