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Discussion Starter #1
I made a mistake and only bought one liter of fork oil when changing fork seals. I bought respol fork oil and my local shop does not carry it. I was wondering if I can mix brands of fork oil as long as its the same weight because im about 30mm low in the last fork. I should have taken everyones advice to order two liters and not try to save money all the time.
 

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In most all likelyhood you would be fine mixing it. The only risk I can think of is some of the additives in either oil destabilizing each other. I doubt you could find a solid answer anywhere on what additives are in each oil and which ones are compatible or not.

If you decide to mix, do a google search of actual weights of fork oil so you find something with a similar weight to stay consistent. Somewhere out there, someone has made a PDF of all the actual weights of the oil. It's quite surprising how far off they are from their stated weights looking at it from what I remember. That all said, you can mix weights, and it won't be in the end of the world.
 

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Discussion Starter #4
Also, would I be ok running my fork oil a few mm low? Im thinking of just sucking some oil out of the one I already filled instead of mixing oil. Im thinking if the oil levels are the same it should be ok. I know it is very bad to have them overfilled.
 

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Also, would I be ok running my fork oil a few mm low? Im thinking of just sucking some oil out of the one I already filled instead of mixing oil. Im thinking if the oil levels are the same it should be ok. I know it is very bad to have them overfilled.

No, that's not OK. An experienced suspension tech might tune a set of forks with the oil level, but the oil level is a precise thing, down to the millimeters. For demonstration of that point, here is an example graph of the effects of changing fork oil levels by millimeters. No, it won't cause you suddenly crash and explode, but it will affect handling.

 

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Here's the skinny,

Just because 2 fork oils SAY the same wt they more then likely will not be. You have to go by viscosity, NOT by oil wt. When companies build the valving, they base it off a certain viscosity. So first, if you didnt check the viscosity of Repsol Fork Oil vs Kawi OEM oil you've changed the way the valving will work. Then by adding different oil with different viscosity it's altering it more. Is it the end of the world? No not at all. Will it affect the way the valving works? Possibly, but you wont know until you go ride it. I would recommend filling the forks to the required oil level with mismatched oil instead of stealing from the second leg. It's a lesser of two evils.

Changing Oil levels is a tuning variable like Kman pointed out. If you made them level you would be 15mm lower in each leg. Is that bad? Not really, Ive dropped oil in bikes I've tuned 20mm before without issue. BUT there was a reason why I was doing it. By lowering the oil you COULD, but not guaranteed, have the possibility of bottoming out your forks. The air gap helps as a pressure cushion so to speak as you get to the bottom of the fork stroke. This is why adding the normal amount of mismatched oil is better than possibly bottoming the forks.
 

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do not mix ohlins oil with any other brand or run other oils in ohlins forks or shocks. they measure their oil differently and it is extremely light weight oil.
 

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Discussion Starter #9
my forks would stop two inches before the bottom when I had the preload all the way out and compression all the soft out so maybe they overfilled at the factory. I can already tell with the repsol 5w that I should be able to use more of my travel and I leveled both forks out 10mm low on each side. I decided not to mix fork oils.
 
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