Can you use car oil as fork oil?

[Tootyred]

My only concern would be composition of engine oil. It has lots of additional elements in it for, cleaning, hydrocarbon resistance etc etc. Parts made for engine internals take this composition into consideration, ie rubbers used will be resistant.

I dont know the answer, but is this true of the bike fork internals?

Having build many many many custom motorbikes in my career, fork, engine, gearbox, autobox etc etc oils are all different with differing additives.

I'm not saying dont do it, but I would proceed with caution as go the longterm effect on parts.

Also, surely, your trying to guess a correct viscosity, if mixing oils?

Buying a product specific to the application has to be advantageous ....yes?

 

[Tootyred]

Also, viscosity is very different in car oils hot to cold. It's why you run an engine prior to emptying the oil. It does not have to be that hot to change. Just leaving a tin in the sun will do it.

Fork oil has a more constant viscosity.

Dont think for a second forks dont get hot. Squeezing oil through small holes heats it up very effectively.

So, car oil in use will surly get thinner as you bounce along for hours, changing your damping?

 

[Gazjacko]

It’s a Magura Rond Quake, seems in good condition but clunks on extension and is very soft at the moment.

Mine did Exactly the same - but after a strip and oil change they were like chalk and cheese

I used 5wt 20 engine oil as it was all I had to had at the time - have you got the manual for them as there are two baths per leg and one was dry in my case and caused an annoying clunk

Nothing, I was going to just undo everything bit by bit recording each stage and hope that I could get it all back together later!

 

[Retro Spud]

It’s a Magura Rond Quake, seems in good condition but clunks on extension and is very soft at the moment.

Mine did Exactly the same - but after a strip and oil change they were like chalk and cheese

I used 5wt 20 engine oil as it was all I had to had at the time - have you got the manual for them as there are two baths per leg and one was dry in my case and caused an annoying clunk

Nothing, I was going to just undo everything bit by bit recording each stage and hope that I could get it all back together later!

Just tied sending the file from my phone - but I think it failed so will try again later from a PC as even compressed it’s about 3mb File

 

[FluffyChicken]

Retro Spud, what year fork is it for ?

 

[Retro Spud]

I’m not sure to be honest - mine are the firmtech version with the Magura’s built in to the rear of the legs
Pre 2000 I reckon but without opening up the file and looking I couldn’t say

Will get back to you

 

[Gazjacko]

Ok so finally got round to taking the fork apart using Retro Spud’s very helpful pdf. However after a good clean I’m having trouble getting the left leg back together. That’s the one with the spring and a plain shaft that goes down and bolts in place by the dropouts. Curiously the shaft is threaded both ends but there’s nothing to thread it into at the top ( beneath the spring housing ) so it just spins! I’ve tried holding it with a bolt but I can’t then remove the top one without undoing the shaft again! I’m sure I have all the bits (that were in there) but wonder if the ‘clunk’ was because I have a bit missing as the top of the shaft appears just to sit in a recess making the top thread redundant.
Weather permitting I will have another go tomorrow!

 

[fattaffracingco]

I have mixed oils to get correct weight , even used transmission oil in motorcycle fork legs to stiffen, oils can be mixed , some behave differently , some airate at different rates, (hot and cold )at a push I'm guessing you could , but why ? Suspension oils are readily available and quite cheap ?

 

[Matthews]

Re:

For oil bath lowers a good lightweight synth engine oil is best thing you can use ( I use 0/30 mobil 1 and have for years ) , damper oil is very different as has loads of antifoam additives , go to local motorbike shop n buy some fork oil ( at sensible price) in whatever grade you prefer , lower baths are lubricant , damper is for damping , different jobs hence different oils .

 

[charliealphamike]

My friendly local motorcycle dealer gave me some motorbike fork oil for free. They'd used some on a bike service, charged the customer for 1 litre, used approx 400ml. They told me they wouldn't use the rest which meant it was effectively in their way as it was taking up shelf space. After a friendly chat about motorbikes (I'm a motorcyclist too) and MTB's, they were quite happy for me to take it.