Subject: RE: fork oil on drum brake loop frames

Author: Tom DeSain

Date: Mar 29, 2002, 9:32 AM

Post ID: 1709951385

I use 10-W50 motor oil in the forks. I notice the front suspension
bottoming out too easily over bumps. Is it related to the oil or is
time
time to spring for new springs??
Thanks
Peter
71 Ambo

Hi Pete, When cold, your 10-50 motor oil is basically 10 weight oil. I
doubt it ever heats up enough to rise viscosity above 10. (This is
opposite what most people think, but you can ask a knowledgible oil
expert, so you don't have to take my word for it) You need to use a
single weight oil in the forks. I would recommend trying straight 30
weight and see if that's better. I've thought about going up to straight
40 weight, but haven't found it yet, and the 30 works pretty good for
me. Part of your problem is also in the stock dampener valving which was
never really aggressive on compression as far as I can see. Remember,
your oil when cold is 10 wt, once the "engine" heats it up the additives
thicken the viscosity to 50wt, not the other way around. Good luck!