fork oil question

i have a 98 and am getting ready to change my fork oil soon. my question is what will a heavier oil do? such as 15wt. i have set my sag and tried adjusting my preload to full stiff to see if that would help but it still seems to dive real easy. i weigh about 190. i know if you add oil it helps it from bottoming out by the less air in the forks, but by putting heavier oil in will it help from diving so easily or is it just going to affect it on the little bumps? thanks in advance.

 

heavier oil = stiffer ride. The stock oil is only 5w. I just did my fork oil and put some 7w in there and it now rides like a dream. You feel more bumps, but it tracks much better in turns. I wouldn't do more than 7w, and I am 230 without gear.

 

I would think a 15w would be very harsh for almost any riding . .Depending on the last time you serviced the oil you may want to change it and go from there.

 

so the springs are what will keep it from diving so easily or maybe the valving?

 

The springs and oil work together. The springs support your ride/travel and the oil controls the speed of travel.

So your going down the road and hit a pot hole, it will take (stock)3/10 of a second for the wheel to hit the hole, go up than down and settle.

With lighter oil the wheel would go up/down faster but take longer to settle and cause the bike to wallow in a turn.

With heavy oil the wheel would not travel as far(up and down) and settle faster. Something must go up and down re leaving the same energy in every case. If the oil is to thick, the forks will run out of time and you and your arms will absorb what the forks could not.

I hope this make sense? It did in my head for a moment.


But to reply to your question, The springs are for the load and the oil is for control of the load.

Same as your car,ie you can remove your shocks and drive with little to no damping. But the springs support the car and without them you'd be on your tires.

 

sorry it took me so long but thanks for your answer vfrbenny