So I installed Ikon progressive fork springs at the very end of last riding season and followed Ikon's instructions - which meant I put in the recommended amount of 10w fork oil and a 12mm spacer. At the time it felt far too stiff to me so I removed the spacer and immediately realized that was not going to work. So I thought maybe I might be overdamped and removed 10mL of oil from each fork and put the spacers back in. That was far worse - the front end would bounce after every bump. I wasn't taking a very scientific approach, and was irritated that I couldn't adjust the preload, but I was getting the idea that the front end was *UNDERDAMPED*, not overdamped. I thought maybe it might be oversprung as well, and since my fork caps weren't in the best shape anyway, got a set of Thruxton adjustable preload caps (and washers) today.
So with the new adjustable preload caps in hand I thought I'd add 30 mL of oil back to each fork; figuring that I may need more damping than I can get with 10W oil in any quantity, I got 15W, under the idea that for my initial addition it won't hurt to use a little bit of different-weight oil.
I was surprised to find out that the Thruxton adjustable-preload caps have a *MINIMUM* preload equivalent to about a 13mm spacer on our Bonneville caps - clearly an indicator that I was not oversprung before.
Anyway, I added 30 mL of 15W oil to the existing (roughly 460mL, IIRC) 10W oil and put the adjustable-preload caps on at their lowest setting and took off for a test ride.
It feels substantially better - surprisingly to me (and clearly I don't understand the way preload and damping affect each other), it actually feels *less* sprung even though it's slightly *higher* preload, and so the initial attack on bumps is smoother and there's no hop afterward. The initial attack is still a bit more unsettling to the bike's geometry than I'd like though.
I turned up the preload two turns and took another ride and noticed that the initial attack feels better at this setting but that the hop returns. So I'm assuming that means I need more damping so I can set the higher preload without getting the after-hop, right? Am I beginning to understand this? If I add more damping (i.e., more or heavier oil) I can have more preload which should allow for a smoother ride until it exceeds the springs' capacity, right?
Anyway, assuming I'm right that at this point I need more damping still, I gather that I'm best to remove some of the existing 10W oil and replace it with 15W rather than adding even more oil to the forks, right? I weigh about 210 lbs (I'm 6'2" and I know that doesn't matter but if I mention the weight I have to say it!) and so I hadn't assumed I'd need 15W oil back when I added the springs, but now I'm thinking I do. Opinions?
I'm finding the front shocks harder to dial in than I'd expected. But these Thruxton caps are fabulous, and I am already seeing that tuning the suspension will be *much* easier with fine, precise control over preload...
So with the new adjustable preload caps in hand I thought I'd add 30 mL of oil back to each fork; figuring that I may need more damping than I can get with 10W oil in any quantity, I got 15W, under the idea that for my initial addition it won't hurt to use a little bit of different-weight oil.
I was surprised to find out that the Thruxton adjustable-preload caps have a *MINIMUM* preload equivalent to about a 13mm spacer on our Bonneville caps - clearly an indicator that I was not oversprung before.
Anyway, I added 30 mL of 15W oil to the existing (roughly 460mL, IIRC) 10W oil and put the adjustable-preload caps on at their lowest setting and took off for a test ride.
It feels substantially better - surprisingly to me (and clearly I don't understand the way preload and damping affect each other), it actually feels *less* sprung even though it's slightly *higher* preload, and so the initial attack on bumps is smoother and there's no hop afterward. The initial attack is still a bit more unsettling to the bike's geometry than I'd like though.
I turned up the preload two turns and took another ride and noticed that the initial attack feels better at this setting but that the hop returns. So I'm assuming that means I need more damping so I can set the higher preload without getting the after-hop, right? Am I beginning to understand this? If I add more damping (i.e., more or heavier oil) I can have more preload which should allow for a smoother ride until it exceeds the springs' capacity, right?
Anyway, assuming I'm right that at this point I need more damping still, I gather that I'm best to remove some of the existing 10W oil and replace it with 15W rather than adding even more oil to the forks, right? I weigh about 210 lbs (I'm 6'2" and I know that doesn't matter but if I mention the weight I have to say it!) and so I hadn't assumed I'd need 15W oil back when I added the springs, but now I'm thinking I do. Opinions?
I'm finding the front shocks harder to dial in than I'd expected. But these Thruxton caps are fabulous, and I am already seeing that tuning the suspension will be *much* easier with fine, precise control over preload...