The current wing has a seat height noticeably lower than my lowered ST. I was surprised.
let's ignore the softer or shorter springs option for now, I was looking at this from the perspective of putting in a shorter preload spacer with the stock spring. That will lower the ride height, which was his goal. As long as the spacer provides some spring compression with no weight on the fork, if the fork needs to extend there is spring tension, so I'm not seeing the free-fall possibility you mention. Or is there a point where if you don't have enough spacer preload the extension force from the spring is just too weak to be practical, and that's why you want the longer top-out spring?You quoted the correct part of my post "to reduce the travel". That is what spacers or longer top-out springs will accomplish, where I would define travel as the full range of fork movement from topped out to fully compressed. The spacers also "shorten the fork" which is what the PO was seeking.
Reducing the preload on the main spring or changing the spring length will change the ride height. It depends what you want to achieve. Just putting softer or shorter springs will change the ride height but would not be my choice for control as there will be a point after an extension (e.g. riding across a dip) where the fork will be in free-fall with little or no spring to absorb chassis energy. Using a top-out spacer keeps the fork under control throughout the full range of movement, and allows the use of a correct spring rate to keep the static ride height at around 1/3-1/4 of the full travel.
Yeah, what you say makes sense in that context, but I think you misread the original post. He has the stock forks raised 3/4" in the triple clamp, presumably with stock spacers since he didn't specify he had modified anything internal to the forks, yet. He was asking about options for 1" of additional lowering. So I'm thinking just shortening the stock spacer by 1" would get him the extra inch of lowering, but would still apply some preload to the stock spring, and should not cause the situation you describe. Mine hasn't been stock for 20 years so I forgot what the stock measurements were. I seem to recall it had more than an inch of preload, but can't say for sure.If I read correctly the OP had already lowered the bike by an inch and was looking for lots more. Normal preload for a straight-rate spring would be around 15mm, so to lower the fork by 3 times that would mean running a spacer 30mm shorter than the gap between the spring and the fork cap. If you have a preload spacer that puts no tension on the spring then unless the spring rate is significantly increased you would run the risk of excessive bottoming under load because the spring would be significantly less compressed than normal at the point the fork tube hits the bottoming stops. In my view you are better off keeping or slightly increasing the spring rate, and limiting the full extension of the fork with changes to the top-out limits. This keeps the fork sitting at the preferred sag range to deal with dips while keeping the wheel in contact with the road at all times.
Dig out the old platform shoes !Just get thicker boots?
I spoke to the nice folks at Traxxion, and they could do the job for $500. I'm not sure what all that includes. The problem is that I would have to separate the forks from the bike and ship to them, or take the bike to Atlanta.
I have a pretty good independent mechanic locally who used to work for a dealer.
Lowering the bike evenly doesn't change the geometry. He lowered the rear which slows handling. In lowering the front (less than the rear was lowered) he's returned the geometry closer to factory. It looks like he wants to lower it a little more to even it out which should make the handling pretty much the same as stock except lowering the cg this —><— much and any changes in fork/road compliance.RobbieAG said:If you're changing the whole geometry of the bike by lowering it
back in the mid-80s I messed around with a KZ1000 I owned at the time, brought some tools along on a long weekend trip and experimented with dropping the forks various amounts in the triple clamp to see what effect it would have on the handling. I seem to remember being around San Simeon on the coast highway and dropping the tubes about 3-4" just to see what would happen. I didn't leave it like that for long (didn't want to bash the fender into the lower triple clamp), and I don't remember it having any real negative effect on the stability, but I didn't take it up to triple-digits either. I'm guessing the sportbikes I owned later came with steeper fork rake from the factory than what I had created by dropping the tubes that far, and they were all very stable at high speed. My guess is if you start with a 700lb bike, with a long wheelbase and rake angle of the ST, you're not going to make it twitchy no matter what you do.Lowering the front of the bike more that the rear would give me pause mainly because I don't know what I'm doing. This would make the bike handle quicker and twitchy to some riders. I've always thought this lessened higher-speed stability.
That was pretty much my intention (except cutting the spacer) until I ran into trouble disabling the anti-dive. Once I decided to send the forks in, it made sense to have them rebuilt because the bike has 57k miles on it and had original seals and bushings. They would probably need to be done before long anyway. Once I was there, it was only another $150 to have them revalved, so that's what I did.Robbie, I'd like to get some aftermarket straight springs, cut a spacer in each fork 1 inch, refill with standard fork oil and call it a day.
The first thing to consider is aftermarket springs aren't necessarily the same overall length as the stock ones, so they often require different spacers anyway. You need to take that into consideration before getting started if you change springs, you'll need to recompute the sag numbers with the new spring rate and spacer combination. And, for comparison you'll need to know the stock sag values. If you keep the stock springs and just go with 1" shorter spacers there's nothing to compute. I think that would be possible given the stock spacer lengths, but I can't say for sure.I could get Sonic middle of the road firmness springs, and not disable the and dive, not revalve, put standard 7.5 weight oil back in, and cut the spacers 1 inch.
In the schematic I clearly see spacer I could cut on one side, but the other is more difficult to see. Would I be able to cut/remove an inch of spacers on both sides based on your experience?
yes, TerryS already mentioned that a week ago, and you quoted it.As I try to think this through, if I have the springs lowered 1 inch, wouldn't it be impossible to also push the fork tubes up in the triple trees 3/4 inch because the top of the fender would hit the bottom of the triple tree?
What am I missing?
hard to say for sure, you'd need to measure it. One way would be to remove the fork cap and compress the fork with no spring, and see how far it can travel upwards. That may be a little pessimistic though, it may be that the spring coil binds before the slider actually bottoms out, and limits upward movement (I suspect that's not the case, but thought I'd mention it anyway as a possibility). To measure that you'd need something capable of compressing the fork fully with the spring installed, which is not very practical, so the first measurement is probably the only one you're going to be able to perform. The next question is even though the fork tube can theoretically travel that far, will you ever encounter that much force while riding. Its a crapshoot, and depends on how concerned you are if the fender hits the triple clamp occasionally.If I lower the forks internally by 1 inch by removing or shortening a spacer, can I still raise the forks in the TT, and if I can, by how much?