Fork springs, sag, ground clearance - help me

So, I was participating in a 3 hr cornering clinic yesterday. Big parking lot for drills, ~30 mph max speed - 20-25 more typical in the larger radius drills.

My Set-up: '08 1300ABS, factory front end - nothing ever done to it. 24k miles. Previous owner to 21k was a big guy - guessing 250+. I properly refilled the rear preload adjuster (I'm surprised the tire wasn't rubbing the fender when he rode it - he had never touched it since new, and the damping was way too light). I set it up for about 32-34 mm rider sag (about 1 turn past the "standard" position - 7 turns I think). I usually add 1 turn preload to stiffen the rear a bit for these clinics. PR3s frt & rr inflated to 42 psi for class (normally run 40). My weight with full gear is about 203 lb. Top box was off, and cases had maybe 3# worth of pant liner and jacket liner, and a water bottle.

With neutral seating position, I was routinely dragging the peg buttons during the drills. If I got off on the inside some, I could gain a little clearance, but usually end up touching the buttons but with a little more roll-on.

After the class was done, I looked at the chicken strips and was seeing about 3/8" front and rear. Yet, peg buttons are no doubt dragging.

I didn't feel like I was running a bunch of lean angle, a la road racers, but I don't really sense that any more - level eyes out at turn exit or beyond and the sense of lean sort of goes away - my experience anyway.

This 3/8" chicken strips and peg buttons dragging does not seem to add up...but this is new to me with the ST. The only unknown is front sag which I have not yet tried to measure.

Any guidance on a good number for rider sag - I've seen 35-38 mm suggested in other posts. I'm wondering if the factory front springs have taken some set and I have excess sag on the front right off the bat (or possibly spring rate has softened). I'm not opposed to a new set of springs, but no need for my normal riding if the suspension height is good. If I recall from the FOM, I think you can shim the factory springs to set the preload - if it needs help, that could be a start. If the spring rate is a bit low, adding a bit extra fork oil can help that.

Any guidance some of you experts on ST suspension can provide - appreciated in advance.

~~~~
Also, I hear it is likely helpful to go with lower viscosity oil to reduce what is claimed to be over-damped front end. It does feel a little harsh on rougher surfaces in normal riding. I'll have to try the zip-ties around the fork tubes to check max compression and see where that is I guess.

Thanks. Also, check my post concerning windshield selection to reduce rider & passenger turbulence. It is horribly noisy in my Shoei RF-1100 unless I duck behind the OEM windscreen (set at any height) and look through it. Need help there to make wife (and me) happy so she will take some road trips with me.

Since everyone's weight is different, riding style is different, handling expectations are different, there's no magic numbers. If you're running out of ground clearance, increasing preload front and rear to raise the ride height is one option, hanging off is another. Increasing preload tends to stiffen the ride as well, and I don't think the 1300 has the suspension adjustments like a typical sportbike to easily dial that out, so you'd have to experiment with fork oil or just live with it. Also, are the peg buttons removable, if so take them off, if not grind them down or cut them off. Bottom line is its not a sportbike, so there's only so much you're going to do if you're an aggressive rider.

dwalby said:

Since everyone's weight is different, riding style is different, handling expectations are different, there's no magic numbers. If you're running out of ground clearance, increasing preload front and rear to raise the ride height is one option, hanging off is another. Increasing preload tends to stiffen the ride as well, and I don't think the 1300 has the suspension adjustments like a typical sportbike to easily dial that out, so you'd have to experiment with fork oil or just live with it. Also, are the peg buttons removable, if so take them off, if not grind them down or cut them off. Bottom line is its not a sportbike, so there's only so much you're going to do if you're an aggressive rider.

Click to expand...

I would not call myself an aggressive rider. The peg buttons touching doesn't really bother me - they just let me know not to push much farther. It just didn't seem to add up that what I was doing in these class drills was to the point the buttons were dragging, but yet I was still so far from running out to the edge of the tread on the PR3s. Just thought someone with more ST13 experience than myself - possibly with the same tire set-up - could comment. As is, suspension is OEM, so no front adjustments short of spring change, oil visc. and level change, or go to adjustable valving for fine-tuning damping. The rear is OEM, with preload and damping set as I stated. Thought somebody could give me insight on whether I should be going into the front end at this time, or just improving my cornering body position and peg loading skills.

I replaced my fork springs with Race Tech springs. I ordered .9 which are slightly stiffer than the stock and used 10 weight oil. My local Honda shop (South Sound Honda, Olympia) did the expert work and the difference is amazing. I no longer pitch forward on a hard stop and can handle dips and bumps much better. The entire ride experience seems better, and because of the better front springs I eased up the back compression preload. The stock springs are not worth trying to fix. I did not use the Race tech valves; I followed the advice on this site of many riders simply happy with the better springs and 10 wt. oil.

Are you looking to do this ? -- This is his first competition on a st1300 -- Pm me and I can give you some help

http://bayarearidersforum.com/forums/showthread.php?t=455715

The ST1300 is sprung for riders under 160 lbs. I'm guessing you weigh about 175 - 180 in your skivvies? With the stock fork springs rider sag at your weight is close to 50 mm when it should ideally be around 30-36 mm. You could replace the stock spring with something in the .9 to .95 kg/mm range and get 15 to 20 mm more ride height with the proper spacers. With the increase in ride height in front you would want to add rear preload to set sag between 26 and 28 mm to preserve steering characteristics. Just raising the front by itself will slow the steering. The stock spring is .86 and too soft for your weight. Really, so is the rear for anything but the ideal <160 lb rider that never rides two up. Increasing preload only raises ride height when done in the normal range of increase. It does not change spring rate or stiffen the spring.

I pretty much mirrored your first post the first couple years I owned my ST1300. I used to drag pegs alot, even fairing and centerstand. I took an instructed track day and a Lee Parks Total Control course and improved my cornering skills then set up my fork to 36 mm sag and 28 mm rear. I'm 150-152 in the shower and right at the top end of the stock spring rates. I never touch anything metal down anymore.

A note on fork oil. Light lubricants do not measure or quantify well under SAE weight. A 5 wt oil of one brand may act thicker than another brand's 10 wt. The only way to compare changes in weight is to stay within a brand or else know all of the centistoke numbers of the oils in comparison. Just because other riders like "10 wt" doesn't mean the different brand 10 wt oil you put in your forks will perform the same. Honda uses SS-8 in the 1300 and denotes it as a 10 wt oil. Personally I blend their 5 wt SS-7 two to one with SS-8 and like that result.

A fork oil comparison chart and lots of info is here: http://www.peterverdone.com/wiki/index.php?title=Suspension_Fluid

A spring rate calculator is here:http://racetech.com/VehicleSearch

Good luck in your quest. There are a lot of riders here that have done a little or done a lot with their suspensions.

I put the Sonic springs and oil in mine a couple of years ago....huge difference....no front dive and sag is good.......any good brand of fork spring is a huge improvement...for like a $100............good luck..............ff..........BTW, really narrow chicken strips and RARELY drag a peg...............

Its all about how much money you want to spend