Suspension Set-Up Help Wanted

[Guest ratchethack]

. . . I've now done a zip tie test and even under the most aggressive braking I'm game to attempt there's 22mm of leg exposed. While the internal bump stops are obviously set to prevent the base castings getting into the stanchions, I'm clearly some way from bottoming. Be interesting to check what distance, springs aside, represents absolute full bump ? So no question, the springs are too stiff ....

Mick, IMHO y'er on the right track. If y'er not motivated at this point to change-out springs, at least you can improve wot you've got to work with by getting laden sag in a more optimum range. While this will not solve the core problem of matching spring rate to load, and the laden and unladen sags will still be out of range, by decreasing preload, at least you'll be getting more effective travel out of the fork. When I set up my fork with more optimally-rated Wilbers springs, by adjusting preload, fork height, and setting air gap, I was able to achieve an effective ~115mm fork travel by howling the front tire whilst braking as hard as I dared over a square-edged pothole and a speed bump to get the fork to go this far. I reckon this is close to ideal for general purpose road work. According to y'er measurement, y'er getting an available 98 mm fork travel now, which you'll improve slightly to over 100 mm by decreasing preload. It'll still be harsh for general purpose road work, IMHO. I'd expect the bulk of the benefit in handling to be quicker turn-in, as you'll be decreasing the effective rake slightly.

 

BTW - I just made a correction to my prev. post, which you probably caught immediately. Chalk it up to working from memory, "topsoil erosion", and "Old Timer's" dain bramage. When setting the air gap, as mentioned, the fork needs to be blocked up as far as it will go with springs out. This puts the scrapers against the lower fork castings on this fork, not against the triple clamp! Too many conventional damper-rod forks over the years. . . Occasionally stuff starts to run together. . . . .

 

Sorry for any confusion.

 

Good luck!

[richard100t]

Its coming time to replace my fork oil again this spring. I am interested in getting the stiffer springs & whatever other components are needed to improve my ride. I weigh about 165lbs without the riding gear, so figure 180ish. Can someone tell me who to buy from & what spring I need for my weight? Oh & if you can tell me about what it should cost for the parts I'd be grateful.

[dlaing]

According to y'er measurement, y'er getting an available 98 mm fork travel now, which you'll improve slightly to over 100 mm by decreasing preload.

I am running a fever right now so my interpretation might not be accurate, but I am pretty sure you got that backward.

Increasing preload increases travel, atleast in the bottoming out direction. In the topping out direction adding preload will lose travel.

98 or 100mm would be a measurement of bottoming out travel.

Total travel remains unchanged, unless the springs bind, which is unlikely.

[Guest ratchethack]

I am running a fever right now so my interpretation might not be accurate, but I am pretty sure you got that backward.

Increasing preload increases travel, atleast in the bottoming out direction. In the topping out direction adding preload will lose travel.

98 or 100mm would be a measurement of bottoming out travel.

Total travel remains unchanged, unless the springs bind, which is unlikely.

Hope you recover soon, Dave. Then take another swag at it. You are incorrect.

[Guest ratchethack]

. . . Be interesting to check what distance, springs aside, represents absolute full bump ?

Mick, max available fork travel is 120 mm. You can easily determine this for yourself by taking the springs out and moving the fork through its full range of travel while it's on the stand. The fork scrapers will contact the lower fork castings at full bottom-out. Considering the length of the stock springs, this is long before they coil-bind. I presume there's an internal "hard" stop at (or very near) that point, but this doesn't much matter. The fork is designed so the air spring rises up exponentially at the end of travel (see Pete Verdone's graph borrowed from Honda at the link above), virtually eliminating any concern over hard metal-to-metal (or metal to scraper) contact. The only way you'd ever have a possibility of a "hard" bottom-out is by blowing the fork seals and completely losing air spring pressure, and I reckon this would mean you've impacted y'er Guzzi against an inanimate object on, or possibly off, the road hard enough where there'd likely be other things of higher priority concern than y'er fork. . . .

[dlaing]

Hope you recover soon, Dave. Then take another swag at it. You are incorrect.

You still seem incorrect to me.

Even thought the fever is down, I guess I better stay home from work

[Guest ratchethack]

Its coming time to replace my fork oil again this spring. I am interested in getting the stiffer springs & whatever other components are needed to improve my ride. I weigh about 165lbs without the riding gear, so figure 180ish. Can someone tell me who to buy from & what spring I need for my weight? Oh & if you can tell me about what it should cost for the parts I'd be grateful.

Richard, you & I weigh about the same. Depending on the following, I may have an idea, or possibly even a recommendation and some specifics.

 

1. What are your laden and unladen sag measurements?

 

2. What improvements in ride are you looking to accomplish? Are you thinking of fork and shock springs, or just fork, or one then maybe the other at a later point?

 

3. Are you an aggressive rider wanting to set up 100% for pushing hard in demanding conditions, or looking for handling & comfort over the long haul, or are you somewhere in between?