Front Preload

[Toast]

Ok, suspension question #hundy n something from me, but this one's pretty specific and shouldn't take too long.

I the interim 'til I get my front fok springs sussed, I checked out the Sport Rider recommended fork settings for me boik.

I've actually ended up softening the compression and rebound as per their recommendations by a small amount, but the wound the preload from 3 lines to 0, which translates to about a 12mm drop.

Took it for a short ride on the Whangaproa closed testing cicuit, and at 100km/ or less it felt pretty good, with less diving in the forks than before, and the front felt more planted with more weight on it.

Question is: Are there any downsides to upping the preload to this degree?

Also, with more weight forward, I take it you've gotta be more committed to the throttle and get weight on the back end again once in to a corner? I'm thinking that a front end slide would be more likely with this set up.

[Brian d marge]

Question is: Are there any downsides to upping the preload to this degree?

Yes you are adding energy into the spring so any chance the spring gets to re;ease this energy it will such as a bump in the road, then you will be asking the rebound to do extra work ...the energy added from the bump in compression PLUS the extra energy you adding into the spring .... so you rebound will be faster it will feel a bit kicky up front and over say ripples round a swee[er the front will eventually lose the plot and you will stand the bike up and have another go !

Also, with more weight forward, I take it you've gotta be more committed to the throttle and get weight on the back end again once in to a corner? I'm thinking that a front end slide would be more likely with this set up.

If the rear spring is to soft then the wieght transfer will to the rear will be more as the spine less spring stuggles to support you and the shift in cog

This will take the wieght of the front , the front will then tend to drift towards the outside of the curve and with it being a bit lively anyways ,, anytime the tyre aint touching the ground it will move towards the outside of the corner ,,, try doing a wheely while cranked over to see what i mean


Untill you get the springs dont worry about a thing, then with stiffer springs matched to your weight get the bike so it tracks the idea line round a corner...( with stiffer springs often people add a shim to the rebound shim stack to slow the shaft down due to the stiffer spring )


Stephen

[cowpoos]

those sports riders setting are a fuckin hav...you set your preload up to your weight and your weight only...

theres a good guide on this website...read it a few times http://www.gostar-racing.com/information/motorcycle_suspension_set-up.htm

[WINJA]

toast ,you need to set up your static sag and that will be about right for you ,you might wanna aim for about 30mm

[Toast]

Ok, cheers you guys. I just went and checked the front forks sag. With the pre-load wound right in, the measurements were:

Unladen length: 126mm
Normal length: 100mm
Laden length: 84mm

Making a static sag of 26mm; and
a rider sag of 42mm

(cheers for that link poos, it's real good, http://www.gostar-racing.com/information/motorcycle_suspension_set-up.htm)

According to the above link, that's in the ballpark for what it should be, so I'll try to find some time for a good, hard ride (definitely not SH16 on an Easter Monday), and we'll see how it feels.

[erik]

This page:
http://www.strappe.com/suspension.html

says to aim for about 30-35% laden sag for street use and 27-30% for the track.