Yamaha FZ-09 Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter · #1 ·
i know this is like the 101st thread about fork springs, but i couldn't find an answer with several searches.

i am 205 with gear
no track available
aggressive street riding on rough tight roads
will be installing a zx10r shock, not sure if i should use zx spring or fz spring (another question)

depending on the site i go to i get different answers...

should i use .90 or .95 springs up front?
and
should i use the zx spring or fz spring on shock?

riders of similar weight and situation please give me your input
 

·
Super Moderator
Joined
·
5,762 Posts
I'm right at 215 lbs with gear. I prefer a stiffer ride as opposed to a softer/mushier ride.... as long as the compression damping is set properly. Softer suspension lends itself to possible wallow in a corner when pushed hard, especially when trail braking into a corner on anything other than a smooth road surface. Having said all that, it really comes down to the type of roads you primarily ride, your body position on the bike, how aggressive you ride, and to some extent, even the tires you choose.... tires with softer or harder sidewalls and air pressures that work best for that tire. I know I didn't give you a definitive answer and say... This is the springs for you, but hopefully I did give you some information that will allow you to sort out some things and make a good/wise decision
 

·
Registered
Joined
·
153 Posts
First... great color choice :D

Now about the rear, my riding weight is just about 190 and with the ZX10 spring, I had to use almost all the preload to get the correct sag figures. so changing the spring may be the way to go here. I think the stock spring is just a bit firmer than the zx10 spring so that will do the trick nicely. My recommendation is always to go just firm enough with the spring an no further. In other words you should not have to max out preload to get decent sag. While we don't want a bike that dives excessively, you also don't want a bike where you use only 10-20% of suspension travel! Also consider that the zx10 damping is on the firm side.

Now for the front. I think the .90 spring would be best unless you are changing the damping in the forks at the same time. The heavier springs with the stock lack of any reasonable high speed compression damping would make riding bumpy roads uncomfortable. If you have upgraded damping in the front then let your preference guide. If you like a firmer ride, go with the heavier spring only, if you prefer a more compliant ride choose the lighter spring. I really don't think either option will have the bike wallowing or diving excessively with your weight.

Personally for my weight I'm glad I went with the .85 springs instead of the .90 My suspension is set up now so that in my most aggressive riding, I will use just about 80% of travel in front.

Hope this helps.
 

·
Registered
Joined
·
320 Posts
Either would probably be okay. When I used to weigh 205 I had a D675 with .90 up front and never had a problem. I'm now 230 and have .95 and they are a touch soft, but I'm in the process of losing weight. If your weight fluctuates or you have plans to change your weight, go with the one on the side you think you will be in the future. Some sites said 1.0 for me and some said .95, but I rounded down due to my weight loss goal.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #5 ·
Thanks for the advice. I especially like the idea of spring rates in relation to weight loss goals! Seriously , that makes for good rationalization for me. Need to loose my pregnancy weight (my wife kept feeding me)

Again, thanks guys. And anyone else with with input is welcome. I'm ordering springs in the next day or so
 

·
Registered
Joined
·
3,079 Posts
I'm 175 lbs w/o gears and use the .90 kg/mm. I'll go .95 kg/mm at a minimum... I would consider 1.0 kg/mm if you like to ride hard and trail brake. On the ZX-10 shock I use the 9.1 kg/mm and it's fine. I tested the 9.7 & 9.4 kg/mm but felt a bit stiff to me. I would keep the FZ09 OEM spring on the ZX-10 shock for you... that should be very close.

Other than that I agree with Triple.
 

·
Registered
Joined
·
464 Posts
I'm kind of in the same boat, I'm looking at sonic fork springs in the front and something else for my zx6r shock before I put it in, I like to ride aggressively on the street but I also ride two up with my gf. I'm 210 without any gear on so I was thinking of .95 in the front? But I have no idea what to get in the rear
 

·
Registered
Joined
·
673 Posts
i know this is like the 101st thread about fork springs, but i couldn't find an answer with several searches.

i am 205 with gear
no track available
aggressive street riding on rough tight roads
will be installing a zx10r shock, not sure if i should use zx spring or fz spring (another question)

depending on the site i go to i get different answers...

should i use .90 or .95 springs up front?
and
should i use the zx spring or fz spring on shock?

riders of similar weight and situation please give me your input
The real questions that can help you determine which rate to go with:

1. How old are you? If you're in your 20s, chances are you'll put on some weight. If you're in your 30s, you'll probably stay around the same weight.

2. Do you already have a girlfriend or wife? If not, expect to put on more weight in the future :D

Oddball questions, I know.. But could save you the trouble of changing springs in the future.

I myself went with the ZX10 shock and the guy I bought it from threw a 105 spring on there (for us heavier riders). I've got the 1.0kg springs up front and I'm 3 full turns of preload in (out of 11 I believe). I'm going to raise it to 4 turns soon, and sacrifice some compliance for reduced dive.

BTW, I'm 260lbs in gear.
 

·
Registered
Joined
·
2,580 Posts
I don't think adding more preload is the best way to reduce dive. I've done it on my vfr800 with 05 gsxr600 forks with too soft springs. It really doesn't work that well it just coils up so much energy in the spring to be released when you don't want it.
I'm maybe 240 in gear, so let's say 220 without.
I have .95 springs, and with .95, it gets my sag right. I had a suspension shop (trooper lu's, they are awesome) work the shim stack for me, it's a now a bit stiffer than something like the GP revalve kit is. 5wt oil, and only a 90mm oil gap. Which sounds too small, but is really good so far- although only 1200ks commuting so far, on my MT09 super commutard.

If it was me, I'd go .95 and then you wouldn't need very much pre load to get the sag right.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #10 ·
I'm 175 lbs w/o gears and use the .90 kg/mm. I'll go .95 kg/mm at a minimum... I would consider 1.0 kg/mm if you like to ride hard and trail brake. On the ZX-10 shock I use the 9.1 kg/mm and it's fine. I tested the 9.7 & 9.4 kg/mm but felt a bit stiff to me. I would keep the FZ09 OEM spring on the ZX-10 shock for you... that should be very close.

Other than that I agree with Triple.
thanks for the advice (all of you). Still on fence, don't the crappy roads I have lead me to the .90's?
Got in a big saggy bounce in a crappy turn tonight and sent me to the outside line, so I am so ready to fix it up, especially the rear.

and Marthy? is the zx 9.1 and the fz 9.7?

and ghengis, got the wife in my 30's, but i always vote to sacrifice the ride of two up for proper set up when I rail the machine alone.
 

·
Registered
Joined
·
226 Posts
For the forks, use both. If you're stuck between the .90 and .95 springs use one of each in each leg. Problem solved.
This is not unusual.
 
1 - 12 of 12 Posts
Top