F4i - Main Forum Main F4i discussion board

Rear Spring Rate

Thread Tools
 
Search this Thread
 
  #1  
Old 02-07-2008, 03:25 PM
xtremef4i's Avatar
Senior Member
Thread Starter
Join Date: Nov 2006
Location: Tipp City, OH
Posts: 477
Likes: 0
Received 0 Likes on 0 Posts
Default Rear Spring Rate

I am wanting to replace my rear spring to one set up for my weight. I am 170-175 and do only street riding (both cruising and agressive). I like to do a lot of twisties. I notice a lot of people running a 16 kg spring and wondered how I know what spring rate I would need. What weight is a 16 kg set up for? Help me decide if I should stay with the stock spring or upgrade.
 
  #2  
Old 02-07-2008, 03:53 PM
charlos's Avatar
Senior Member
Join Date: May 2006
Location:
Posts: 245
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Rear Spring Rate

http://www.racetech.com/evalving/eng...ngname=english

there's a calculator here that has the stock spring rate and race tech's recommendation for a spring rate.
 
  #3  
Old 02-07-2008, 03:58 PM
devlzluv's Avatar
Senior Member
Join Date: Dec 2006
Location:
Posts: 597
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Rear Spring Rate

lol i weigh 250, me and my friend tuned the suspension for my weight with the stock spring and she handles quiet well. we did this cuz i dont have the money to upgrade as of yet but the stocker should suit u just fine. i run mine at the track and havent had any prob with it, track as in road track not drag
 
  #4  
Old 02-08-2008, 02:22 AM
kukku's Avatar
Senior Member
Join Date: Sep 2007
Location: Malta - Europe
Posts: 202
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Rear Spring Rate

Interesting read. According to the racetech's link, my weight is just about right for the stock spring at 165 lbs. However, I ride a lot with my wife as pillion which adds another 104 lbs. How do you tune for both instances? Does this mean that I should be lookingat upgrading the spring?
 
  #5  
Old 02-08-2008, 07:04 AM
xtremef4i's Avatar
Senior Member
Thread Starter
Join Date: Nov 2006
Location: Tipp City, OH
Posts: 477
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Rear Spring Rate

ORIGINAL: kukku

Does this mean that I should be lookingat upgrading the spring?
I would not worry about replacing the spring unless you ride a passenger all the time. you should be fine with stock

After looking at RaceTech's link I gues there is no real need for me to replace the factory spring. Not to mention the rougher ride on the street
 
  #6  
Old 02-08-2008, 11:02 AM
charlos's Avatar
Senior Member
Join Date: May 2006
Location:
Posts: 245
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Rear Spring Rate

yeah, i believe honda oversprings the rear in anticipation of some 2-up riding. but iirc the fork springs are way too soft.


 
  #7  
Old 02-08-2008, 10:24 PM
Jaybird180's Avatar
Senior Member
Join Date: May 2006
Location: Prince George's County, MD
Posts: 3,477
Received 2 Likes on 2 Posts
Default RE: Rear Spring Rate

That's what preload is for. There are 7 preload settings on the stock shock. Factory value is 3. When I had my stocker 3 was too soft for me and had my rear end sagged down (I saw an old pic of me riding). I bumped preload to 6 and it healed that condition but I lost a bit of feel.
I'm 213 in street clothes.
 
  #8  
Old 02-10-2008, 12:57 PM
charlos's Avatar
Senior Member
Join Date: May 2006
Location:
Posts: 245
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Rear Spring Rate

ORIGINAL: Jaybird180

That's what preload is for. There are 7 preload settings on the stock shock. Factory value is 3. When I had my stocker 3 was too soft for me and had my rear end sagged down (I saw an old pic of me riding). I bumped preload to 6 and it healed that condition but I lost a bit of feel.
I'm 213 in street clothes.
preload will change the sag settings, but it doesn't change the rate of the spring (unless it's progressive, and it might be, but even then it just changes the progressive characteristics of the spring.). a 16kg/mm spring will compress 1mm for every 16kg of load, regardless of the preload setting. but the preload setting determines the baseline for which the spring will actually start working--as in, if the spring is preloaded 5mm, the spring will not compress until there is 5*16kg or 80 kg on the bike. after there is, it will still compress at its rate. in the end, proper sag is VERY important, but if the spring is the wrong rate (too soft or hard), then sag settings won't correct that condition.
 
  #9  
Old 02-10-2008, 01:05 PM
devlzluv's Avatar
Senior Member
Join Date: Dec 2006
Location:
Posts: 597
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Rear Spring Rate

ORIGINAL: charlos

ORIGINAL: Jaybird180

That's what preload is for. There are 7 preload settings on the stock shock. Factory value is 3. When I had my stocker 3 was too soft for me and had my rear end sagged down (I saw an old pic of me riding). I bumped preload to 6 and it healed that condition but I lost a bit of feel.
I'm 213 in street clothes.
preload will change the sag settings, but it doesn't change the rate of the spring (unless it's progressive, and it might be, but even then it just changes the progressive characteristics of the spring.). a 16kg/mm spring will compress 1mm for every 16kg of load, regardless of the preload setting. but the preload setting determines the baseline for which the spring will actually start working--as in, if the spring is preloaded 5mm, the spring will not compress until there is 5*16kg or 80 kg on the bike. after there is, it will still compress at its rate. in the end, proper sag is VERY important, but if the spring is the wrong rate (too soft or hard), then sag settings won't correct that condition.
i totally agree, he really needs to get one of his friends to help him set the sag and get the suspension tuned then see if he needs one. i know he doesnt cuz me and my boy set my bike up and i weigh 250 and it feels damn good when i take her to the, not saying ya if i had the money i would love to get a total suspension overhaul
 
  #10  
Old 02-10-2008, 03:15 PM
Jaybird180's Avatar
Senior Member
Join Date: May 2006
Location: Prince George's County, MD
Posts: 3,477
Received 2 Likes on 2 Posts
Default RE: Rear Spring Rate

I can assure you that at 250 lbs it is highly compromised.

Someone can check but IIRC the stock springs are progressive. I don't have my stocker anymore so I can't be sure.
 


Quick Reply: Rear Spring Rate



All times are GMT -5. The time now is 06:47 PM.