International Full Size Jeep Association
Home Forums Reader's Rigs Tech Library Trail Stories FSJ-List
International Full Size Jeep Association  

Go Back   International Full Size Jeep Association > Tire Kickin' > General FSJ Tech

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 03-24-2009, 01:49 PM
JERSEY JOE's Avatar
JERSEY JOE JERSEY JOE is offline
Master Mechanic
 
Join Date: Jan 15, 2004
Location: KEARNY, NEW JERSEY
Posts: 1,358
LEAF SPRING TECH

OK I have this 1987 J-20 project and I want to start thinking about a leaf spring swap. As we all know the stock springs make it ride like a lumber wagon. I am not looking to make it ride like my 2008 F-150 FX 4 and I don't need the ability to carry a total GVW of 8600 either. I will have a class 3 trailer hitch and I would like the flexibility of being able to tow my trailer and CJ 7 on it without the nose it the air stance. It's funny, when I load the CJ 7 on the trailer with my F-150 the truck stays nearly level and it still rides great while empty. HOW IS THAT DONE? Progressive rate springs?

My options:

1. new front and rear J-10 spec springs with extra rear leaves

2. current J-20 springs with reduced spring pack

3. something else
__________________
1977 CJ 7 360 T-18 IHC D300 FARM TRUCK NY
1985 CJ 7 AMC 401, CLARK 285SV 5 SPEED, DANA 60, DANA 44, RUBICON 4.5 LIFT. 37 KRAWLERS
1987 J-20 401 90% COMPLETED.
1985 J-20 360 6 inch lift, 37's plow truck
1986 J-20 360 stock well rusted plow truck
1970 AMX CURRENT PROJECT
Reply With Quote
  #2  
Old 03-24-2009, 07:27 PM
Tornado230's Avatar
Tornado230 Tornado230 is offline
Master Mechanic
 
Join Date: Sep 14, 2008
Location: Fleetwood, PA
Posts: 1,475
Joe,
Don't know what they did, but the '77 J-20 rides better than the '82 J-10.
Take a look at the springs when you get in the neighborhood.
Reply With Quote
  #3  
Old 03-24-2009, 08:57 PM
JERSEY JOE's Avatar
JERSEY JOE JERSEY JOE is offline
Master Mechanic
 
Join Date: Jan 15, 2004
Location: KEARNY, NEW JERSEY
Posts: 1,358
SPRINGS

ANYONE???
__________________
1977 CJ 7 360 T-18 IHC D300 FARM TRUCK NY
1985 CJ 7 AMC 401, CLARK 285SV 5 SPEED, DANA 60, DANA 44, RUBICON 4.5 LIFT. 37 KRAWLERS
1987 J-20 401 90% COMPLETED.
1985 J-20 360 6 inch lift, 37's plow truck
1986 J-20 360 stock well rusted plow truck
1970 AMX CURRENT PROJECT
Reply With Quote
  #4  
Old 03-24-2009, 09:03 PM
DAHoyle's Avatar
DAHoyle DAHoyle is offline
Master Mechanic
 
Join Date: Nov 25, 2005
Location: Colorado
Posts: 1,000
Well, if your F150 handles it without the nose up in the air, chances are that the Jeep will as well. There is a lot more to towing than your leaves. How balanced is the trailer. If you don't have a lot of tongue weight, then the truck won't squat. That is the key. Get the load balanced, with about 500 lbs on the hitch, and you will never have a lot of squat in the rear end. Ideally, you want your tongue weight to be 10 to 20% of the total trailer weight, unless you are pulling a gooseneck.

Doug
__________________
67 M715
Cummins 4BT/Allison 54/Ford203/Ford205,
Front 89 HP60/Rear 81 GM D70HD
Discs all around/ 12 bolt H1 Rims
Build still very much in progress


78 Levi edition Honcho 360/T18/D20


Reply With Quote
  #5  
Old 03-25-2009, 05:56 AM
JERSEY JOE's Avatar
JERSEY JOE JERSEY JOE is offline
Master Mechanic
 
Join Date: Jan 15, 2004
Location: KEARNY, NEW JERSEY
Posts: 1,358
TRAILER LOADING

Doug I have not measured the tongue but I always had the CJ in the same place on the trailer. When I decided on the spot I drove the CJ on until the bed of the truck dropped a little bit. I have an equalizing hitch and the setup does not sway at 70 mph.

Anyone have a suggestion on springs?
__________________
1977 CJ 7 360 T-18 IHC D300 FARM TRUCK NY
1985 CJ 7 AMC 401, CLARK 285SV 5 SPEED, DANA 60, DANA 44, RUBICON 4.5 LIFT. 37 KRAWLERS
1987 J-20 401 90% COMPLETED.
1985 J-20 360 6 inch lift, 37's plow truck
1986 J-20 360 stock well rusted plow truck
1970 AMX CURRENT PROJECT
Reply With Quote
  #6  
Old 03-25-2009, 07:48 AM
billyrb's Avatar
billyrb billyrb is offline
BJ's Off-Road
 
Join Date: Aug 15, 2001
Location: Acworth, GA 30101
Posts: 10,067
the best thing you can do is buy a new suspension, then use air-bags for when you tow heavier loads. This takes the added weight off the springs and puts it on the bags. That way, you have the best of both worlds: nice comfy suspension for regular duty, and bags to handle the heavy towing.
__________________
BJ's Off-Road
ryan@bjsoffroad.com
Your source for '63-'91 FSJ Parts
Reply With Quote
  #7  
Old 03-25-2009, 09:34 AM
DAHoyle's Avatar
DAHoyle DAHoyle is offline
Master Mechanic
 
Join Date: Nov 25, 2005
Location: Colorado
Posts: 1,000
Well, it seems that you want to have your cake and eat it too.

You need to decide what is more important to you. Towing ability, or ride quality.

There are no magic springs. If it was me, I would run a quality springpack like a Deaver, and tell them what you want.

Leaf springs react to weight, period. Put X amount of weight on the spring, and it is going to deflect Y amount. It is all based on the spring rate. Nothing surprising about that. Go with a soft spring, and it will settle more for a given load than a stiffer spring. As billyrb pointed out, the only way to get around that is with some sort of adjustable helper, such as air bags. The two choices you offer really don't mean anything, without knowing the spring rate you are going for. What's to say that a J-10 spring with extra leaves isn't as stiff or stiffer than J-20 springs. The reverse is also true. Take J-20 springs and pull a few out, and you may actually have something softer than the J-10 springs.

Guess what I'm saying is that you need to decide on a spring rate, and shoot for it. If you think you want something midway between a J-10 and J-20, then find out what their respective spring rates are, and you have your answer. I'm sure the information is out there.

Nobody will be able to give you a good idea what you want, until you offer a bit of clarification.

Doug
__________________
67 M715
Cummins 4BT/Allison 54/Ford203/Ford205,
Front 89 HP60/Rear 81 GM D70HD
Discs all around/ 12 bolt H1 Rims
Build still very much in progress


78 Levi edition Honcho 360/T18/D20


Reply With Quote
  #8  
Old 03-25-2009, 11:32 AM
JERSEY JOE's Avatar
JERSEY JOE JERSEY JOE is offline
Master Mechanic
 
Join Date: Jan 15, 2004
Location: KEARNY, NEW JERSEY
Posts: 1,358
SPRINGS

Thanks Doug and Billyrb for the reply. I guess my question then is should I just buy a new set of J-10 springs and add one extra rear leaf as well as some type of adjustable overload ( air bag ) and call it a day.

Are new J-10 springs available off the shelf or do they need to be custom made? You mentioned Deaver. Are they a spring company?

Once again thanks for the help
__________________
1977 CJ 7 360 T-18 IHC D300 FARM TRUCK NY
1985 CJ 7 AMC 401, CLARK 285SV 5 SPEED, DANA 60, DANA 44, RUBICON 4.5 LIFT. 37 KRAWLERS
1987 J-20 401 90% COMPLETED.
1985 J-20 360 6 inch lift, 37's plow truck
1986 J-20 360 stock well rusted plow truck
1970 AMX CURRENT PROJECT
Reply With Quote
  #9  
Old 03-25-2009, 12:17 PM
red mistress's Avatar
red mistress red mistress is offline
Bleedin' Gasoline
 
Join Date: Sep 13, 2007
Location: TX
Posts: 2,268
spring company's

some of the major's:

Deaver
National Spring
Alcan

They have the technology to build "progressive" spring rates.
They have specs on your truck and U can tell them what you want.

I may go the custom spring route + air bags for when loaded.


Also - Good idea on trying the J10 springs then add a leaf if needed.
__________________
67 Gladiator 15K J3000 AMC 327, PTO, 35" BFG's
69 Jeepster 8701 convertible
82 CJ-8 75K org SR decals
82 Cheroeke Laredo 24K
83 CJ-8 50K 401, ARB60's, F&R Winch, 38"
84 CJ-7 38K Garnet Int., Jeep 8274 winch
87 J 20 36K smooth alum camper & boat rack.
Reply With Quote
  #10  
Old 03-25-2009, 12:27 PM
Grantshire's Avatar
Grantshire Grantshire is offline
Master Mechanic
 
Join Date: Oct 16, 2002
Location: Richmond, VA
Posts: 826
Stock springs with air bags is the way to go. I use them on my Suburban to level the load since I have everything from fourwheelers to an M715 on my trailer. Mine have a in-cab air pump and gauge so I can adjust on the fly.
__________________
Richard

62 Willys SW
66 CJ6
67 M715
69 C101 Commando
74 Wagoneer Custom
79 WT Cherokee Chief
81 Scrambler
86 CJ10A
Reply With Quote
  #11  
Old 03-25-2009, 12:47 PM
JERSEY JOE's Avatar
JERSEY JOE JERSEY JOE is offline
Master Mechanic
 
Join Date: Jan 15, 2004
Location: KEARNY, NEW JERSEY
Posts: 1,358
SPRINGS

Rich that's the way I would go with the onboard compressor. I think I saw it in your truck when we went to Charlottsville last year. It's just that the factory J-20 springs are way too stiff, and this truck will be empty 90% of the time. I guess with the J-10 springs it should ride as nice as my old 82 Cherokee Chief.

Dennis do you kow for a fact that I can buy new stock rate J-10 springs?
__________________
1977 CJ 7 360 T-18 IHC D300 FARM TRUCK NY
1985 CJ 7 AMC 401, CLARK 285SV 5 SPEED, DANA 60, DANA 44, RUBICON 4.5 LIFT. 37 KRAWLERS
1987 J-20 401 90% COMPLETED.
1985 J-20 360 6 inch lift, 37's plow truck
1986 J-20 360 stock well rusted plow truck
1970 AMX CURRENT PROJECT
Reply With Quote
  #12  
Old 03-25-2009, 03:23 PM
red mistress's Avatar
red mistress red mistress is offline
Bleedin' Gasoline
 
Join Date: Sep 13, 2007
Location: TX
Posts: 2,268
84 J-Truck spring rates

REAR:

SWB J-10 standard 165 lbs/in HD option 4+1 265 lbs/in.
LWB J-10 standard 245 HD option 4+2 340

LWB J20 standard 340 HD option 3+2 510


From 84 Sales data book

I'm sure that any of the spring companies have this data and can build to whatever spring rate that you want. Also lift and progressive like the new trucks have.
__________________
67 Gladiator 15K J3000 AMC 327, PTO, 35" BFG's
69 Jeepster 8701 convertible
82 CJ-8 75K org SR decals
82 Cheroeke Laredo 24K
83 CJ-8 50K 401, ARB60's, F&R Winch, 38"
84 CJ-7 38K Garnet Int., Jeep 8274 winch
87 J 20 36K smooth alum camper & boat rack.
Reply With Quote
  #13  
Old 03-25-2009, 06:03 PM
Ted Wendel Ted Wendel is offline
Member
 
Join Date: Oct 24, 2002
Location: Varina,VA
Posts: 138
Quote:
Originally Posted by JERSEY JOE
It's just that the factory J-20 springs are way too stiff, and this truck will be empty 90% of the time.

Empty 90% of the time,it should be hauling the trail CJ-7 90% of the time.
Reply With Quote
  #14  
Old 03-25-2009, 07:22 PM
Kali's Avatar
Kali Kali is offline
Bleedin' Gasoline
 
Join Date: Mar 29, 2005
Location: New Hampshire
Posts: 2,367
for what its worth, some years you could get a "light duty" j-20 with 6800 GVW. thats slightly more than the j-10 (6200) and slightly less than the "regular duty" j-20 (7600?). maybe try finding a set of those springs?
__________________
1982 J-10
1977 J-20 - 360 4bbl / Wagoneer Interior
1979 J-10 (Parts), 1983 J-20 (Parts), 1988 Grand Wagoneer, 82 J-10, 77 J-10

2006 Grand Cherokee DD

Webshots Photos

"The J-series Jeep pickups are simultaneously the ugliest and the most beautiful trucks ever made."
Reply With Quote
  #15  
Old 03-26-2009, 08:01 AM
billyrb's Avatar
billyrb billyrb is offline
BJ's Off-Road
 
Join Date: Aug 15, 2001
Location: Acworth, GA 30101
Posts: 10,067
there are lots of folks running our springs that are very happy with them, for regular duty, off-road use and for towing. We also have customers that use our lift kits paired with air-bags for heavy towing that are also very pleased. Plus, saves about 30-50% off the cost of using Alcan's, etc.
__________________
BJ's Off-Road
ryan@bjsoffroad.com
Your source for '63-'91 FSJ Parts
Reply With Quote
  #16  
Old 03-26-2009, 08:14 AM
KaiserMan's Avatar
KaiserMan KaiserMan is offline
I got the Willys....
 
Join Date: Jun 21, 2005
Location: Huntington, Ma.
Posts: 8,251
Why not go for some new J20 (6800lb) springs and mount some of those over loads that sit above the springs and rest on brackets mounted to the frame.
That should give you a good ride with the ability to handle a heavy load.

Crappy pic but you get the idea. They should not be resting on the mounts without load, these springs are probably just clapped out.
__________________
Thomas Russell



2003 Grand Cherokee

1971 Gladiator J2000 Custom-Cab Platform-Stake Dump 350/T18


1970 Gladiator J3000 3407Z Camper Truck 350/T18

1963 Gladiator J300 Townside 350/TH400


Last edited by KaiserMan : 03-26-2009 at 08:16 AM.
Reply With Quote
  #17  
Old 03-26-2009, 08:29 AM
red mistress's Avatar
red mistress red mistress is offline
Bleedin' Gasoline
 
Join Date: Sep 13, 2007
Location: TX
Posts: 2,268
Jeep SE

http://i226.photobucket.com/albums/d...r/DSC02172.jpg

How Jeep dealt with ride quality and heavy loads.

I think I'm going to run the helper springs on J20, but will have to make drop down brackets due to lift.
__________________
67 Gladiator 15K J3000 AMC 327, PTO, 35" BFG's
69 Jeepster 8701 convertible
82 CJ-8 75K org SR decals
82 Cheroeke Laredo 24K
83 CJ-8 50K 401, ARB60's, F&R Winch, 38"
84 CJ-7 38K Garnet Int., Jeep 8274 winch
87 J 20 36K smooth alum camper & boat rack.
Reply With Quote
  #18  
Old 03-26-2009, 06:29 PM
JERSEY JOE's Avatar
JERSEY JOE JERSEY JOE is offline
Master Mechanic
 
Join Date: Jan 15, 2004
Location: KEARNY, NEW JERSEY
Posts: 1,358
BJ OFFROAD SPRINGS

I MIGHT BE TEMPTED TO BITE FOR THESE IF I CAN FIND ANYONE THAT IS CURRENTLY RUNNING THEM. PLEASE POST UP.
__________________
1977 CJ 7 360 T-18 IHC D300 FARM TRUCK NY
1985 CJ 7 AMC 401, CLARK 285SV 5 SPEED, DANA 60, DANA 44, RUBICON 4.5 LIFT. 37 KRAWLERS
1987 J-20 401 90% COMPLETED.
1985 J-20 360 6 inch lift, 37's plow truck
1986 J-20 360 stock well rusted plow truck
1970 AMX CURRENT PROJECT
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 08:01 AM.


Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
corner corner