Split Mono-Leaf Springs
Printed From: TheAMCForum.com
Category: Competition
Forum Name: Drag Racing
Forum Description: Your latest numbers, events you attended and more
URL: https://theamcforum.com/forum/forum_posts.asp?TID=92562
Printed Date: Apr/23/2024 at 7:55am
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Topic: Split Mono-Leaf Springs
Posted By: Rebel Machine
Subject: Split Mono-Leaf Springs
Date Posted: Feb/16/2018 at 7:40pm
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Thinking of softening the rear suspension on my '69 AMX. Jeg's has Calvert Racing split mono-leaf springs in a couple of heights. http://www.jegs.com/p/Calvert-Racing/Calvert-Racing-Split-Mono-Leaf-Springs/4018744/10002/-1" rel="nofollow - http://www.jegs.com/p/Calvert-Racing/Calvert-Racing-Split-Mono-Leaf-Springs/4018744/10002/-1 Since this car spends 99% of it's life on the street I'm hoping they're good on both street and strip. Any opinions? Thanks, -Steve- |
Replies:
Posted By: Class Guy
Date Posted: Feb/17/2018 at 6:39am
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Those are designed to be used with CalTracs. If you are doing that, they will probably work well for you. If I were looking at primarily street performance, I would look at some other solution. They do not ride particularly well and they don't lend themselves to cushioned bushings. If your "street" use is less than 3000 miles per year and it is mostly cruising, you will be able to tolerate them. If you actually take trips in the car, you will not like them. ------------- Addicted to acceleration. Owner and Admin for www.classracerinfo.com |
Posted By: Rebel Machine
Date Posted: Feb/17/2018 at 7:19am
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Currently have Cal-Tracs on my AMX with Espo 5-leaf springs. Front bushings are aluminum, rear are urethane. Rides stiff as a railway car right now so I'm used to it. The arch in them is a bit excessive also. I've done some reading on other brand forums about the split-leaf on the street. Most say they're stiff due to the front half spring being so thick. Others said ride quality really didn't change. My AMX doesn't see the highway much. Since I've already got the Cal-Tracs it sounds like going with the split-mono will be a good upgrade, will save a few pounds as well. -Steve- |
Posted By: goops
Date Posted: Feb/17/2018 at 11:23am
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I had split leafs and caltracs on 74 Jav AMX and used their recommended adjustable shocks and it rode quite nice . You can order ride height you want in springs. They were very good to deal with and used their recommended setup . |
Posted By: Rebel Machine
Date Posted: Feb/19/2018 at 8:55pm
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Took the plunge and bought a pair of the standard ride height split-mono springs and a pair of the adjustable shocks. -Steve- |
Posted By: Rebel Machine
Date Posted: Feb/26/2018 at 9:20pm
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Guess I should have stated the reason for this change. My goal is to get the car to hook with DOT tires. Currently have 255 60 15 M/T ET Street S/S tires. Would like to fit some 275 50 15 but not sure if they'll clear. I've used the Cal Trac bars for several years and the car hooks well with slicks but rebounds kind of bad. Pretty sure that'll cause a loss of traction on DOTs. I'm the R/W/B AMX. |
Posted By: Rebel Machine
Date Posted: Feb/27/2018 at 5:44pm
Parts are here! |
Posted By: Rebel Machine
Date Posted: Mar/04/2018 at 5:11pm
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Installed the springs and shocks today and with all aftermarket parts there's always an issue or two. When I first put this car together I used a set of Espo leaf springs. I added a pair of Cal-Trac bars with stock shocks. Noticed the shock mounting post on the Cal-Trac piece doesn't mirror the original AMC. The original AMC is angled to match the direction of the shock. Guess Calvert Racing assumed the post was straight because that's how their parts are. I was able to get the stock shocks in place with no clearance issues despite this.  The new split mono leaf springs went in pretty smoothly. The Calvert Racing shocks are wider on the bottom than the stock shocks. When I went to install the them it was clear the shocks were going to have an interference problem with the exhaust.  The good news is there's plenty of room on the axle tube side. I may be able to solve this by correcting the shock post angle problem and move the shock back towards the axle. I'd rather not do any exhaust work if I can avoid it.  |
Posted By: SC397
Date Posted: Mar/05/2018 at 1:29pm
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It is not good to have the bottom of the shock on a bind like that. Ultimately it puts a side load on the valving system. (I work for the company that makes those shocks) |
Posted By: Rebel Machine
Date Posted: Mar/05/2018 at 3:59pm
Good to know, thanks for the info! I'll post updated pics when I get the mounts modified. -Steve- |
SC397 wrote:Posted By: Rebel Machine
Date Posted: Mar/05/2018 at 9:51pm
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Got the plates modified and mocked up with the shock in place. Looks like we've made some room. This is at ride height.  Bolt lines up much better. Slides in without a fight. I'll have to shallow up that spacer to maximize the space available.  Welded them up this eve, need to give them a coat of paint since I burnt off that nice powder coated finish. -Steve- |
Posted By: bcsideshow
Date Posted: Mar/06/2018 at 8:35am
I have 275/50-15 MT ET streets on my 70 AMX and they fit good with 4.5" backspace. Rubs 1/4 slightly on big bumps but car is lowered about 2 inches the rear. Factory leafs ------------- 1969 SCRambler "B" 1970 AMX 390 Auto 1968 AMX 390 Auto 1970 Rebel Machine Project 1969 AMX 390 4SPD Project 1969 AMX 390 Auto Project 1969 Javelin 390 project 1997 Cherokee lifted 1998 TJ Lifted |
Posted By: Rebel Machine
Date Posted: Mar/07/2018 at 4:50pm
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Finished the install. Looks like there's more room between the leaf and tire, might be room for a 275 tire after all. -Steve-    |
Posted By: Rebel Machine
Date Posted: Mar/14/2018 at 6:00pm
If I remember right the '70 rear is 1" narrower than the '69. That jars the numbers a bit. -Steve- |
Posted By: bcsideshow
Date Posted: Mar/15/2018 at 3:30pm
I always forget that!!!
------------- 1969 SCRambler "B" 1970 AMX 390 Auto 1968 AMX 390 Auto 1970 Rebel Machine Project 1969 AMX 390 4SPD Project 1969 AMX 390 Auto Project 1969 Javelin 390 project 1997 Cherokee lifted 1998 TJ Lifted |
Posted By: hemicop
Date Posted: Sep/08/2018 at 3:57pm
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If it were me, I'd re-locate the exhaust & set the shocks up like many "serious" drag cars are---perfectly vertical. The reason is simple---a vertical shock will have NO binding while travelling as there is no side-load due to an angled mount (like a street car. This may not seem critical to you but since your interest is in drag racing every little bit to minimize friction in the driveline & suspension helps. And it won't adversely effect the car's street manners. you can look at any photos of drag cars from stockers to ProMods and if they have shocks, they're vertically mounted-there's a reason for it.
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Posted By: PHAT69AMX
Date Posted: Sep/09/2018 at 11:55am
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This is copy and pasted text from long ago I have. So although pretty confident, unable to say totally accurate... 1970 Rim offset might be different than 1969.... 1967-72 AMC Parts Manual does show different Part #'s for 68-9 than 70 AMX, Javelin Rearends Memory tells me "idealy" 5 inch Backspace works "best"... to maximize tire width, fit within fender, spring clearance, but it has very limited availablility.. Hub to Hub, both front and rear, is 1.0 inch greater than stock Track Width dimensions based on stock wheel offset. 1968-69 Dims from Technical Service Manual 59.38 inch = Front Hub to Hub = 58.38 Stock Front Track + 1.0 inch 58.00 inch = Rear Hub to Hub = 57.00 Stock Rear Track + 1.0 inch 1970 dims from AMA Data sheets 60.30 inch = Front Hub to Hub = I6 59.30 Stock Front Track + 1.0 inch 60.70 inch = Front Hub to Hub = V8 59.70 Stock Front Track + 1.0 inch 58.00 inch = Rear Hub to Hub = 57.00 Stock Rear Track + 1.0 inch This below pretty much matches what I got when I trial fitted on a '69 15x8 w/ 5-/12 b.s. with 255/60/15 tires ( 1/8" to 0 sidewall to leaf spring) Calculated distance between sidewalls of 255/60/15 on 5-1/2 backspace. 255mm = 10.04 ÷ 2 = 5.02 + 1.0 offset = 6.02 Hub to Inner Sidewall 12.04 = 2 * 6.02 Hub to inner sidewall on each side 45.96 = calculated between Sidewalls 58.00 hub to hub - 12.04 46.00 = Distance outside to outside of the Leaf Springs 2.50 = Width of Leaf Springs 1.25 = Distance from Sidewall to Leafspring 15x8 w/4.5 BS & 255/60/15
-------------  Link to a http://www.youtube.com/watch?v=MySiKQsmWxU" rel="nofollow - Short YouTube Burnout Video |
Posted By: brownspirit
Date Posted: Sep/09/2018 at 3:28pm
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I wish it was easier to mount the shock straight up, I was able to straighten them out a bit on my car, but not very much, and I have no tail pipes. Andy ------------- 69' BBB AMX 390/4-speed 69' s/crambler project 69’ International F210d Cummins/5+4 |