Less weight=better performance

[j99xj]

What do ya guys think about these? Has anyone tried them?
http://flex-a-form.com/products.asp

They weigh 8 lbs. So that is 16 lbs total for two springs.

That saves about 74 lbs of weight according to their 45 lb per spring figure for steel leaf packs.

That should improve 1/4 mile times by a few tenths and maybe add a tad of fuel economy.

I might consider these since my current leafs are getting a little saggy.

Only downside is the price.

[Michaelarchangelo]

$400 for a set, and I haven't heard of anyone running them.

[j99xj]

$400 for a set, and I haven't heard of anyone running them.

It's a lot thats for sure. I just wondering if anyone tried them to see if they would hold up to high power and off road loads.

[Michaelarchangelo]

Well, if Im not mistaken, the Corvettes use them (so they are fine for high power) and offroad they should do fine, as long as you don't smack them with anything. They are supposted to hold their arch better than steel, and never get fatigue.

[Beej]

I've seen fibreglass and carbon-fiber leafs on race vehicles locally. The weight savings was the reason for the expense. Although, I don't think losing a mere 75lbs is going to equate to shaving a couple of tenths in the 1360...

:D

[BlueCuda]

Alot of Astro Vans have fiberglass or compsite rear springs.

[Hellbent]

i wonder how well they would hold up to being bashed and/or ground on rocks? i just envision them splintering....snapping. i don't think the price is that awful, considering they seem to be "custom" per each order, and the weight savings that seem pretty substantial.

[MaXJohnson]

Well, if Im not mistaken, the Corvettes use them (so they are fine for high power) and offroad they should do fine, as long as you don't smack them with anything. They are supposted to hold their arch better than steel, and never get fatigue.
Corvettes use trailing links to control power. The composite leafs are mounted transverse and don't see any torque load. Besides that, they are up high and out of harms way. A car like the Corvette that is all about handling can really benefit from 75 less pounds of unsprung weight. With solid axles from and rear, it's not likely that unsprung weight was a high priority in the XJ's design.

I'm with Beej on the 1/4 mile; two tenths is dreaming, and any gain in gas mileage would be miniscule.

[BlueCuda]

The heavier your junk is the less wieght will effect it. For instance taking 75lbs off of a 4000lb jeep with not do shit, if you took it off of one that wieghs 2000lbs that would make a difference.

[Michaelarchangelo]

Not always, there are two diffrent kinds of weight, sprung and unsprung.

[Kittrell]

What Beej and Max said, two tenths isn't even gonna come close to happening. A pretty basic rule of thumb is one tenth off your 1/4 mile for every 100 pounds shed. If you are trying to lighten your Jeep as much as possible, then this is a step in the right direction. Just don't expect much of a difference as a solitary mod.

$400 for a set, and I haven't heard of anyone running them.

Just depends on what you are willing to spend. I paid $529 for my springs, and there are two other choices I had that would have run me more $$$.

[BlueCuda]

What Beej and Max said, two tenths isn't even gonna come close to happening. A pretty basic rule of thumb is one tenth off your 1/4 mile for every 100 pounds shed. If you are trying to lighten your Jeep as much as possible, then this is a step in the right direction. Just don't expect much of a difference as a solitary mod.

Sprung and unsprung wieght has no effect on total actual curb wieght if i am not mistaken. Oh and the rule of thumb for rotating wieght is 25lbs=.1 in the quarter.

[Michaelarchangelo]

Sorry, I was thinking more along the lines of handling. My brain is fried.

[tealcherokee]

as far as those weight:1/4 times you guys are talking about, thats w/ 500 horse, and GOOD aerodynamics

so basically, youll spend $400 to shave like .25 of a sec

[j99xj]

Losing 75 lbs is like gaining 5 hp. I know its not a lot but its "more than before" as I like to say.

A tenth might not seem like much, but let me explain this in a more "visible" way.

My last 1/4 mile e.t. and mph was 18.55 seconds, and 75 mph respectively.
(I know its slow but my Jeep is about 2 tons, lifted, and running at 5000 feet of elevation, all of which kills acceleration)

75 mph is 110 ft/sec, so in 1 tenth of a second I'm rolling 11 feet.

11 feet could make the difference between a win and a loss.

Its something to think about.

I downloaded an engine simulator and plugged in different weights and losing 75 lbs is about a 1 tenth gain. So I'm effectively retracting my statement "a few tenths". I'm sorry.

[BrettM]

does anyone even know what XJ packs weigh!? I doubt 45 pounds each, that number is used on the site saying some leaf packs are that heavy, and they are likely using 1-ton or more springs for that number.

[ChicksDigWagons]

I would say 45lbs is probably pretty close. I don't know if you've ever tried to man handle 1-ton springs but they roll in a lot closer to a buck than 50 cent. Maybe I'm just small and weak...

[Big_Al]

My last 1/4 mile e.t. and mph was 18.55 seconds, and 75 mph respectively.
(I know its slow but my Jeep is about 2 tons, lifted, and running at 5000 feet of elevation, all of which kills acceleration)



May I ask what size tires and gears you're running? Al

[Mr_Random]

Alot of Astro Vans have fiberglass or compsite rear springs.


Did anyone else even see this? Might be good news if you want to test some junkyard pieces. Just make your own mount and drill the center pin in the correct place and see what you can get!

and I think XJ leafs (stock) weigh ~35lbs. I don't know for lift packs

[j99xj]

May I ask what size tires and gears you're running? Al

Geez, I never would have imagined to see this thread pop up again. Anyway at the time I was running stock 3.55 gears with 30x9.50 all terrain tires.

[PurpleCherokee]

Seems to me that with the huge difference in weight and responsiveness of fiberglass over steel that these would ride a whole lot better than stock leafs. And because you wouldn't have several metal slabs sliding over each other in order to flex. Is anyone else getting this impression?

[j99xj]

Yes. I would imagine they would allow the rear axle to articulate better.

[urban yan]

on the one hand your Jeep should handle better with less unsprung weight.
on the other hand, its a Jeep with solid axles.

[PurpleCherokee]

Better handling, better ride = a win in my book :D

Somebody pony up and try it out for us!

[besthaticouldo]

Better handling, better ride = a win in my book :D

Somebody pony up and try it out for us!

you pony up.

its a jeep. if you want it to ride better get a coil conversion for the rear. i can tell you my ZJ rides tons better then my XJ ever did.

leaf springs dont ride well.

also fiberglass doesnt have a very high impact coefficient. and it will not likely stand up to any abuse off road. moreover...its not meant to be flexed a lot. its meant to be more stationary...the steel bends and flexes, because thats the design.

fiberglass...not a good idea on a jeep...

[Darky]

Nothing wrong with trying to get better handling out of a Jeep. Nothing wrong with trying to lose weight from a Jeep. So 75lbs doesn't sound like much, but coupled with other weight savings techniques it adds up.

[PurpleCherokee]

you pony up.

:rattle:

Butt hurt much? Seriously, every post I make I can expect a whiney, "my butt hurts" kind of response from you. Personally, I can't stop laughing, but it gets annoying and you end up contributing nothing to the thread. If you don't think this is worth looking into for those of us looking for a better ride and/or handling then you're really dumb cause it definately is. So please quit being such a baby and get a life.

By your logic things like CAI and exhaust are worthless cause they don't make a big difference by themselves. That's kinda the whole point of owning an XJ, to improve it.

And if steel flexes better than fiberglass then why are pole vaulting poles, fishing rods, and a lot of golf clubs fiberglass? Face it, fiberglass will flex at least as much as steel.

[besthaticouldo]

Butt hurt much? Seriously, every post I make I can expect a whiney, "my butt hurts" kind of response from you. Personally, I can't stop laughing, but it gets annoying and you end up contributing nothing to the thread. If you don't think this is worth looking into for those of us looking for a better ride and/or handling then you're really dumb cause it definately is. So please quit being such a baby and get a life.

By your logic things like CAI and exhaust are worthless cause they don't make a big difference by themselves. That's kinda the whole point of owning an XJ, to improve it.

And if steel flexes better than fiberglass then why are pole vaulting poles, fishing rods, and a lot of golf clubs fiberglass? Face it, fiberglass will flex at least as much as steel.

no...it won't actually...

those items are being used sparingly and with very little force compared to what a leaf spring is having exerted on it. the leaf spring is constantly moving up and down and having forces exerted on it.

i've been playing hockey for 18 years. i use a carbon fiber stick. i can tell you i use one every 3 months. i get a new one. they LOSE whippyness and flexiness and become very soft and fragile very fast. i've broken more sticks then i can remember.

fiberglass won't be able to stand up to the rigors of a leaf spring for an extended period of time, especially in an off road vehicle...period.

there is no face it. or are you an expert of flexion as well as everything else? lol

and...im not sure what logic you are referring to, but i had a cold air on my xj. breathing mods improve it, but removing your cat is stupid...im not sure who you have me confused with.

yea i contributed nothing to the thread. i love how you quoted the first three words of my entire post and say i contribute nothing. selective quoting...good work.

and for the record...you want someone to pony up to do something...why shouldn't it be you? you're so curious...you pony up $400 bux for something that has a high risk of breaking the first time its actually wheeled, like most of the people here do with their rigs...

i wasnt butt hurt about anything. but telling someone else to try something out for you is just stupid...

[urban yan]

bling bling
http://shop.505performance.com/product.sc?categoryId=2&productId=17

wow
http://www.naxja.org/forum/showthread.php?t=87268

[wolfpackjeeper]

And if steel flexes better than fiberglass then why are pole vaulting poles, fishing rods, and a lot of golf clubs fiberglass? Face it, fiberglass will flex at least as much as steel.


No offense, but I think this is a bad comparison. Pole vaulting poles and fishing poles are fiberglass/carbon fiber for the weight savings more than anything else (so they do tie into the springs a little). However, if you were to use a metal pole in the same application it would probably last much longer. Pole vaulting poles do not have a long lifespan, and my buddy is always buying a new fishing pole. The plastics and glasses are higher prone to fatigue than a metal is. Yes, you can engineer plastics that perform better, but the cost of manufacturing rises sharply.

The fiberglass springs are great in their application, but they strike me as a seasonal replacement item on a dedicated drag car. I can't really see a useful Jeep application, unless that application is dedicated drag car. For off road or mixed use, there are better places to spend the money.


Then again on the other Hand...
you have more fingers

[wolfpackjeeper]

bling bling
http://shop.505performance.com/product.sc?categoryId=2&productId=17

wow
http://www.naxja.org/forum/showthread.php?t=87268

I believe fabtech has a kit out now as well. Or Full Traction I don't remember which

[PurpleCherokee]

No offense, but I think this is a bad comparison. Pole vaulting poles and fishing poles are fiberglass/carbon fiber for the weight savings more than anything else (so they do tie into the springs a little). However, if you were to use a metal pole in the same application it would probably last much longer. Pole vaulting poles do not have a long lifespan, and my buddy is always buying a new fishing pole. The plastics and glasses are higher prone to fatigue than a metal is. Yes, you can engineer plastics that perform better, but the cost of manufacturing rises sharply.

The fiberglass springs are great in their application, but they strike me as a seasonal replacement item on a dedicated drag car. I can't really see a useful Jeep application, unless that application is dedicated drag car. For off road or mixed use, there are better places to spend the money.


Then again on the other Hand...
you have more fingers

I do see how fiberglass is seemingly less durable than steel but then again look at some of the amazing polymers/resins/coatings or whatever ya wanna call it that is on the market now. I doubt these springs are just straight fiberglass with no attention paid to adding anything to them to form some kind of "alloy" to make them durable. The coating on synthetic winch lines comes to mind for what I'm thinking of. But then again, maybe they haven't developed them to that point :dunno:

[wolfpackjeeper]

I do see how fiberglass is seemingly less durable than steel

they can be very durable, but the basic flaw that it would come down to is that essentially they are made up of glass, which has a very low tolerance to deformation on a structural level against its clevage line. Basically you can design it to take stress in a directional assault, but not on every direction. I would not worry about them in a drag environment as they are certainly designed for the shock loading of a launch, the part that would worry me would be the probability of have an impact occur on the spring from say a rock or log, especially while it is under strain from the weight of the vehicle.

I threw a feeler onto a drag forum I am a member of from my SS camaro and crotch rocket days to see if anyone is using them or has experience with them. A couple of those guys have records from the LSX shootout so someone should.

[PurpleCherokee]

Well the trail rigs aren't too concerned with weight or ride quality anyways so I was assuming that this was sort of directed towards the street and performance crowd. But I wonder if rocks kicked up from gravel roads or just road debree in general would pose a threat. Surely they've taken that into account right? There's hardly any info at all on the website.

[bjoehandley]

If I'm remembering things right, the C4-C6 Vettes used transverse composite monoleaf springs on both ends.

[badron]

improve 1/4 mile times
=============================
Getting back to that.
Use the 400 to lighten up the front end. Fiberglass fenders, hood plexiglas etc. I bet you will trim a lot more weight that way then with the springs.
2WD XJ how about a light weight front axle. Way over 400 bucks but 100s of lbs in saving. Chat with some prerunners about axles,
Leave the beef on the butt. Better traction with stock or near stock tires.
Sorry but fiber springs would be way down the list of things to spend 400 bucks on.

[PurpleCherokee]

Are all those other fiberglass parts you speak of custom?

Nobody here is saying that this is the most cost effective way to lose weight. It's not a "how to get rid of as much excess weight as possible" thread, it's a "hey, these can help you get rid of some weight and get you better performance" thread. Don't read into it too much.

[Talyn]

Are all those other fiberglass parts you speak of custom?

Fenders aren't. Besides, what are you expecting for fiberglass parts for an XJ?

Don't read into it too much.

We try not to read into your posts much at all.

[FlexdXJ]

i would think they would splinter under extreme flex anyways. I don't see the point in paying 400 bucks for them. Its a Jeep not a Corvette! :doh:

[FlexdXJ]

We try not to read into your posts much at all.

:roflmao: Here we go again!

[urban yan]

He's incapable of not being a douchebag. Meh, oh well.
Sheesh. If I buy you a litre of cola, and promise to rename my Jeep 'Team RamRod' will you promise not to be so crabby?

[alex22]

Goodbye technical discussion of a product, hello name calling and bickering.

And purple....
:yelclap:congratulations.:yelclap:

[srimes]

look for springs all around you, what are they made of? Steel has been the #1 choice for a long time for many reasons. But that doesn't mean fiberglass can't work.

The corvette proves that it can work very well for that situation. But how much wheel travel do corvettes have? And that spring only provides lift, it doesn't position the axle like ours do. I read an article about GM working on fiberglass springs for a long time but they moved away from it. I think novas use them some years maybe?

They're are fiberglass sailboat masts, they take quite a load, and the unstayed ones can bend like a fishing pole in heavy air. Those giant wind turbines that are sprouting up everywhere use fiberglass blades, which will experience heavy cyclical loads. If they don't last a very long time a lot of people will be out a whole lot of money...

For high deformation (long travel) multi leafs have an advantage over mono leafs do to their geometry. If you're making a road race xj the fiberglass may make sense, but I wouldn't use it off road. Call the manufacturer and see what they recomend.

[Talyn]

Product? What product? The fiberglass springs? Please.. nice in theory, but not for an XJ. Combine that with the fact that Purple chimed in equals no real tech.

[bigdaddyjlove]

I am looking hard at these for my next project.
Now, its going to be a street only project ad should be switched to SUA and TJ front springs for a small suspension drop.

For something like that, these look pretty good.


Before I catch to much @#$@# about "not what Jeeps are made for" I have a very serious off road Cherokee and I'd like to remind everyone of the SRT8

[bigalpha]

You'd be better off chopping off the top of the Jeep and re-building it lightweight.

Or chopping it off and making it a ragtop.

And having lightweight doors and hatch.