On average how much weight would a full cage add to a car?

Is the weight noticeable and what affect does it have on you spring rates...as in did you have to go to a higher rate?

 

Depends on the weight of the car, the rules you must/can adhere to, the use of the word "full."

I have always been under the impression that you would finally be able to effectively use those higher rates with a well designed, well positioned and well built custom welded cage, rather than being required to go to higher rates. Everyone I have spoken to that went with really well built cages from bolt-ins/weld-in-bolt-ins have said the difference in the cars rigidity is night and day. I even noticed a difference in feel when I had my custom rollbar made for my street car.

Will you notice the weight?? Seems to me that every pound you put on the car in cage provided its placed out to the right spots, you'll get back out in chassis strength. I'd think its all upside on a well made custom cage, probably a lot more questionable on bolt in - both would be considered a full cage to many sanctioning bodies.

Where are you planning on running the car? That can have some rather significant effects on what you can/can not do.

 

As Adam mentioned, it depends on the car and your definition of "full."

I'll bet you anything that the "full" cage you're thinking of in no way compares to the "full" cage in Adam's car.

But, and I'm going by memory here so I could be totally wrong, I think 1.5 inch .120 wall DOM tubing weighs in at something like 1.7 lbs per foot.
Walt could probably give us an exact answer though.

 

An Autopower bolt-in SCCA legal "road race" cage weighs right about 100lbs.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by keithg &raquo;</TD></TR><TR><TD CLASS="quote">An Autopower bolt-in SCCA legal "road race" cage weighs right about 100lbs.</TD></TR></TABLE>

My cage is way over built for the weight of the car, not to mention a couple of extra braces. In the end, it weighs in at a little less than 150#. A good custom cage can be designed to be as safe or safer than mine at a fraction of the weight.

 

FWIW - my autopower "race" rollbar is 75#

 

the AP's are DOM 1.5 .095 or .120?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by essex &raquo;</TD></TR><TR><TD CLASS="quote">the AP's are DOM 1.5 .095 or .120?</TD></TR></TABLE>

Depends on the weight of the car its going into.

 

My MR2 Kirk bolt in Cage is about 110#, it's pretty basic but there is a petty bar.

 

115 - 130 lbs is typical for an 8 point SCCA legal IT cage with triple door bars (NASCAR syle) on the driver's side. As for the added weight slowing the car down, remember that you've gutted about 250 pounds of creature comforts, so with adding back 115 lbs for the cage you're still lighter than when you started...and stiffer

Also when calculating your cage weight, remember your 6 - 8 footplates, any brackets for window net, mirrors, kill switch etc. and figure a couple of pounds for the actual welds.


Modified by Track rat at 9:00 AM 8/30/2004

 

Tubing weights for DOM
1 1/2 x .095 = 1.42 lb/ft
1 1/2 x .120 = 1.76 lb/ft
1 3/4 x .095 = 1.67
1 3/4 x .120 = 2.09

A poorly done .120 wall cage can be can be 150# plus and offer not chassis stiffness and still save you life. A car with a .095 can be done and be around 100# and make a car very stiff, which will make it very responsive to suspension improvements and save your life. The big thing to help with weight saving in a roll cage is to avoid long tubes going from a weak mounting location, because you will get no significant stiffness out of it. If we had put a petty bar in phats' new car it would have added 8.5 lbs. A good set of door bars (which are required) will keep the right front suspensiuon where it needs to be, much more than a 6 ft tube teeing into a 4 ft span.

 

Just out of curiousity, measured my cage last night:

75 feet: 1 3/4" x .095 @ 1.67 lbs per ft = 125.2 lbs
3 feet: 1 1/2 x .095 @ 1.42 lbs per ft = 4.2 lbs (halo and main hoop corner braces)
8 foot plates = approx 2 lbs + a few corner gussets and the weight of a zillion welds = 2 lb?
Approx cage total = 133.5 lbs.

My cage is over built. 8 points. Triple driver door bars. Big X @ passenger door. In-dash bar. Diagonal over drivers head. Main hoop is braced top and bottom to the rear shock towers. There's an extra main hoop cross tube for seat back support (poor planning, the required cross brace should have been about 4" lower ) I'm at class minimum weight with 2 gals in the tank

No Petty bar. My cage guy agrees with Walt.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by essex &raquo;</TD></TR><TR><TD CLASS="quote">On average how much weight would a full cage add to a car?

Is the weight noticeable and what affect does it have on you spring rates...as in did you have to go to a higher rate? </TD></TR></TABLE>

Depends. This is like asking, "how much do tires weigh, on average?" The answer won't be very helpful.

Is the weight noticeable? Depends. How sensitive are you? In what kind of car?

Do you have to go to a higher spring rate? Depends what your driving style is.

 

the extra 75lbs is noticeable in my b18b hatch. since i installed the bar i've been trying to find ways to trim down... battery saved 20lbs and fibergalss hood will save another 30.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MichaelJComputer &raquo;</TD></TR><TR><TD CLASS="quote">the extra 75lbs is noticeable in my b18b hatch. since i installed the bar i've been trying to find ways to trim down... battery saved 20lbs and fibergalss hood will save another 30.</TD></TR></TABLE>

I have to think this is psychological that you feel 75lbs placed in what should be a pretty good location to not upset the weight of the car. One of the quickest ways I can think of to get that weight gain/loss at zero is a pair of race buckets - at 11 to 15lbs. per, they can often times represent a significant weight savings over OE and if using a harness, its a lot safer than OE seats IMO.

Wait, isn't 75lbs. rather bulky for a rollbar for a Honda hatchback?

 

people say that sound deading **** helps out alot too, my vx doesn't have much to begin with

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by phat-S &raquo;</TD></TR><TR><TD CLASS="quote">
Wait, isn't 75lbs. rather bulky for a rollbar for a Honda hatchback?</TD></TR></TABLE>

Yeah, that seems real heavy for a roll bar. Should be less than 50 lbs with 1 3/4 x .120?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by phat-S &raquo;</TD></TR><TR><TD CLASS="quote">Wait, isn't 75lbs. rather bulky for a rollbar for a Honda hatchback?</TD></TR></TABLE>

I think the shipping weight was 75lbs, but I could be wrong. I don't notice the extra weight in turns, but it has definitely hurt my acceleration.

 

Our KIRK 8-point cage kit weighed 135 shipped. Installed weight including the door bars and tabs is well over 120. Your weight will vary depending on tubing diameter and wall thickness. ours is DOM. Those using Chromoly will be different as well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jc836 &raquo;</TD></TR><TR><TD CLASS="quote">Our KIRK 8-point cage kit weighed 135 shipped. Installed weight including the door bars and tabs is well over 120. Your weight will vary depending on tubing diameter and wall thickness. ours is DOM. Those using Chromoly will be different as well.</TD></TR></TABLE>

Chromoly, DOM, ERW all weight nominally the same.

 

i think he means because the chromo cages might have a different wall thickness req.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson &raquo;</TD></TR><TR><TD CLASS="quote">i think he means because the chromo cages might have a different wall thickness req.</TD></TR></TABLE>


OK, but I didn't think I told him he was wrong. I just said that all the steels weighed the same.

 

i didnt say you were wrong either

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MichaelJComputer &raquo;</TD></TR><TR><TD CLASS="quote">

I think the shipping weight was 75lbs, but I could be wrong. I don't notice the extra weight in turns, but it has definitely hurt my acceleration.</TD></TR></TABLE>

i had a b18b in my hatch befor and after i had the roll bar in and i can honestly say i couldn't tell the difference, maybe im just not preceptive though

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammed_93_hatch &raquo;</TD></TR><TR><TD CLASS="quote">

i had a b18b in my hatch befor and after i had the roll bar in and i can honestly say i couldn't tell the difference, maybe im just not preceptive though</TD></TR></TABLE>

I am with you man, 187 factory hp in 1987 @ 2960 lbs. + custom rollbar and I couldn't tell any difference in acceleration or deceleration, did think the car was more stiff however. Maybe I did other things at the same time to account for the extra 60 or so lbs. ?? like didn't fill the gas tank that day I still think its psycological that you'd feel the weight difference of a roll bar (even in a straight line) - else, don't sit on a bar stool, you got one sensitive tushy there