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Lightweight Rollbar
I am in the process of adding a rollbar to my 84 Carrera and was looking for some specs for weight. Didn't seem to find any. I was hoping to find a lightweight CroMo bolt in. I know the DAS seems to be the rollbar of choice but not sure how much it weighs and it looks pretty heavy.
Anybody have any wieghts or experience with a lightweight bar? Thanks - -Jeff
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Jeff |
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11-22-2005, 11:28 AM
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Yeah....Rolf Stommelen had a bad experience at Riverside with a "light-weight" rollbar !!
-Wil
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Wil Ferch 85 Carrera ( gone, but not forgotten ) |
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11-22-2005, 11:47 AM
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Nice one Wil -
I was not wanting to sacrifice strength for weight...
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Jeff |
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11-22-2005, 11:57 AM
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I didn't mean to come off that way.....but you're quite correct, we can't sacrifice safety for weight....
My recollection is that the rear-section of a DAS bolt-in roll bar weighs something like 35-50 lbs. Maybe their web page can offer some insight. The full cage Safety Devices cage ( front/rear) weighs...I think....close to 80-100 lbs, and should be fairly typical of this type of construction. There are options however. You can opt-out of mild steel and regain strength by using thinner walled or smaller diameter stronger steel ( Chrome Moly), ...this could conceivably bring weight down. However, if the bar/cage is used in a racing series, there might still be minimum specs that you can't work around in terms of diameter and thickness. Best, - Wil
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Wil Ferch 85 Carrera ( gone, but not forgotten ) |
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11-22-2005, 12:06 PM
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Jeff,
Build it to SCCA specs. That is what every organization (PCA, POC, NASA, PRC, etc.) uses as the standard. It is just like considering a cheap helmet; what is your head (neck) worth? You can download the SCCA “General Competition Rules” (5.8M pdf) GCR here. Look at many other installations first. Get together with someone who is experienced in proper roll bar/cage fabrication and installation. A good bolt-in will not damage your 911. Best, Grady
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11-22-2005, 12:10 PM
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Build it out of Magnesium, with a Schrader valve so you can pressurize the structure to check for cracks! Just don't smoke in the car!
 I had the DAS bar in my '88 Carrera, it was awesome. Be sure to order it with harness loops welded on. It's difficult to powdercoat it before shipment, as the powdercoating tends to get scuffed no matter how well it's packed, so you may want to have it shipped directly to a local shop to pretty it up before bolting it in. Installation requires removal of the front seats so you can see what you are doing, but is otherwise pretty easy. I don't know of anyone who makes Al bars now that Matter is no longer in business. Not sure you'd want anything less than the SCCA specs referenced above by Grady.
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'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
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11-22-2005, 01:13 PM
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Quote:
I live about an hour from Charlottesville so I can save a bunch on shipping and was going to add the harness hoops. There is a powdercoater nearby that I use regularly. According to DAS it is about 55lbs  Heavy - but sturdy.Did you bolt in for the track and un-bolt after? Not sure how safe it is to run around on the street in case of an accident. I will be using shells (non-recline) so I need to get some kinda of back brace also and roll bar padding. -Jeff
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Jeff |
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11-22-2005, 01:23 PM
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use 4130 Cro-mo and go with a Matter hoop design. I have one and it's light.
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" The reason the Irish are always fightin each other is that there are no other worthy opponents" |
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11-22-2005, 02:14 PM
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Quote:
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Jeff |
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11-22-2005, 02:16 PM
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Our base ST chrome moly roll bar weighs under 20 lbs, in club race trim with diagonal and shoulder harness cross bar weighs 28 lbs. contact us at info@tremotorsports.com
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1970 914-6 street"evil cockaroach" 1970 911 Targa "ST" Jade Green IROC Tribute (ready to race) |
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11-22-2005, 03:33 PM
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...got one on order--can't wait.
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Bill G. '68 911 Ossi Blue coupe |
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11-22-2005, 03:36 PM
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drag racing the short bus
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The Terror of Tiny Town |
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11-22-2005, 03:38 PM
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11-22-2005, 03:39 PM
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Wow, that is an awesome weight on the TRE bar.
Other than cost, why don't more cars have 6061-T6 alum bars? I would think the strength is there.
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Ed Hughes 2015 981 Cayman GTS 6 speed,Racing Yellow Past:1984 911 Targa (Ruby), 1995 993C2 (Sapphire), 1991 928S4 |
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11-22-2005, 03:39 PM
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11-22-2005, 03:40 PM
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aluminum is no longer legal in almost all racing events. With Rolf Stommelen losing his life in a aluminum tube 935 at Riverside, the sanctioning organizations took a hard look at the specs and outlawed them. For sure you will see aluminum tubed restored 935's , 917, and other purpose built older race cars, but the alloy cages are essentially gone.
The upper pic shows a side view of our club race version The lower pic shows the early ST installed in a swb 911. Our new production run places the main hoop much further back behind the B pillar , so you 1- enjoy more protection 2- enable the use of oem shoulder harness bolt up 3- enable the driver to see out the back window! And yes Bill- you are getting one of the new ones - going out Fed X wednesday- Thanks!
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1970 914-6 street"evil cockaroach" 1970 911 Targa "ST" Jade Green IROC Tribute (ready to race) Last edited by TRE Cup; 11-22-2005 at 04:07 PM.. |
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11-22-2005, 03:43 PM
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11-22-2005, 03:49 PM
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drag racing the short bus
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The Terror of Tiny Town |
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11-22-2005, 03:58 PM
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Drawn over mandrel (DOM) , Sharon tubing (very similar to DOM), and Chrome moly. Most tube based cars are built with a combination of rectangular steel and DOM tubing- easier to repair in case of an accident. Chrome moly is good to use on a 911 tub for roll bar and/or cage IF the welding is done correctly!
The rear legs of our roll bars are made from DOM as chrome moly will not take to flattening for the rear mounting areas
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1970 914-6 street"evil cockaroach" 1970 911 Targa "ST" Jade Green IROC Tribute (ready to race) |
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11-22-2005, 04:10 PM
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Dave,
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Bill G. '68 911 Ossi Blue coupe |
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11-22-2005, 04:13 PM
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1984 Porsche 911 Targa 3.4L
Sapphire
