Group Buy on Roll Bars and Cages
03-10-2004, 12:09 AM
#16
Instructor
Join Date: Apr 2002
Location: Palo Alto, CA
Posts: 151
Likes: 0
Received 0 Likes
on
0 Posts
BruceWard:
First, I want to qualify that I don't have any experience with DasBoot, and I have not seen the roll bar or cage you are asking about.
Anyway, I believe their price is probably higher because the are using DOM tubing. Some cage makers use seamed tubing wich is prone to coming apart at the seam during stress.
True DOM tubing has no seam, as the material is Drawn Over a Mandrel to form it. You have to be careful because some tube is claimed to be DOM, but it is actually seamed and then the seam is rolled for strength; this is not as good as DOM. You should verify with the vendor as to if they are using true DOM tubing.
The downside of DOM is that it has inconsistant wall thickness. At a minimum it matches the stated thickness, but it may actually be thicker in various portions. The result is increased weight.
By the way, some vendors make their bars and cages from Chromo, which is considered bad practice according to what my research has found. While Chromo has a stronger tensile strength than typical steel, and allows for a thinner wall thickness, which equates to lightness, it is not as tolerent in plasticity (plastic-elongation) as steel. The result is the possiblity that if the cage fails under stress, it will snap and the broken tube will act as razor sharp projections that are life threatening. It's a bad situation.
I totally freak out when I see these Hondas and all with decorative aluminum roll-cages... this is death on wheels.
Good luck,
Abdul
First, I want to qualify that I don't have any experience with DasBoot, and I have not seen the roll bar or cage you are asking about.
Anyway, I believe their price is probably higher because the are using DOM tubing. Some cage makers use seamed tubing wich is prone to coming apart at the seam during stress.
True DOM tubing has no seam, as the material is Drawn Over a Mandrel to form it. You have to be careful because some tube is claimed to be DOM, but it is actually seamed and then the seam is rolled for strength; this is not as good as DOM. You should verify with the vendor as to if they are using true DOM tubing.
The downside of DOM is that it has inconsistant wall thickness. At a minimum it matches the stated thickness, but it may actually be thicker in various portions. The result is increased weight.
By the way, some vendors make their bars and cages from Chromo, which is considered bad practice according to what my research has found. While Chromo has a stronger tensile strength than typical steel, and allows for a thinner wall thickness, which equates to lightness, it is not as tolerent in plasticity (plastic-elongation) as steel. The result is the possiblity that if the cage fails under stress, it will snap and the broken tube will act as razor sharp projections that are life threatening. It's a bad situation.
I totally freak out when I see these Hondas and all with decorative aluminum roll-cages... this is death on wheels.
Good luck,
Abdul
03-13-2004, 09:48 PM
#17
Addict
Rennlist Member
Rennlist Member
Abdul;
Good points in theory. However, I'll believe it when I start to see a lot of ERW failing. Any "inherent weakness" it may have can be more than made up for with good triangulation and load dispersion. Witness the Tipo 60/61 "Birdcage" Maserati. I believe my bar gives you this load dispersion.
The best thing is you know what you are going to get with ERW. It is pretty consistent in my experience. It remains ductile at all times, welds nicely, and is quite good at absorbing energy. There was a time where inferior DOM was getting into the country. This stuff would completely lose its ductility after welding and shatter like un-annealed CR.
You make good points in theory, but good old ERW is still hard to beat!
Good points in theory. However, I'll believe it when I start to see a lot of ERW failing. Any "inherent weakness" it may have can be more than made up for with good triangulation and load dispersion. Witness the Tipo 60/61 "Birdcage" Maserati. I believe my bar gives you this load dispersion.
The best thing is you know what you are going to get with ERW. It is pretty consistent in my experience. It remains ductile at all times, welds nicely, and is quite good at absorbing energy. There was a time where inferior DOM was getting into the country. This stuff would completely lose its ductility after welding and shatter like un-annealed CR.
You make good points in theory, but good old ERW is still hard to beat!
03-14-2004, 10:13 AM
#19
Addict
Rennlist Member
Rennlist Member
Hey Jack;
That's what I do now! I build in batches to order. I feel that I have priced this bar as low as I can already. This is a better deal than ever considering steel $$ has gone up by 30% this year.
You will note if you study that there is no other bar available that does not require mods, and can be taken in and out easily. It is not the be-all and end-all of roll bars. It is a unique product in a unique niche. There is no competition. Ask anyone who has one and they will tell you!
I have put the word out on this forum before about the next batch, and no one was serious. Just a lot of jabber. I am not aware of anyone in my current batch (18) that came from this forum. If someone wants to put the word out and put together a group, that would be fine by me.
Price, however, will still be $489 + shipping.
That's what I do now! I build in batches to order. I feel that I have priced this bar as low as I can already. This is a better deal than ever considering steel $$ has gone up by 30% this year.
You will note if you study that there is no other bar available that does not require mods, and can be taken in and out easily. It is not the be-all and end-all of roll bars. It is a unique product in a unique niche. There is no competition. Ask anyone who has one and they will tell you!
I have put the word out on this forum before about the next batch, and no one was serious. Just a lot of jabber. I am not aware of anyone in my current batch (18) that came from this forum. If someone wants to put the word out and put together a group, that would be fine by me.
Price, however, will still be $489 + shipping.