MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: danishmkvgti on February 10, 2010, 08:31:05 am

Title: ARB, general theory
Post by: danishmkvgti on February 10, 2010, 08:31:05 am
Well, i for one are not fully understanding the pros and cons of ARB hollow versus massive. I get that it works torsionwise but in my thinking there would torsionwise be benefits with hollow against massive. Again what materials are the ones to go for, a specific steel formula?  :confused:
None of the vendors seem to tell what steel they use.  :sad1:
Could a wiser person enlighten me regarding this subject??   :notworthy:
Title: Re: ARB, general theory
Post by: Hurdy on February 10, 2010, 10:04:19 am
You probably already know the general manufacturers in this category, so I'll not list them.

I have Autotech hollow lightweight ARB's front and rear.

http://www.jbsautodesigns.co.uk/product/371/lightweight-anti-roll-bar-front-25mm

The advantages of a hollow ARB are that they are lighter for an equivalent torsional rigidity than a solid bar.

Example - Autotech in the link quote a 32% extra rigidity over an equivalent ARB whilst having 31% less weight.

This is only possible by utilising the larger diameter of a hollow bar.

The downside of using a hollow bar is that with a larger diameter comes larger stress.

Wikipedia is your friend for this, but it does get quite deep into the calculation side of things.

http://en.wikipedia.org/wiki/Torsion_(mechanics)

Mechanical and Production engineering was my thing back at Uni, so I love this kind of stuff :smiley:

Basically removing the middle of a bar gets rid of the material that has low value torsional rigidity and adds it to the outside where it has higher value. :happy2:

Title: Re: ARB, general theory
Post by: tony_danza on February 10, 2010, 10:38:18 am
Yup, nobody will tell you anything specific about their ARBs, so you can only go on a rough theory.

H&R, Eibach and Whiteline favour the x% increase over stock method, so still have a bigger front than rear with S/M/H adjustability and higher tensile rates. It matches stock on the same settings i.e. will eventually understeer, so you set the rear progressively harder to get neutral or oversteer.

Eibach and H&R will most likely be the same bar, they share everything else.

US manufacturers favour matched bars front and rear for a more neutral set up when both set to the same S/M/H.

Hollow ARBs are much lighter and therefore made out of much higher grade material. My Autotech ones weigh 4 and 5 pounds rear/front respectively.. much lighter than a solid bar as you can imagine.

Bigger isn't necessarily better, particularly on a road car or track with big gradients and cambers, like the 'Ring - some body roll can be a good thing, it makes the car more progressive and stops it skitting around on bumpy surfaces.
Title: Re: ARB, general theory
Post by: danishmkvgti on February 10, 2010, 10:46:01 am
my instinct said to go for hollow, and as most other i plan on only the rear, Autotech sounds like the right type for me  :happy2:
Title: Re: ARB, general theory
Post by: tony_danza on February 10, 2010, 10:52:05 am
They're not that easy to get hold of, sadly - most importers will only order once they've got a few sets to bring in. I may be wrong though, but nobody seems to carry stock. Try Dubtek and Regal too.

Neuspeed do hollow rears, H&R possibly too on their race versions?
Title: Re: ARB, general theory
Post by: danishmkvgti on February 10, 2010, 11:22:33 am
They're not that easy to get hold of, sadly - most importers will only order once they've got a few sets to bring in. I may be wrong though, but nobody seems to carry stock. Try Dubtek and Regal too.

Neuspeed do hollow rears, H&R possibly too on their race versions?

I just checked both Neuspeed and Autotech are 25mm but Neuspeed is 100$ more than autotech  :surprised:
H&R do 22m and 24mm and the 24mm is the same as Neuspeed, so Autotech looks like a strong contender  :wink: