3200/AC/4200/GS anti-roll bar diameters comparison.

[mjheathcote]

For a comparison between the models/years, I'll start with my 2002 4200 Coupe Classico diameters:

Front bar: 28mm
Rear bar: 16mm

Also Formula Dynamics replacements:

Front bar: 38.6mm
Rear bar: 24mm

It must be noted that the FD replacements have a choice of end pick up positions that also will change the stiffness of the bar to a greater or lesser degree.

If you have a digital caliper, it would be useful to measure and post yours if a different year/model to compare.
You don't need to jack the car up to measure, just lie down the side quite easy to do.


Edit: If you have a MC Victory that would be interesting to know compared to a standard GS.

 

[adam01]

Will measure up mine - may need to jack up as GS are a bit lower std.

 

[mjheathcote]

Will measure up mine - may need to jack up as GS are a bit lower std.

Great, the front bar is straight in your face when you look behind the front wheel, can't miss it.
The rear bar again you need to look from behind the wheel, plenty of room to see the bar and insert your hand holding measuring calipers.

 

[allandwf]

I can do mine in a fortnight if no one has done it by then.

 

[Contigo]

3200 front ARB 20mm
3200 Asetto Corsa front ARB 22mm

 

[alfatwo]

What with the 4200 front bar at 28mm and the 3200 at 20mm.. that must be nearly 6 times stiffer!

Ok the 3200 has more forward weight due to it having a normal diff at the back not a transaxle and its slightly lighter overall..

But that's a massive difference in roll stiffness on the front for the 4200...maybe the spring rates are different.

Eibach in Germany are the original manufactures of 3200/4200 Maser road springs and roll bars.. I only found this out a few months ago as I have an a account with them.....So does anyone have any info on the original spring rates?


Dave

 

[mjheathcote]

Regarding road springs, my early 02 Classico has 3200 springs. Maserati only changed the springs once again from 03 so all variants including the GS had the same. According to part numbers.

I don't know if the front 3200 bar is a different shape to the 4200. The end arm lengths might be different effecting the stiffness but as the front suspension and bodyshell is effectively the same I would imagine they are similar.

 

[allandwf]

Are we assuming the steel used is the same?

 

[mjheathcote]

Are we assuming the steel used is the same?

True if different grades of steel are used that will have an effect, but can't really imagine a different grade would have been used and if so, the mechanical properties difference compared to increased in diameter being small in calculation.

 

[allandwf]

It will depend on the tempering etc. Possibly the thinner bar has greater torsion strength, and the thicker one has less, but the end result is much the same. I am sure the bean counters will play there part, if say a thicker bar is cheaper than a thin one with the same properties but takes more to produce. The 4200 was produced with a much keener eye on price. Do we know what the GS has anti roll bar wise?

 

[adam01]

ARB measurements for a GS MCV

Front: 31mm
rear: 21mm

 

[mjheathcote]

ARB measurements for a GS MCV

Front: 31mm
rear: 21mm

Well that is interesting.
We need a standard GS owner to measure now and also a post 2003 4200.

 

[davy83]

The 3200 has one of 3 spring rates, i cant remember how you work out what you have there is a coloured band on it. my car had one spring different to the others and it was only doing corner weights that highlighted the problem. If you look at eurospares web site i think the different springs are all listed. the ARB dims are interesting, what would be more interesting is if we can determine which is the best compromise? presumably if it was stiffened up for the 4200 Maserati must have concluded that the 3200 was too soft in the corners, which sounds right.

 

[Andy]

Well that is interesting.
We need a standard GS owner to measure now and also a post 2003 4200.

Having a 4200cc from March 2004:

Front:31
Rear:21

 

[mjheathcote]

Having a 4200cc from March 2004:

Front:31
Rear:21

Thanks Andy.
Seeing that your sizes are the same as the MC Victory, one can only assume the GS will be the same too.

So it appears that the first generation 02 classico has 28/16 bars and then from the second generation to the end of production all variants have 31/21 bars. This ties in with the part numbers for the springs too with the same springs listed for all variants also from the second generation.
I guess a bit disappointing with the GS and MC Victory, although sold as more sporty, it appears the sporty is simply dropped slightly on the spring platforms and lower profile tyres.
The Formula Dynamics bars are significantly bigger being 38/24 so a significant reduction in roll stiffness is to be expected when fitted to all variants, especially first generation classico cars.
Regarding the 3200/AC the front bar appears weedy in comparison to the 42/GS. It would be interesting to know if the shape is the same, as a worthwhile benefit could possibly be gained by fitting the 42/GS bar. No idea on the 3200 rear bar diameter/shape.
Thanks for measuring guys.

 

[alfatwo]

The 3200's rear bar is an equally weedy 15mm, but then there's no weight at the rear"you don't want anymore oversteer"!! same with the AC version

It seems then since the early 3200's came out they progressively stiffened the later cars then fitted lower profile tyres and 19" rims and lots more grip on the last GS models...
Suppose that's normal development, as there's 10 years between the first 3200's and the last GS's..

What the classic 3200GT really needs is a 25mm front bar!

Dave

 

[Zep]

From what I have seen rooting around under my car and others, the front bars are different. The 3200 bar connects to a tie rod that is attached the the lower damper securing bolt while the 4200 / GS is attached to a specific bracket which is mounted a good 30mm or so inboard of the damper mount. This appears to be true for both early and late 4200.

As the mount is closer to the pivot on the 4200 / GS the effect of the thicker and stiffer bar would be reduced because the leverage at the mounting point would be greater.

As for fitting a newer bar to a 3200, the mounts don't look a million miles out and we know the lower arms have the bosses cast into them but not threaded so potentially possible. One useful upgrade appears to be fitting a later ARB to an early 4200...

 

[Contigo]

The 3200's rear bar is an equally weedy 15mm, but then there's no weight at the rear"you don't want anymore oversteer"!! same with the AC version

It seems then since the early 3200's came out they progressively stiffened the later cars then fitted lower profile tyres and 19" rims and lots more grip on the last GS models...
Suppose that's normal development, as there's 10 years between the first 3200's and the last GS's..

What the classic 3200GT really needs is a 25mm front bar!

Dave

The AC bar makes a mahoosive difference. I am still searching for one

 

[highlander]

The AC bar makes a mahoosive difference. I am still searching for one

Make sure you find two then please.
Would it be so difficult to get it engineered then?

 

[Contigo]

Make sure you find two then please.
Would it be so difficult to get it engineered then?

Nothing is impossible! I can get access to an AC one and see if I can get something made up if there is enough demand. From what I remember the AC ARB bushes are readily available too which makes things easier.