Suspension modeling

[burgerkong]

Thanks for the post! I would assume that for a mainly street driven car, the Whiteline kit would still be fine? For $135 I am tempted to try them anyways.

Where are you finding them for $135?

 

[xXDavidCXx]

Right so say you take the 400lb/in spring we were talking about before and you have 2 degrees of roll which might put you through 0.5 inches of travel. Making up reasonable numbers here this would have to be modeled. This gives you 200lb of roll resistance.

Now a 22x2mm roll bar, depending on how its mounted, might provide on the order 100lb of roll resistance per degree of roll.

Its reasonable to say that in this case that half of the roll stiffness might come the bars and half the springs. Now street tires can only take so much wheel rate. In this case we need the roll bars to make up the difference.

I've calculated that the wheel rates for the Hochkis front bar on soft is 367 & stiff is 413.

I don't have any measurements of the OEM front bar, or the 034 rear bar. Let me know if you have those lying around.

 

[Raguvian]

Where are you finding them for $135?

https://rcagarage.com/shop/suspensi...roll-centre-bump-steer-correction-kit-kca472/

CYBER2020 gets you a few bucks more off. Not sure how much shipping would be to you in CA but for me it's $134 flat.

 

[Oversteermybagel]

I've calculated that the wheel rates for the Hochkis front bar on soft is 367 & stiff is 413.

I don't have any measurements of the OEM front bar, or the 034 rear bar. Let me know if you have those lying around.

I do not. But Hotchkis says their front bar is 95% stiffer than stock in soft and 125% in hard. 367/195=188 413/225=184. I'd guess 185 sounds about right

 

[burgerkong]

https://rcagarage.com/shop/suspensi...roll-centre-bump-steer-correction-kit-kca472/

CYBER2020 gets you a few bucks more off. Not sure how much shipping would be to you in CA but for me it's $134 flat.

Oh shit. Purchased.

 

[Oversteermybagel]

This is what I found for the rear. Cannot validate.

http://imgur.com/a/fgMUBCc

 

[tpellegr]

This is what I found for the rear. Cannot validate.

http://imgur.com/a/fgMUBCc

Superpro quotes 30% and 50% over OEM for both their front and rear bars depending on which setting used.

 

[xXDavidCXx]

I've calculated that the wheel rates for the Hochkis front bar on soft is 367 & stiff is 413.

I don't have any measurements of the OEM front bar, or the 034 rear bar. Let me know if you have those lying around.

I do not. But Hotchkis says their front bar is 95% stiffer than stock in soft and 125% in hard. 367/195=188 413/225=184. I'd guess 185 sounds about right

Okay, further investigation into my spread sheet found another error. The bar diameter was 1 inch, but should be 1.25 inches bringing the new bar rates to 934/1112.

And it's hollow, need to do more work the get the correct info.

 

[Raguvian]

Oh shit. Purchased.

Post a review! I'm going to order them but won't get them on for a while.

 

[burgerkong]

Post a review! I'm going to order them but won't get them on for a while.

Only thing I know is that it won't clear some BBK since some change the rotor offset which means the BJ now hit the rotors:

 

[00Zero]

I have found the following for the rear bars.

I haven't taken into account changes in the bar arm lengths. I know the diameters and thickness on the vw and eibach are correct (tuv certs and a call into eibach us) the rest are based on MFG quoted increase over GTI or bar dimension calculations.

Rear
Size	OD	Thickness	Stiffness	Increase over GTI	Solid dim	Stiffness
	[mm]	[mm]	[mm^4]	[%]	[mm]	[lb/in]
Golf	19.6	3	104581	-41%	18.0	196
GTI PP	20	--	160000		20.0	333
Clubsport S	21.7	3.6	177532	11%	20.5	369
22mm solid	22	--	234256	46%	22.0	488
whiteline mid	22.5	--	256289	60%	22.5	533
whiteline stiff	23	--	279841	75%	23.0	582
eibach eu	25	4.7	331401	107%	24.0	690
Hotchkis						716
eibach us	25	6.4	367736	130%	24.6	765
034 soft	25.4	--		153%	25.4	842
034 mid				164%		877
034 stiff				174%		912
HR Race	26		456976	186%	26.0	951
Neuspeed race	26.42		487227	205%	26.4	1014

 

[00Zero]

Similar data on front bars.

Front
Mfg.	OD	Thickness	Stiffness	Increase over GTI	Solid dim	Stiffness
	[mm]	[mm]	[mm^4]	[%]	[mm]	[lb/in]
	23.2	3.5	220828	-15%	21.7	136
	22		234256	-10%		144
vw	24	3.8	259437	0%	22.6	160
e-golf	25	4.0	307104	18%	23.5	189
	24		331776	28%	24.0	205
whiteline	24.5		360300	39%	24.5	222
	25		390625	51%	25.0	241
h&r	26		456976	76%	26.0	282
eibach EU	28	4	454656	75%	26.0	280
			505901	95%	26.7	312
			557789	115%	27.3	344
eibach US	29	6.35	636690	145%	28.2	393
	28		614656	137%	28.0	379

 

[xXDavidCXx]

I have found the following for the rear bars.

I haven't taken into account changes in the bar arm lengths. I know the diameters and thickness on the vw and eibach are correct (tuv certs and a call into eibach us) the rest are based on MFG quoted increase over GTI or bar dimension calculations.

Rear
Size	OD	Thickness	Stiffness	Increase over GTI	Solid dim	Stiffness
	[mm]	[mm]	[mm^4]	[%]	[mm]	[lb/in]
Golf	19.6	3	104581	-41%	18.0	196
GTI PP	20	--	160000		20.0	333
Clubsport S	21.7	3.6	177532	11%	20.5	369
22mm solid	22	--	234256	46%	22.0	488
whiteline mid	22.5	--	256289	60%	22.5	533
whiteline stiff	23	--	279841	75%	23.0	582
eibach eu	25	4.7	331401	107%	24.0	690
Hotchkis						716
eibach us	25	6.4	367736	130%	24.6	765
034 soft	25.4	--		153%	25.4	842
034 mid				164%		877
034 stiff				174%		912
HR Race	26		456976	186%	26.0	951
Neuspeed race	26.42		487227	205%	26.4	1014

There are only 2 holes for the 034 rear bar. The mid value does not exist.

 

[00Zero]

There are only 2 holes for the 034 rear bar. The mid value does not exist.

One side stiff and the other soft would be the middle setting.

 

[xXDavidCXx]

One side stiff and the other soft would be the middle setting.

Good point