Front a-arm & suspension weight discussion

CMS-GT4

Active member
Sirius":2aeu17ui said:
I've just measured the distance between the rear (ST205) strut tops. As best I can get its 1113mm. Give or take a little.

Its a bit hard to get it accurately as the strut brace is in the way and the tops are recessed behind the plastic inner covers.

Thanks. The 185 strut tops are around 1105mm apart. So if our measurements are correct there is only a few mm difference on each side if at all. I would almost bet that both of our measurements are slightly off of accuracy and there is a good chance the mounting locations are pretty much the same. So I think it is safe to say that the 205 rear suspension can be used on a 185 and will increase the rear track.
Once I get other things done to the car, I will start on swapping these parts over.
 

phattyduck

New member
CMS-GT4":3d1615ju said:
So I think it is safe to say that the 205 rear suspension can be used on a 185 and will increase the rear track.
Once I get other things done to the car, I will start on swapping these parts over.
Its not only safe to say, its true. I already have a full ST205 rear end on my Camry Alltrac (all same P/N's for the rear end as the ST165/ST185). It widened the rear track by 2' - 2.2". You need all the arms and axles. You will also need 1 or 2 camber bolts on each side since adding that much to the track adds about 3* of camber.

-Charlie
 

RedCelicaTRD

Moderator
CMS-GT4":3dpqbasx said:
So I think it is safe to say that the 205 rear suspension can be used on a 185 and will increase the rear track.
Once I get other things done to the car, I will start on swapping these parts over.

The strut tops are the same distance apart. I run a st205 factory rear strut tower bar on my st185 and didn't have to modify anything.
 

Roundy

New member
gtfour77":1r4afw04 said:
Quick Wilwood part numbers that would work for our application:

Front Rotors: 160-7172 (right) 160-7173 (left)
Hats: 170-8132 (bolt pattern: 12x8.75")
Hat offset: 0.41"

All of this will fit the alltrac spindle without much trouble (simple single plane bracket like the one I posted in my autocross build)

Another daft question from me :D

The hat offset you have there, is that right?

I am only asking because the C5 rotors are 46mm total height (like our rotors) and the wilwood replacement guide for the corvette has a hat offset of 0.25" but the total height is right on the money.

However with some 0.3" thickness is could shift the rotor further outboard!

Seriously looking at upgrading my brakes, and just trying to work out things like this before i order any parts.
 

gtfour77

New member
Roundy":14v0ooaz said:
gtfour77":14v0ooaz said:
Quick Wilwood part numbers that would work for our application:

Front Rotors: 160-7172 (right) 160-7173 (left)
Hats: 170-8132 (bolt pattern: 12x8.75")
Hat offset: 0.41"

All of this will fit the alltrac spindle without much trouble (simple single plane bracket like the one I posted in my autocross build)

Another daft question from me :D

The hat offset you have there, is that right?

I am only asking because the C5 rotors are 46mm total height (like our rotors) and the wilwood replacement guide for the corvette has a hat offset of 0.25" but the total height is right on the money.

However with some 0.3" thickness is could shift the rotor further outboard!

Seriously looking at upgrading my brakes, and just trying to work out things like this before i order any parts.


The 0.41" offset should be correct, you might want to call Wilwood to confirm this though. The total offset is 46mm but the hat thickness should be right at 1/4" or 5mm which would make it a 41mm offset. (less hat thickness) I am currently working on a lightweight brake setup using 11.75" rotors and JSK (Datsun) lightweight aluminum hats. Will have pictures soon. (after I come back from the DC Pro Solo next weekend)
The rotors will be about 45% of the corvette rotor weight, about 12lb saving on each side.
 

sleeper

New member
Reviving this tread...
Did anyone make a new a-arm?

Would be REALLY nice to get one that is adjustable, and does not use normal bushings wich really binds up the arm..
 

CMS-GT4

Active member
I am talking to racerx right now on building mine. Just waiting for some warmer weather so I can measure some parts before mailing then off.
 

CMS-GT4

Active member
I did think about it, but I have a damaged arm already. For the work of getting it done plus the cost of making the extended ball joint I can just have a whole setup made that will get me plenty of adjustability.
 

gtfour77

New member
CMS-GT4":1jecu1fz said:
I did think about it, but I have a damaged arm already. For the work of getting it done plus the cost of making the extended ball joint I can just have a whole setup made that will get me plenty of adjustability.
Plus it's going to be a LOT nicer looking I am sure...:) Thanks for the shoutout on youtube by the way, I have been following your videos, keep up the good work! You make me wish I had my altar still! ;)
 

CMS-GT4

Active member
Thanks. A shout out is the least I can do for all you have done for our chassis, not to mention motivating us to go faster.
 

sleeper

New member
CMS-GT4":3ba39450 said:
I am talking to racerx right now on building mine. Just waiting for some warmer weather so I can measure some parts before mailing then off.


Hi.

Could you send me a PM with more info if you get him to make you something? Looking into changing alot of the stock parts myself..
 
sleeper":1d0uvbme said:
CMS-GT4":1d0uvbme said:
I am talking to racerx right now on building mine. Just waiting for some warmer weather so I can measure some parts before mailing then off.


Hi.

Could you send me a PM with more info if you get him to make you something? Looking into changing alot of the stock parts myself..



DITTO!!
 

CMS-GT4

Active member
I'll have no problem passing the info along. So far its looking like 3 others besides me will want it anyhow. I had been horribly sick the past few days with a stomach bug and had been unable to work on this. I did read some exerts from some chassis engineering books though, but I still want to see what I can figure out.

My big confusion now seems to be ride height. I had measured a low milage 185 suspension height late last year, and I now have a stock suspension on my car. It seems that the stock suspension I have now is higher than the suspension on the other 185. So I am referencing the bgb for correct ride height. They measure from the ground to the center of the bolt in the LCA. I had been using the method from the center of the axle to the fender. Anyhow, in the bgb I found the fwd and awd models both have different ride heights. I also found that if I am looking at their inclination angle drawing right, it looks like our scrub radius might be something like 0 from the factory.

The big thing I have been trying to work up is the roll center. I now have a better understanding as why to correct it from what I have been reading, but I do not have access to the suspension software for plotting it and calculating it for me. I did from mention of some open source software, but no links so far.
I have the measurements that Adrian took here: http://corner-carvers.com/forums/showth ... 371&page=2
I will try and look over them some. I think the simplest thing I can do is try and keep the arms parallel in relation to the axle like they are or with the ground, but I am unsure of actual camber gain ect. The mono ball pin will be adjustable, but he is making it to fit out spindles, so he wants me to get it close to what I need as is, and the adjustment would be for fine tuning.
 

bajallama

New member
With a caster of almost zero, I'm not surprised the scrub is zero. They probably made it that way since the car is very nose heavy and possibly wanted to reduce the stress on the steering components. Do you know how to use any CAD software? We used that in college for FSAE to measure our dynamic camber, kingpin inclination, associated scrub, roll center and akerman.
 

CMS-GT4

Active member
I know how to draw in cad, but no functions beyond that. All the 3d I do is in animation software. I have found a couple of spread sheets with calculations built in for all sorts of suspension calcs. I am going through them to see if I can input my measurements and get some results.

EDIT: I think I figured out what I want to do. I am going to take my measurements with the car at stock height. I will then pull off the front springs and then put the wheels at the height I want. From there I can take measurements of the angle I want to go with and how long of a ball stud it would require to obtain that. I just ran across a drawing that made the angle more clear to me. Also, looking at Adrian's drawings, he suggests at 1.9" that extending the LCA .5" and extending the ball joint .5" would reduce the roll couple by 1.5"
I am curious though if the same length LCA can be retained and a different length ball joint could be used to come to a similar result. I do think I prefer the method of changes LCA length vs the long stud though due to brake and wheel clearance.
 

MWP

New member
This guys subframe / arms are pretty popular. People are buying his stuff from all over the world.

Might be a good idea to model something of his work?

https://www.facebook.com/pages/RaceFab/ ... 13?fref=ts

11050291_10153141997014414_6541030487186824045_n.jpg
 
MWP":1t6048fa said:
This guys subframe / arms are pretty popular. People are buying his stuff from all over the world.

Might be a good idea to model something of his work?

https://www.facebook.com/pages/RaceFab/ ... 13?fref=ts

11050291_10153141997014414_6541030487186824045_n.jpg

Went to their website and its exactly what we need. The castor adjustment on some of the arms they make is pretty sweet. I'm sure the cost is up there, I'm guessing $2k+ for a set of front arms.... and i dont know how different 165 vs 185 arms are if they or anyone can make a set that would work for both....

wondering if my car will be competetive has been haunting me lately :(
 

CMS-GT4

Active member
I just checked part numbers for 165 and 185. The 165 has unique numbers for all its LCA parts. Seems even the 162 has different pn. I have seen claims of using 185 parts on them in the past, but I can not confirm it. I know the 165 uses a different sort of bushing than the 185.
 
Talking to klue the rear bushing is different but if the mounting holes in the chassis are the same then one arm should fit both. As long as the ball joint shaft diameter is the same....
 
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