free castor mod? - Page 3

stretch · 05-23-2007, 03:13 PM

Quote:

Originally Posted by mxpop

It's little enough to be a non-issue.

Sure?

The lines drawn in this picture below shows what three degrees of movement looks like. The ALK + caster mod probably do more than that, but I don't know how much the ALK moves the mount outwards. That may only be a faction of an inch of forced deflection in the bushing, but that's a helluva important bushing that carries a lot of load. It makes me nervous. Did you have to muscle the A-arm into place after doing both modifications?

lackskill · 05-23-2007, 03:45 PM

Quote:

Originally Posted by AnorexicSTI

I've been researching ALK... seems like Whiteline, GTspec, and Perrin are the 3... with Whiteline being the original.... I can't stand that eye piercing yellow!!! They should come out with a more conservating color or something... good thing it's at least in a spot where we can't see it unless working on the car.

So in theory, do you think this free castor mod would work even with an aftermarket ALK for even MORE castor? I noticed the Whiteline bushing is ALREADY offset in the middle... so this would push it out even FURTHER... I wonder if the other connection point of the A arm will have enough play to allow this.

did you do this free castor mod prior to when we pulled your motor? that would explain the difficulty we had bolting your control arms back up.

AnorexicSTI · 05-23-2007, 04:06 PM

Quote:

Originally Posted by lackskill

did you do this free castor mod prior to when we pulled your motor? that would explain the difficulty we had bolting your control arms back up.

Not unless the previous owner did it or we switched it by accident when we removed the stud from the LCA.

AnorexicSTI · 05-23-2007, 04:09 PM

Quote:

Originally Posted by stretch

Sure?

The lines drawn in this picture below shows what three degrees of movement looks like. The ALK + caster mod probably do more than that, but I don't know how much the ALK moves the mount outwards. That may only be a faction of an inch of forced deflection in the bushing, but that's a helluva important bushing that carries a lot of load. It makes me nervous. Did you have to muscle the A-arm into place after doing both modifications?

TiC needs to come out with a bushing where the metal insert goes in at a 3 degree angle to compensate

. I wonder how hard that would be to make bushings where the holes are slanted 3 degrees... either that or somebody needs to come out with an alum. insert that corrects 3 degrees and then TiC can come out with a smaller bushing/smaller insert to go on there. Shouldn't be too hard to machine up.

CGMDan · 05-23-2007, 04:32 PM

tr

Quote:

Originally Posted by AnorexicSTI

I've been researching ALK... seems like Whiteline, GTspec, and Perrin are the 3... with Whiteline being the original.... I can't stand that eye piercing yellow!!! They should come out with a more conservating color or something... good thing it's at least in a spot where we can't see it unless working on the car.

So in theory, do you think this free castor mod would work even with an aftermarket ALK for even MORE castor? I noticed the Whiteline bushing is ALREADY offset in the middle... so this would push it out even FURTHER... I wonder if the other connection point of the A arm will have enough play to allow this.

It's starts getting to the point of asking how much caster is too much. Yes some cars are designed with greater amount of caster, but how much can you safetly add to the STi?
I've got the WL ALK and already notice the power steering having "issues" when turning the wheel at idle.
I've got RCE springs and get rubbing on the wheel well when turning the wheel say 50% and braking at the same time at slow speeds, or turning the wheel and going over bumps at slow speeds.

I don't think I would want to add more caster.

lackskill · 05-23-2007, 04:34 PM

Quote:

Originally Posted by AnorexicSTI

Not unless the previous owner did it or we switched it by accident when we removed the stud from the LCA.

that thing doesnt spin by accident on your car at least.

AnorexicSTI · 05-23-2007, 04:42 PM

Quote:

Originally Posted by CGMDan

tr

It's starts getting to the point of asking how much caster is too much. Yes some cars are designed with greater amount of caster, but how much can you safetly add to the STi?
I've got the WL ALK and already notice the power steering having "issues" when turning the wheel at idle.
I've got RCE springs and get rubbing on the wheel well when turning the wheel say 50% and braking at the same time at slow speeds, or turning the wheel and going over bumps at slow speeds.

I don't think I would want to add more caster.

Are your tires bigger than the stock dia of 24.9" when new? I'm thinking of just doing the Whiteline ALK without turning that stud around and calling it a day.

thrlskr · 05-23-2007, 05:31 PM

Dan,

What are your alignment specs?

mxpop · 05-23-2007, 05:46 PM

Quote:

Originally Posted by stretch

Sure?

The lines drawn in this picture below shows what three degrees of movement looks like. The ALK + caster mod probably do more than that, but I don't know how much the ALK moves the mount outwards. That may only be a faction of an inch of forced deflection in the bushing, but that's a helluva important bushing that carries a lot of load. It makes me nervous. Did you have to muscle the A-arm into place after doing both modifications?

Unless I am brain-farting, your pic shows what would be an alignment change (kinda), not a caster change.

An ALK locates the rear pivot LOWER (downward, not inward/outward) which rotates the entire arm backwards for a more slack steering angle (thus adding caster). That is why spacers are needed to clear the "U"-shaped front brace as the ALK (and it's new pivot location) now sits lower and would interfere without spacers.

As for a potential bind situation, mine went together freely and without any indication of binding etc. I did have to regrease the bushings after a rain race because they started squeeking. When I regreased them, they still felt free. It's poss that they may bind at extreme travel/angles but I'm not worried about it after over 10k miles and many successful race days.

CGMDan · 05-23-2007, 06:19 PM

Quote:

Originally Posted by AnorexicSTI

Are your tires bigger than the stock dia of 24.9" when new? I'm thinking of just doing the Whiteline ALK without turning that stud around and calling it a day.

I am and have been running A046's, so 235/45/17.

Alignment.... About -2.5* up front.

thrlskr · 05-23-2007, 06:55 PM

Dan, caster not camber.

CGMDan · 05-23-2007, 10:26 PM

Once evened out I gained about .75*. So without digging out my last alignment sheet I think I'm at about 5.25*.

I did take pic tonight of what rubbing. As soon as I get them onto photobucket I'll post them.

stretch · 05-24-2007, 02:55 AM

Quote:

Originally Posted by mxpop

Unless I am brain-farting, your pic shows what would be an alignment change (kinda), not a caster change.

An ALK locates the rear pivot LOWER (downward, not inward/outward) which rotates the entire arm backwards for a more slack steering angle (thus adding caster). That is why spacers are needed to clear the "U"-shaped front brace as the ALK (and it's new pivot location) now sits lower and would interfere without spacers.

That's what the "anti-lift" part of the kit does, but the kit also positions the rear A-arm bushing further out from the center of the car. This pivots the a-arm out and forwards, which is where the additional caster comes from. That's exactly what this free caster mod does, too.

Greg · 05-24-2007, 07:29 AM

^^^ Another way to think about it is to consider that if you want to affect caster you have to either move ball joint (forward or back) or move the upper strut bearing (forward or back). Lowering the rear mount of the control arm does neither. Moving the rear control arm bushing outboard spins the control arm a small amount effectively pushing the ball joint forward a tiny bit.

Without the ALK, as the control arm moves up and down, the ball joint moves forward under compression and backward under rebound. As a result the pre-ALK configuration provides some small amount dynamic caster. Technically, the ALK removes a bit of that dynamic caster by making the control arm parallel with the ground. This may be why WL choose to add a bit back in. But its more likely that is because they could and a little more caster is a good thing.

fullerton · 10-25-2007, 06:20 AM

anyone with long-term updates on this?

any noticeable bushing wear?

05-23-2007, 05:31 PM	#38
thrlskr The Next Petter Solberg Car: 05 WRX STi Fav Mod: Seat Time Location: San Diego, CA Posts: 916 Join Date: Mar 2005 Trader Rating: (4)	Re: free castor mod? Dan, What are your alignment specs?

05-23-2007, 06:55 PM	#41
thrlskr The Next Petter Solberg Car: 05 WRX STi Fav Mod: Seat Time Location: San Diego, CA Posts: 916 Join Date: Mar 2005 Trader Rating: (4)	Re: free castor mod? Dan, caster not camber.

05-23-2007, 10:26 PM	#42
CGMDan Spec C Club Car: '05 CGM STi Fav Mod: What's RCE made lately? Location: Beaverton, Or Posts: 1,467 Join Date: Nov 2004 Trader Rating: (0)	Re: free castor mod? Once evened out I gained about .75. So without digging out my last alignment sheet I think I'm at about 5.25. I did take pic tonight of what rubbing. As soon as I get them onto photobucket I'll post them.

05-24-2007, 07:29 AM	#44
Greg Silver Member Car: 2006 - CGM Location: Western Washington Posts: 829 Join Date: Nov 2005 Trader Rating: (0)	Re: free castor mod? ^^^ Another way to think about it is to consider that if you want to affect caster you have to either move ball joint (forward or back) or move the upper strut bearing (forward or back). Lowering the rear mount of the control arm does neither. Moving the rear control arm bushing outboard spins the control arm a small amount effectively pushing the ball joint forward a tiny bit. Without the ALK, as the control arm moves up and down, the ball joint moves forward under compression and backward under rebound. As a result the pre-ALK configuration provides some small amount dynamic caster. Technically, the ALK removes a bit of that dynamic caster by making the control arm parallel with the ground. This may be why WL choose to add a bit back in. But its more likely that is because they could and a little more caster is a good thing.

10-25-2007, 06:20 AM	#45
fullerton abracious Car: AW GDF-D Fav Mod: Track time Location: Near a 100oct pump Posts: 16,562 Join Date: Oct 2005 Trader Rating: (10)	Re: free castor mod? anyone with long-term updates on this? any noticeable bushing wear? This ad is not endorsed by this member. Please register or login to hide this ad.