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-   -   GT Steering knuckle differences (http://www.ptcruiserlinks.com/forum/showthread.php?t=63634)

myckee 20 May 2017 12:06 am

GT Steering knuckle differences
 
This topic has interested me for some time. When I first got my cruiser, I noted that there was a different part number for GTs than NA cars and I didn't understand what the difference was. I even mentioned that difference in one of my first posts here but nobody seemed to know why.

Here we are a few years later, and now I know the answer. I've been meaning to post about my findings with spindles for a while and just haven't found the time.

It began with me needing new wheel bearings and remembering having watched a video of Ed Peters, the infamous Chrysler engineer, on YouTube. The video lecture was sponsored by Modern Performance, and he was lecturing to SRT4 owners about the merits of swapping regular lighter brakes from a NA PT onto their SRT4 to reduce the unsprung weight of the car to gain a few extra HP. He then was speaking about how the 1st gen Neons could also benefit from the PT's brakes and that the manual Pts had a faster steering ratio due to the location of the drilled hole for the outer tie rod. The manual cars had the hole drilled closest to the knuckle giving a slightly faster ratio than the automatics. Interesting!

So, when I pulled off the spindles on my 03 Dream 5spd, I was shocked to see that the drilled hole was the furthest away from the knuckle giving the slowest steering ratio. :eek: So began the quest to find the 'better' manual knuckles from a NA car.

I found them on an 05 NA 5spd PT at the local yard and bought them. I also bought a set from an 03 NA Automatic to compare. My yard actually has a decent return policy so there was no risk involved. When I compared the knuckles I had, the originals from the car, and the two pair I bought at the junkyard, I found out that despite the difference in part number in the parts catalogue, all of the knuckles actually have the same part number cast into them. It would appear that the different part numbers specified where the tie rod hole was drilled. Otherwise the knuckles are identical. The yard also had an 04 GT Automatic, and I noticed that it had the same 'slow ratio' tie rod hole drilled in it, the same as my GT 5spd. You can see a picture below showing the hole location difference I am speaking about. The picture is showing passenger side knuckles.

What I found was that my 03 GT 5spd had the slowest steering ratio, the 03 NA Automatic had an intermediate steering ratio, and the 05 NA 5spd had the fastest. I decided I would use those faster, 'better' 05 mtx knuckles So, since I don't have my own press, I took my new to me 05 NA mtx knuckles to a local shop and had them press in my new Timken SET49 wheel bearings I had bought from Rock Auto last year, in anticipation of the inevitable wheel bearing replacement sometime in the future. That time had finally come.

I installed those 05 NA 5spd knuckles on the 03 GT DC2 5spd. Since the tie rods had to be lengthened around 1/2-3/4inch, to reach the new tie rod hole, I just eyeballed the new setting to get the toe decent enough to test drive it and then drive it to the shop to get an alignment.

To be honest, I didn't really feel any difference in the quickness of the steering. In theory I would have to turn the wheel slightly less with these new knuckles to achieve the same turn on the originals. The difference was not apparent enough for me to feel, although no doubt it was there. What I did find though, was that with these new knuckles, my turning radius was horrendous!!

Now I understood the complaints from NA cruisers complaining about how they needed to do a 3 point turn to park their car. I always just assumed they were bad drivers, since, in my GT, I didn't find it too bad at all. Sure, it was not as good as my 01 Intrepid, but not nearly as bad as I heard some others complain. Well, now I understood their complaints. I needed to investigate this to see why my steering radius was now so terrible.

What I found was that on the GT's the engineers sacrificed the steering ratio in favour of giving the car a better turning radius. By drilling the hole furthest inboard, shortened the tie rod arm length and allowed the knuckle to be pulled as tight as possible to the control arm when turning, on one side, and as far out as possible on the other. This yielded the best turning radius, but at a slightly slower steering ratio. Since the steering ratio, at least to me, was really not apparent, but the turning radius was, I believe the engineers made the right compromise. The NA Automatic knuckles, which have the hole in the middle of the pad are right in the middle. They offer a median steering ratio and a median turning radius. So their turning radius is not as poor as the manual NA knuckle but poorer than the GT knuckle.

What it boils down to is the knuckles are all interchangeable from 02-10. The difference lies in the steering ratio and turning radius. I have found that the steering ratio difference is insignificant, but the turning radius change can be very significant. All you NA drivers out there would really benefit from installing GT knuckles on your car, especially the 5spd NA cars!

http://myckee.altervista.org/stuff/knuckles.jpg

pasadenahotrod03Dreamer 20 May 2017 01:19 am

Re: GT Steering knuckle differences
 
That is interesting information. So, are the outer tierod ends different in length on all three application or is there enough threads to safely use one on al, I wonder?

rckstein 20 May 2017 01:33 am

Re: GT Steering knuckle differences
 
Quote:

Originally Posted by pasadenahotrod03Dreamer (Post 654585)
That is interesting information. So, are the outer tierod ends different in length on all three application or is there enough threads to safely use one on al, I wonder?

Looking at the RockAuto catalog and using the the pic from myckee, their catalog lists the same part numbers for the inner and outer tie rod ends for all 3 models.

VsandFords 20 May 2017 07:08 am

Re: GT Steering knuckle differences
 
This is great information to have. Great to know that all years will interchange. Also great to know that you should check the tie rod placement in the spindle/knuckle if replacing only one side.

Busted_PT 20 May 2017 09:30 am

Re: GT Steering knuckle differences
 
Quote:

Originally Posted by VsandFords (Post 654593)
This is great information to have. Great to know that all years will interchange. Also great to know that you should check the tie rod placement in the spindle/knuckle if replacing only one side.

All knuckles are no the same. There is the early ones with the narrow bearing. Not sure if this extends to 02s or not. :cool:

Jeffz 20 Nov 2018 05:36 pm

Re: GT Steering knuckle differences
 
Interesting. My experience is seemingly the opposite of what you are saying.
I bought a 2002 PT Limited NA, MT, brand new. Drove and loved it for 9 years 'til
it needed timing belt, engine mounts, etc.
Years later, bought (still have) a 2003 GT turbo AT. Never thought about turning radius until after buying this car. Noticed early on that this car's turning radius is
appreciably larger, no doubt about it. You can't tell during normal driving, but when you go to turn around on a narrow street, you sure notice. I bought this car used, so maybe parts have been changed.
I welcome other opinions on this.

Handy_Cruiser 20 Nov 2018 08:01 pm

Re: GT Steering knuckle differences
 
1 Attachment(s)
Quote:

Originally Posted by Jeffz (Post 697115)
Interesting. My experience is seemingly the opposite of what you are saying.
I bought a 2002 PT Limited NA, MT, brand new. Drove and loved it for 9 years 'til
it needed timing belt, engine mounts, etc.
Years later, bought (still have) a 2003 GT turbo AT. Never thought about turning radius until after buying this car. Noticed early on that this car's turning radius is
appreciably larger, no doubt about it. You can't tell during normal driving, but when you go to turn around on a narrow street, you sure notice. I bought this car used, so maybe parts have been changed.
I welcome other opinions on this.

Why not check the location of the holes. You should be able to just snap a photo with your cell phone from the underside to tell where the holes are in the casting. ;)

PS: Here's mine. I just took my own advice, went out to my PT in the dark, bent down and took five photos blind from behind the driver side wheel where I figured the tie rod was. It literally took less than one minute.

According to Myckee's guide, looks like my 2007 Turbo Touring Vert has the holes in the middle. :cool:

http://www.ptcruiserlinks.com/forum/...1&d=1542762425

rckstein 20 Nov 2018 08:33 pm

Re: GT Steering knuckle differences
 
Quote:

Originally Posted by Jeffz (Post 697115)
Interesting. My experience is seemingly the opposite of what you are saying.
I bought a 2002 PT Limited NA, MT, brand new. Drove and loved it for 9 years 'til
it needed timing belt, engine mounts, etc.
Years later, bought (still have) a 2003 GT turbo AT. Never thought about turning radius until after buying this car. Noticed early on that this car's turning radius is
appreciably larger, no doubt about it. You can't tell during normal driving, but when you go to turn around on a narrow street, you sure notice. I bought this car used, so maybe parts have been changed.
I welcome other opinions on this.

When you had your '02 there was no Turbo so there was only 1 steering knuckle used.

When you got your '03 GT there were different knuckles used based on the GT and NA, and what transmission was also in the car (according to the Parts Catalog).

That may be why you now notice a difference over the 2 PT's that you've owned. ;)

Rob_2002 28 May 2019 07:09 pm

Re: GT Steering knuckle differences
 
Greeting to all,

Can anyone offer information regarding using later steering knuckles on the pre 03 cars?

I understand that the bearings in the early (08/10/01, 11-24-01 or 11-27-01 -I've seen a few cutoff dates) model years 2001 and 2002 are 33 mm bearings.

The 2003 to the 2010 bearings are 39 mm.

Aside from the wider bearings and presumably corresponding hubs, does anyone know what would preclude upgrading the early car to the later steering knuckles?

The old ones knuckles in recycling places are starting to get hard to find and the hub and bearing set (SKF) is close to three hundred dollars a side now, with limited quantities available.

Any insight into what might be different and if any modifications could be performed by a machine shop to adapt the later versions to an 01/02 car.

Thanks in advance for any comments.

myckee 29 May 2019 09:29 am

Re: GT Steering knuckle differences
 
You can install the newer knuckle in your 01 without any issue. Of course you would need to have a wheel alignment done. I recommend the GT knuckle since you will get a bit better turning radius with them. There really is a noticeable difference. I had installed the knuckle from an 05, non turbo, manual car because, in theory, it would offer quicker steering. While I didn't notice the quicker steering, the turning radius went from "okay" to horrendous immediately.


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