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Mr.Oldskool
Samba Member
Joined: November 04, 2012
Posts: 27
Location: Belgium
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 Posted: Tue Jul 12, 2022 1:50 am Post subject: rack and pinion question |
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ok, so hear me out.
I'm in the process of sourcing al the parts for a rack and pinion conversion. I just prefer the predictability of a rack and pinion over the old steering box.
But in my quest to find al the parts it seems that the rack and pinion of a polo 86c is the way to go because the connecting rods are longer and prevent bump steer. witch I understand, BUT:
why do all the big cars have the rack and pinion setup were the rods connect to both the outer ends of the rack? porsche has it, the newer vw's have it. Porsche 924 en 944 that see a lot of trackdays tend to use a golf MK1 R&P because of the shorter steering ratio. Hell, even the mazda guys upgrade the first gen RX7's to golf MK1 R&P//
I understand dat the rods are at an angle on the spindles of a beetle, but this can be overcome with a bump steer kit?
is there an other reason I don't see why aircooled folks prefer the polo rack?
thank you,
glauco |
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Era Vulgaris
Samba Member
Joined: August 22, 2012
Posts: 1916
Location: Raleigh, NC
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| Posted: Tue Jul 12, 2022 5:26 am Post subject: Re: rack and pinion question |
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You don't need to source the parts separately
https://www.kerscher-tuning.de/kaefer/index.php?gruppe1=Lenkung&gruppe2=Lenkung
I think the polo rack is popular because it fits in the very limited space that's available, the design of the mount has been proven, and it works with no modifications to the double trailing arm front suspension.
But it's not the only one people use. These are quite a bit more work to install though
https://www.coolrydescustoms.com/t-1-front-suspension.html
https://www.red9design.co.uk/type1.htm
_________________
Currently own:
66 Karmann Ghia, L390 Gulf Blue, under construction, here: www.thesamba.com/vw/forum/viewtopic.php?t=760505&highlight=
99 Mazda MX-5 10AE, Sapphire Blue Mica, 6 speed, LSD
Previously owned:
98 Porsche Boxster, silver, 2.5L -- 67 Karmann Ghia, Black, 1500sp -- 98 BMW Z3, Atlanta Blue Metallic, 2.8L I6 -- 75 Porsche 914, Laguna Blue, 2270cc -- 72 Porsche 914, Signal Orange, 1.7 FI -- 74 Karmann Ghia, Black, 1600dp -- 74 Triumph TR6 with O.D., sapphire blue |
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Braukuche
Samba Member
Joined: September 03, 2004
Posts: 11204
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| Posted: Tue Jul 12, 2022 7:22 am Post subject: Re: rack and pinion question |
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I’d stay away from Coolrydes, check his feedback.
_________________
Go Reds! Smash state!
Retirement is here!
1960 double cab
1960 Baja Bug
1963 stretched double cab
1962 Golde sunroof Ghia
1963 356 B coupe
1963 Notchback
1967 21 window less rusty now
1989 Westfalia |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 13291
Location: North Carolina
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| Posted: Tue Jul 12, 2022 7:30 am Post subject: Re: rack and pinion question |
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I’m still trying to figure out how the stock steering is “unpredictable”.
_________________
Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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Mr.Oldskool
Samba Member
Joined: November 04, 2012
Posts: 27
Location: Belgium
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| Posted: Tue Jul 12, 2022 7:58 am Post subject: Re: rack and pinion question |
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It is when you don't want to pay 900euro for a rack and pinion that costs 100euro and a bracket that's nothing more than some pieces of steel.. |
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Mr.Oldskool
Samba Member
Joined: November 04, 2012
Posts: 27
Location: Belgium
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| Posted: Tue Jul 12, 2022 7:59 am Post subject: Re: rack and pinion question |
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| TDCTDI wrote: |
| I’m still trying to figure out how the stock steering is “unpredictable”. |
Mine is, especially with the dropped spindles, but that's another story.. |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 13291
Location: North Carolina
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| Posted: Tue Jul 12, 2022 9:28 am Post subject: Re: rack and pinion question |
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| Mr.Oldskool wrote: |
| TDCTDI wrote: |
| I’m still trying to figure out how the stock steering is “unpredictable”. |
Mine is, especially with the dropped spindles, but that's another story.. |
I’m thinking that there is more to the story than just dropped spindles.
Other than a slight increase in track width (yes, this does alter geometry.), and caster angle (if the rear isn’t also lowered.), drop spindles should have no effect on steering geometry.
_________________
Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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Mr.Oldskool
Samba Member
Joined: November 04, 2012
Posts: 27
Location: Belgium
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| Posted: Tue Jul 12, 2022 9:48 am Post subject: Re: rack and pinion question |
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| TDCTDI wrote: |
| Mr.Oldskool wrote: |
| TDCTDI wrote: |
| I’m still trying to figure out how the stock steering is “unpredictable”. |
Mine is, especially with the dropped spindles, but that's another story.. |
I’m thinking that there is more to the story than just dropped spindles.
Other than a slight increase in track width (yes, this does alter geometry.), and caster angle (if the rear isn’t also lowered.), drop spindles should have no effect on steering geometry. |
+ camber is way of also, I'm no longer able to get them to zero, let alone negative camber. Bump steer also went from bad to worse, because I changed the angle of the adjustable axle as wel.
I just want to start from scratch and modernise the ghia after 15 years of ownership, and for me, that consists of a more modern rack and pinion. |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 13291
Location: North Carolina
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| Posted: Tue Jul 12, 2022 10:20 am Post subject: Re: rack and pinion question |
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“Adjustable axle”?
I’m guessing that you installed a narrowed, adjustable beam, if so, this is where your problem lies.
By making the beam shorter, the tie rods must be shorter, when you lower the adjustable beam, the short side tie rod (driver side) is now at a pretty nasty angle.
A rack & pinion will help this out, but there is still going to be a lot of horrific geometry
_________________
Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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Mr.Oldskool
Samba Member
Joined: November 04, 2012
Posts: 27
Location: Belgium
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| Posted: Tue Jul 12, 2022 11:02 am Post subject: Re: rack and pinion question |
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| TDCTDI wrote: |
“Adjustable axle”?
I’m guessing that you installed a narrowed, adjustable beam, if so, this is where your problem lies.
By making the beam shorter, the tie rods must be shorter, when you lower the adjustable beam, the short side tie rod (driver side) is now at a pretty nasty angle.
A rack & pinion will help this out, but there is still going to be a lot of horrific geometry |
not narrowed, but yes, adjustable front axle, or beam, if you will.
I didn't want a narrowed axle because that wil stiffen the ride, witch is stif enough for my likings, especially with the koni dampers..
the geometry is what is is, but the cars stance is like I want it so it will have to do..
I added double caster shims so the caster should be better. I also added a extra range camber nut, but that didn't help, I might consider bent upper control arms for this.
but this wasn't the question..  |
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Era Vulgaris
Samba Member
Joined: August 22, 2012
Posts: 1916
Location: Raleigh, NC
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| Posted: Tue Jul 12, 2022 1:20 pm Post subject: Re: rack and pinion question |
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| Mr.Oldskool wrote: |
It is when you don't want to pay 900euro for a rack and pinion that costs 100euro and a bracket that's nothing more than some pieces of steel.. |
Well it's a bit more than just a bracket. But a bracket that fits correctly on the first install. I first tried alex77's kit from the classifieds that was significantly less expensive, and it didn't fit at all.
But beyond the rack mounting bracket, there's also the adapter bracket to connect the tie rods to the rack, the tie rods themselves, the inner tie rod ends, the adapter for the steering column, the u-joint, all the hardware, etc etc and that's all in the Kerscher kit....and all of it fit perfect on the first try. No guesswork, no fucking around, no time wasted.
The time saved from having to source and fabricate all of that was worth it to me. And I also didn't pay $900 euros, but this was a couple years ago when it was a good bit less expensive, and I also didn't have to pay VAT.
_________________
Currently own:
66 Karmann Ghia, L390 Gulf Blue, under construction, here: www.thesamba.com/vw/forum/viewtopic.php?t=760505&highlight=
99 Mazda MX-5 10AE, Sapphire Blue Mica, 6 speed, LSD
Previously owned:
98 Porsche Boxster, silver, 2.5L -- 67 Karmann Ghia, Black, 1500sp -- 98 BMW Z3, Atlanta Blue Metallic, 2.8L I6 -- 75 Porsche 914, Laguna Blue, 2270cc -- 72 Porsche 914, Signal Orange, 1.7 FI -- 74 Karmann Ghia, Black, 1600dp -- 74 Triumph TR6 with O.D., sapphire blue
Last edited by Era Vulgaris on Tue Jul 12, 2022 1:32 pm; edited 4 times in total |
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Era Vulgaris
Samba Member
Joined: August 22, 2012
Posts: 1916
Location: Raleigh, NC
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| Posted: Tue Jul 12, 2022 1:23 pm Post subject: Re: rack and pinion question |
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| TDCTDI wrote: |
| I’m still trying to figure out how the stock steering is “unpredictable”. |
I've always thought the VW box was absolute garbage. I wouldn't necessarily call it unpredictable, but it's certainly not stable. Just the fact that there's an acceptable amount of play, I find unacceptable.
_________________
Currently own:
66 Karmann Ghia, L390 Gulf Blue, under construction, here: www.thesamba.com/vw/forum/viewtopic.php?t=760505&highlight=
99 Mazda MX-5 10AE, Sapphire Blue Mica, 6 speed, LSD
Previously owned:
98 Porsche Boxster, silver, 2.5L -- 67 Karmann Ghia, Black, 1500sp -- 98 BMW Z3, Atlanta Blue Metallic, 2.8L I6 -- 75 Porsche 914, Laguna Blue, 2270cc -- 72 Porsche 914, Signal Orange, 1.7 FI -- 74 Karmann Ghia, Black, 1600dp -- 74 Triumph TR6 with O.D., sapphire blue |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 13291
Location: North Carolina
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| Posted: Tue Jul 12, 2022 1:33 pm Post subject: Re: rack and pinion question |
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| Mr.Oldskool wrote: |
but this wasn't the question.. |
No, it wasn’t. I am trying to unpack all of the potential fuckery that you may have caused with aftermarket crap that would cause the stock steering to not work correctly.
Yes, the short driver side tie rod is a source of bump steer which is only exaggerated by extreme angles caused by excessive lowering. A “bump steer kit” will help a bit by straightening the angles, as will flipped tie rods.
Since a lot of the posters here are in the US, & Polos weren’t imported to the US market, that particular rack is not going to be as popular due to availability.
Rabbit racks are more popular due to availability and the fact that a majority of cars newer than that are equipped with power steering.
_________________
Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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Ian Godfrey
Samba Member
Joined: September 25, 2006
Posts: 1204
Location: Melbourne Australia
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| Posted: Tue Jul 12, 2022 3:39 pm Post subject: Re: rack and pinion question |
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Glauco, the golf rack has tie rods that are about the same length as the lower suspension arms on a 924/944 so that gives them the least bump steer. I've got a golf rack with special tie rods on my Mendeola suspension for the same reason. I have less than 1mm of bump steer over 100mm of suspension travel. Another reason is you can get RHD and LHD quick steer racks for the Golf from Quaife to make them more responsive.
With a beam suspension you need the tie rods as long as possible to reduce the bump steer, so a polo rack with the inner tie rods ends almost touching each other in the middle is the best answer. The short Golf tie rods would be terrible, worse than the stock steering. I've got one of the Polo racks for a beam front end. It has more bump steer than the Golf/Mendeola set up, but pretty good. I hope this helps. |
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Ian Godfrey
Samba Member
Joined: September 25, 2006
Posts: 1204
Location: Melbourne Australia
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| Posted: Tue Jul 12, 2022 4:10 pm Post subject: Re: rack and pinion question |
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Thinking about the old suspension when going fast....
we'll take it as a given that lower is better, so now you need to rotate the steering box on the tube to get the bump steer back in spec and now it doesn't line up with the steering shaft. so maybe add a double uni joint. In my case I also added a channel in the top of the pan so the longer tie rod could sit lower after the steering box was rotated.
And as the front of the car drops you need more caster, so either single or double caster shims. It's lucky you added the uni joints in the steering shaft.
Then you need some neg camber so camber eccentrics go in. Still not enough neg camber? so now bend the top arms in.
all this means you have to shorten the tie rods a bit so the bump steer gets a bit worse again, and different side to side.
next step is the polo rack, it gets rid of the annoying play when the wheel is straight ahead and evens out the feel side to side and you don't need the pocket in the top of the tunnel and the bumps steer is the same side to side, not too much and predictable.
apologies for the long rave but I have been working on this for years on my road race Ghia  |
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Ian Godfrey
Samba Member
Joined: September 25, 2006
Posts: 1204
Location: Melbourne Australia
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| Posted: Tue Jul 12, 2022 4:21 pm Post subject: Re: rack and pinion question |
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Thinking about the old suspension when going fast....
we'll take it as a given that lower is better, so now you need to rotate the steering box on the tube to get the bump steer back in spec and now it doesn't line up with the steering shaft. so maybe add a double uni joint. In my case I also added a channel in the top of the pan so the longer tie rod could sit lower after the steering box was rotated.
And as the front of the car drops you need more caster, so either single or double caster shims. It's lucky you added the uni joints in the steering shaft as now the long tie rod really bangs into the top of the tunnel 
Then you need some neg camber so camber eccentrics go in. Still not enough neg camber? so now bend the top arms in.
all this means you have to shorten the tie rods a bit so the bump steer gets a bit worse again, and different side to side.
next step is the polo rack, it gets rid of the annoying play when the wheel is straight ahead and evens out the feel side to side and you don't need the pocket in the top of the tunnel and the bumps steer is the same side to side, not too much and predictable.
apologies for the long rave but I have been working on this for years on my road race Ghia
here's the version before the rack:
note the cut back shock towers so I have reasonable steering lock |
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SandHamwich
Samba Member
Joined: April 26, 2020
Posts: 102
Location: Orangevale
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| Posted: Tue Jul 12, 2022 10:25 pm Post subject: Re: rack and pinion question |
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| Ian, can you please share where you acquired that front sway bar setup? |
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Mr.Oldskool
Samba Member
Joined: November 04, 2012
Posts: 27
Location: Belgium
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| Posted: Tue Jul 12, 2022 11:50 pm Post subject: Re: rack and pinion question |
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| Ian Godfrey wrote: |
Thinking about the old suspension when going fast....
we'll take it as a given that lower is better, so now you need to rotate the steering box on the tube to get the bump steer back in spec and now it doesn't line up with the steering shaft. so maybe add a double uni joint. In my case I also added a channel in the top of the pan so the longer tie rod could sit lower after the steering box was rotated.
And as the front of the car drops you need more caster, so either single or double caster shims. It's lucky you added the uni joints in the steering shaft as now the long tie rod really bangs into the top of the tunnel
Then you need some neg camber so camber eccentrics go in. Still not enough neg camber? so now bend the top arms in.
all this means you have to shorten the tie rods a bit so the bump steer gets a bit worse again, and different side to side.
next step is the polo rack, it gets rid of the annoying play when the wheel is straight ahead and evens out the feel side to side and you don't need the pocket in the top of the tunnel and the bumps steer is the same side to side, not too much and predictable.
apologies for the long rave but I have been working on this for years on my road race Ghia
here's the version before the rack:
note the cut back shock towers so I have reasonable steering lock |
this is the explanation I was looking for. And it makes perfect sense. I'm glad that I'm not the only one getting who's getting headache from the geometry..  .
I considered getting the best out of the stock steering box, but the amount of work it would take couldn't justify the simplicity of the polo rack and therefor I want to go that route..
I'm also going to bend the upper control arms, do you by any chance know how much they have to be bent?
thank you for the great explanation! |
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Ian Godfrey
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Joined: September 25, 2006
Posts: 1204
Location: Melbourne Australia
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Era Vulgaris
Samba Member
Joined: August 22, 2012
Posts: 1916
Location: Raleigh, NC
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| Posted: Wed Jul 13, 2022 5:55 am Post subject: Re: rack and pinion question |
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| Ian Godfrey wrote: |
next step is the polo rack, it gets rid of the annoying play when the wheel is straight ahead and evens out the feel side to side and you don't need the pocket in the top of the tunnel and the bumps steer is the same side to side, not too much and predictable.
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So glad to hear you have experience with this. I didn't know of anyone with experience running this setup, so have kind of been forging ahead on my own. That horrible play when the wheel is straight is the whole reason I went down this path with the polo r&p setup.
I'm running the polo rack on 2.5" drop spindles on a stock width beam. Do you have any recommendations for my setup?
I should have my car running and driving later this year. Most of my driving will be below 55mph (not doing any racing ). I don't have caster shims. Do you think they'll be necessary?
I also have a 3/4" front sway bar, just not yet installed in this pic.
_________________
Currently own:
66 Karmann Ghia, L390 Gulf Blue, under construction, here: www.thesamba.com/vw/forum/viewtopic.php?t=760505&highlight=
99 Mazda MX-5 10AE, Sapphire Blue Mica, 6 speed, LSD
Previously owned:
98 Porsche Boxster, silver, 2.5L -- 67 Karmann Ghia, Black, 1500sp -- 98 BMW Z3, Atlanta Blue Metallic, 2.8L I6 -- 75 Porsche 914, Laguna Blue, 2270cc -- 72 Porsche 914, Signal Orange, 1.7 FI -- 74 Karmann Ghia, Black, 1600dp -- 74 Triumph TR6 with O.D., sapphire blue |
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