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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Thu Jun 10, 2021 9:08 pm Post subject: Rack and Pinion for Kustom Bugs? |
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Does anyone make a good offset shaft manual rack and Pinion conversion kit for a Volkswagen bug beam axle?
I need the steering shaft to come out in approximately the same place as it would with the bug but I will be rotating the rack down to match my lower steering shaft angle.
Right now I have a ball joint beam axle vintage 1973 as far as I can tell. All the steering is stock Volkswagen so far except that the steering gear has been rotated on the beam axle as I mentioned.
The car is all custom and you can see it in my SS100 Kit Kar thread hereabouts.
I have plenty of latitude for clearance in the body or chassis as required.
It is obvious I can get an inexpensive rack and pinion set up from a Honda car new for $125... Probably lots of similar stuff is available on eBay, where I saw that, for Korean cars in Chinese cars etc.
I don’t wanna have to prototype the whole setup if I don’t have to. _________________ SS100 kit kar
1600cc DP |
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didget69 Samba Member
Joined: July 22, 2004 Posts: 4927 Location: Raleigh, North Carolina
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Posted: Fri Jun 11, 2021 1:20 pm Post subject: Re: Rack and Pinion for Kustom Bugs? |
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Use the Search feature on thesamba.com Forums?
bnc _________________ I never found the need to impress people with any mechanic certifications, trophies or track wins... unless it was for Mom to post on the refrigerator door. |
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finster Samba Member
Joined: May 26, 2012 Posts: 7935 Location: north o' the border
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Sat Jun 12, 2021 11:16 pm Post subject: Re: Rack and Pinion for Kustom Bugs? |
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Thanks a bunch. You may have saved me much tedious searching. _________________ SS100 kit kar
1600cc DP |
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Sat Jun 12, 2021 11:41 pm Post subject: Re: Rack and Pinion for Kustom Bugs? |
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didget69 wrote: |
Use the Search feature on thesamba.com Forums?
bnc |
I believe that you were trying to be helpful, rather than annoying, but I taught engineers to build & program computers for over 20 years. I built my first breadboard computer in 1968. Boolean algebra is one of my specialties.
I searched for the thread title “rack and pinion” & it returned 160 threads. I didn’t want spend all day reading thru them yet.
Instead I was hoping one of the members who actually sells such a kit would pop his head up. Or maybe I would get opinions from different users who have them and would bother to tell me their experience.
Anyhow, if you have any experience with this, I’d be glad to read it. _________________ SS100 kit kar
1600cc DP |
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Sun Jun 13, 2021 7:20 am Post subject: Re: Rack and Pinion for Kustom Bugs? |
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I read thru some threads abut the Polo rack conversion last night, but it's a bust for me. I won't find Polos or cheap Polo parts in the US. People are asking nearly $1k for a used Polo rack setup on eBay.
From an engineering standpoint, I didn't like the overall design either...lots of eccentricity and overhung loads.
New Asian stuff is so inexpensive, I can't imagine using obsolete German parts if I don't have to.
I may take a measuring expedition to Pick-A-Part and see what looks promising.
Using a manual R&P would be lightest, but it seems like using a power R&P with a hydraulic bypass loop could give me adjustable stabilization, by changing oil viscosity, or by adding a needle valve to throttle the loop. The VW hydraulic stabilizer is one of the bits that interfere with the SS100 bodywork, causing an irregular hump in the front valance, which should be flat and lower with louvers.
Even if I keep the VW box stock, my plan was to drop or invert it somehow. It doesn't have enough clearance once the body panels are aligned.
The odd valance.
The two big ugly holes on top bolt to the top of the beam axle. _________________ SS100 kit kar
1600cc DP |
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didget69 Samba Member
Joined: July 22, 2004 Posts: 4927 Location: Raleigh, North Carolina
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Posted: Sun Jun 13, 2021 8:27 am Post subject: Re: Rack and Pinion for Kustom Bugs? |
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Ulu wrote: |
didget69 wrote: |
Use the Search feature on thesamba.com Forums?
bnc |
I believe that you were trying to be helpful, rather than annoying, but I taught engineers to build & program computers for over 20 years. I built my first breadboard computer in 1968. Boolean algebra is one of my specialties.
I searched for the thread title “rack and pinion” & it returned 160 threads. I didn’t want spend all day reading thru them yet.
Instead I was hoping one of the members who actually sells such a kit would pop his head up. Or maybe I would get opinions from different users who have them and would bother to tell me their experience.
Anyhow, if you have any experience with this, I’d be glad to read it. |
I'd recommend reading the forum regarding rack & pinion setups on VW beams... You'll find answers to your questions.
I've seen little need for Boolean Algebra in VW repair.
bnc _________________ I never found the need to impress people with any mechanic certifications, trophies or track wins... unless it was for Mom to post on the refrigerator door. |
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Sun Jun 13, 2021 9:48 am Post subject: Re: Rack and Pinion for Kustom Bugs? |
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didget69 wrote: |
I'd recommend reading the forum regarding rack & pinion setups on VW beams... You'll find answers to your questions.
I've seen little need for Boolean Algebra in VW repair. |
Boolean Algebra is very useful for searching.
I can see what I do Not want to do mostly being done: Replacing a nearly rare VW part with a rare and expensive one.
I have a stock '73 German gear in good repair. Not stiff. Doesn't leak. It is probable I will end up keeping it initially. I have lots of other fish to fry. But since I'm at the "frame off" stage, now would be prime time...
I really want to dump the hydraulic stabilizer, and have equal tie rods. So much so that I considered an idler arm and relay rod.
For about 30 seconds. Yuck. R&P rules. _________________ SS100 kit kar
1600cc DP |
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Sun Jun 13, 2021 10:43 am Post subject: Re: Rack and Pinion for Kustom Bugs? |
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So far, the pre-tested kits I find are no longer available.
After lots of reading here and abroad, I am shifting gears mentally.
My car won't need a bolt-on solution. I am entertaining all ideas.(Even relay rods! ) I can fab clamps and brackets and rods.
Since my chassis is a foot longer than a bug, and has lots more clearance in many respects, and I must add u-joints to my death spear steering column, I am looking back at "center-pinion" aftermarket racks.
My rack need not mount to the beam either. it can mount to this appliance, which extends the frame, and which would itself enjoy (structural) closure.
Something else just occurred to me as I was looking at the preview & I was considering the ackerman situation with this car.
The center is farther away, since the wheelbase grew. Being so low and tail-heavy, the car can easily tailslide a bit to combat the longer turn radius, so a bit of neg Ackerman is not a sin.
BUT...since this car has unequal tie rods, does it have unequal steering knuckles, designed in a rough attempt to equalize steering? I gotta measure the arms to know! _________________ SS100 kit kar
1600cc DP |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5474 Location: Seattle
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Posted: Sun Jun 13, 2021 1:20 pm Post subject: Re: Rack and Pinion for Kustom Bugs? |
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VW says there is 2 degrees of tow out on turns when the inside tire is turned 20 degrees from strait. It would appear to me the Ackerman steering point would be behind the rear wheels of the stock Bug. It makes some sense as that would encourage under steer, possibly neutralizing some of the tendency for over steer in a rear heavy car.
Tan72 times the wheelbase is 291 inches
Tan70 times the wheelbase is 260 inches
So for those 2 points to be the same point on the rear axle line the track width would have to be only 31 inches. We know it is larger than that so the inside tire is not turned enough for full Ackerman steering correction. _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Sun Jun 13, 2021 5:28 pm Post subject: Re: Rack and Pinion for Kustom Bugs? |
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EVfun wrote: |
VW says there is 2 degrees of tow out on turns when the inside tire is turned 20 degrees from strait. It would appear to me the Ackerman steering point would be behind the rear wheels of the stock Bug. It makes some sense as that would encourage under steer, possibly neutralizing some of the tendency for over steer in a rear heavy car.
Tan72 times the wheelbase is 291 inches
Tan70 times the wheelbase is 260 inches
So for those 2 points to be the same point on the rear axle line the track width would have to be only 31 inches. We know it is larger than that so the inside tire is not turned enough for full Ackerman steering correction. |
Thanks EVfun. In action, I think body roll adds some more toe out. Not sure how that all works dynamicaly, after a car gets stretched. I measured the appliance, and my car is 13.5" longer.
So to work that back, I find out I still need another .49 deg toe out, while the stock WB VW needs another 1.1 deg for the full Ackerman. At rest.
BTW, I took a few cursory measurements and there appears to be no significant difference between the knuckle/arms from left to right. Mind you I didn't take them off and do precise measurements, but I believe equal length tie rods will be the way. _________________ SS100 kit kar
1600cc DP |
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GS guy Samba Member
Joined: December 03, 2007 Posts: 968 Location: Maryland
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Posted: Mon Jun 14, 2021 4:59 am Post subject: Re: Rack and Pinion for Kustom Bugs? |
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I've seen an early Rabbit rack used (matches tie rod end taper and Super Beetle U-joints) as well as Saco type racks on off-road cars. I believe the ideal inner tie rod pivot positions, for a BJ beam, needs to be roughly centered and just behind the upper torsion bar tube - for minimal bump steer. This implies using a center load type rack (like the Saco rack) and also used on many FWD modern cars. Subaru Gears was starting to offer a Suby rack conversion kit, but doesn't seem to have it available on their site? Might try an inquiry to them? Otherwise, you're growing your own from bone yard bits. One thing to keep in mind is the rack ratio. The VW steering box IIRC is pretty close to 16:1 which is considered a fairly "quick" ratio (for manual steering). Most manual racks are made with slower ratios (to ease parking effort), while power racks can be quite a bit quicker. You have to determine what ratio provides acceptable steering effort, without 50 hand over hand exercises to turn the corner!
Jeff _________________ 70's vintage Deserter GS buggy - undergoing transformation to Super GS! |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12708 Location: Western Canada
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Posted: Mon Jun 14, 2021 6:14 am Post subject: Re: Rack and Pinion for Kustom Bugs? |
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Ulu I like the direction you are going here! I also am impressed with the responses, there are some people here that understand steering geometry after all!
I have heard that the Lupo/Polo steering rack is a good fit. Might be a difficult one to find though. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Mon Jun 14, 2021 3:39 pm Post subject: Re: Rack and Pinion for Kustom Bugs? |
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Thank you gentlemen. I have been combing the web for ideas, but the Saco setup sure seems workable. It looks bad on a stock bug, but has much more favorable u-joint angles on my car. This will allow me to hide the steering shaft and close up this ugly gash in my fender.
_________________ SS100 kit kar
1600cc DP |
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Mon Jun 14, 2021 3:44 pm Post subject: Re: Rack and Pinion for Kustom Bugs? |
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GS guy wrote: |
One thing to keep in mind is the rack ratio. The VW steering box IIRC is pretty close to 16:1 which is considered a fairly "quick" ratio (for manual steering). Most manual racks are made with slower ratios (to ease parking effort), while power racks can be quite a bit quicker. You have to determine what ratio provides acceptable steering effort, without 50 hand over hand exercises to turn the corner!
Jeff |
This led me to a manual Honda box with only 2.7 turns lock to lock. Not sure it has sufficient travel yet. Getting measurements is tough.
I haven’t been to a Junkyard in about 20 years. It must be time.
EDIT...
I find my car has 2.4 turns lock-to-lock, and 5.25" total travel, as measured on the damper rod. This is at full droop, and also My steering never hits the stops because the gear is rotated up several degrees.
ALSO, Where are the bump/droop stops on the BJ suspension? It appears to rely on the shock absorber for this. I remember the fat snubber on the link pin cars. _________________ SS100 kit kar
1600cc DP |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5474 Location: Seattle
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Posted: Mon Jun 14, 2021 5:39 pm Post subject: Re: Rack and Pinion for Kustom Bugs? |
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Ulu wrote: |
GS guy wrote: |
One thing to keep in mind is the rack ratio. The VW steering box IIRC is pretty close to 16:1 which is considered a fairly "quick" ratio (for manual steering). Most manual racks are made with slower ratios (to ease parking effort), while power racks can be quite a bit quicker. You have to determine what ratio provides acceptable steering effort, without 50 hand over hand exercises to turn the corner!
Jeff |
This led me to a manual Honda box with only 2.7 turns lock to lock. Not sure it has sufficient travel yet. Getting measurements is tough.
I haven’t been to a Junkyard in about 20 years. It must be time.
EDIT...
I find my car has 2.4 turns lock-to-lock, and 5.25" total travel, as measured on the damper rod. This is at full droop, and also My steering never hits the stops because the gear is rotated up several degrees.
ALSO, Where are the bump/droop stops on the BJ suspension? It appears to rely on the shock absorber for this. I remember the fat snubber on the link pin cars. |
Full Bug steering is 2.6 turns lock to lock so you are not missing much. I swapped to 14 inch Bus front wheels (ET+47.5mm) and adjusted my steering stops (front bolt holding the brake backing plate on for king and link pin Bugs) and only have 2.0 turns lock to lock. I figure my 80 inch wheelbase buggy has about a 40 to 41 foot turning circle. Roughly the same as a new Toyota Tacoma extended cab pickup. The Bug front suspension isn't great for making tight circles, stock the Bug takes about 36 feet to pull a u-turn. _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Mon Jun 14, 2021 6:54 pm Post subject: Re: Rack and Pinion for Kustom Bugs? |
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I drive a Tacoma crew cab long bed. It does have kind of a broad turning circle unless you drift; or you tap the gas pedal just right, and then the rear axle hops around the corner and you’re going straight again.
As trucks go, it’s a gas to drive.
On the SS, I don’t quite get the full 2.6 turns because my Pitman arm hits the frame extension at one point.
At least they got the steering wheel centered on the worm.
I am finding it impossible to get a center pull rack from Saco online. They seem to be on back order everywhere. _________________ SS100 kit kar
1600cc DP |
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Q-Dog Samba Member
Joined: April 05, 2010 Posts: 8699 Location: Sunset, Louisiana
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Ulu Samba Member
Joined: April 21, 2020 Posts: 711 Location: CenCal
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Posted: Tue Jun 15, 2021 7:10 am Post subject: Re: Rack and Pinion for Kustom Bugs? |
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Clearly not.
_________________ SS100 kit kar
1600cc DP |
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GS guy Samba Member
Joined: December 03, 2007 Posts: 968 Location: Maryland
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Posted: Tue Jun 15, 2021 7:24 am Post subject: Re: Rack and Pinion for Kustom Bugs? |
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Unfortunately, I believe SACO has closed it's doors. Might be able to find some NOS on the shelf somewhere, until someone else tools up to make the racks. I'm not too current on off-road specific gear, but the SACO rack seems to be the Cadillac of all the similar racks out there.
Some googling on center load rack & pinion will turn up other similar rack options, some serious research would be in order to find one suitable for road use (ie: build quality, proper sealing, reliability, etc).
Jeff _________________ 70's vintage Deserter GS buggy - undergoing transformation to Super GS! |
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