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MrGoodtunes Samba Member
Joined: May 14, 2012 Posts: 852 Location: South Florida
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Posted: Tue Jul 28, 2020 12:39 pm Post subject: Re: What did you do yesterday on your buggy? |
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EVfun wrote: |
... What is the scrub radius of a stock Bug? |
Could find only a couple clues in my ref books:
1. Kingpin centerline inclination (AKA: Steering axis inclination) = 5°
2. Wheel centerline inclination (AKA: Camber) = 0° 30' = 0.5°
That's for 1961-65. For 1968-74 (except Super Beetle) it's the same. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12714 Location: Western Canada
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Posted: Fri Aug 07, 2020 7:43 am Post subject: Re: What did you do yesterday on your buggy? |
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By scrub radius I am assuming you are talking about what I call "toe out on turns" which compensates for the two different radii the front wheels take when turning a corner. |
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MrGoodtunes Samba Member
Joined: May 14, 2012 Posts: 852 Location: South Florida
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Posted: Fri Aug 07, 2020 12:48 pm Post subject: Re: What did you do yesterday on your buggy? |
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oprn wrote: |
By scrub radius I am assuming you are talking about what I call "toe out on turns" which compensates for the two different radii the front wheels take when turning a corner. |
Glad you brought that up, because the scrub while moving thru a turn is different from the scrub while stop'd and turning steering wheel. Avoiding this latter scrub is why a positive steering roll radius or a negative steering roll radius is desired; it allows the wheel to roll, making it easier to park than it would be with zero steering roll radius, even tho zero SRR gives optimum road handling. |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5475 Location: Seattle
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Posted: Fri Aug 07, 2020 1:33 pm Post subject: Re: What did you do yesterday on your buggy? |
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oprn wrote: |
By scrub radius I am assuming you are talking about what I call "toe out on turns" which compensates for the two different radii the front wheels take when turning a corner. |
Actually, I was referring to where the king pin rotational axis hits the ground under the tire. It can hit outside of the center of the tire, at the center of the tire, or inside the centerline of the tire (most common.) If the center of the turning axis at the road contact point is inboard of the center of the tire tread you have a positive scrub radius. When turning the outside tire swings forward slightly. Tires with a smaller diameter or wheels with a less positive offset would make a positive scrub radius become larger. This is why most aftermarket wheels noticeably increase stationary steering effort in a Bug.
My buggy went the other way. Stock 15 inch wide 5 Bug wheels are 15x4 ET+33. I'm running 14 inch Bus wheels up front, they are 14x5 ET+47.5. I should have a turning circle like a double cab long bed full size pickup as they run a lot farther inboard and hit the front of the trailing arms with less steering input -- about 2 turns lock to lock with a stock box and steering arm. I'm curious to see the effect on higher speed stability.
Do you have the steering at lock angles? That is the toe out on turns. I cannot find them right now, but remember the ones for the Bug being interesting because they are different left and right (due to the non-symmetrical steering linkage.) With those numbers and the front track I could calculate the factory designed Ackerman steering correction. It is usually set to an imaginary steering point somewhat less than the actual vehicle wheelbase. They try and over-turn the inside front tire just a bit to remove a little weight (and outside tread wear) from the outside front tire. I have wondered if that is still true in a beach buggy with an 80 inch wheelbase. _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12714 Location: Western Canada
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Posted: Fri Aug 07, 2020 8:22 pm Post subject: Re: What did you do yesterday on your buggy? |
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Ok, yes I see what you are referring to. The closer the center of the tread is to the king pin center line the less effort ot takes to steer. Also rocks and chuck holes have less chance of jerking the wheel out of your grip. Reduces steering wheel shock.
This issue of tow out on turns came up years ago when I was looking for a replacement front spindle for my Chevy pickup. My question to the parts guy was "Is it the same spindle for a short box as it is for a crew cab long box?" He said "Yes." without looking it up of course. When I asked him to double check the part numbers for me he looked at me like I was mentally deficient and moved on to the next customer.
I still don't know the answer but in theory it should not be the same part as your wheel base dictates the ideal angles as does track width. Yes I believe our shortened Buggies do not track properly through a turn. The outside edges of the front tires on mine are showing some scuffing inspite of several wheel alighnments and meticulous air pressure optimizing. |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5475 Location: Seattle
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Posted: Sat Aug 22, 2020 11:19 am Post subject: Re: What did you do yesterday on your buggy? |
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EVfun wrote: |
oprn wrote: |
By scrub radius I am assuming you are talking about what I call "toe out on turns" which compensates for the two different radii the front wheels take when turning a corner. |
Actually, I was referring to where the king pin rotational axis hits the ground under the tire. It can hit outside of the center of the tire, at the center of the tire, or inside the centerline of the tire (most common.) If the center of the turning axis at the road contact point is inboard of the center of the tire tread you have a positive scrub radius. When turning the outside tire swings forward slightly. Tires with a smaller diameter or wheels with a less positive offset would make a positive scrub radius become larger. This is why most aftermarket wheels noticeably increase stationary steering effort in a Bug.
My buggy went the other way. Stock 15 inch wide 5 Bug wheels are 15x4 ET+33. I'm running 14 inch Bus wheels up front, they are 14x5 ET+47.5. I should have a turning circle like a double cab long bed full size pickup as they run a lot farther inboard and hit the front of the trailing arms with less steering input -- about 2 turns lock to lock with a stock box and steering arm. I'm curious to see the effect on higher speed stability.
Do you have the steering at lock angles? That is the toe out on turns. I cannot find them right now, but remember the ones for the Bug being interesting because they are different left and right (due to the non-symmetrical steering linkage.) With those numbers and the front track I could calculate the factory designed Ackerman steering correction. It is usually set to an imaginary steering point somewhat less than the actual vehicle wheelbase. They try and over-turn the inside front tire just a bit to remove a little weight (and outside tread wear) from the outside front tire. I have wondered if that is still true in a beach buggy with an 80 inch wheelbase. |
I found some info about the toe out on turns. Here are a couple of posts in the same thread showing the alignment numbers for king pin and ball joint Bug front ends. Using the 2 degree difference at 20 degrees steering input I can calculate the Ackerman correct wheelbase is about 3 times [1] the scrub radius track width (like the front track width, but measured at the steering point under the tires instead of the outside of the front tires.)
This would provide less than full Ackerman correction leaving the inside front tire pushing the outside front tire a little when turning. That would suggest that VW was trying to encourage understeer. Since rear heavy cars are prone to oversteer when pushed past their limits this would be understandable.
[1] Using the king pin alignment number of 2 degrees toe out on turns at 20 degrees for the inside tire, the exact calculation is 1/(tan72 - tan70) _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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tcmia Samba Member
Joined: April 30, 2019 Posts: 212 Location: Cleveland TN
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Posted: Sat Aug 22, 2020 7:23 pm Post subject: Re: What did you do yesterday on your buggy? |
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I finally mustered up and went downtown to get my tag and insurance. Took it out for a short ride. I still need to replace my rear tires but it was a nice ride. Any recommendations which ones in 275/60/15? |
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Lockley Samba Member
Joined: August 13, 2010 Posts: 9 Location: Old Fort,NC
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Posted: Mon Aug 31, 2020 6:37 am Post subject: Re: What did you do yesterday on your buggy? |
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Rebuilt the whole thing yesterday and the last year.
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clonebug Samba Member
Joined: January 29, 2005 Posts: 4027 Location: NW Washington
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Posted: Wed Sep 09, 2020 8:00 pm Post subject: Re: What did you do yesterday on your buggy? |
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tcmia wrote: |
I finally mustered up and went downtown to get my tag and insurance. Took it out for a short ride. I still need to replace my rear tires but it was a nice ride. Any recommendations which ones in 275/60/15? |
B.F. Goodrich Radial TA is probably the nicest looking tire out there if you like whitewalls. You can turn the whitewalls inside if you want the blackout look.
Summit Racing carries BFG TA tires and ships them quickly if you have a way to mount and balance them.
You can also order them through Walmart online and ship them to the nearest store in your area. _________________
vwracerdave wrote: |
Take a good long look in the mirror and report back on what you see. |
Paul.H wrote: |
That one line on that chart is probably better info than you can get from this place in a month |
My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash
http://www.shoptalkforums.com/viewtopic.php?f=3&t=127936 |
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tcmia Samba Member
Joined: April 30, 2019 Posts: 212 Location: Cleveland TN
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Posted: Thu Sep 10, 2020 7:43 am Post subject: Re: What did you do yesterday on your buggy? |
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Thanks for the info. Drove the Bad Bug yesterday again. Tweaked the carbs a little and drove it again. I think I have a bad ground up front since I replaced the beam. Gotta check that next weekend. It was fun finally getting to drive it! |
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shermer-high Samba Member
Joined: September 20, 2006 Posts: 132 Location: ct
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MrGoodtunes Samba Member
Joined: May 14, 2012 Posts: 852 Location: South Florida
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Posted: Thu Feb 11, 2021 12:51 pm Post subject: Re: What did you do yesterday on your buggy? |
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Bought this shiney new oil filler extension:
https://www.amazon.com/gp/product/B00BBJT9GA/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
And then, install'd it on my spare engine:
But it look'd too good to just sit there while the one on my buggy could use an upgrade. Plus, I wanted to try out a new path for the crankcase breather tube; even tho it would have a tight turn, which of course caused my new thin vinyl tube to buckle. So I found an old spring (probably was once in a wheel cylinder) to use as a "stent" helping keep the tube open:
No, the hose is not white; it's clear. The whiteness is tiny beads of condensation that would soon form dropletts which collect up into drips that run down and out. After awhile, the new vinyl tube will yellow and become stiffer; I'll remove the 2 "training" clamps at stent ends, probably leave the stent in there, and ultimately cover the hose with plastic conduit sleeving.
Edit - I later noticed that some of the drops in the first inch of tubing could drip back into my engine! So I went ahead and put sleeving over the first several inches of tube, in an effort to keep it warmer than the lower tubing. That way, relative coolness closer to the end of tube should get condensation to be forming where it drips out away from engine. |
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dhubz Samba Member
Joined: July 02, 2003 Posts: 61
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Posted: Mon Mar 01, 2021 9:19 am Post subject: Re: What did you do yesterday on your buggy? |
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Got my dash plate cut from stainless on a plasma cnc, missing a gauge but it should be soon. Installed it, now the fun of wiring everything up.
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joescoolcustoms Samba Member
Joined: August 08, 2006 Posts: 9054 Location: West By God Virginia
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Posted: Mon Mar 01, 2021 10:05 am Post subject: Re: What did you do yesterday on your buggy? |
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I am still building on the buggy we will race in Baja '22 and later today going to paint store to buy painting supplies.
Already bought everything for my Wife's buggy except paint, (color agreed upon) that will get started in late Spring and be done for Fall.
Now buying parts for my Towd to be built in Winter 21-22. Just bought some customized air shocks from Down South Motorsports in San Diego. Have all suspension parts now for long travel front and rear. Rounding up parts for custom transaxle that will get built later this Spring. Purchased Flake for it. Need to decide on windshield, roll bar or traditional frame.
Also buying parts for a Ecotec Clone X-body buggy build for '22. Have engine, header, adapter/flywheel/clutch, wire harness and ecm, wheels, custom Trans already built. Need suspension pieces yet. _________________ Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race
Everyone is gifted. Some just do not open the package.
Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone |
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slayer61 Samba Member
Joined: June 01, 2021 Posts: 1018 Location: CA
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Posted: Fri Jun 11, 2021 1:51 pm Post subject: Re: What did you do yesterday on your buggy? |
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Received front end/steering/suspension/brakes parts. It's about to get serious. |
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slayer61 Samba Member
Joined: June 01, 2021 Posts: 1018 Location: CA
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Posted: Tue Jul 06, 2021 2:39 pm Post subject: Re: What did you do yesterday on your buggy? |
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Front beam has been rebuilt with new leaf springs & seals, 2.5" drop spindles, new ball joints top & bottom, new tie rods with tie rod ends, new pitman arm and beam adjusters, new drilled & slotted rotors, bearings etc and new calipers. Also removed the transaxle for delivery to the local trans shop. |
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Tom_Kathleen Samba Member
Joined: August 26, 2004 Posts: 919 Location: Vernon, CT
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Posted: Wed Aug 11, 2021 2:51 pm Post subject: Re: What did you do yesterday on your buggy? |
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We went to a large car show in the next town & ran into another cool ride.
_________________ Manxter #16, 1968 Meyers Manx & Kick-Out SS #16 (WIP)
Manx Club & CVA |
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hillmotorsports Samba Member
Joined: December 27, 2014 Posts: 432 Location: Morrisburg, Ontario, Canada
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Posted: Wed Aug 11, 2021 6:52 pm Post subject: Re: What did you do yesterday on your buggy? |
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The things you see....
Rosemarie and I came across one of those coming out of a tunnel on the Blueridge Parkway as we were entering. The closing speed was too great to get a picture but needless to say it was an unexpected surprise! _________________ Rosemarie and Paul Hill
Morrisburg, Ontario
(With way more projects than spare time!) |
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slayer61 Samba Member
Joined: June 01, 2021 Posts: 1018 Location: CA
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Posted: Mon Aug 23, 2021 11:31 am Post subject: Re: What did you do yesterday on your buggy? |
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Front end done and awaiting tires
Rear end is done and awaiting tires
Brakes are done, but I'm not sure I won't take them apart for something else, so no fluid yet.
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MrGoodtunes Samba Member
Joined: May 14, 2012 Posts: 852 Location: South Florida
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Posted: Wed Oct 20, 2021 6:25 pm Post subject: Re: What did you do yesterday on your buggy? |
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I blew out my original German brake light switch, and replaced it with a motorcycle part.
As another Samba member said, "You're never too old to learn something the hard way." Do NOT connect brake lights wire to one terminal of brake light switch while +12 volts is connected to the other terminal when there's pressure in master cylinder. (I had the pedal prop'd.)
First thought for a fix was to go with the slick pedal switch kit by Gearhead Keith. But it won't work for my buggy, 'cuz its location is where my foot needs to be in order to use accelerator pedal.
https://www.thesamba.com/vw/classifieds/detail.php?id=2140061
Searching Samba, I found this thread by @toxicavenger with a post by @sjbartnik that gave me the Harley switch idea.
https://www.thesamba.com/vw/forum/viewtopic.php?p=9319372
Now that I have a more sensitive (i.e. quicker) brake light switch, I'ma make it even quicker by replacing incandescent bulbs with LEDs. I already have an LED, but currently only in my high center 3rd brake light which is shown here:
https://www.thesamba.com/vw/forum/viewtopic.php?p=9448122 |
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