Go Back   Great Lakes 4x4. The largest offroad forum in the Midwest > 4x4 Talk > General Tech
GL4x4 Live! GL4x4 Casino







Search
Reply
 
Thread Tools
Old May 24th, 2012, 09:22 AM   #1
cerial
Senior Member
 
cerial's Avatar
 
Join Date: 09-06-08
Location: Caledonia,MI
Posts: 1,725
iTrader: (3)
Mentioned: 1 Post(s)
Default Bump Steer?

I want to run a double triangualted 4 link up front. The engine is in the rear and there is very little limiting link placment in the front. If I use a rack and pinion mounted on the axle from PSC that will control any bump steer correct? I don't see how it would not. But, maybe I missed somethimg I could catch now avoiiding a costly mistake.
cerial is offline   Reply With Quote
Old May 24th, 2012, 09:33 AM   #2
Dylan
Senior Member
 
Dylan's Avatar
 
Join Date: 08-24-06
Location: K-zoo
Posts: 1,120
iTrader: (7)
Mentioned: 0 Post(s)
Default

i'm curious, but how were you going to run the steering link from the wheel to the rack and pinion and still let it cycle with the suspension? Normally isn't the rack and pinion fixed to the frame? I don't quite follow this.
Dylan is offline   Reply With Quote
Old May 24th, 2012, 10:27 AM   #3
cerial
Senior Member
 
cerial's Avatar
 
Join Date: 09-06-08
Location: Caledonia,MI
Posts: 1,725
iTrader: (3)
Mentioned: 1 Post(s)
Default

Same way you run a driveshaft
cerial is offline   Reply With Quote
Old May 24th, 2012, 11:23 AM   #4
Yota Bill
Senior Member
 
Join Date: 08-24-08
Location: Morrice, Mi
Posts: 3,229
iTrader: (11)
Mentioned: 0 Post(s)
Default

Please post a link to your pics on the scary steering site after you do this!!

It takes very little common sense to see why this is a brain dead idea.
Yota Bill is offline   Reply With Quote
Old May 24th, 2012, 05:03 PM   #5
cerial
Senior Member
 
cerial's Avatar
 
Join Date: 09-06-08
Location: Caledonia,MI
Posts: 1,725
iTrader: (3)
Mentioned: 1 Post(s)
Default

Enlighten me as to why it is a brain dead idea?

I don't think you need a crappy picture. Think of a rack and pinion mounted in the same manner as a double hydro ram. Now think of a slip shaft drive shaft going from the rack to the firewall. There is a smaller shaft parallel to the floor behind the firewall connecting to the steering wheel. As the suspension cycles the steering shaft extends and contracts. Because the rack and pinion is hydraulic it should resist bump steer. This should give me as much flexibility as with a full hydro running a 4 link while still providing a manual interaction in the event of a loss of hydraulic pressure. I would think at extreme droop of over 15" the steering shaft may move slightly as the u joints align. But, for daily driving with a travel of 10"(max) I do not see it causing any issues. Although feedback is helpful and perhaps I am missing something.

If I can not do it I will need to run a standard cross over steering system with assist. I will also need to run a 3 link with a pan-hard bar because using a triangulated 4 link or 3 link with a watts linkage will bump steer like crazy.

I am not doubting you at all. I simply just want to know why it is a brain dead idea?
cerial is offline   Reply With Quote
Old May 24th, 2012, 05:08 PM   #6
87mopar
Web Wheeler :(
 
87mopar's Avatar
 
Join Date: 10-08-08
Location: Lansing
Posts: 1,663
iTrader: (10)
Mentioned: 0 Post(s)
Default

I have nothing helpful to add. I would like to see pictures though just because im curious.
__________________
"Insert Comedic and or ego boosting quote questioning another members sexual orientation here"
http://www.greatlakes4x4.com/imageho...60bd7ea6d9.gif
87mopar is offline   Reply With Quote
Old May 24th, 2012, 05:20 PM   #7
cerial
Senior Member
 
cerial's Avatar
 
Join Date: 09-06-08
Location: Caledonia,MI
Posts: 1,725
iTrader: (3)
Mentioned: 1 Post(s)
Default

This is what I am pretty much copying with more travel, heavier duty components, and mounts.

http://www.customclassictrucks.com/t...ing/index.html

After reading this a few times I am pretty sure it will work with no issue. Any one have any reason why it will not or any freaky quirks I can expect?
cerial is offline   Reply With Quote
Old May 24th, 2012, 06:55 PM   #8
Tab
Senior Member
 
Tab's Avatar
 
Join Date: 11-05-05
Location: Freeland, mi
Posts: 4,768
iTrader: (29)
Mentioned: 2 Post(s)
Default

There is a buggy in the latest issue of crawl right with the rack and pinion set up you are talking about. I believe the price of the correct rack that can withstand the abuse an offload rig can put out will prevent you from doing it though. It will in no way be cheap. Why not just run a three link front with a track bar and conventional steering maybe with a hydro assist? Or is that too simple and proven?
Tab is offline   Reply With Quote
Old May 24th, 2012, 07:59 PM   #9
joe_jeep
welfare wheeler
 
joe_jeep's Avatar
 
Join Date: 03-03-06
Location: hazel park, mi
Posts: 5,644
iTrader: (36)
Mentioned: 2 Post(s)
Send a message via Yahoo to joe_jeep
Default

with limited travel, and not so extreme use i think it could work.

with extreme travel and serious abuse it would be tricky to make it live very long i think.

i have never seen a slip joint in a steering shaft that could handle serious articulation/flex, not that it could not be designed though.

i wonder about the steering strength(can it turn big tires off road effectively)?

can it handle the abuse of say 36" tires(lateral forces applied by big tires hitting trail obstacles at speed)?

seems like alot of work and money. a 3 link and hydro ram work fine.

i dont think bump steer would be an issue though.
joe_jeep is offline   Reply With Quote
Old May 24th, 2012, 09:09 PM   #10
Yota Bill
Senior Member
 
Join Date: 08-24-08
Location: Morrice, Mi
Posts: 3,229
iTrader: (11)
Mentioned: 0 Post(s)
Default

Imagine one side of the axle stays still while the other droops, the axle will effectively move towards the side, at best it will pivot at a point somewhere near the link point on the side that stays stationary. With the steering wheel stationary, that will mean the the steering shaft going into the rack will turn, steering the tires. There's the bump steer you think your avoiding. If it doesn't steer, it will turn the wheel in your hands. Better keep your fingers clear.
Then there's how much strength you would need in the rack itself (good luck finding one that will hold up to a heavy tire/wheel combo, not to mention being slammed sideways in an off road situation), and the amount of slip you would need in the steering shaft, plus the rag joints or u-joints in that shaft will take alot of abuse.
I don't see any way this could be done and made more functional then a basic crossover, or full hydraulic.
Yota Bill is offline   Reply With Quote
Old May 24th, 2012, 09:17 PM   #11
Yota Bill
Senior Member
 
Join Date: 08-24-08
Location: Morrice, Mi
Posts: 3,229
iTrader: (11)
Mentioned: 0 Post(s)
Default



http://128.83.80.200/taco/scarysteering10.html



Build what you want, if you think it will work. Good luck.
Yota Bill is offline   Reply With Quote
Old May 24th, 2012, 11:16 PM   #12
cerial
Senior Member
 
cerial's Avatar
 
Join Date: 09-06-08
Location: Caledonia,MI
Posts: 1,725
iTrader: (3)
Mentioned: 1 Post(s)
Default

Thanks for talking some sense into me. I knew about the cost to do this right and was ok with it considering what I wanted in the lines of travel. But, a 3 link leaves considerable less room for error, gives me a lot more freedom in mounting the bags, and is more reliable. A 3 link is ultimately more stout and that is overall what is most important in this build. I will just set the panhard for the 8" street height, when the clearance drops to 4" at higher speeds or raises to 15" for trail use the panhard will pull the axle.
With somewhere around 200" of hydraulic hose I really don't feel comfortable with full hydro at highway speeds. So the 3 link with assist is the best option.

Thanks again.
cerial is offline   Reply With Quote
Reply
Great Lakes 4x4. The largest offroad forum in the Midwest > 4x4 Talk > General Tech
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT -5. The time now is 03:32 AM.


Powered by: vBulletin, Copyright 2000 - 2012, Jelsoft Enterprises Ltd.
User Alert System provided by Advanced User Tagging (Lite) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd. Runs best on HiVelocity Hosting.
Copyright 2005 - 2012 Cracker Enterprises - Powered by Linux
vB Ad Management by =RedTyger=
Page generated in 0.13276 seconds with 34 queries