Frontend Alignment - The 1947 - Present Chevrolet & GMC Truck Message Board Network

PMS · 08-05-2005, 04:39 PM

Just lowered 72 GMC long bed 1/2 ton. 4.5" front with 4" rear. I am running 8" ralley wheels with 255 / 60 / 15 on front and 275 / 60 / 15 on the rear. What should the frontend specs be? I would like it to handle better. It does have a front sway bar. I know with a wider tire the toe should be more than stock but would changing the caster / camber from original specs help any?

Thanks,
Parrish

neonlarry · 08-05-2005, 09:15 PM

How does it handle now? i.e. what is it doing, specifically, that you would like to change?
Increased toe will make it track better in a straight line but will make it more difficult to turn in on a corner. I personally run almost no toe on all my vechicles. Alignment setting are almost always a tradeoff.
Increased negative camber will usually help make that end of the vechicle stick better in a corner, but since our trucks mostly oversteer and you can't adjust the rear, thats more of a help in front drivers that tend to understeer. On my GTP I run about 2° negative with no noticeable increase in tire wear.
Caster will affect how easy it is to turn in and return to straight. Our trucks have very little caster which is one of the reasons most people like to convert manual trucks to power steering. to change the caster much you need some tubular A-arms that are made with some built-in caster our I have heard you can swap sides on the upper arms.
If you really want it to handle better I can give you a primer in order of effect
1. Driver practice at speed.
2. Better tires (50 series, 295 in back, stickier rubber, better tread pattern)
3. 1¼ front swaybar, rear swaybar.
4. Better springs and shocks

PMS · 08-06-2005, 11:18 AM

Thanks for the information. We haven't got the front end lowered yet, will be doing that today. Even with front and rear sway bars the truck "swayed" alot in corners at speed. We are changing shocks to KYB and lowering as stated at the top of the thread. Do they make 15" 50 series handling tires anymore?... If anyone has used them please let me know brand and largest size that will fit on 15x8 wheels.

Thanks,
Parrish

08-05-2005, 04:39 PM	#1
PMS Registered User Join Date: Aug 2004 Location: Overland Park, KS Posts: 79	Frontend Alignment Just lowered 72 GMC long bed 1/2 ton. 4.5" front with 4" rear. I am running 8" ralley wheels with 255 / 60 / 15 on front and 275 / 60 / 15 on the rear. What should the frontend specs be? I would like it to handle better. It does have a front sway bar. I know with a wider tire the toe should be more than stock but would changing the caster / camber from original specs help any? Thanks, Parrish

08-05-2005, 09:15 PM	#2
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,746	How does it handle now? i.e. what is it doing, specifically, that you would like to change? Increased toe will make it track better in a straight line but will make it more difficult to turn in on a corner. I personally run almost no toe on all my vechicles. Alignment setting are almost always a tradeoff. Increased negative camber will usually help make that end of the vechicle stick better in a corner, but since our trucks mostly oversteer and you can't adjust the rear, thats more of a help in front drivers that tend to understeer. On my GTP I run about 2° negative with no noticeable increase in tire wear. Caster will affect how easy it is to turn in and return to straight. Our trucks have very little caster which is one of the reasons most people like to convert manual trucks to power steering. to change the caster much you need some tubular A-arms that are made with some built-in caster our I have heard you can swap sides on the upper arms. If you really want it to handle better I can give you a primer in order of effect 1. Driver practice at speed. 2. Better tires (50 series, 295 in back, stickier rubber, better tread pattern) 3. 1¼ front swaybar, rear swaybar. 4. Better springs and shocks __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

08-06-2005, 11:18 AM	#3
PMS Registered User Join Date: Aug 2004 Location: Overland Park, KS Posts: 79	Thanks for the information. We haven't got the front end lowered yet, will be doing that today. Even with front and rear sway bars the truck "swayed" alot in corners at speed. We are changing shocks to KYB and lowering as stated at the top of the thread. Do they make 15" 50 series handling tires anymore?... If anyone has used them please let me know brand and largest size that will fit on 15x8 wheels. Thanks, Parrish Last edited by PMS; 08-06-2005 at 11:19 AM.



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