Go Back   EcoModder Forum > EcoModding > General Efficiency Discussion
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 09-30-2022, 02:20 AM   #1 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,005

ND Miata - '15 Mazda MX-5 Special Package
90 day: 42.54 mpg (US)
Thanks: 2,866
Thanked 2,501 Times in 1,547 Posts
Efficient alignment

I could use some opinions on alignment numbers.

I haven't taken the MX-5 in for an alignment yet. It tracks straight, but it's a fair bet that the previous owner had a fairly aggressive, perhaps even autocross-oriented alignment on the car, based on how much front camber there is.

Factory specs, per wheel:

Front:
Caster: 5.5° to 7.5°
Camber: -1.7° to 0.3°
Toe: -1/16" to 1/8" (ideally 1/32" toe in)

Rear:
Camber: -2.7° to -0.7°
Toe: -1/32" to 5/32" (ideally 1/32" toe in)


Flyin' Miata recommends the following for aggressively driven street cars:

Front:
Caster: 8.0°
Camber: -1.8°
Toe in: 1/32" per side

Rear:
Camber: -1.8°
Toe in: 1/32" per side

~

I take corners at rather high speeds, so I'm looking for a reasonable compromise. I'm thinking of dialing the caster back just a bit, perhaps 6°, and setting camber to something like -1.5°. What I'm not certain about is toe. I can see a reason for having just a bit of rear toe in, but since the car is propelled by the rear wheels and it ought to have a tendency to toe-in anyway under power. What would be the purpose of slight front toe in? Thoughts on zero toe, front and back?


Last edited by Ecky; 09-30-2022 at 05:07 PM..
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 09-30-2022, 09:38 AM   #2 (permalink)
Corporate imperialist
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,175

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)

Snow flake - '11 Nissan Leaf SL
SUV
90 day: 141.63 mpg (US)
Thanks: 269
Thanked 3,522 Times in 2,796 Posts
Zero toe in back is normal, zero toe in up front is considered "in spec" on most vehicles.
I ask for zero toe in on the leaf when I get it aligned.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
  Reply With Quote
The Following User Says Thank You to oil pan 4 For This Useful Post:
Ecky (10-01-2022)
Old 09-30-2022, 10:06 AM   #3 (permalink)
Tire Geek
 
CapriRacer's Avatar
 
Join Date: May 2008
Location: Let's just say I'm in the US
Posts: 794
Thanks: 4
Thanked 388 Times in 237 Posts
Toe in is stable, toe out is unstable (the vehicle can't figure out which side to follow).

On solid rear axles, toe isn't a problem because it is very close to zero.

Camber tends to cause good cornering, but at the expensive of tire wear. So it is very important to get the toe very close to the target value if you want good tire wear.
__________________
CapriRacer

Visit my website: www.BarrysTireTech.com
New Content every month!
  Reply With Quote
The Following User Says Thank You to CapriRacer For This Useful Post:
Piotrsko (09-30-2022)
Old 09-30-2022, 10:18 AM   #4 (permalink)
Somewhat crazed
 
Piotrsko's Avatar
 
Join Date: Sep 2013
Location: 1826 miles WSW of Normal
Posts: 4,043
Thanks: 462
Thanked 1,103 Times in 973 Posts
A nice new tight front steering system might get away with zero toe for a while. Test stuff and see if the system flexes, and how much. The how much is twice what your setting should be for a side if your preventing the other side from moving. Ditto for the rear.

Camber is a more personal thing since it loads the steering. I like lots of negative in the F250, but not much in the golf because I feel it makes the steering heavy and less responsive. Positive makes steering bump twitchy on some cars, neutral makes the tie rods flex erratically and any play is magnified.

My $0.02. YMMV and I don't worry about wear as much as handling or traction since my tires tend to sun rot
__________________
casual notes from the underground:There are some "experts" out there that in reality don't have a clue as to what they are doing.
  Reply With Quote
Old 09-30-2022, 11:49 AM   #5 (permalink)
EcoModding Apprentice
 
Join Date: Jun 2022
Location: Bremerton, WA
Posts: 104

Passat TDI Wagon - '97 VW Passat Wagon TDI
90 day: 55.81 mpg (US)

Blue - '21 Hyundai Sonata Blue
90 day: 53.79 mpg (US)
Thanks: 32
Thanked 57 Times in 44 Posts
I would keep some toe in on the front (in the middle of the recommended spec for toe in), and use the minimum recommended toe in on the back.

Toe in is required because suspension flexes at higher speed from tire drag. This will cause it to be zero toe in at highway speed or during braking. What you don't want is toe out at speed. That leads to very twitchy and dangerous steering. Aftermarket racing suspension is much stiffer than stamped steel factree components and you can get away with less toe in than stock since there is less flex.

If you hypermile at 50 mph or less, you could get away with zero toe in front and back.

As far as caster, more positive caster is more stable at speed but leads to harder (effort used) steering at low speed. Camber, IDK. I like zero just for tire wear, especially if you are running maximum tire pressure for gas mileage. There is some advantage with having camber cornering, as it allows the maximum size contact patch on the road.
__________________
97 Passat TDI Wagon
Bosio 520 DLC nozzles, chip tune
Mufflerectomy
306k miles
Scan Gauge II
full belly pan
26 gallon tank
  Reply With Quote
Old 09-30-2022, 12:04 PM   #6 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,561
Thanks: 7,736
Thanked 8,554 Times in 7,041 Posts
Quote:
Originally Posted by CapriRacer
On solid rear axles, toe isn't a problem because it is very close to zero.
I had a street rod shop do a four-wheel alignment on my Type III notchback, and it had the most responsive steering of anything I've driven. I think it was the rear toe, but IDK if it was plus or minus from zero.
__________________
.
.
Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster

____________________
  Reply With Quote
Old 09-30-2022, 04:18 PM   #7 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,756

spyder2 - '00 Toyota MR2 Spyder
Thanks: 104
Thanked 407 Times in 312 Posts
High caster is supposed to give better steering feel and reduced camber when the wheel is turned. I would keep max caster. -1.5 camber is not bad for tire wear at all, I would be okay with that.

Not sure about toe, but my uninformed opinion is to err towards 0. If factory asks for toe in, I would personally feel the urge to reduce the toe in.
  Reply With Quote
Old 09-30-2022, 05:08 PM   #8 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,005

ND Miata - '15 Mazda MX-5 Special Package
90 day: 42.54 mpg (US)
Thanks: 2,866
Thanked 2,501 Times in 1,547 Posts
For what it's worth, the G1 Insight aliment specs, which I'm sure are no-compromise economy specs, are zero camber, zero toe in the front, and very slight toe in at the rear.

Last edited by Ecky; 09-30-2022 at 06:44 PM..
  Reply With Quote
Old 09-30-2022, 05:58 PM   #9 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,561
Thanks: 7,736
Thanked 8,554 Times in 7,041 Posts
Quote:
...and very slight toe in at the rear.
It sounds like that's the way.

Farm tractors have massive positive front camber. I guess it makes for straighter furrows?
__________________
.
.
Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster

____________________
  Reply With Quote
Old 09-30-2022, 08:13 PM   #10 (permalink)
Master EcoModder
 
redneck's Avatar
 
Join Date: Jun 2009
Location: SC Lowcountry
Posts: 1,795

Geo XL1 - '94 Geo Metro
Team Metro
Boat tails and more mods
90 day: 72.22 mpg (US)

Big, Bad & Flat - '01 Dodge Ram 3500 SLT
Team Cummins
90 day: 21.13 mpg (US)
Thanks: 226
Thanked 1,353 Times in 711 Posts
.

0-0-0




>

.

__________________


Woke means you're a loser....everything woke turns to ****.

Donald J Trump 8/21/21




Disclaimer...

I’m not a climatologist, aerodynamicist, virologist, physicist, astrodynamicist or marine biologist..

But...

I play one on the internet.

  Reply With Quote
The Following User Says Thank You to redneck For This Useful Post:
Ecky (09-30-2022)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com