(SUSPENSION) measuring and adjusting camber, caster & toe-in
I'm in the process of rebuilding my suspension and once installed I would like to learn how to align and adjust it myself. I've heard you can build simple tools for doing this. Does anyone have any tips for me? Are there specific settings I should aim for? I want to autox the car but it needs to be streetable too. TIA
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Great Question!
Finally something worth reading about. I too, would like to know. |
well for tow in and out, you can use a string. meausre the distance between front on the tires and rear of the tires.
say stock is like 65" (for example) it would be the same both for front and back of the tire now you want .05" toe-in so the front of the tire will be 65-.05-.05=64.90 and the back of the tire 65+.05+.05=65.10 for camber and caster it's a little more complicated and it's better to live it to whoever that does the alignment |
I guess my other question would be: "How adjustable is the camber/caster on stock struts?"
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Originally posted by inittab I guess my other question would be: "How adjustable is the camber/caster on stock struts?" i've also redone my suspension and have been battling alignment troubles for the last month to get it all set. my plan of attack has been to do like the haynes says and measure (with a simple ruler) how much of the tension rods are sticking out of the bolts. i get those as even as possible and then put the tires on, drive around, and see how it feels then measure the toe in/out. i'm aiming for a bit of toe out for a bit better handling for autox, but for the street you'll want some toe in. use a string like he said and measure the difference between the distances of the front vs. rear of the front tires. after that, it's just trial and error. |
Camber can be checked with a plum-bob and some basic trig - (cos, sin etc.
I have a length of fishing line attached to an old broom handle, on the other end of the line is attached a plum-bob (got it from Homedepot). This line and plum-bob give you a vertical reference - zero degrees. The broom handle is laid down on the hood with the line suspended down by the wheel face and in line with the center of the wheel. Line is wound around the handle until the plum-bob just clears the ground. I steady the line (it tends to swing like a pendulum) then measure and record the distance from the fishing line to the top of the rim then to the bottom of the rim. Try to measure perpendicular from the line and hope your car is sitting on level ground. I take the difference between these two measurements and the distance between the 2 points measured from on the rim and form a right angle triangle. Then use trig to determine the camber. That was very difficult to explain but I have a spreadsheet and I just plug in my numbers. Well I thought it was simple!:cool: |
i believe the max camber on stock strut with no camber/caster plate is 1degree pos/neg
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You can slot the upper strut holes a bit for more camber.
The stock strut is not in the middle of the upper strut mount, it is offset to one side, this allows you to adjust the camber by loosening the strut assy and rotating the upper mount. the caster is adjusted by the long rod that runs from your lower control arm to the front of the car. It has a nut for adjustment. |
Originally posted by Bruceman That was very difficult to explain but I have a spreadsheet and I just plug in my numbers. Well I thought it was simple!:cool: |
Originally posted by yayarx7 the caster is adjusted by the long rod that runs from your lower control arm to the front of the car. It has a nut for adjustment. Bruceman has a good way to measure camber. Does anyone have any suggestions for measuring caster? Are there any specs for what the optimum caster should be? |
Originally posted by inittab Yup, that would be the panhard rod. Before I dissasembled my suspension, my caster was visibly WAY outa wack on the passenger side. The wheel wasn't even centered in the wheel well. |
Originally posted by adssoccer isn't that the tension rod. i thought the panhard rod was something in the rear suspension. also, isnt that how you change toe in/out. |
I just found a great web site on how to do a $20 alignment. There is some really good info here: http://www.vtr.org/maintain/diy-alignment.html
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Yes, finally something worth reading about!
The tension rod is in the front and is used to change caster. It's mounts to the control arm on one end and a bracket on the frame at the other end. A panhard rod is used in-lieu of a watts link in the rear to control lateral movement of the axel. Toe in/out is changed by turning the threaded adjusters that are inbetween the pairs of tie rod ends, in the front of the car. Camber (and caster) can be changed by rotating the top of the front strut towers, read your haynes or factory shop manual on how to do it. You can get 1 deg neg camber and 1 deg pos caster this way. VERY worthwile to do. Just be sure to set your toe afterwards or it'll eat up your tires quick. Or you can slot the strut towers and get more camber. This is what the SPEC 7 racers do. The plum-bob way works well. Some ppl string up the whole car all the way around and take the wheels off and rest aluminum plates on the wheel studs and measure it that way, but that's another story. BradP |
Originally posted by DriveFast7 The tension rod is in the front and is used to change caster. It's mounts to the control arm on one end and a bracket on the frame at the other end. |
Originally posted by DriveFast7 Camber (and caster) can be changed by rotating the top of the front strut towers, read your haynes or factory shop manual on how to do it. |
Well, it's common for the caster to be different from side-to-side in order to compensate for "the crown of the road" - which is how most streets are not flat, but curved downwards on each end left to right, allowing rain to drain down into the gutter. Quite the run on sentance there. I can't remember which side gets more caster, it's been 4 years since I tweaked the cars alignment myself.
I'd also reccomend counting the number of exposed threads on the end of the tension rod and put it back together the same way, in addition to setting it to your original wheelbase measurements. Then drive slowly to a competent alignment shop and have them do it right. The car will wobble and pull a bit since this is your first attempt at anything alignment related. That's fine, mine did too. Just go slow. Find a shop that has some real race cars parked out front (not rice cars, race cars) and have them align it. And have them dial in some negative camber for God's sake!!!!! If you really want to do it yourself, do a web search on DIY alignments, theres pleanty of pages out there for that. Yes, alignment, along with carb jetting and tire temp setting is a black art. Brad |
I am an Alignment God :D
One thing to keep in mind is that all alignment settings must be measured with the car at normal ride height. This means NOT on jackstands, and NOT right after you set the car down after making an adjustment. Unless you have $500 sliding turn plates to set the front wheels on, what you must do after you set the car back down is roll it back and forth about 10 feet in each direction, about 4 or 5 times. I set toe using a pen and a 2x4. I get within 1/8" that way - 1/8" isn't going to make or break ya. Camber I usually set by eye (usually just dump the adjuster to max negative on each side) and I play with caster until the car drives straight. All cars will follow the road crown so you need to check for drifting or pulling on the center of the road. |
Originally posted by peejay I am an Alignment God :D One thing to keep in mind is that all alignment settings must be measured with the car at normal ride height. This means NOT on jackstands, and NOT right after you set the car down after making an adjustment. Unless you have $500 sliding turn plates to set the front wheels on, what you must do after you set the car back down is roll it back and forth about 10 feet in each direction, about 4 or 5 times. I set toe using a pen and a 2x4. I get within 1/8" that way - 1/8" isn't going to make or break ya. Camber I usually set by eye (usually just dump the adjuster to max negative on each side) and I play with caster until the car drives straight. All cars will follow the road crown so you need to check for drifting or pulling on the center of the road. so which side do you adjust the caster if it is pulling and you got the toe correct? The side that is pulling, or the other? I have done a few alighnments but it always with an expensive machine, it makes it to easy, you do not have to know anything about it to do it. |
Originally posted by peejay One thing to keep in mind is that all alignment settings must be measured with the car at normal ride height. This means NOT on jackstands, and NOT right after you set the car down after making an adjustment. Very good point! That's why we put the suspension up on jackstands and use levels to make sure it's flat. BradP |
Toe has nothing to do with pulling! You get caster and camber first, then toe last. The only exception is if you put new parts on the car and toe is so far out of whack that the wheels aren't even pointing in the same time zone, and then you roughly set toe close first.
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Originally posted by peejay I am an Alignment God :D |
Originally posted by peejay Toe has nothing to do with pulling! You get caster and camber first, then toe last. The only exception is if you put new parts on the car and toe is so far out of whack that the wheels aren't even pointing in the same time zone, and then you roughly set toe close first. |
Originally posted by yayarx7 I need to read up on the suspention alignment specs and set the caster I guess. |
if you want a top notch alignment find a shop that aligns race cars as was said before. if you look at the back of scca's mag you will see camber/caster measurement tools. they are 200+. why, because precision is important when you are tuning. other wise you don't get the results and you can eat your tires. if you want the cheap way of gaining some extra caster/camber, use the offset on the struts top plate. i can't remember who said this already. anyway, the point were the strut bolts on is offset towards ONE screw. i think everyone would want the extra camber so that screw goes on the inside. now since i want easier movement at low speeds for autox, i put the screw toward the front to dial out some caster. i would suggest a setting of 1/16"-1/8" toe out.
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Originally posted by jeremy the point were the strut bolts on is offset towards ONE screw. i think everyone would want the extra camber so that screw goes on the inside. HOMEWORK ASSIGNMENT EVERYONE: Okay rotorheads, go out and look at the little arrow on top rim of your stock struts and report back here on which way they point! Go! Do it now! please..... Maybe we can get some sort of consensus. :) Thanks! :) Mine was set to: right side: front/inner left side: rear/inner |
i had mine all screwy when i put new struts and lowering springs in. i'm not sure if the caster 0's or goes negative with it forward. it depends on the geometry that mazda incorperated. i will check this once i take it in for an alignment.
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From this page:
http://www.familycar.com/alignment.htm If the top of the strut is leaning toward the rear of the car, then the caster is positive, if it's leaning toward the front, it is negative. |
yes, i know. but who said that the tower is in direct alignment with the hub.
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Originally posted by inittab I have yet to find any specs. If you have or find the specs, please PM me or post them here. Thanks! :) as per the 80 FSM.... Caster....RH side....4 degrees 30' (+/- 30') LH side....4 degrees 0' (+/- 30') max difference in caster between sides...+/- 40' Camber....1 deg. 10' (+/- 30') max diff..........+/- 30' toe in 0~0.24in |
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