Suspension & Brakes Theory, alignment, spring rates....

String Alignment & EG vs DC Rear Track Width

 
Old 10-19-2011, 07:39 AM
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Default String Alignment & EG vs DC Rear Track Width

Does anybody have any insight into this:

I just finished an EX/DelSol VTEC 10.3" front disc swap on my 94 CX and need to align the front end. I was planning on giving the string method a try, so I went to my Helm manual to look up front & rear track widths. I found the 92-95 Civic specs to be:

- Front = 1,475mm (58.1")
- Rear = 1,465mm (57.7")

Then I remembered my car has a full rear suspension from a 94+ Integra. So being a good boy-scout, I double checked those numbers against the 94 & 98 Integra manuals. To my surprise the rear was track was wider by 5mm:

- Front = 1,475mm (58.1") [Type-R = 1,480mm]
- Rear = 1,470mm (57.9")

So if the rear is different, I'm wondering where the difference comes from. The following parts share the same part numbers between both 94 Civic and 94 Integra GSR:
- rear lower subframe/cross-member
- rear upper control arm
- rear trailing arm (different part number on 98+ Integra)
- rear hub/bearing
- rear compensator arm

The only part with a different number is the rear LCA (both with ABS), but the difference could simply be the individual bushings which are all different part numbers as well (they have metal inserts in the rubber).

So does anybody know exactly where the rear track difference comes from? I want to be sure to get my string as straight as possible to do this. I did a quick drawing in AutoCAD and found that if the rear of the string is off by that 2.5mm, it could effect the outcome of the front total-toe by .84mm (~.11*). I don't know if that's a lot, but I want to be as close to zero as I can get.

***EDIT***
Short answer: My setup is 9mm narrower track in the rear (not 10 or 5mm like the books say). This is because I have a modified (lowered) suspension. This makes my rear string offset number 4.5mm.

If you have a modified suspension: The first time you attempt an alignment, you should run a string down either side of the car (out past the bumpers). Set your string based on the book track widths. Now have a helper precision measure the front & rear string separation with a tape measure (I had my wife hold it at the precisely at the 1" mark while I wrote the number at the other side). If the strings are closer together at the rear, your rear track is narrower than expected. Bump the strings out 1mm from the rear center caps and measure again. If the strings are wider at the rear, then your rear track is wider than expected. Move the strings 1mm closer to the rear center cap. Do this till you get the strings to run parallel (distance is the same front & rear). Once you do this once, write down the number somewhere and never forget it. You will never have to do this again (unless you change your ride height). From here on out, you simply use your new rear string offset number at the rear and only do one string at a time.

Tips in post #10 below!

Last edited by 94eg!; 10-24-2011 at 06:33 AM.
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Old 10-19-2011, 11:30 AM
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Default Re: String Alignment & EG vs DC Rear Track Width

why wouldnt it just be from the chassis, where the arms mount anyway?

string alignment is regardless of track width. as long as the two sides of the same axle are the same. you set the two strings parallel to each other. they dont have to be equal distance apart from the edge of the wheels. sure it helps the numbers, but as long as the two strings are parallel, thats all you need to go from.
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Old 10-19-2011, 11:48 AM
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Default Re: String Alignment & EG vs DC Rear Track Width

Integra has the same part number for the rear lower subframe (chassis). That is why I don't think the difference is in the chassis.

Well if your strings are not parallel to the center-line of the chassis, then you cannot possibly zero out the wheels (I don't think). The way I learned to setup up the strings was by measuring a specific distance out from the center cap (same wheels & center caps front & rear). Then you adjust one end to compensate for different track width. In the case of our Civic we would:

- Set the string 100mm away from the front center cap
- Set the string 105mm from the rear center cap

That makes the string parallel to the chassis center line because rear track is 10mm narrower (5mm on each side). Now you can measure the distances from the leading & trailing edges of the rim to the string to figure out your toe (in mm).

If there is a better way, that would be great.

For reference: Toe spec is 0 +/- 2mm. That means your leading edge has to be within 1mm from your trailing edge on either side of the car.

Last edited by 94eg!; 10-19-2011 at 12:07 PM.
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Old 10-19-2011, 12:51 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

I feel like I remember reading somewhere that the extra track width comes from the hubs and wheel bearings. Might be something that's worth looking at if you are really trying to find out.
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Old 10-19-2011, 01:19 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

Good thinking, but the hub/bearing is the same for Civic ABS and Integra GSR too.

I've added it to the first post.

An unrelated FYI: The Type R rear hubs have a 10mm wider rear bearing (with 2 more *****). The R's rear hub-face only sticks out 5mm further though. That extra distance is then negated by the wheels having a 5mm higher offset. Thus the rear track of the Type-R stays the same... lol
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Old 10-21-2011, 06:45 AM
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Default Re: String Alignment & EG vs DC Rear Track Width

Well I gave it a shot last night and found this to be REALLY easy to make adjustments. Since I couldn't find the exact cause of the difference in rear track, I decided to set my rear track right in the middle of the EG & DC setting. That means I set the strings as follows:

- 100mm from the front center cap
- 103.75mm from the rear center cap (Right between 102.5 & 105)

This will cut my margin of error in half form the numbers posted above. Weather we've got extra toe in or out depends on if I really have an Integra rear track or a Civic. If it's Integra, then that's toe-out. If it's Civic then that's toe-in.

Making the adjustments was surprisingly easy in the front. Even with the string in the way. There is definitely a measurable difference in toe with only an 1/8 turn of the tie-rod (~.5mm). The rear is a bit tricky to adjust, but easy once you figure it out. As soon as you loosen the adjusting bolt, the tire toes-way out! The only difficulty I've found is that it seem pretty easy for the steering wheel to move while making adjustments. When I went for my test drive, I found the car to be pretty straight, but the steering wheel was off by quite a bit in the opposite direction as before... lol

Oh well, I'll try again this weekend. Now if only I could get the wife off my *** and let me get it done...

I think I'm gonna get one of these for $30 on amazon. S&G Tool Aid 66400 Steering Wheel Holder/ Pedal Depressor:


Last edited by 94eg!; 10-21-2011 at 09:01 AM.
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Old 10-21-2011, 02:43 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

Good job
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Old 10-21-2011, 03:56 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

Thanks. I think I'm gonna borrow 2 more jackstands and setup strings on both sides of the car this weekend. Then I can figure out the true rear track of my setup by adjusting the back jackstands until the two strings run parallel to one another (while maintaining equal distance from the center caps left & right).

It's gonna be a little more work, but once I know the exact difference in rear track, I'll never have to do it again. I'll update this thread once I get my numbers.
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Old 10-23-2011, 12:33 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

how long does a full string alignment take?
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Old 10-23-2011, 02:14 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

***UPDATE***

My rear string offset had to be +4.5mm in order to make strings on both side parallel. That means my rear track is 9mm narrower than the front. I'm guessing it's more to do with my lowered ride height rather than the hybrid suspension. Of course adding camber kits will make your track widths change as well. Bottom line: It's important to do this if you have a modified suspension. The good news: You only need to do it once.

Originally Posted by pwebb0207 View Post
how long does a full string alignment take?
Depends on how screwed up your alignment is...

String setup on one side takes about 2-5 minutes. That is including pulling out your string, jackstands, scale and level. I am keeping my length of string with tied loops hanging on the wall for future use. If you already know your track widths, then jackstands can be positioned right past the rims, instead of out past the bumpers. This makes it much easier to measure to set the center caps distance while micro-adjusting the jackstands at the same time. If your jackstands are too far away, it's much harder to get the string positioned.

The front adjustments can be quick as 5 minutes if you have a tool to hold the steering wheel centered. You just slide your arm under with your 14mm & 19mm open end wrenches and go to town. If you don't have a tool to hold the steering wheel, you going to spend a lot of time fighting. Every time you turn the tie rod, the steering wheel moves as well as the tire. That means you need to adjust the tie rod, re-center the steering wheel and then measure. I was using a level sitting on top of the air bag to re-center the steering wheel. Not that great. It will greatly increase your ease of adjustment by making some simple slip-plates for the front tires with some thick glossy plastic shopping bags and a little grease inside or some spray lube. This allows the wheel to turn easily without putting much force back into the steering wheel screwing up your centering (not needed for the rear).

Making adjustments to the rear is tricky cause you cannot do it in small accurate increments. You essentially loosen the bolt, lever the trailing arm, tighten the bolt and re-check. You do this until you get lucky and bolt it down where you want it. This is because every time you loosen the adjusting bolt, the rear just toes way out. I did one corner of the rear today and it took about 8-10 minutes to get it right (after the string was setup). Depends on how lucky you get making adjustments.

I can say with confidence that I can measure accurate within .25mm. My fishing line is .2mm thick and it's easy to tell if your 1/4, 1/3, 1/2 etc. between marks.. The best way I've found to get repeatable measurements is to attach a level to your scale. Tilting the scale up & down WILL skew your measurements.

Just keep in mind there is a learning curve so don't expect perfection the first time. Once you develop a technique, you'll be able to do a full car in well under an hour.

Last edited by 94eg!; 11-07-2011 at 09:45 AM.
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Old 10-24-2011, 12:30 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

Originally Posted by 94eg! View Post
Good thinking, but the hub/bearing is the same for Civic ABS and Integra GSR too.

I've added it to the first post.

An unrelated FYI: The Type R rear hubs have a 10mm wider rear bearing (with 2 more *****). The R's rear hub-face only sticks out 5mm further though. That extra distance is then negated by the wheels having a 5mm higher offset. Thus the rear track of the Type-R stays the same... lol
Thanks for the clarification. Interesting little tid-bit of information.
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Old 10-27-2011, 01:22 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

Well I did my second string alignment last night on my wife's 04 Pilot. The steering wheel holder sure does the trick. Also I learned that it really helps to make some simple slip plates for the front tires to sit on. This allows the tires to turn much easier and keeps feedback from moving the steering wheel. This is what I used to make mine for free.

- two sheets of glossy paper cut out of a junk mail ad (use the glossiest you can find)
- two plastic grocery bags

I laid the 1 sheet of glossy paper right in front of each front tire. Then I laid a plastic bag flat on top of each sheet of paper. Next I moved the car forward till I was directly on top. You will be able to tell that the steering gets much easier once your in the middle of the bag.

Now setup your strings and go to town.

I think next time around I'm going to use a thick glossy plastic shopping bag (like from a department store) and spray a little bit of lube or smear a little grease inside the bag to further reduce friction between the two layers of plastic. No mess since you just toss the bag when your done.

Last edited by 94eg!; 11-07-2011 at 09:46 AM.
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Old 10-27-2011, 07:27 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

interesting topic about the ITR. i suppose this is considered basic knowledge among ITR folks, but its good to know.

so is it just the rear hubs/bearing that is different? does the rear unit fit on non ITR trailing arms?
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Old 10-27-2011, 08:47 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

It does physically fit onto the regular rear-disc trailing arm, but there is problem as 4-lug trailing arm spindle is shorter. Since the 5-lug hub's inner race is so wide, there is a large portion of the bearing that hangs off the smooth press-fit section and covers some of the threaded portion for the hub-nut. I've seen a thread on here where people installed the ITR 5-lug hub along with a thinner Mazda hub nut (Protege I think) without the washer in between. But even in this case, the thinner nut is still hanging off the end of the spindle slightly. Kinda iffy if you ask me. And I have no idea what rotor and caliper they were using.

As for the fronts, the only difference is the 5-lug hub itself (bearing & knuckle are the same as GSR/Civic 10.3" brakes). The ITR front hubs must stick out about an extra 7.5mm on each side. ITR has a 5mm wider front track than Civic/GSR, even though it has an extra +5 of wheel offset (7.5 + 7.5 - 5 - 5 = 5).
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Old 02-11-2017, 08:35 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

Bumping up my old thread cause I found this amazingly simple helpful tip.... DIY Slip Plates for less than $20. I purchased 8 of these cheapo cutting boards at Walmart for $1.88 each. 2 stacked together under each tire with a dash of motor oil between is as slippery as ice. I get no feedback whatsoever into the steering when making front end adjustments. There is one problem with these particular cheap Walmart cutting boards though. They are dished on one side. This means they don't stack nicely with the weight of the car on them. My simple solution was to trim the edges off of 4 and use those as the bottom plates. Then the 4 remaining dished ones sit face up on top of each flat one. The neat thing is you are able to roll or drive the car up onto them and the wheels simply drop into the dish and the car stays put. Once in place your steering is loose as ice and you can do your alignment without any binding or feedback into your perfectly centered steering wheel.

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Old 12-12-2017, 11:07 AM
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Default Re: String Alignment & EG vs DC Rear Track Width

Great idea - less friction than some of the well-used "professional" alignment systems I've seen! (One of the reasons that the numbers on their computer print-outs are so often inaccurate.)

For measuring front and rear track (after all, it's just the difference you need) I use a straightened piece of steel fuel tube with a length of 1/8" rod inside it. Each has to be straight enough to slide, but bent enough to stay where you put it. Much easier and faster than measuring between the two inner sidewalls with a tape.

If you do want an actual number, you can hook the end of the tape into a groove on one tyre and measure to the corresponding groove on the other. (Not so easy with asymmetric tread.)
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Old 05-13-2019, 01:31 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

I wanted to update this thread because budget racing and track driving is life and I wanted other people to have the opportunity to partake in that life.

I have a 1993 Honda Civic DX with 94-01 Integra knuckles up front and 94-01 Integra trailing arms in the rear.

This is a common setup for the current Honda Challenge H4 class.

If you're going to string align the car you will need the front and rear track width. Here is the printout from a Hunter Alignment I got a year or two ago.


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Old 05-13-2019, 03:42 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

Originally Posted by Dilbones View Post
I wanted to update this thread because budget racing and track driving is life and I wanted other people to have the opportunity to partake in that life.

I have a 1993 Honda Civic DX with 94-01 Integra knuckles up front and 94-01 Integra trailing arms in the rear.

This is a common setup for the current Honda Challenge H4 class.
um, where is that in the rules?

7.9.5 Brake rotors and/or drums must be the same type, material, and dimensions as OEM. Brake rotors and/or drums may be cryogenically treated.


a little history: i asked the rules "committee" for clarification on whether the EF civic SI could use CRX Si brakes and pads, seeing that the CRX Si pads were bigger. (Same rotor.) and was denied.

so i dont see how swapping out knuckles and changing the front brakes is allowed.

rear rules dont list trailing arms either.
7.9.5.1 Rear drum brakes may be update/backdated to OEM rear disc brakes. (Including spindle, hubs, rotors and calipers.)

I see no allowance for changing track width in H4.

but whatever, this is just me stirring **** again.
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Old 05-13-2019, 05:16 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

Originally Posted by Tyson View Post
um, where is that in the rules?

7.9.5 Brake rotors and/or drums must be the same type, material, and dimensions as OEM. Brake rotors and/or drums may be cryogenically treated.


a little history: i asked the rules "committee" for clarification on whether the EF civic SI could use CRX Si brakes and pads, seeing that the CRX Si pads were bigger. (Same rotor.) and was denied.

so i dont see how swapping out knuckles and changing the front brakes is allowed.

rear rules dont list trailing arms either.
7.9.5.1 Rear drum brakes may be update/backdated to OEM rear disc brakes. (Including spindle, hubs, rotors and calipers.)

I see no allowance for changing track width in H4.

but whatever, this is just me stirring **** again.

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Old 05-13-2019, 08:02 PM
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Default Re: String Alignment & EG vs DC Rear Track Width

Ha, so H4 has become a 2500lb b18b spec class? Lame. Yeah I skipped over that, didn't think it could be that dumb.
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Old 05-14-2019, 12:24 AM
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Default Re: String Alignment & EG vs DC Rear Track Width

Originally Posted by Tyson View Post
Ha, so H4 has become a 2500lb b18b spec class? Lame. Yeah I skipped over that, didn't think it could be that dumb.
Kick rocks cuz
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