Home Made Toe Gage How-to
 

Hi all! There seems to be some interest in changing alignment settings for better mpg, so I thought I'd show how I made my own toe gage out of common hardware store materials.

The idea behind this gage is to use something to measure the distance between the front edge of the rims, then compare it to the distance between the rear edge of the rims. There's really no need to measure the actual distance since this tool allows me to see and measure the difference. This gage should be used on a flat, level surface. Since this gage can't do a 4 wheel alignment it's best used only on the front wheels. If you mess up the alignment on the rear wheels your car could end up going down the road slightly sideways.

The first pic (see pic 1) shows the toe gage sitting on my kitchen floor.

Materials: the center portion is made with 1/2" x 3' angle iron (note, my car is about 67" wide measured to the outsides of each rim. Check your car. If it's much wider, use longer materials. Smaller cars won't have a problem using these materials), the verticle endpiece is 3/8" x 3' round bar, the other side (pic 2) is a threaded rod 3/8" x 3' with a matching turnbuckle on the end for fine adjustments, and a quantity of 6 U shaped clamp things 3/4" ID (silver parts in the pics). These parts cost about $18 from my local hardware store.

To build it, start by measuring the distance from the ground to the center of your wheels. The gage needs to touch the front/rearmost portion of the rim. Notice there's a curve in the vertical portion to clear the bulge in the tire sidewall. Start with the round bar and bend near the ends first, do the inner bends last. I used a 30 degree bend at 2" in from the end, a 5 degree bend at 6", and an 85 degree bend centered at 22" in( or whatever works for your wheel size), use a gentle radius. The last bend forms the foot so the gage doesn't fall over, so it's done 90 degrees off axis in relation to the first set of bends (see pic 1) Use a 90 degree bend 6" from the other end. 3/8" rod is easy to bend so you can correct it if needed.

The other endpiece is made nearly the same way, except the turnbuckle needs to be horizontal, so use a 85 degree first bend at 2", then continue with a 10 degree bend at 6", then a 85 degree bend at 22"( or whatever fits your car). If the turnbuckle is the right size it will spin freely on the threaded rod. This is bad for accuracy, we want it to turn with light resistance so it doesn't spin while moving the gage. I tightened it by slightly crushing the turnbuckle with vicegrips. I also thought about gumming up the threads with rubber cement. I'm sure there are other ways of accomplishing the same results.

Assemble the parts using 2 U clamps at each side. The other two U clamps are used as feet so the gage rests on the ground the same way each time. Since this is a DIY project feel free to add/delete features to suit your needs.

To use it, start by sliding the gage under the car and set the end pointers on the frontmost part of each rim. (see pics 3 and 4) If the gage touches a balance weight, roll the car forward or back so the weight isn't in the way. The first time you use it you'll probably need to adjust the U clamps to set the distance between the rims. Once it's close, use the turnbuckle so both pointers on the gage almost touch the rims. I like to see the slightest gap, less than 1mm between gage and rim. Check to make sure there is no tension in the gage, and that it's resting on the ground with nothing else touching or pushing on it since this could throw off the readings. Once you have the gage in the correct position with the pointers almost touching the rims, remove it from in front of the rims. This isn't as easy as it sounds since most tires bulge at the sidewall. If you just pull the gage outward you could bend it and throw off the reading. Instead, slide the gage so the pointer on one side is off the outermost edge and fits into a recess slightly inboard. That will give you some slack so you can pull the other side away from the tire. Yes, you'll be doing plenty of walking from one side to the other while doing the alignment.

Place the gage in a similar position on the back edge of the wheels. Again, use care when positioning the gage so you don't bend it and ruin the reading. Walk the gage into position taking advantage of any recesses in the rims. Compare the distance between the pointers to see if the back edge of the rims are closer or farther away. If the backside is wider, you have toe in. If the backside is narrower, you have toe out. Measure the difference and adjust the tie rods to compensate. Re-check the measurements after any adjustments. Any tool is only as good as the user, so take several readings before making any adjustments. Check that all readings are the same each time, if not, something isn't right and shouldn't be trusted for accurate alignments.

OK I don't know what happened to the first pic, but it didn't show up in the original post, so here's pic 1.

I adjusted the toe in on all 4 wheels of my Swift using a 9' long straight edge made from steel U channel. Just park on a level surface, set the straight edge up on a cinder block along side the door so it lines up with the center of the wheels front and back, then check the distance between the straight edge and the front and back of each rim. Quick and easy with nothing to fabricate.

Q

Are you talking about changing the alignment settings from what a shop would do, or are you just outlining a method for people to do alignments themselves. In other words, does the alignment shop not align the vehicle for optimal mpg?

they put it to factory specs, so whatever the car maufacturer decides is what they set it to. my dad and i made one and its really accurate because we set my trucks alignment with it and then drove straight to an alignment shop (we had to redo the casstor/camber and no way to check that at home) and when it was done and we got the report sheet about how much they adjusted it, it was only off by less than 1/8 inch (accuacy between thier laser alighment tool and our homemade one)

As is the case with recommended tire inflation pressures, the manufacturers' specs don't reflect the optimum for FE. Well, except for maybe in extreme cases like the Insight.

Okay, but with high tire inflation pressure, there's a trade-off -- not as comfortable or cushy a ride, perhaps decreased performance, etc. So the factory has other priorities in mind when specifying inflation pressure.

So I guess I'm asking how alignment specs could be altered to affect various aspects of performance. If the factory/alignment shop doesn't set the specs for ideal efficiency (i.e., lowest rolling resistance), then what is optimized? stability? traction? even tire wear?

Mmm-hmm. Like tire pressure, it's a balancing act. I'm guessing that they balance stability and tire wear most closely.

More toe-in = more stable = higher tire wear = lower FE

more negative camber (I think) = better handling = less stability = more tire wear

So they balance all of that to get what they think people want.

Yes, that's a quick and easy way to do it. Your method wouldn't work on my car since the front and rear wheels are not the same distance apart. The front wheels are .8" farther apart than the rear, so it's not square.

I've also added a touch of negative camber to the front wheels to make it corner better, which works nicely. The front end doesn't scrub as much when I take corners near the limit. The tradeoff is that it tends to follow truck ruts and grooves a little more intently now. Raising my tire pressure also increased this tendency. Has anyone else noticed this effect with high tire pressure?

Yes. Due to studded tires use the roads here have deep ruts. Both my Toyota pickup and my Swift tend to follow the ruts pretty badly with high tire pressure.

Q