String To Align Your Car
- Thread starter KBabcock
- Start date
abarth4
True Classic
I think every race car since time began has been aligned this way. With regards to the toe measurements, the accuracy of the strings with reference to the center line of the car is HUGELY critical. This can be a good "field method" of aligning the car. No substitute for a modern, laser alignment system, but if done correctly it can be cheap, robust and pretty effective.
Lowtechprime
Retro Grouch
Actually, 'modern' laser alignment at shops just try for a 'green light', and can be out by as much as 20%... I go to an old school place that does it all by hand, and understands race and adjustable suspensions...
fiatrn
Jonathan is the FiatRN
I replaced the steering rack in a car, and reset the toe using string, a jig of 1x2 cheap wood, cardboard under the front tires, and a lot of measuring and remeasuring. It was actually kinda fun - focus on the measurements and rechecking over and over. The car felt perfect when I drove it ,but I didnt trust myself. So I took it to an alignment shop afterwards who told me I was spot-on with the centering, but a little off between right and left - but that it would have made no difference in wear.
I would think with a known flat floor you could also do a decent job of setting the camber at home, but I am unsure about how you would measure and set caster?
I would think with a known flat floor you could also do a decent job of setting the camber at home, but I am unsure about how you would measure and set caster?
Mark_Toro
True Classic
I do this for all my Alfas. Camber and toe. Toe is easy with the string method. Camber is "good enough" with a carpenter's square on the garage floor. Once you get the process down it is fun to set a lot of camber for an autocross day, and then easy to set it back for the street. If I make the changes close enough together, I just count the shims on the lower A-arms and the turns on the tie rod ends.
I have yet to figure out a way to measure caster. To date, I just verify the caster rods are equal side to side and call it good. If I am replacing or modifying the caster rod components (105 castor rod mod is common on the transaxle Alfas), I measure from the chassis to the end of the upper control arm before starting the job, and then match the measurement once the new parts are installed.
I have yet to figure out a way to measure caster. To date, I just verify the caster rods are equal side to side and call it good. If I am replacing or modifying the caster rod components (105 castor rod mod is common on the transaxle Alfas), I measure from the chassis to the end of the upper control arm before starting the job, and then match the measurement once the new parts are installed.
Lowtechprime
Retro Grouch
I use one of these to measure caster and camber.. there are magnets on all 4 sides. You can stick it on the strut tube to measure castor angle...
www.harborfreight.com
If you don't trust cheap electronic tools, you can use one of these as well.
Digital Angle Gauge
Amazing deals on this Digital Angle Gauge at Harbor Freight. Quality tools & low prices.
www.harborfreight.com
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Fiataccompli
Chris Granju
I believe caster is often (or always?) measured by measuring camber with the wheels turned 20 degrees in & 20 degrees out from the 'straight' (which technically isn't straight, yes?) position & then multiplying the differenced by 2. A bit ago, I got this Tenhulzen rig that is set up to measure toe/camber/caster using a set of toe plates, tape measures, applicable standoffs for the wheels & a digital level. It's a bit clunky but I did my '85 X1/9 & my '72 124 Coupe with it (combined with a nifty steering wheel holder to keep it centered) and I have to say both cars are aligned/feel/etc. as good as any Ive had a professional shop do (ref comments above about the 20% close enough & move one mentality). Just to make things more luxurious I also got some turnplates that i lower the car onto (with the ideal same height piece of lumber to bring the other end of the car level). Anyway, the answer for caster is that it's geometry. You can probably find a lot of ways of figuring the geometry if you google DIY Caster Measurement. The kit I have has the luxury of being able to zero the caster gauge for the 'in' reading which makes the +/- bit even simpler (which I guess is nice since 124s have a + 30 degree caster as a standard spec)
Actually an angle finder like that would be really great if it were more coarsely graded. I digital level can be a bit of a silly thing giving perhaps more significant figures than it's accuracy warrants. The Summit product looks a lot like the carpentry angle finder my father in law tossed me 15 years ago for free, except his didn't have a racing sticker.
Actually an angle finder like that would be really great if it were more coarsely graded. I digital level can be a bit of a silly thing giving perhaps more significant figures than it's accuracy warrants. The Summit product looks a lot like the carpentry angle finder my father in law tossed me 15 years ago for free, except his didn't have a racing sticker.
dllubin
Don
Back in the 70s, I built a giant caliper to set toe in. It used two 10 foot sections of 3/4" ridgid conduit pieces to hold the caliper blades which contained bolts that touched the wheel rim. The bolts could be screwed in or out to just touch the rim. By measuring the distance between the front contact points and the distance between the rear contact points, the toe in could be easily calculated. I used the ridgid conduit on a project a few years ago so I'll have to get some replacements if I used this method again. I also made a device to make sure the thrust angle on the rear was correct in addition to the toe in.
PaulD
Paul Davock
I use one of these to measure caster and camber.. there are magnets on all 4 sides. You can stick it on the strut tube to measure castor angle...
If you don't trust cheap electronic tools, you can use one of these as well.Digital Angle Gauge
Amazing deals on this Digital Angle Gauge at Harbor Freight. Quality tools & low prices.
I use a smart camber gauge to set the camber and castor with my own string set up for toe.
The smart camber gauge costs a lot more now then when I got mine years ago. It does, however, not need a level floor.
The results are repeatable The procedure for setting the castor is a bit fussy, as with most systems.
SmartCamber — Smart Racing Products
I actually came up with the SmartCamber gauge before the SmartStrings – I needed something to replace my old trusty Dunlop gauge, and wanted something digital and could be used to measure the angle of other things on the car also. Proper camber settings are significant, not just for good tire wear f
www.smartracingproducts.com
For the lowdown on really doing it right, check Rupunzell's set up:
Miata Chassis Alignment..
Similar but related. The 96' NA miata got put up on the chassis set up rig. Learned much about the Miata's chassis and suspension. This project began with making and installing anti-roll bar links. To replace the wore out stock links. The anti-roll bar links installed: One discovery...
xwebforums.com
(this is on her miata, I could not find the X1/9 page)
Lowtechprime
Retro Grouch
I just use those tools to get my alignment close enough that I can drive it to the alignment shop and not destroy my R compound tires on the way there...
kmead
Old enough to know better
I miss Bernice ( @Rupunzell ) being around, she has has been a good teacher..I use a smart camber gauge to set the camber and castor with my own string set up for toe.
The smart camber gauge costs a lot more now then when I got mine years ago. It does, however, not need a level floor.
The results are repeatable The procedure for setting the castor is a bit fussy, as with most systems.
SmartCamber — Smart Racing Products
I actually came up with the SmartCamber gauge before the SmartStrings – I needed something to replace my old trusty Dunlop gauge, and wanted something digital and could be used to measure the angle of other things on the car also. Proper camber settings are significant, not just for good tire wear f
For the lowdown on really doing it right, check Rupunzell's set up:
Miata Chassis Alignment..
Similar but related. The 96' NA miata got put up on the chassis set up rig. Learned much about the Miata's chassis and suspension. This project began with making and installing anti-roll bar links. To replace the wore out stock links. The anti-roll bar links installed: One discovery...xwebforums.com
(this is on her miata, I could not find the X1/9 page)
Dr.Jeff
True Classic
Several years ago while traveling abroad I saw a neat alignment system being used in a shop. It was simple and allowed measurement of toe, caster, and camber for both the front and rear wheels. I really liked the concept so when I returned home I started searching for something like it. To my surprise there wasn't anything even close available in the US, and only a couple anywhere else. But the cost to buy one of them and have it shipped here was more than I wanted to spend for my own use.
I decided to do more research and see if it could be easily replicated for a DIY system. The general concept is a bit like the "Tenhulzen rig" Chris referenced, kind of a mix of the "Smart Racing" item (Paul's reference) with laser lights instead of strings and targets to read the light beams. Over the next two years I discussed the theory of it with some alignment equipment companies at trade shows to help refine my thoughts better. And I came up with several of my own designs. The necessary components were very affordable. There was only one area that might require machining for better accuracy and some simple fabrication otherwise. My estimates were well less than $100 to manufacture it (including labor and everything else) and I figured it should sell for no more than $150, marketed for home use as well as small shops that don't do a lot of alignments. And to me the low price was key; pretty much everything on the market is very expensive for what it is [this market seems to have a very high profit margin]. Therefore I submitted the concept to a couple of companies hoping someone would manufacture them - not for my profit (I gave them the full plans for free) but in order to have them make me one in exchange. They all said they liked the idea but did not have time. Then a few months later I saw a version of mine offered for sale by one of those companies. Although they had tried to make it appear more complex (which actually made it less accurate and more difficult to use) and their asking price was outrageous. Unsurprisingly it never sold.
I did not pursue it further after that. I still have the plans and someday I'd like to make one for myself...along with a gazillion other things.
I decided to do more research and see if it could be easily replicated for a DIY system. The general concept is a bit like the "Tenhulzen rig" Chris referenced, kind of a mix of the "Smart Racing" item (Paul's reference) with laser lights instead of strings and targets to read the light beams. Over the next two years I discussed the theory of it with some alignment equipment companies at trade shows to help refine my thoughts better. And I came up with several of my own designs. The necessary components were very affordable. There was only one area that might require machining for better accuracy and some simple fabrication otherwise. My estimates were well less than $100 to manufacture it (including labor and everything else) and I figured it should sell for no more than $150, marketed for home use as well as small shops that don't do a lot of alignments. And to me the low price was key; pretty much everything on the market is very expensive for what it is [this market seems to have a very high profit margin]. Therefore I submitted the concept to a couple of companies hoping someone would manufacture them - not for my profit (I gave them the full plans for free) but in order to have them make me one in exchange. They all said they liked the idea but did not have time. Then a few months later I saw a version of mine offered for sale by one of those companies. Although they had tried to make it appear more complex (which actually made it less accurate and more difficult to use) and their asking price was outrageous. Unsurprisingly it never sold.
I did not pursue it further after that. I still have the plans and someday I'd like to make one for myself...along with a gazillion other things.
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Kevin Reay
Daily Driver
Go-kart people use a laser thing called a Sniper. They are quick and work great, don't know if they can be adapted as they magnetically attach to the axle (axle is not tapered).
Dr.Jeff
True Classic
It looks like the basic concept on that Sniper kit is very similar to the design I saw in Europe for cars. Those "grids" on the receiving end are the same kind of laser light targets that I was describing in my prior post. The main difference is what you said, having a apparatus to attach the components to automotive wheels. And the one for cars also had a toe alignment setup that can reach around the wheels instead of over them (I believe that's how the Sniper does it?).