Setting up a string line for alignment. f R track difference?
06-07-2013, 11:13 PM
#1
Burning Brakes
Thread Starter
Setting up a string line for alignment. f R track difference?
Hi Folks
Setting up a stringline to do alignment on a 997 C2s. I'm measuring from the crest in the middle of the mags to the line. Apparently rear track is 30mm wider than front track so I'm putting line 15mm closer to rear hub.
Am I measuring to the right place? Should I be taking off the crests and going to the hub directly? Is 15mm correct?
Cheers
Matt
Setting up a stringline to do alignment on a 997 C2s. I'm measuring from the crest in the middle of the mags to the line. Apparently rear track is 30mm wider than front track so I'm putting line 15mm closer to rear hub.
Am I measuring to the right place? Should I be taking off the crests and going to the hub directly? Is 15mm correct?
Cheers
Matt
06-07-2013, 11:51 PM
#2
You're trying to adjust the toe in the front? what are you trying to align (toe front, rear? camber? etc).
I think doing the string line front and rear is going to be pretty tough as the rear has it's own toe. the math is pretty tough.
If you really want to do the toe in front, I'd probably take 2 2x4"s, drive a long (spike)nail in each one so it is mid rim height (about 10" off the ground). Use it to measure inside of the front rim to front rim on the front of the wheel and then back of the wheel. you need to measure this distance very accurately. Then you can use those distance to calculate the toe angle.
Though, toe isn't really enough here.. you want camber to be set well too. And you have to be super accurate when measuring. I've done this before and gotten good results but it may be worth it to just go pay someone with an alignment rig to align it really well.
I think doing the string line front and rear is going to be pretty tough as the rear has it's own toe. the math is pretty tough.
If you really want to do the toe in front, I'd probably take 2 2x4"s, drive a long (spike)nail in each one so it is mid rim height (about 10" off the ground). Use it to measure inside of the front rim to front rim on the front of the wheel and then back of the wheel. you need to measure this distance very accurately. Then you can use those distance to calculate the toe angle.
Though, toe isn't really enough here.. you want camber to be set well too. And you have to be super accurate when measuring. I've done this before and gotten good results but it may be worth it to just go pay someone with an alignment rig to align it really well.
06-08-2013, 12:06 AM
#3
Burning Brakes
Thread Starter
Yeah I'm sort of out of time for a shop! I have all the measurements and formulas no problem, but I'm just making sure I have the line parallel to the car, which means knowing the difference between the front and rear tracks so you can adjust it accordingly to the hub face (which I'm assuming to be the face of the crest inserts - don't know if that is right or not).
I'm only doing Toe at the front. Camber at front is as much as I can get it which is only about .8deg! (was 0.5 and 0.3 right/left)
Rear is good.
I'm only doing Toe at the front. Camber at front is as much as I can get it which is only about .8deg! (was 0.5 and 0.3 right/left)
Rear is good.
06-08-2013, 10:00 AM
#4
doublechecking, you're not using rears as a benchmark for parallellism right? you're taking a string that's paralell to the front wheels and measuring to a distance outside the rear track, right? then you measure the differences in track and then subtract half that and do the match.
you want rim face to rim face or tire face to tire face. The rear wheel has a toe of it's own so you really should measure your line to both the lead and trail of the rear rim and average the two and use that for your calc. Or you could take a big t square and use that in the rear with the T across the rims.
the method that i'm showing above is a different (and i think probably more accurate) method. Your method assumes the front and rear track measures are dead on to specs which might not be the case.
you want rim face to rim face or tire face to tire face. The rear wheel has a toe of it's own so you really should measure your line to both the lead and trail of the rear rim and average the two and use that for your calc. Or you could take a big t square and use that in the rear with the T across the rims.
the method that i'm showing above is a different (and i think probably more accurate) method. Your method assumes the front and rear track measures are dead on to specs which might not be the case.
Last edited by 997_rich; 06-08-2013 at 10:18 AM.
06-08-2013, 10:31 AM
#5
here's a pic showing exaggerated toe in the rear so you get a sense of it. The front and rear track (red) is different so you have to know that dim really well.
also note that your steering may not be truly centered so you may get for example 4 deg toe on one side and 2 on the other. that just means you really have 3 degree toe on both sides.
Perhaps you're using a different method than the two methods laid out here. If so, you should explain as there a few ways to do this.
also note that your steering may not be truly centered so you may get for example 4 deg toe on one side and 2 on the other. that just means you really have 3 degree toe on both sides.
Perhaps you're using a different method than the two methods laid out here. If so, you should explain as there a few ways to do this.
06-09-2013, 12:58 PM
#7
I've thought about doing this myself too. I think to have even a shot at getting it close you need to have the right tools.
No affiliation, but check out the video o this page:
http://www.quicktrickalignment.com/qt-products/
Shows how to do the toe and camber..
No affiliation, but check out the video o this page:
http://www.quicktrickalignment.com/qt-products/
Shows how to do the toe and camber..
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07-13-2013, 07:02 AM
#8
Burning Brakes
Thread Starter
Right, took it to a shop with the front maxed out (in) camber wise, used a Hunter machine and went to the "Performance" specs and ended up with:
Left Front ----------------------- Right Front------------------ Spec (from machine)
Camber 0.85deg---------------- 0.9deg ---------------------- .25-.75deg (neg)
Caster 7deg50'------------------7deg37'-----------------------7deg35'-8deg50' (pos)
toe 2.8'----------------------------1.9'----------------------------0-5' (IN)
Total toe 4.7'------------------------------------------------------0-10'
Left Rear--------------------------Right Rear-------------------Spec
Camber 1.75deg-----------------1.75deg----------------------1.4deg-1.9deg (neg)
Toe 8.4'-----------------------8.4'---------------------------5'-15' (IN)
Came out to 0deg thrust angle and 0deg steer ahead which is pretty good...
Basically the specs are the same as "Performance ROW" but caster has a larger error margin than those specs.
Left Front ----------------------- Right Front------------------ Spec (from machine)
Camber 0.85deg---------------- 0.9deg ---------------------- .25-.75deg (neg)
Caster 7deg50'------------------7deg37'-----------------------7deg35'-8deg50' (pos)
toe 2.8'----------------------------1.9'----------------------------0-5' (IN)
Total toe 4.7'------------------------------------------------------0-10'
Left Rear--------------------------Right Rear-------------------Spec
Camber 1.75deg-----------------1.75deg----------------------1.4deg-1.9deg (neg)
Toe 8.4'-----------------------8.4'---------------------------5'-15' (IN)
Came out to 0deg thrust angle and 0deg steer ahead which is pretty good...
Basically the specs are the same as "Performance ROW" but caster has a larger error margin than those specs.
