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24 Oct 2011, 19:32 (Ref:2976191) | #1 | ||
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Dunlop Optical Alignment kit
What do we think of this kit? I find it interesting that many garages swear by the big multi-£k laser alignment rigs for setting up road cars yet many racers and teams seem to use the Dunlop kit.
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1989 Porsche 944 S2 |
24 Oct 2011, 21:13 (Ref:2976241) | #2 | |||
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Quote:
Obviously it's limited on what it can do with it but they have survived a long time and haven't changed much over the years. A bit of innovation with axle stands and a bit of string can almost do the same as the million pound laser gear. |
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Balls of steel (knob of butter) They're Asking For Larkins. ( Proper beer) not you're Eurofizz crap. Hace más calor en España. Me han conocido a hablar un montón cojones! Send any cheques and cash to PO box 1 Lagos Nigeria Africa ! |
24 Oct 2011, 21:43 (Ref:2976253) | #3 | ||
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Well that is sort of what I thought. I managed to get my car to track nicely a few years back just with bits of string, counting threads on the track rods and a couple of test drives and tweeks. I was going to get it 'properly' aligned after but it drove perfect anyway. I guess the main problem with the Dunlop kit is it assumes you must have a straight body shell? and all the axle mountings are straight and perpendicular to the centre line of the shell i.e. no thrust angle etc.
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1989 Porsche 944 S2 |
24 Oct 2011, 22:13 (Ref:2976274) | #4 | ||
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The body shell doesn't have to be "completely straight" as most are built to a tolerance.
As long as the suspension pick up points are within a "gnats" and the wheels run in the same axis from front to back and the wheel base is the same on both sides you wont be far out. Get a camber/caster gauge and you're there. Once you get used to a certain type of set up equipment and know what you're doing with it I don't see any sense in spending mega money. Don't forget that tools are only as good as the people using them, and that applies to 4 wheel laser alignment emporiums as well ! |
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Balls of steel (knob of butter) They're Asking For Larkins. ( Proper beer) not you're Eurofizz crap. Hace más calor en España. Me han conocido a hablar un montón cojones! Send any cheques and cash to PO box 1 Lagos Nigeria Africa ! |
25 Oct 2011, 11:24 (Ref:2976471) | #5 | ||
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Just remember that they will allow you to align both your front and rear axels correctly, but not nessacarily to each other. The result could be a crab effect. Now in some cars ths may not be significant, and this also depends on the level your at.
In a high downforce single seater a 'crab' of only 0.5 deg can (and we have tested in wind tunnels and CFD) increase the drag by as much as 5%. Now at 145 mph a drag reduction of 5% = 8mph better top end or an increaced acceleration. This is significant if everything elso on the car is spot on, but this is only normally the case with a national level car with a race engineer, aero guy, dynamics guy and data team. 2nd ly the 4 wheel laser kit is much faster to use with the correct knowlage, and allows you to tell a customer exactly how there car is set, as if you just say 'its ok' they may disagree. If you say 'your front tow is x, your rear tow is y, and your thrust misalignment is z' no one can argue with those facts. |
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25 Oct 2011, 15:41 (Ref:2976610) | #6 | |
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I put a bit of string around the car, touching the tyres, when I use the Dunlop stuff, so you can see which wheels need adjusting to eliminate crabbing.
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RICHARD TROTT |
25 Oct 2011, 20:21 (Ref:2976760) | #7 | ||
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Or if you are desperate/broke -
Couple of bits of string, four axle stands, bit of wood with some triangles cut in it, a square and a steel rule. |
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25 Oct 2011, 23:00 (Ref:2976829) | #8 | ||
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Join Date: Nov 2009
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TBH thats not only if your broke! Good method full stop.
The most common way of tracking top single seaters/LMPs is still to use fishing line streched between two rods front and rear. If your doing it commonly on one car then just weld up a backet to solidly mount them to a hard-point, then once you have mesured from a referance to exactly the same distance out each side, slice a small groove into the pole. From then on you can just bolt on your tracking bars, have some pre cut and tied bits of fishing line (with a loop at each end) that you strech over the bars and locate in the slot. You can then always squair everythig to the chasss... Provided you make them stiff and accurately! |
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26 Oct 2011, 07:02 (Ref:2976905) | #9 | ||
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Yes, stringing a car up is a great and extremely accurate way to check & set up the suspension, effectively, all that the laser equipment does is to draw a laser line around the car instead and make the job a little easier.
However, neither method has the biggest advantage of the Dunlop Optical equipment, the comedy value of greasing the eyepiece before 'showing' a trainee how the equipment works and then watching their bewildered expression when everyone starts laughing at their 'black eye'! |
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Incognito: An Italian phrase meaning Nice Gearchange! |
26 Oct 2011, 20:04 (Ref:2977360) | #10 | ||
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Gordon, I have had one of those Sealey camber/caster gauges with the big magnet in the end for sticking onto brake disks. I would like to stick it onto a steel bar instead that can be offered up against the wheel. Its actually very helpful when setting camber, something I found a few years back when I noted just how much the camber can shift on my car when tightening up the upper bolt on the front struts. Keeping one eye on the gauge you can see straight away if that last nip on the bolt has knocked it out.
Anyways I am asking all this stuff as I found this year the only way I can afford to race is to try and sort everything I can on the car myself. |
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1989 Porsche 944 S2 |
1 Nov 2011, 15:43 (Ref:2980174) | #11 | ||
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The advantage I found the one time I forked to use one of those fancy laser computer controlled jobbies was that it not only gave alignment data for each wheel, but "axle" alignment information. They clamped a set of mirrors to the body and each wheel and took a set of readings, then rolled the car forward half a turn of the wheels and took a second set. As well as the usual info, the printout actually gave the centre line offset of each "axle" and the angle of each to the centre line. On my car I found that my front "axle" (ie suspension mounting points) weren't exactly 90deg to the centre line of the car, and that the rear axle was at 90 deg but actually offset slightly to the centre line of the front suspension. And it all took about 10 mins. I think that's quite an advantage over string.
Having said that, once the "axles" are set up right, I find a camber gauge and a Dunlop tracking gauge are fine. Although if I adjust the rear toe. I do cross check by clamping a cheap laser level to the back hubs to check the offset is equal at the font axle. |
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10 Nov 2011, 17:54 (Ref:2984063) | #12 | |
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I Inherited my fathers old Dunlop stuf and it works a treat, simple and logical and you can work your way all round the car with it
have also got a magnetic bubble gauge which was cheap but needs callibrating before use! |
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22 Jul 2014, 12:20 (Ref:3436630) | #13 | |
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ive a question about these gauges
does it matter the width of the car? im thinking the wider the car the gauge will measure differently as its an angle its measuring and like a triangle the angle softens the longer the base line? |
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22 Jul 2014, 12:43 (Ref:3436646) | #14 | ||
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No it wont make any difference as you are measuring it from whatever width car you are putting it on, and if it did it wouldn't make any odds as it would be within the tolerance.
What is important is making sure that the gauge is accurate for a start by putting them together and making sure the read out is on zero or reset it , I've seen a lot of "so called" tyre fitting and tracking cowboys that never check the equipment (or don't know how) consequently the tracking is set wrong. I suppose they will flog more tyres that way ! |
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Balls of steel (knob of butter) They're Asking For Larkins. ( Proper beer) not you're Eurofizz crap. Hace más calor en España. Me han conocido a hablar un montón cojones! Send any cheques and cash to PO box 1 Lagos Nigeria Africa ! |
22 Jul 2014, 14:53 (Ref:3436689) | #15 | ||
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suntiger, you're measuring the angle over the diameter of the wheel so it wouldn't matter if the car is a mile wide the diameter and the angle will be the same as if it is a couple of feet wide.
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22 Jul 2014, 16:29 (Ref:3436713) | #16 | ||
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On the subject of Dunlop Optical Tracking Gauges. How many on here were given a 'Black Eye' as a youngster when an older work colleague asked you to look into the sight after carefully lining it with either Engineers Blue or plain black grease?
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Incognito: An Italian phrase meaning Nice Gearchange! |
22 Jul 2014, 18:17 (Ref:3436737) | #17 | ||
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Blimey most of the sight rubbers must have disappeared into dust by now, mine has !
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Balls of steel (knob of butter) They're Asking For Larkins. ( Proper beer) not you're Eurofizz crap. Hace más calor en España. Me han conocido a hablar un montón cojones! Send any cheques and cash to PO box 1 Lagos Nigeria Africa ! |
22 Jul 2014, 19:05 (Ref:3436751) | #18 | ||
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25 Aug 2014, 18:53 (Ref:3447400) | #19 | ||
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Late to the party, but oh well.......
The Dunlop gear was and remains excellent. But then does a simple trammel bar! However, you MUST ensure there is no wear as the difference can be significant in terms of degrees of TI or TO. Same with any bit of precision kit: take out the wear!! In the workshop days, I had a huge wooden box of Laycock geometry kit; did everything but make the tea! However, for basic tracking and wheelbase measurement (BTW don't forget any trammel bar can also be used to check relative Offside/Nearside wheelbase (you might well be surprised!), the Dunlop Optical was the best. had all those strange swivelling drive on platforms too. Personally, I always preferred the reliable Dunlop device. Don't forget! check the TI/TO: and then move the vehicle forward/backwards until the road wheels have rotated 50% (Chalk mark on sidewalls works well and is cheap!)and check again. The optimal adjustment is the mean difference between both measurements. |
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