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Old 08-03-2009, 05:15 AM   #1
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Default steering throw

hi, i am confused with the steering geometry, put my m03 on the setup board to set up toe and checked steering throw while i was at it. Adjusted endpoints so they matched, about 14 deg both ways, but i noticed the gauges measured the inside angle not the outside, so i measured the outside and while the inside are both 14 the outside is 10 and 14. how can this be and how do i fix it.

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Old 08-03-2009, 06:02 AM   #2
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This difference is intentional, it is called Ackerman.

I could try to explain it but I am sure there are better sources on the internet.

Like: http://en.wikipedia.org/wiki/Ackerma...ering_geometry

So your car is fine, no need to adjust anything.

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Old 08-03-2009, 06:09 AM   #3
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sorry, i dont mean that the two sides are different inside and outside at the same time, ala ackerman. but one direction outside is 10 deg, other direction is outside 14 deg. yet both are 14 inside. bit hard to explain
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Old 08-03-2009, 06:18 AM   #4
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It sounds strange, contradictory almost.

There is no way for the outside of 1 wheel to be 10, and the inside 14 without the wheel being tapered. Unless I misread again.

It is perhaps the way you are reading the setup board, do you have a picture of it?

Also, if possible, use a setup station, where the plastic parts go on instead of wheels, then there is no mistake between inside and out.

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Old 08-03-2009, 06:26 AM   #5
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sorry, still not explaining it right, its late here.

its on a setup board with gauges, not wheels. On the left wheel when turning left it is 14 deg. on right wheel when turning right its 14 deg, but....on the right wheel when turning left its 10 deg, and the left wheel when turning right is 14 deg

does that make sense. you know how the clear plastic ruler at top of setup board only measures inside wheel angle, then you slide it over for other inside wheel, i'm talking about the other wheel.
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Old 08-03-2009, 06:45 AM   #6
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Firstly I would say don't place all your faith in the setup board, it can give misleading results since the car is not actually on its running wheels when being measured. Get the car to running weight, put the running wheels on, and check again.

Second, if there is a difference in the ackermann from one lock to another, the only explanation can be that one side of the car's geometry is different. Most obvious would be an off-centre steering crank and uneven length steering arms, but it could be any number of things. Double check everything for uneven settings, wear or damage.
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Old 08-03-2009, 06:51 AM   #7
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Ok, I understand now.

It sounds like an odd issue.

If I were to guess, I would say that you steering linkages were different lengths. I mean the link from the steering hub to the central steering post.

I'm not sure if they are adjustable on the m03 though.

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Old 08-03-2009, 06:54 AM   #8
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I can only see two "normal" possibilities here.

One is that there is so much slop in the bearings/linkages on the right wheel that it is not turning all the way. This possibility is somewhat unlikely since the wheel seesm to be turning all the way the other way.

The second is that the something blocks the wheel turning fully whilst the servo saver takes the effort (a c-hub for instance). Again unlikely since the other wheel seems to be going full throw.

Perhaps it's worth checking just to eliminate these possibilities.

Edit: took so long to type someone else has come up with some other ideas. I assumed your geometry is right and the bellcrank is centered.
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