260DET Posted July 14, 2005 Share Posted July 14, 2005 We checked the bump steer on avatar car while getting a wheel alignment done today, on bump the toe change is towards toe in from a static 3mm toe out. On the plus side this should tend to improve braking stability but won't help turn in where turn in coincides with some braking. Correct? May try to minimumise turn in braking if that is the case. Anyway, we'll see how it goes at the track on Saturday, with the new front spherical (monoball) inner bearings replacing the stock items and the steering arm mods aimed at gaining some Ackermann in turns. Driving back after the alignment at ~100kph the car felt quite stable with the 3mm toe out, a little tendancy to wander but quite acceptable. This was a pleasant surprise, all going well at the track it will stay at that toe setting Quote Link to comment Share on other sites More sharing options...
johnc Posted July 14, 2005 Share Posted July 14, 2005 Toe-in on bump is not a good thing. It tightens your line and tends to make the rear of the car loose. Quote Link to comment Share on other sites More sharing options...
auxilary Posted July 14, 2005 Share Posted July 14, 2005 how does one go about measuring toe in/out at bumpsteer? it has to be shock induced, right? You can't just tie down the chassis to the ground and compress the suspension while having wheel cranked, can you? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 14, 2005 Share Posted July 14, 2005 It's been discussed before Alex. You can search and find it in greater detail. Bottom line is removing the springs from the suspension, disconnecting the sway bars, moving the suspension up and down in the normal travel range, and measuring the toe change that happens while the suspension moves. I measured mine with a makeshift bumpsteer gauge. I used 2 dial indicators, one at the front of the rotor and one at the rear, and I jacked the body of the car up and down, not the suspension arm. Quote Link to comment Share on other sites More sharing options...
260DET Posted July 15, 2005 Author Share Posted July 15, 2005 how does one go about measuring toe in/out at bumpsteer? it has to be shock induced, right? You can't just tie down the chassis to the ground and compress the suspension while having wheel cranked, can you? As Jon said, plus it can be done on an electronic wheel alignment machine as we checked it. To do it properly you would want to be able to fix the suspension height at various points throughout the normal range of suspension movement. Then you just read the toe setting off the aligner's screen at each point. We just bounced the car up and down to get a rough idea. Forgot to mention that no extra noise or harshness from the front suspension was noticed with the spherical bearings, fitted in place of the stock rubber items. Another pleasant surprise Quote Link to comment Share on other sites More sharing options...
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