On the subject of bump steer

[obcuz]

Here's a conversation topic on bump-steer aimed at those who are technically or practically apt.

Since I've owned this 182, it has a very definate tendancy to bump steer, which makes the car uncomfortable - getting towards unpleasant to drive, the handling is absolutely fine otherwise on smooth roads, but we don't have any of those around here, I have not driven another 182 so can not relate to how bad this really is or am I being over sensitive

Just to clear up what I mean by bump steer - a small directional change when going over undulating surfaces, bumps, holes etc, this is caused by toe angle changeing when the suspension is in compression/uncompression at the front, this feels like the sterring wheel is being snatched when hitting a pothole, hands off driving down a bumpy road will definately confirm this problem if you think you have it.

I have had the suspension checked, replaced parts where necessary and the problem persists, unless this is a problem with the basic design of the suspension, it leads me to believe that the geomery of the suspension has changed since it was new, as I can not believe that a car can have this amount of bump steer as 'normal'.

The car has standard cup suspension, wheels/tyres etc.

I know from this forum that this is a known problem for the 182 and perhaps the 172? and many have had this problem and have tried to put it right with varying amounts of success, but I have not seen a definitive 'result' or explanation.

Has anyone ever had their car checked with a bump steer gauge?, it doesn't look too difficult to construct one of these.

Is it possible to make a small change to the height of the rack relative to the suspension or is it possible that the rack could move in the vertical plane thus altering the toe angle?

In my case, although I not sure about it. I think the tendancy is toe-out on un-compression - thus stearing 'into' the hole, the problem seems less noticable on compression.

I would be very interested in other peoples (sensible) comments/views on this.

 

[MG cup]

I am also intersted as to how people have adjusted their bumpsteer on clio's. I am building a race car just now and I'm mocking up my cup racer setup which is different to road going but it appears with the racer setup the bumpsteer dosent seem to be much but can't be sure untill I put a gauge on it.gauges are an unneeded expense at the minute.

Adjustment can be quite expensive with the rack setup clio's have. A small adjustment can be had up and down by slotting rack holes which isn't ideal, making up spherical track rod ends which can be shimmed to suit, allowing easy adjustment. After I have mine checked I am going to have new rack mounts machined to suit I think as this will kill 2 birds with one stone. 1...solid mounting the rack, no rubber bushes 2....give correct bumpsteer. This setup will only allow one ride height really but I don't have plans to change that after corner weighting....just camber, toe in/out, arb and tire pressure adjustments to achieve a good setting.

I never looked at standard geomatery before removing although I'm goin to mock up and check.

 

[Chip-mk1]

Compared to a lot of cars the amount of steering induced by a bump is relatively small on a clio as the steering arms are located fairly low and are not greatly dissimilar in length to the bottom wishbone.

Are you sure you dont have something else going on like play in the steering back bushes that is exaggerating it> Mine was terrible till I replaced them.