DC2 VTI-R Overhaul

[Muzz]

Ive read plenty of very good suspention books and have never come across a relationship between bump steer and castor.

As im sure you guys know, bump steer is caused by the angles of the steerings tie rod ends, moreso there angle in the vertical plane. As the suspension is compressed the angle increases pulling the steering knuckle inwards toward the car.

I fail to see why swapping ucas to move the mounting point backwards for a small increase in castor (probaly only 1-2 degrees), is going to alter the angle of the steering arms in anyway that will be detrimental to bump steer.

Adding this slight caster would move the steering knuckle joint downwards, which is exactly whats required when the bump steer angles are bad due to lowering (the steering arms are angled upward due to lowering, tilting the hub back will make the arms more horizontal).

Im really interested in those graphs you mentioned string but cant seem to find em. Im really keen to check it out though if you can see them.

Was it a single trace of the bumpsteer after swapping the uca's, because that woulnd prove anything usefull, it needs to compare the traces of the bumpsteer both before and after the ucas are swapped.

[tinkerbell]

Ive read plenty of very good suspention books and have never come across a relationship between bump steer and castor.

As im sure you guys know, bump steer is caused by the angles of the steerings tie rod ends, moreso there angle in the vertical plane. As the suspension is compressed the angle increases pulling the steering knuckle inwards toward the car.

I fail to see why swapping ucas to move the mounting point backwards for a small increase in castor (probaly only 1-2 degrees), is going to alter the angle of the steering arms in anyway that will be detrimental to bump steer.

Adding this slight caster would move the steering knuckle joint downwards, which is exactly whats required when the bump steer angles are bad due to lowering (the steering arms are angled upward due to lowering, tilting the hub back will make the arms more horizontal).

Im really interested in those graphs you mentioned string but cant seem to find em. Im really keen to check it out though if you can see them.

Was it a single trace of the bumpsteer after swapping the uca's, because that woulnd prove anything usefull, it needs to compare the traces of the bumpsteer both before and after the ucas are swapped.

yes, the funny thing is that the method of reducing "bumpsteer" effect that is experienced on extremely lowered vehicles (as mentioned on the HT threads) is to lower the mount point of the steering control arm in relation to the hub (e.g. by mounting it onto the underside...) to ensure the steering arm retains a similar angle to the original angle prior to lowering...

using your imagination (or do it practically if you like), what is the effect of the LCA swap on the vertical position of the steering control arm?

what does this tell you about *possible* bumpsteer effects?

[tune2look]

I fail to see why swapping ucas to move the mounting point backwards for a small increase in castor (probaly only 1-2 degrees), is going to alter the angle of the steering arms in anyway that will be detrimental to bump steer.

I believe whiteline kit will give you up to 2.5.
So 1~2 degrees will do stuff.
People even worry about few psi on tyre pressure.
In suspension wise, 1mm, 1 degree will do a lot I think.

*I remember Ben's castor kit is only around 1.5?

[tinkerbell]

Muzz is not saying that the UCA swap doesnt increase castor.

[midnightdood]

To all that have done this mod. Are the front wheels pushed back measurably?

[T-onedc2]

To all that have done this mod. Are the front wheels pushed back measurably?

It tilts back slightly but you wouldn't ever pick it.