Bump steer is something that you need to reduce or eradicate while setting up your suspension. It's probably more important to fix than any other part of your chassis setup. If you have the hawk build manual, there is a section in there in how to fix it, if not I'm sure someone on here can give you a link to it.
The split alloy bearing is fitted on the intermediate steering shaft. Owners generally replace them with a proper bearing of some kind.
I have the build manual and have read this up.
What are the symptoms of bump steer?? as all I am trying to dial out is the straight ahead sensitivity at the mo. Car was built by the legendary Bob Pilot rip so with all the shimming evident I think it is fair to say I will not touch yet.....
Unpleasant straight ahead.
Car steers straight with no hands, just sensitive to hands!! Ie no Ackerman effect.....
Further transformed after a professional setup today.
Used a firm in Colchester that specialise in track hardware - mostly drifting.
The biggest change is in tyre pressure up to 28 front 30 rear from 22 all round. Castor wound back to 4 degrees, 1.5 deg camber on front, .7 on rear, and parallel toe rear and 2 deg toe out front.
Was a bit mystified until I drove it and found it delightful (not a delightful handful). We will have to see. The overall comment was nothing much is going to remove the twitchiness until I source different tyres as the super soft TB15's will always tramline due to their stickiness......
So I gave him the task of finding a set of matching tyres (there aren't any other than the Pirelli equivalents are there??)....
[QUOTE=Lancialulu;29755
Used a firm in Colchester that specialise in track hardware - mostly drifting.
The biggest change is in tyre pressure up to 28 front 30 rear from 22 all round. Castor wound back to 4 degrees, 1.5 deg camber on front, .7 on rear, and parallel toe rear and 2 deg toe out front.
.[/QUOTE]
hope you've got good insurance.......
Tim, those tyre pressures sound way too high to me. Keep an eye out for uneven tread wear, especially in the centre sections! How does the steering self centering feel?
They're not trying to get you out there drifting are they?
Guy I was surprised too but after a long discussion I thought it could be worth a try. If they get work then they will heat up and pressure will go up but on the road they will not get this work as evidenced on my return the fronts were stone cold. I have to say the ride and steering feel was better.... No I am going drifting either.... If the tyres heat up then drop some pressure...., but the self-centering is compromised by the wider than spec super sticky "race" tyre. I will look out for uneven wear though as there isnt much tread to play with to begin with! Shame Friday looks quite wet as it is my travelling day to Goodwood and I doubt I will go in Shades after my boating experience this morning!Originally Posted by Guy Mayers
BTW what is the mph / 1000 suppose to be for a 164 12v fifth gear re tyre diametre as is seemed high c 27mph/1000?
Last edited by Lancialulu; 12-04-2016 at 20:51.
Craig
its the sticky 235 TB15's on the front that make it twitchy not the rears... Can you recommend a standard compund 15 gp4 tyre front and back. Noted I trye to drive carefully. It is early days but I am persauded to live with this until alternative tyres can be found at which point I will set the front differently.
Tim
Michelin TB15 215/55/15's have a nice big compliant side wall which shouldn't cause any issues. At the temperatures you are running on the road then I doubt the tyres can really be classed as sticky. Guy runs a wider squarer front tyre which should yield more issues than yours.
Have you actually taken the time to remove the damper & check the bump steer? You have mentioned a number of times that you have altered the front castor. Are you aware that each time you alter the castor you should then double check the bump steer as castor adjustment alters the relationship between the steering arm & the steering rack which in turn provokes bump steer. About 4 pages ago we covered the subject of twitchyness & the subject of bump steer was raised. If you are now happy with your ride height, toe settings & tyre pressures then can I suggest you actually check the bump steer before buying new tyres to replace the ones that plenty of others here run with out issue.
Last edited by Strat Fan; 13-04-2016 at 23:14.
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