TR6 Replaced steering rack in my TR6- very twitchy now

[71TR6]

I replaced the factory steering rack in my TR6 with a 3.5T Bastuck rack and have a question for the forum. I notice the Bastuck rack is very twitchy. I am wondering whether this is the nature of these racks or is it just that it is new and not worn like the old one. Driving down the road feels like balancing on a marble to keep the car going straight. The car was professionally aligned after I installed the rack.

Has anyone else experienced this with an aftermarket Bastuck rack?

Ron

 

[PAUL161]

Have you checked the tow-in? I've seen this happen on some cars with no tow in. My TF was quite sensitive until I added 1/8" tow in and the twitchiness disappeared. PJ

 

[bobhustead]

In order to make a car want to go straight, something in the three planes of steering geometry needs to be in a non-neutral but steady position. If you have worn parts in the suspension, out of whack toe in may be the factor that put your system into non-neutral territory. i.e., incorrect toe in was compensating for misalignment of worn parts somewhere else. When you put the toe in right, the geometry can go neutral or allow a sloppy joint somewhere to suddenly take up slack when you turn the wheel just a little bit.
Bob

 

[Hamish Racing]

My guess would be lack of toe in.
toe in helps centralise the straight driving.
i run my 3a parallel to compensate for wider lower tyres and to aid quicker corner “turn in” not what you want on the street.

 

[PAUL161]

I'm not a TR guy, but the Bastuck steering rack has very positive reviews and is reported to have a slower reaction steering than the original setup, plus the guys seem to like it. I would check to make sure all your linkages are tight with no slack and again add about 1/8th inch toe in to start. JMHO. PJ

 

[71TR6]

Thanks everyone! To clarify, do I adjust the toe in so the tire to tire distance of each tire is in by 1/8" total or does each tire get adjusted in by 1/8"? I just want to be clear where and how the toe-in is measured in this case.

Ron

 

[mezy]

measure from the centre line of the rims not the tyre from inside edge to inside edge back and front of the wheel, the front need to be shorter than the back, hence tow in, unlike front wheel drive cars that toe out.

 

[71TR6]

Thanks Mezy. So is the 1/8” total toe in ( move each wheel in 1/16”) or do I move each wheel in 1/8” for a total of 1/4”?
Ron

 

[bobhustead]

I don't know the spec, but whatever it is it is total. Toe in is measured at the level of the spindle.
Bob

 

[mezy]

Thanks Mezy. So is the 1/8” total toe in ( move each wheel in 1/16”) or do I move each wheel in 1/8” for a total of 1/4”?
Ron

it is the total amount, but i think it is 1/16" but you will need to chack the vehicle specs to be 100% sure,
too much toe in will cause tyre ware on the outside of the tread

 

[CJD]

+1 on the toe. Darting is a symptom of having toe-out.

 

[Alphonso61]

Get a tracking gauge for under £100 and recheck the tracking as that is what will be doing it.

 

[Sbardon]

I replaced the factory steering rack in my TR6 with a 3.5T Bastuck rack and have a question for the forum. I notice the Bastuck rack is very twitchy. I am wondering whether this is the nature of these racks or is it just that it is new and not worn like the old one. Driving down the road feels like balancing on a marble to keep the car going straight. The car was professionally aligned after I installed the rack.

Has anyone else experienced this with an aftermarket Bastuck rack?

Ron

Ron, it sounds like you are on the right track,.... but back to the beginning... sometimes Alignment shops pump up the tires rock hard... 40+psi for setting the alignment. Did you check the tire pressure after? my 6 is is beyond twitchy, it is scary and drives like on ice, with the tire pressure at 35+ instead of the 20, Just a thought.....

 

[malbaby]

Did your alignment shop align all 4 wheels...do they have a laser system.

 

[mctriumph]

Malbaby is spot on. find a good alignment store and get the full reading all round. If you have any
questions , remember all readings should be in the green when finished.
Mad dog

 

[tr6nitjulius]

Perhaps what you consider twitchy is responsive. R&R OEM rack several years ago for hi-ration quick rack aka racing rack. Eliminates full turn lock to lock: OEM 3-1/2 turns hi-ratio 2-1/2 turns. Realized how much unnecessary slop/movement/corrections required while driving down the road with OEM rack even rebuilt.

Trade off hi-ratio is very responsive 1/8 turn of wheel is a lane change where as OEM 1/4 turn,. Gave 2 fellow TR6 owners a ride on roads they were familiar with both heard hi-ratio would be too twitchy both impressed after the ride with less effort to turn, mounts adjustable to make steering responsive to suit