Bump steer

[Tiger tamer]

As seen in the tie rod thread I am going to fit a power steer rack.
In this part of the world we have to have such modifications certified.
I have just been talking to the certifier and he wants to know the Tigers bump
steer measurment. Normally I would have to take the car in and have it measured but as it is already apart so I can't without putting it all back together.

If I can't give him the original Tiger measurment then it has to be set up to 8mm bump steer. Don't know if that would be possible.

Has anyone had it done and recorded ?. Seen it recorded anywhere official like.

Cheers Mal

 

[grelley]

Bump Steer

I am not sure what the original measurement was, but my car, fitted with Dales upgraded suspension and, midget rack and MGB arms had considerable bump steer. Ideally you should have none. If you have to get it certified then I would fit rod ends in place of the ball joints, and get these certified at the same time and included in the one price. I have these fitted to my car and they allow you to move the steering link up or down to get rid of the bump steer. To fit the rod ends I made up a tapered bush to fit in the steering arm, and put a 7/16 HT bolt through it. By swapping the steering arms side to side, and shimming the ends I was able to get rid of nearly all the bump steer, which makes the car much nicer to drive. What the certifier will require will be a maximum of 8mm total bump steer, from full compression to full droop.

 

[Tiger tamer]

I am not sure what the original measurement was, but my car, fitted with Dales upgraded suspension and, midget rack and MGB arms had considerable bump steer. Ideally you should have none. If you have to get it certified then I would fit rod ends in place of the ball joints, and get these certified at the same time and included in the one price. I have these fitted to my car and they allow you to move the steering link up or down to get rid of the bump steer. To fit the rod ends I made up a tapered bush to fit in the steering arm, and put a 7/16 HT bolt through it. By swapping the steering arms side to side, and shimming the ends I was able to get rid of nearly all the bump steer, which makes the car much nicer to drive. What the certifier will require will be a maximum of 8mm total bump steer, from full compression to full droop.

I take it that you have had your set up certified and passed the 8mm of total bump steer ?. You have basically made your own bump steer kit.
He was telling me to make the mounting plates with slots so the rack can be lifted and lowered until the bump steer was correct. So I asked him if the bump steer kits you can buy are OK to use in NZ and he didn't know about them. Thought that was a bit strange.
There really is no room to put the rack in a Tiger except where it is. I think the bump steer kit option or as you have done is a good way to go.

Do you know the regulations on the rod ends we can use and where to get them ?.

Cheers Mal.

 

[grelley]

TBH, I havent had the rod ends certified because I didnt want to pay the $400 odd that they require, but I did talk to the certifier about what I was doing. As I understand it any reputable rod end is ok as long as it dosent have a grease nipple fitted. I have been through 2 WOFs since I did this, and as the rack and linkages have been cert'd then the whole thing passes ok. I think I got my bump steer down to less than 3 mm from around 27 mm. I dont think it would be practical to try to move the rack. Where abouts in NZ are you.
Regds

 

[grelley]

Hi Mal, here is a photo of the setup I am using.
Regds Stephen

 

[Tiger tamer]

Thanks Stephen
The tie rod hex extension you have, is that something you have made from scratch or something you can buy and cut to suit. ?.
I talked with the certifier again today and he told me to get good quality Teflon lined hemi rod ends.

What brake set up do you have there ?.

Cheers Mal.

 

[grelley]

Hi Mal, the extensions are ones I just made up out of hex bar, with left and rh threads. The brake set up is vented discs and Willwood Dynalite calipers. Again I think it may be a kit from Dale. They were fitted to the car when I bought it.