steering rack wanted

[marjon]

I have a Hawke 2B witha race steering rack almost got myself damaged first time out,it was to direct very twitchy as I got faster it got to the point where you couldnt correct without spinning,nasty moments.So Im told I need a modified triumph rack,does any one have one in the garage? even damaged,I can try and find a spitfire at a wreckers but this route is first.
Thanks

[rv greg]

Here is a link to a rack that might work. They have several different sizes.
http://www.appletreeauto.com/RACK-an...8.5-16-2181-0/

http://www.ebay.com/sch/i.html?_nkw=...ng+rack&_rdc=1

[Charles Warner]

Before you go changing the design of the car make sure you don't have another issue. Are there any other similar cars with similar racks that do not have the problem?

First look at the rear toe. Any appreciable rear toe out will cause the car to act exactly as you describe. I have never known a race car to come with a rack too sensitive to drive. Look elsewhere.

[provamo]

any history on this car?.......................still kicking myself for selling mine when i was back east

[racerdad2]

I believe Charles has it. Rear bump steer, worn suspension bits, loose rear hub...

[Brian]

All triumph racks have the same ratio. If you want to slow it down, get longer steering arms. It has triumph uprights as I recall, and there were different length arms available. But as said the steering probably isn't the issue.

Brian

[marjon]

Hmmmmm ok,I rebuilt this car,it was a frame with the 4 corners,I made up the links measuring other 2As and 2Bs the steering rack was bought along with 4 shocks and springs that had belonged on a later ford,late eighties to early 90s,its a light alum rack,very similar to the stock rack shown in pegasus catalogue,
I will certainly get the front and rear set up redone as most here advise, the cut down triumph rack was on this model,would it be advisable to replace the rack anyway or should it work just as well with the rack I have,does anyone have particular way to measure the ratio of turn from st wheel to road wheel

John

[racerdad2]

I believe Loshak ( my memory is iffy ) has stated that turning steering wheel 180º translates to 20º of the wheels turning ? Just an average.... don't know the particulars on your car. My Reynard loves 2º toe-out front. 2º toe-in rear. There are guys on here with vast knowledge & experience. They'll chime in

[Lee Johnson]

If you want to do the alignment yourself, I can strongly recommend that you get a copy of Carrol Smith's "Prepare to Win" & check out his words of wisdom on suspension alignment. Although the book was published nearly 40 years ago, the basics it presents are still valid. For that matter, all of Carrol's books offer useful info for (road-)racers at any level. If you decide to hire the work out, reading the book(s) will sure make you a better informed customer

As others have suggested, be sure to look at the possibility of something being loose (broken, worn-out or mis-adjusted). Also, attend to the self-steering problems that can result from bump-steer. Carrol's book has some good descriptions of the phenomenon & how to fine tune it to suit your skill-level and type of car.

Good luck & have fun,

Lee

[marty7]

Some quick comments.

A successful single seater designer I know said his rule of thumb was 10 degrees of wheel for steering wheel. That is 90 degrees at the steering wheel will give 9 degrees at the wheel. Easy to measure and calc. You know rack shift, steering arm length. Use trig. None of my FF cars are near 10% -One is around 8.5% from memory the other 9%. Still moves pretty quick when needed.

Set up depends on tyres, for a crossply eg: Dunlop, you are safe with say 4 - 5 degree castor at front, 1 degree camber , Early cars were toe in at front but you can run tow out - try it up to 2mm per side out. Rear - critical - check for bump steer. Adjust rear castor till you have zero bump steer. You can tolerate bump toe in, no bump toe out. Bang in some rear toe in say 2mm a side, 1/2 to 1 degree camber. That will be a good safe starting point.

Bump steer at the rear is far more critical than front. You can live with front. But do check and fix if it is there.

Set up is not difficult - flat floor, two bits of fishing line, ruler. To do camber you can use a builders square and ruler, a level and a ruler, or a camber gauge. I use a camber gauge. Quick way to make friends at a track when they spot in the tool box. I have made changes at the track. Camber gauge makes life easier - money well spent.

[Charles Warner]

My Reynard loves 2º toe-out front. 2º toe-in rear.

I've never known a car that needed, or wanted, that much toe in at the rear. Even the Shadow with 500 hp and relatively soft springs only needs about .7 degrees toe in. I seriously doubt you get any real toe change on acceleration. Reduce the toe out to almost zero. You'll save tires and free up the car. And I doubt you 'll feel much difference.

[racerdad2]

Thx ! I spaced out on the phone key board I meant 2 mm. I will try zero toe as I get faster. Thx for the heads up ! I've got much to learn & my hard drive is getting full

[brownslane]

Have you set up the suspension and bump steered the car? If not, you are just guessing what may be the problem.

Charles is absolutely correct. The rack is not the problem. At least not the speed it is responding.

It takes a complete day to set up a car from zero. If you do not have the tools or the knowledge, then get somebody who can do it for you. Without a stable, consistent platform any discussion of minutes or degrees of toe is premature. If you get somebody to do the work, ensure you are there throughout the process and get them to explain what they are doing and why. You need to understand how your cars suspension works.

You need to make sure all four wheels are pointing in the same direction throughout the full range of suspension travel.

You say that you copied other Hawke's suspension? Are you sure that you got the suspension links exact? Did you get the rack installed at the correct height? Something as basic as a rack mounted the thickness of a washer higher or lower will change the cars handling. Same deal with corner weights; You need to have the car balanced, aligned and bump steered. Only then can you start tuning the chassis.

[Hawke]

If you have copied some other Hawke's setup, it still may be incorrect.

I have seen some that that have put the rack on the inside of the front bulkhead. This must make the set up for the bumpsteer a bugger.

I have my rack on the outside - front - of the front bulkhead, and I have set it with zero bumpsteer.

I've going along with the others. There is something else drastically wrong with the set up.