How tight is too tight?

I've had a small smattering of interesting cars over the years, but I'm building my first actual race-capable car.

Some of the ratios I've owned have been in the 14:1 - 12.5:1 range, (some variable, some fixed) but I also realize that those numbers are dependent on other things, like the spindle's steering arm length and (to a smaller degree) ackerman angle.

How does one compare apples to apples, and at what point does the ratio become subjectively a chore on the highway?

I've driven vehicles with a 1:1 ratio on the highway, wasn't a chore at all.

That's because the ratio itself isn't the whole answer. Power assist, caster, camber, offset, wheel width, etc all come into play.

The problem still usually isn't that it's a chore on the highway, as in high effort, it's that the vehicle can become so twitchy you can't keep it going in a straight line, especially if you dare to try to change the radio volume or such.

Where it can very much become a chore, it in a parking lot. Where I've had steering wheels I flat couldn't turn due, in part, to the ratio. And since cars don't typically have split brakes like tractors do, you're just kinda stuck.

And there is still subjective feel and personal preference. A board member and I were talking about that with regards to race cars and slaloms. To my surprise, I was able to hustle an old Mustang through slaloms faster and easier than my Spitfire because of the huge steering wheel and higher ratio steering box. I could finese the line I took far more easily than I could with the small steering wheel and quick ratio steering of the Spitfire.

OH, we're talking about cars...

Yeah the problems with quick ratios on the street are heavy effort at low speed (although this can be worked out, with a powerful PS system if nothing else) and twitchiness on the highway (which is unfortunately made worse by the things that reduce steering effort at low speed).

You can reduce highway twitchiness with a variable/progressive-rate rack but personally I really don't like those...feels completely wrong, especially when powersliding or drifting.

VW has sold hot hatches that are 1.5 turns lock to lock at the steering wheel.

Which VWs had those racks?

Raze wrote: OH, we're talking about cars...

Its Curtis's thread. I was clicking expecting something else.

Brett_Murphy wrote: Which VWs had those racks?

Golf R32.

Raze wrote: OH, we're talking about cars...

That's what she said.......

Yeah, just the ratio doesnt make much difference. Has anyone ever driven a Citroen SM? lol

Sorry... I misused the word "chore." I should have phrased it like "too twitchy" or "too responsive" for highway duty. I understand the ratios and the assist. When I said "chore," I meant that as in making it stressful to drive and keep control on the highway due to the steering being too responsive. At this point my discussion has nothing to do with steering effort, just steering speed/ratio.

My question was, at what point does steering ratio (lower numerically) become too tight for highway use due to its fast wheel turning?

... and, since the ratio describes the number of steering wheel turns vs. the number of turns at the pitman arm, it says nothing of actual wheel angle since the length of the arm on the knuckle also affects that.

... and how does steering ratio work when it comes to racks? For instance, on my 12.7:1 ratio traditional steering box in my Chevy, it would take 12.7 turns of the steering wheel to make one turn of the pitman shaft. That makes sense, but since R&Ps are linear motion instead of radial, how are R&P ratios measured?

My concern is this. In engineering this car's chassis I need an apples to apples comparison of how the ratios are calculated and how tight I can go with the ratio before highway driving gets twitchy and stressful. For instance, if I decide to ditch the old-school 16:1 box for a steering rack from a Durango, how do I know what the effective ratio will be given the other parameters I have like steering knuckle arm length?

foxtrapper wrote: The problem still usually isn't that it's a chore on the highway, as in high effort, it's that the vehicle can become so twitchy you can't keep it going in a straight line, especially if you dare to try to change the radio volume or such.

Bingo... that's what I'm talking about. I just have writing ineptitude this week. I don't want it to be so tight that I end up in oncoming traffic every time I sneeze.

And there is *still* subjective feel and personal preference. A board member and I were talking about that with regards to race cars and slaloms. To my surprise, I was able to hustle an old Mustang through slaloms faster and easier than my Spitfire because of the huge steering wheel and higher ratio steering box. I could finese the line I took far more easily than I could with the small steering wheel and quick ratio steering of the Spitfire.

I understand that notion. I kinda feel like I'm 39 and I've been on training wheels the whole time. I agree that the slower ratios are more forgiving much like taller sidewalls give up grip more progressively, but I want to sit at the big boy's table. I suppose if I don't like it I can always change it.

Don't worry too much about it. Keep the scrub radius low and add castor to reduce twitch, use electric ps and turn it up in the parking lot, turn it down once you get moving (speed sensor is your friend)

Giant Purple Snorklewacker wrote: Don't worry too much about it. Keep the scrub radius low and add castor to reduce twitch, use electric ps and turn it up in the parking lot, turn it down once you get moving (speed sensor is your friend)

I thought about using a Cadillac PS pump with the variable assist but instead of using the failure-prone clockspring in the column to control it I could use something like a variable gain pot on the dash and a speed sensor to vary the pulsewidth. Crank it up for lots of assist for daily driving and turn it down for more spirited outings.

Scrub radius has been on my mind. The wheel offset will probably move scrub radius a little on the positive side, but it will still be within the range of alteration with a little more kingpin inclination. Then the positive camber gain from kingpin axis in the rearward arc can be handled with increased caster. (He says hopefully).