The effective gear ratio also changes as the tire gets smaller, resulting in slower speed at the same RPM.Originally Posted by Custer55
The effective gear ratio also changes as the tire gets smaller, resulting in slower speed at the same RPM.
56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension
Other vehicles:
56 Chevy 2-door BelAir sedan
56 Chevy 210 4-door sedan
57 Chevy 210 4-door sedan
1962 327/340HP Corvette
1961 Willys CJ3B Jeep
2001 Porsche Boxster S
2003 Chevy Silverado 2500 HD Duramax
2019 GMC Sierra Denali Duramax
In case you didn't know, track width is measured from the wheel CENTERLINES, not the outside width. A narrower track loads the outboard tire more while taking weight off the inside tire, decreasing total traction. If you stand with your feet together, you can't lean to the side very far before you tip over. If you spread your feet wide apart you are much more stable, and can lean quickly side to side, while keeping both feet planted. A wider track has the same effect as lowering the center of gravity. If you have ever have done any Kart racing it makes more sense. You know pretty quick when you have narrowed the track too much to adjust weight transfer, while on your head laying underneath the kart looking up at the sky.How could a wider track/narrower tire corner better than a wider tire, when BOTH tire outside edges are at the same width? The wider tire also has more traction.
If what you say is true and a narrower tire with a wider track is better, you should be using a 195 rear tire pushed out to within 1/2" of the wheelwell lip to get a track width of 62.8". That's even better than the 255 by 2.3"!!
Try that.
On your car you said you narrowed the track 3 inches with your current wheels, so if you went 2 inches wider on the wheels/tires inboard, wouldn't you have narrowed the track width by like 7 inches? Then yes, a 195 wide tire would probably corner better.
Last edited by 55 Rescue Dog; 04-04-2017 at 01:15 PM.
I sure would like to see the math on that.
Plenty math here to look at.
https://www.physicsforums.com/thread...hysics.281902/
My take is wider tires will always have better traction given the same tire design and compound. Wider track width will have better stability. So somewhere there is a optimum compromise between the two which would take many$$ worth of testing to find and even then it would only be valid for the parameters of that test. On race car you have to fall within the rules of your sanction body. On a street car you have to keep your tires within the available space of your wheel wells without rubbing on anything, and not may street driven vehicles will ever be driven to the limits of what they are capable of anyway. At least mine never will. My goal is more about the right look and stance than perfect handliing. So to me this is a pointless discussion.
Thanks, Brian
What does this prove?
A 'theoretical' argument...The *real world* involves compromises on compromises.. just as Brian states.
No shit Sherlock? If you did ther math you'd see that my numbers I quoted are for the tire centerlines, i.e. track width.
A narrower track with the same tire width, yes. That's because the outside edge of the tire moves inboard. As I showed, you can narrow the track with a wider tire and have the outside edge of the tire in the exact same place. How can that hurt handling?A narrower track loads the outboard tire more while taking weight off the inside tire, decreasing total traction.
<irrelevant stuff deleted>
I narrowed the track from what? From a stock C4 rear with C4 wheels? I narrowed the suspension such that the wheel mounting surfaces are 3" narrower than a stock C4. That allows me to put a wider tire on the rear and I can adjust the track width by the wheel offset. I plan to put different custom wheels on the car sometime after it's finished and wrung out a little. You can't get any wider track width on your car than I can, unless you hack the wheelwells. And I can get a lot more rubber on the road.On your car you said you narrowed the track 3 inches with your current wheels, so if you went 2 inches wider on the wheels/tires inboard, wouldn't you have narrowed the track width by like 7 inches? Then yes, a 195 wide tire would probably corner better.
You obviously are confused about track width versus narrowing the suspension. You can narrow a suspension without affecting track width. My tires are currently inboard as far as they can go due to the dogbones and swaybar. Even if I didn't narrow the suspension and used the same wheels and tires, they'd be as far inboard as they could go due to wheel offset and tire width. Any additional width to get to a 335 or 345 tire would have to be outboard. I have room to go outboard, either with wheel spacers, wider wheels, or different offset. Narrowing a suspension doesn't necessarily change track width unless you use the same wheels.
Surely you're kidding about a 195 tire cornering better than a 295 tire with the outboard edges in the same place. That's absolutely ridiculous.
I think you put way too much emphasis on track width without understanding what else is going on. IMO if the outside of the tires are at the same location, actual track width is pretty much irrelevant. On a turn the outside of the outside tire is taking most of the load. It doesn't matter as much where the center of the tire is as it does where the outside edge of it is.
Exactly WHAT in that link is at all relevant to this discussion? I see nothing. How about showing some of that "math" here?Plenty math here to look at. https://www.physicsforums.com/thread...hysics.281902/
Last edited by chevynut; 04-05-2017 at 08:01 AM.
56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension
Other vehicles:
56 Chevy 2-door BelAir sedan
56 Chevy 210 4-door sedan
57 Chevy 210 4-door sedan
1962 327/340HP Corvette
1961 Willys CJ3B Jeep
2001 Porsche Boxster S
2003 Chevy Silverado 2500 HD Duramax
2019 GMC Sierra Denali Duramax
RD, you seem to be obsessed with the fact that I narrowed my suspension and think that somehow I screwed it up. But you have yet to explain what the effect of that was and how it hurts my suspension. I have explained to you WHY I did it, and what the effects are.
In the rear of my Nomad the outside of my tires are currently 68" wide. They're 12" 295s so the rear track width is 56". I can put 1 1/4" spacers between the wheels and the discs and get it to 70 1/2" wide and 58 1/2" track width, which I think is good. That's probably where I'll end up with custom wheels but perhaps with a wider tire (325 or 335??), so the track width will shrink <gasp!>. A stock C4 rear with 50mm offset wheels and 275 tires has a theoretical track width of 59.33" and an overall tire width of 70.49".
Here's a couple of questions for you, see below. In diagram A the tires have the same track width...which will perform better (handling) and why, or are they the same?
In diagram B, the tires have the same outside width, but the large tires have a smaller track width. Which will perform better, and why? Of course these are exaggerated, so don't get hung up on that.
20170405_001.JPG
20170405_002.JPG
56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension
Other vehicles:
56 Chevy 2-door BelAir sedan
56 Chevy 210 4-door sedan
57 Chevy 210 4-door sedan
1962 327/340HP Corvette
1961 Willys CJ3B Jeep
2001 Porsche Boxster S
2003 Chevy Silverado 2500 HD Duramax
2019 GMC Sierra Denali Duramax
Assuming this is 4 different rear axels that are cornering, I would say that the 2nd one on drawing "A" both would transfer the same amount of weight, but the wider tire could achieve most grip of the 4 examples. On drawing "B" the narrow tire would have less load transferred, and maybe perform better, because in bottom drawing it looks like it could lift the inside tire off the ground, and tuck the outboard tire under and flip the car.
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