Big/tall tires?

[Charger68]

A lot of opinions here...I'm against taller tires. It's makes your car slower, and while speed isn't everything, it cost me bragging rights back in the 1970's. I switched my 1971 Z28 E60-15 bias for G70-15 radials. I really didn't know any better. This, and revving past the sweet spot, slowed up my car to the point of eventual embarrassment.

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[ChitownStang]

A lot of opinions here...I'm against taller tires. It's makes your car slower, and while speed isn't everything, it cost me bragging rights back in the 1970's. I switched my 1971 Z28 E60-15 bias for G70-15 radials. I really didn't know any better. This, and revving past the sweet spot, slowed up my car to the point of eventual embarrassment.

Curious how it makes it slower?
Lets say the diameter is 1" larger. Aren't you going faster .
At 80mph on my dash my radar detector show I'm going like 84mph

 

[Junkyard Dog]

Curious how it makes it slower?
Lets say the diameter is 1" larger. Aren't you going faster .
At 80mph on my dash my radar detector show I'm going like 84mph

A taller tire is the same as a taller rear gear, i.e., lower numerically. Who knows what gear he had in his 1971 Z28, probably 3.73 (standard for 1971, although 4.11 was available), with only 330 horsepower (actually a lot for 1971 but laughable for today as the Ecoboost would stomp it in a drag race). E60 tires are 26.1 inches in diameter (about the same as modern 305/30R19). When he went for '70s Cool and installed the G70 tires (and probably air shocks, lol), the diameter increased to almost 28 inches.

So this lowered his rpm as he floored the gas when the light turned green on Main Street, and the car he wanted to challenge, a 4 speed 1971 Cuda with cheater slicks and 4.56 gears, revved it up and dumped the clutch and ran off and left him while that Z28 small block was struggling to turn those large diameter wheels.

He never forgot it and would post about it in the future, in the year 2026, when we all have flying cars and a base on the moon.

 

[robvas]

We also don't have three speed automatics with 2.73 gears these days

 

[Charger68]

Curious how it makes it slower?
Lets say the diameter is 1" larger. Aren't you going faster .
At 80mph on my dash my radar detector show I'm going like 84mph

One inch is huge. Top end is higher because you're effectively changing (higher) the rear axle ratio maybe 4%. In my case the ratio went from 4.10 to estimating 3.9. Acceleration is slower with a higher rear axle. BTW, top end was 116 MPH.

 

[robvas]

Even with the stock size tires you could in theory go way over 200mph if you had the HP

 

[robvas]

Curious how it makes it slower?
Lets say the diameter is 1" larger. Aren't you going faster .

Missing a word here that makes it more clear

'accelerates slower'

If it wasn't for air resistance you would eventually go faster with larger tires

 

[ChitownStang]

Missing a word here that makes it more clear

'accelerates slower'

If it wasn't for air resistance you would eventually go faster with larger tires

Is that because of weight or diameter.
Seems like the weight of my new wheels are lighter than stock wheels but tires are heavier.
May be close to same weight as stock 19 setup

 

[robvas]

Is that because of weight or diameter.
Seems like the weight of my new wheels are lighter than stock wheels but tires are heavier.
May be close to same weight as stock 19 setup

Diameter

Think about gears on an ten speed bike

Weight is a much much smaller variable

 

[Charger68]

Missing a word here that makes it more clear

'accelerates slower'

If it wasn't for air resistance you would eventually go faster with larger tires

No, go slower to a higher, not faster, top end speed. I'll confuse semantics by saying a 33 1/3 RPM record is it's rate, not speed.

 

[robvas]

No, go slower to a higher, not faster, top end speed. I'll confuse semantics by saying a 33 1/3 RPM record is it's rate, not speed.

201 mph is faster than 200 mph

You're talking about reaching that speed faster or as most would say quicker

 

[Charger68]

201 mph is faster than 200 mph

You're talking about reaching that speed faster or as most would say quicker

You get slower to go faster.

 

[robvas]

You get slower to go faster.

which is why I said

Missing a word here that makes it more clear

'accelerates slower'

 

[Junkyard Dog]

BTW, top end was 116 MPH.

I had 3.73 gears in an 81 Z28, with a highly modified 400 cubic inch engine (6.6 liters, for you youngin's) huge cam, too much compression, headers, 4 barrel, aftermarket cylinder heads, and I went 140mph. The car was still accelerating, but, um, that was about 7,000 rpm, and no, back in the 80s and 90s small block Chevy 400s weren't built for 7000 rpm and there were no reliable high horsepower overdrives (I ended up eventually blowing up the T10 4 speed with no overdrive as it was and eventually killed the rod bearings in the engine).

It was the fastest car I had ever owned back then, but I bet my Dark Horse would beat it.

 

[Junkyard Dog]

This is my setup 275/35/20-315/35/20

Looks a lot nicer than I thought it would.

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