Sidewall Height Question

[rogergrubb]

I've got a '65 Malibu and have a set of Bonspeed 18X9 Malibu wheels on order.
It's getting coilovers, heavy front sway, adjustable rear sway, quick ratio steering, adjustable upper control arms
.
Stock 283 at the moment but I do have a real '65 L79 short block on my engine stand. This week I decided to sell that for a nice all aluminum LS powerplant so if you know anyone who wants to buy a L79 or sell a LS... =0)

It's going to be super snug in the rear and I want this car to handle. Maybe a half a dozen Auto-X's/yr primarily a spirited street car.

I have little experience in setting up a car like this for AutoXing. I assume smaller sidewall is better at the cost of my spine when on the street?

Is there a sweet spot for sidewall height when this car is a DD and a AutoXer?

Sorry if I ran on a bit...

Roger

[BANKO]

Roger, welcome to the board!

Sounds like you a have good plan to make your car handle. What you are planning for the rear suspension mods? Do you have a tire size in mind? With 18" wheels you have a lot of options for tires. The BFG Rival in a 245/40/18 would be a great choice.

I ran the following on my Chevelle and enjoyed some GG autocross & ASCS events. I would've liked a bit more sidewall in the rear because the contact patch did not change when I aired down the tires.

18"x7" - 225/45/R18
20"x8.5" - 245/35/R20

[WSSix]

Welcome, Roger. Any low profile performance tire is going to serve you well. Choose your tires based on how they'll look on the car, ie how does it fill the wheel well, and how they'll look comparing front to rear. More than likely, you'll end up with a 50 series or smaller sidewall. Also, tire width is important as well. From there, you have many other variables to make the car handle and provide a smooth ride on the street. You don't have to sacrifice comfort and tolerate a bone jarring ride in order to have a car that handles.

[rogergrubb]

Josh,
The plan for the rear is just the adjustable upper arms, dual-adjustable shocks or coilovers (I love height adjustability), and the tires/wheels.

For tire size, I was thinking that I would stretch the tires to the wheels. In other words, use the narrowest allowable suggested by the manufacturer. Rival's are at the top of the option list. those hella cheap Federal's look interesting too. Just to try them out.

Good grief man, you've got a seriously killer '65! What is your front spring weight? Looks like it's taking a serious dive. =)

Originally Posted by BANKO

Roger, welcome to the board!

Sounds like you a have good plan to make your car handle. What you are planning for the rear suspension mods? Do you have a tire size in mind? With 18" wheels you have a lot of options for tires. The BFG Rival in a 245/40/18 would be a great choice.

I ran the following on my Chevelle and enjoyed some GG autocross & ASCS events. I would've liked a bit more sidewall in the rear because the contact patch did not change when I aired down the tires.

18"x7" - 225/45/R18
20"x8.5" - 245/35/R20

[rogergrubb]

Hey Trey, thanks for your input. Yep', that's the idea. Form and function.

Nice build thread BTW. I flipped thru the whole thing a few nights ago. Impressive. =-)

Originally Posted by WSSix

Welcome, Roger. Any low profile performance tire is going to serve you well. Choose your tires based on how they'll look on the car, ie how does it fill the wheel well, and how they'll look comparing front to rear. More than likely, you'll end up with a 50 series or smaller sidewall. Also, tire width is important as well. From there, you have many other variables to make the car handle and provide a smooth ride on the street. You don't have to sacrifice comfort and tolerate a bone jarring ride in order to have a car that handles.

[rogergrubb]

So here's the chart for the g-force Rival.

I"m running 18X9 wheels so optimally they call for a 255/40/18.

But I like the idea of extra responsiveness so want to go just a size or 2 more narrow.

Does anyone have any experience with this and what the advantages/disadvantages are?

http://www.tirerack.com/tires/tires....8GFR&tab=Sizes

[rogergrubb]

Josh, you answered my question and I read right over it. 245/40/18.

Thank you.

[BANKO]

No worries. In looking at the Rival tire specs, you could get away with the 275/35/18 that will give your more than an 1" additional section width without changing the overall height by very much (+0.1"). This will be better for grip, you will just have to consider how much bulge you are willing to accept since the 9" wheel is on the small size for that tire. Based on feedback from the Rival release event, the tires offer outstanding grip and longevity. Pretty amazing. I'll try them out when they make a 19" tire.

I tried stretching a 275/35 BFG on a 10.5" wheel and I didn't like the result. The tire rolled away from the wheel face too much and exposed the wheel face in an unsightly way.

I am running Hotchkis 2" SBC springs rated at 512 lb/in. The car is not diving that much in the speed stop pic, here is a picture of it parked. The car is just really low

[Flash68]

Welcome Roger. I am a fellow East Bayer myself.

Josh is a good one to be talking to.