Modern Wheels and Tires

[64Orange]

I was reading an article on Hemmings this afternoon discussing modern modifications to make to your car to make it better for long drives. I want my '64 Fury capable of multiple trips from Bishop, CA (central CA, just a little south of Yosemite) to Orange County, CA (approx. 300 miles). The article had some good points but two points stumped me.

1) Consider using 17 inch or 19 inch wheels as it is becoming more difficult to find tires that fit 14" or 15" wheels. Any truth to that statement?
2) Use 9:1 compression ratio on your motor since 10:1 and above compression ratio motors prefer 93. The 9:1 compression can be more favorable for lower octanes. (I'm still new to engine building so if this question is silly, whoops).

Link to article: https://www.hemmings.com/stories/2021/09/16/basics-for-building-your-next-long-distance-driver

 

[MoparLeo]

14 and 15 inch tires are still available. Just not in a very wide selection as opposed to the 17" and up sizes.
Also consider that when going to the "modern sizes" that they require a more expensive rim, they will ride harder because of the short sidewalls, tire/wheel clearance can be a problem.
Modern cars from the suspension up are designed for the modern tire/wheel sizing. Our cars were not.
BFG, Cooper, Mickey Thompson, Goodyear (repro) Firestone (repro) are available to fit our cars and are more period correct.

 

[Dan64]

14" is harder to find sizes in but i've never had a problem finding what i wanted in a 15". Larger rim ( like 20") ride more harsh than a 15" due to less sidewall. I know someone will disagree but i've found it to be true. A true 10 to 1 should run fine on 91 pump fuel, we have 93 around my way but i still like to stick to about 10 to 1 even with aluminum heads because i may not always be able to get 93. I have run 91 octane in a 9.6 to 1 engine with no problems. If your'e in the market for tires check out Diamond Back Tire, they cater to classic cars style and size wise.

 

[Hubbarocks]

+ 1 for BFG , love mine, ride great , price is right. i put 2~3k miles on a year

 

[beanhead]

9:1 would be fine for a cruiser if you stayed down near sea-level...but keep in mind you lose (roughly) 3/4 point of compression with a 4000' elevation change..so if you build it at 9:1, when you're up in your area it will be as if you built it closer to 8.25:1. Of course this is all academic as the static compression is calculated based on mechanical distances/volumes inside the cylinder, but that's the way it works out. You don't want it to be soft, and you sure don't want it to ping down at the lower elevations either...but that's all stuff to discuss with your engine builder.

All that aside, if your building it around the idea of regular drives down to SoCal (which sounds awesome btw) the one best upgrade you could add, in my opinion, would be an EFI system...(and I'm a carb guy!)
That is to me the main advantage of EFI over carbs; the ability to self-adjust for the air conditions. It'll run the same at 100' and 90° as it did up at 4000' and 75°...

 

[64Orange]

9:1 would be fine for a cruiser if you stayed down near sea-level...but keep in mind you lose (roughly) 3/4 point of compression with a 4000' elevation change..so if you build it at 9:1, when you're up in your area it will be as if you built it closer to 8.25:1. Of course this is all academic as the static compression is calculated based on mechanical distances/volumes inside the cylinder, but that's the way it works out. You don't want it to be soft, and you sure don't want it to ping down at the lower elevations either...but that's all stuff to discuss with your engine builder.

All that aside, if your building it around the idea of regular drives down to SoCal (which sounds awesome btw) the one best upgrade you could add, in my opinion, would be an EFI system...(and I'm a carb guy!)
That is to me the main advantage of EFI over carbs; the ability to self-adjust for the air conditions. It'll run the same at 100' and 90° as it did up at 4000' and 75°...

If I build the motor with 10:1 compression at 4000' and I drive to 0' then I would have 10.75:1? Would that be problem?
And I recently purchased the Holley Sniper EFI so it looks like I'm making good choices!

 

[beanhead]

If I build the motor with 10:1 compression at 4000' and I drive to 0' then I would have 10.75:1? Would that be problem?
And I recently purchased the Holley Sniper EFI so it looks like I'm making good choices!

Not quite, the compression ratio is derived from stroke length, chamber size, piston-to-head distance at TDC, and a few other fixed values. That number by itself doesn't care about the elevation you're at...but that fixed or 'static' compression ratio's effect on cylinder pressure is diminished as you gain elevation...if I'm making any sense which I'm probably not. Your camshaft selection plays a part here too; but in other words if your engine's calculated compression ratio is 10:1, then it's 10:1 everywhere...it's just that at 10:1 it will "behave" in Bishop the same as a 9.2:1 build would at sea level...but if you cranked up the static ratio to 10.75 offset the elevation, you might run into detonation issues at sea level. Personally I wouldn't push it past 10:1 especially if the cam is going to be on the mild side. Even with premium gas (which you should plan on running anyway) there's too much inconsistency in the fuels we get..

 

[64Orange]

Not quite, the compression ratio is derived from stroke length, chamber size, piston-to-head distance at TDC, and a few other fixed values. That number by itself doesn't care about the elevation you're at...but that fixed or 'static' compression ratio's effect on cylinder pressure is diminished as you gain elevation...if I'm making any sense which I'm probably not. Your camshaft selection plays a part here too; but in other words if your engine's calculated compression ratio is 10:1, then it's 10:1 everywhere...it's just that at 10:1 it will "behave" in Bishop the same as a 9.2:1 build would at sea level...but if you cranked up the static ratio to 10.75 offset the elevation, you might run into detonation issues at sea level. Personally I wouldn't push it past 10:1 especially if the cam is going to be on the mild side. Even with premium gas (which you should plan on running anyway) there's too much inconsistency in the fuels we get..

That makes so much more sense! Thank you.
I wasn't planning on going past 10:1 compression. My engine builder shared with me the changing qualities of gasoline.

 

[beanhead]

That makes so much more sense! Thank you.
I wasn't planning on going past 10:1 compression. My engine builder shared with me the changing qualities of gasoline.

Good luck with it!

 

[Ron H]

Of course, opinions differ a lot on wheel sizing for old rides and all fine. I’m more old school and can’t get thrilled by too oversize wheels and lower profile tires (add lowering the ride radically). A larger wheel, to an extent, looks better than stock IMO. Common 14” wheels back in the day look pretty tiny to me now and I swapped out to 15” but part of this was for caliper clearance.

If I would have a do-over I think 16” would be neater on my old b-body. I have purchased BFG tires from Coker a couple times over the past three decades and never had any problems with them. Got my 15” mag 500’s from them as well. No idea if their prices are higher than other suppliers. And was always a fan of white letters – but now I’d opt to drop them if I buy a new set. Again, just IMO, going huge wheels and losing the tire height just doesn’t seem like a great idea for an old ride. Now guys that got them can disagree and I can’t drum up a debate since I never setup my car that way.

 

[66 Sat]

If I build the motor with 10:1 compression at 4000' and I drive to 0' then I would have 10.75:1?

Haha that is the quote of the day! Not taking the piss, but that's gold - the easiest way to make a high compression motor, just build it on the top of a hill....

 

[64Orange]

Haha that is the quote of the day! Not taking the piss, but that's gold - the easiest way to make a high compression motor, just build it on the top of a hill....

Gotta learn one way or another right?

 

[WileERobby]

14 and 15 inch tires are still available. Just not in a very wide selection as opposed to the 17" and up sizes.
Also consider that when going to the "modern sizes" that they require a more expensive rim, they will ride harder because of the short sidewalls, tire/wheel clearance can be a problem.
Modern cars from the suspension up are designed for the modern tire/wheel sizing. Our cars were not.
BFG, Cooper, Mickey Thompson, Goodyear (repro) Firestone (repro) are available to fit our cars and are more period correct.

^^^ Bingo ^^^

 

[440 PHIXX]

Restomods are hot right now, as to the finished BAT auctions. They seem to go for higher than OEM in most cases.

Having said that, I don’t think I’m ready to give up the 15’s yet. Or the overcammed 440.

Bigger rims will certainly handle better, and a 3G Hemi will idle like a police car.

 

[Moparmann]

Upgraded to a 15 x 7 one piece alloy wheel to maintain the original look and gain access to more tire choices! Gave the car a much more aggressive stance and most don't notice that it's not a trim ringed wheel, LOL!!

 

[Purepony]

I think the best upgrades for a long ride would be fuel injection, overdrive, and reclining seats.

 

[Ron H]

Not to steal this post; maybe for a minute, lol, I put on 15x7 magnums and P235/60's. I've been pondering more on the 16" aluminum wheels (ones that look like magnums) with redline tires. Just seems this would add a kick to my '63 having the red trim. Was always an old school fan of white letters (cuz I'm old) but maybe a change would be nice.
Any thoughts? My tires have about 3k on them and likely would put them up for sale if I decide to make the swap..
Thanks

 

[Master Gunner]

Everyone seems to be missing the elephant in the room regarding the compression ratio. The static ratio is not what the engine actually sees, because the compression stroke does NOT start at BDC. The compression stroke starts when the intake valve closes, what's known as the dynamic compression ratio, which considers cam timing and rod ratio.
https://uempistons.com/p-27-compression-ratio-calculator.html
Keeping the dynamic ratio close to 8.5 will let your engine live with pump premium.

Mark