Don't get snippy with me. You do whatever you want to your vehicles, I'll do whatever I want to mine. Every thread, you drag out the same crap. "I'm an engineer". Who cares? In my opinion, which only matters to me, you come here to argue and try to dog other posters. And just try to stay on track, I've never owned one of the vehicles you listed, or the roller skates you're trying to belittle me with.


Kiss my tire pressure, you pretentious snot.

 

The 2015 VW R Beetle comes with 235/40 19" tires, only 1 inch narrower than the 255/60 15".
It weighs less than 3,000 LBS, less than any C3.
The tire pressure front and rear is 33 PSI.
How does that fit in with everything you are stating?

 

Are you going to try your Pier experiment with your VW and B-210?
I couldn't recommend trying it with the roller skates.

 

I asked you honest questions and you came back with an immature and very hateful response; certainly not what any professional person would do. The big 255X60R15's weren't designed to go on C3's but rather designed as a tire of given dimensions and therefore suitable for many different applications. When used on a C3 only 20 psi was needed and when used on a 5000# vehicle perhaps 25-30 psi was needed; depending on how much additional load that vehicle will carry.

 

Hellooo, how does this fit in with your theories?

 

Think about it. Maybe he should?

 

I'm done with you.

 

My '80 came with 255/60/15's and on the door plate it says:

"Cold Pressure Front 35psi, Rear 35psi" wonder what that would be warmed up

 

Just put him on your ignore list if he is that aggravating. I don't because he's a source of cheap, inexpensive entertainment.

 

That is just ludicrous. Using your logic then, a 285x35R19 is designed as a tire of given dimensions and therefore suitable for many different applications but not for a brand X vehicle. Don't bother to explain because we all understand what you are saying and it does not make sense, full stop.

 

Normally ok. Someone pointed out that I'm a bit grouchy today, so I'll just lay low till I'm over it.

 

Maybe you need a snickers

 

Since purchasing my "75" in September I have made a mental list of what I need to do before the spring and summer cruise season. One thing on my "to do" list is to replace the 17 year old TA radials that came on it. When I found this thread I thought it could help me in my decision little did I know that a war of air pressure would dominate the discussion. I am not a novice in fast cars both on the street and on dirt ovals but the Vette is my first encounter with an American classic with independent rear suspension. After reading all of the different approaches and reasoning for what pressure is the "best" on a C3 Vette I decided to ask BF Goodrich for their opinion. I offered the curb weight, horse power, wheel diameter, wheel width and overall condition of the suspension in my car. I also indicated my tire preference in tire size configuration and speed rating. My stated choice is the BFG TA radial in 255/60R/15, this fit nicely with some of the responses on this thread. After the first response to my E-Mail I requested further clarification on proper tire pressure and within 2 hours I received a phone call from BFG. The gentleman on the phone spent 20 minutes with me, answering all of my questions and concerns. His recommendations were to inflate to a minimum of 26 psi in the 255's and if the handling seemed to suffer to INCREASE pressure by increments of 2 psi until the proper handling is achieved. He also stated the maximum pressure is 35 psi and I should approach this pressure with caution.
I know some on this thread someone will say that this approach is to lessen the occurrences of law suits due to tire failure or accident. It is my opinion that if BFG rely on a 26 psi minimum to avoid law suits due to catastrophic tire failure I'm guessing my "75" will be safe at 26 psi also.

 

Marcia Marcia Marcia first. Then maybe a Snickers.

 

I would accept 26 PSI as the "low pressure" threshold to tune the tires from.

If Mr. Toobroketoretire indicated 26/26 as his preferred tire pressures, I probably would not take issue with that. I'm not sure I would EMULATE it, but I would view it as his preference. Absolutely.

The statement "handling seemed to suffer"...I would take that to include the 'wallowing' I experienced when running the pressures suggested by our esteemed colleague?

Bear in mind that if you run your tires at 26 PSI, you could potentially have inconsistent wear in the centers of your tires after you've driven your 1975 Corvette 30,000 miles.

(that last bit was sarcastic, in case you couldn't tell...)

 

From September to my insurance lay up date of December 1, I ran 28 to 30 psi even with the tires being way too old to be on the road. With slow leaks in the rear tires My pressure would drop to 20 psi in just a few days if I didn't check every time out. On the 2 occasions where I did not bother to add air to go 2 miles down the road for coffee and donuts I will say she handled like crap. When I get my new meats they will have 30 psi in them to start. No doubt in my mind. I will adjust from there.

 

Who at BF Goodrich did you talk to? If he wasn't a mechanical engineer you'd have to take what he said with a grain of salt.

I want to remind you guys my 24/20 psi is a COLD pressure and that increases several psi as they warm up. So its likely they are reaching 28/24 after a good summer freeway run. Now as far as the 35 psi maximum pressure that is embossed on the side wall keep in mind if you run 35 psi COLD the pressure will increase beyond that maximum pressure on a hot summer day when the instructions say to NEVER exceed that 35 psi.

On a C3 with a 350" engine anything above 20 psi will wear the centers out long before the sides wear out but if that doesn't bother you go ahead and run whatever pressure you want to run.

 

As an American you have the right to say whatever you want and run whatever tire pressure you want. It is also my right to totally ignore what you say.
Being as my "75 is titled as antique in PA I am allotted 5,000 miles per year usage. That being said if my tire centers wear out in 6 or so years I will write and apologize to you.

Also I wasn't aware that you were appointed czar over whom had the correct information at BF Goodrich.

 

And it only takes a moment for a tire to fail. I'm not arguing against gradual wear and neglect resulting in catastrophic failure - I'm sure everyone reading this thread is at least smart enough to notice if their tires are degrading that badly. I'm talking about momentary overload that results in failure; either lost of traction or separation of bead from rim.

I know a guy who smoked for 90 years and never got lung cancer. What's your point?

I'm not advocating 30+ PSI, I'm saying 20 PSI is illogical. I'm experimenting between 26 and 30. My door jam says 20 front and 20 rear, but I think that's bollocks. 25 or 26 is as low as I'm willing to go based on my rational above.

If you intend to never dynamically load your tires, by all means, run at 20psi, they'll probably be fine. Your fuel economy, tire temps and stopping distance will all suffer, but you won't lose any sleep.

If however, you think you might actually care about road safety, maybe consider a few more PSI.

This article is by no means authoritative, though if you believe the introduction it was written by someone who worked at a major tire company for many years. Mac's comments echo the common sense already stated in this thread (by everyone but tbtr):

That's based on modern PSI recommendations, which are ALL substantially higher than 20, even for comparably light cars.

Here is how ridiculous your argument is: In 1978 (the same year as the C3 the OP has), Mazda released the RX-7 which weights.... wait for it.... 3131 lbs. Yes, lighter than our C3s.

Guess what their recommended pressures were? 26 PSI front, 26 PSI rear.

Now, you might point out that the RX-7 had narrow tires at 185 vs our 225. Fair enough, though isn't it strange they recommended 26psi for both the 165 and 185 widths? Isn't it also strange, that every single size of BF Goodrich GT Radials has different loads at exactly 35 PSI? Doesn't that tell you that perhaps you're reading too much into this simplistic linear math formula that makes you feel that 17 PSI is the right answer, and 20 PSI is just what the GM engineers rounded up to (like you knew them personally).

Here's an idea, perhaps they didn't have it all figured out. Perhaps you don't either.

If everyone but you seems to be crazy, how do you know you're not crazy? That's the thing about crazy people, they don't know they're crazy... that's what makes them crazy!


Well done sir, surely no one can argue with that logic.

Oh god... it happened...

OMG, you can't be serious, now you're just making **** up.

 

OzBeast - That picture gave me a good laugh. Thanks.