Tire pressure on reproduction bias ply's? - CorvetteForum - Chevrolet Corvette Forum Discussion

Notices
C1 & C2 Corvettes General C1 Corvette & C2 Corvette Discussion, Technical Info, Performance Upgrades, Project Builds, Restorations

Tire pressure on reproduction bias ply's?

Old 05-15-2018, 08:13 PM
  #1  
Panama 58
CF Senior Member
Thread Starter
 
Panama 58's Avatar
 
Member Since: May 2001
Location: Mint Hill North Carolina
Posts: 1,249
Thanked 53 Times in 52 Posts
Default Tire pressure on reproduction bias ply's?

Following the thread on radials tire pressure, what pressure are people running on reproduction bias ply's? Some of us idiots haven't converted over yet.
Panama 58 is offline  
Old 05-15-2018, 08:34 PM
  #2  
Captain Bud
CF Senior Member
 
Member Since: Jul 2014
Posts: 267
Thanked 28 Times in 8 Posts
Default

I'm running 37PSI on my Coker bias ply on my 1960 and it seems to work fine.
Captain Bud is offline  
Old 05-15-2018, 08:38 PM
  #3  
dplotkin
CF Senior Member
 
dplotkin's Avatar
 
Member Since: Feb 2012
Posts: 1,753
Thanked 150 Times in 111 Posts
2015 C2 of the Year Finalist
Default

Originally Posted by Panama 58 View Post
Following the thread on radials tire pressure, what pressure are people running on reproduction bias ply's? Some of us idiots haven't converted over yet.

I run 35 in the front.

Dan
Attached Images  
dplotkin is offline  
The Following User Says Thank You to dplotkin For This Useful Post:
6T5RUSH (05-16-2018)
Old 05-15-2018, 09:54 PM
  #4  
Redbird
CF Senior Member
Support Corvetteforum!
 
Redbird's Avatar
 
Member Since: Apr 2009
Location: Georgetown TX
Posts: 2,233
Thanks: 0
Thanked 31 Times in 29 Posts
2016 C2 of Year Finalist
Default

I have always ran 32 lbs, regardless of bias-ply or radial, for the past 55+ years.
Redbird is offline  
Old 05-16-2018, 02:05 AM
  #5  
SDVette
CF Senior Member
 
SDVette's Avatar
 
Member Since: Jan 2000
Location: Poway CA
Posts: 3,754
Thanked 272 Times in 209 Posts
2016 C1 of Year Finalist
Default

I have radials on my car, but my '61 owner's manual says 24 lbs cold, 27 warm (city), and 29 warm (highway).

You guys running higher pressures... they must get pretty high when warmed up?
SDVette is offline  
Old 05-16-2018, 05:31 AM
  #6  
phil2302
CF Senior Member
 
phil2302's Avatar
 
Member Since: Apr 2015
Location: Long Island NEW YORK
Posts: 1,159
Thanked 164 Times in 122 Posts
Default

Why not just use what the sidewall recommends?
phil2302 is offline  
Old 05-16-2018, 05:48 AM
  #7  
DansYellow66
CF Senior Member
 
DansYellow66's Avatar
 
Member Since: Jan 2003
Location: Central Arkansas
Posts: 10,106
Thanked 566 Times in 508 Posts
Default

Originally Posted by SDVette View Post
I have radials on my car, but my '61 owner's manual says 24 lbs cold, 27 warm (city), and 29 warm (highway).

You guys running higher pressures... they must get pretty high when warmed up?
This is pretty much what I remember back in the day - 24 cold minimum all around. I don't remember any recommendations for over 30 psi in that period. Maybe modern bias belted are different. What does the sidewall say.
DansYellow66 is offline  
Old 05-16-2018, 06:09 AM
  #8  
tubman
CF Senior Member
 
Member Since: Sep 2007
Location: Marathon Florida Breezy Point Minnesota
Posts: 357
Thanked 22 Times in 21 Posts
Default

24 and 27 from the manual for my '51 Ford as well. I was surprised and kinda confused by this when I first read it. Then I bought a set of radial WSW so I don't have to worry about it. I think you guys running much higher pressures will be looking a strips of cord down the middle of the tread if you run the tires for a long time.

Last edited by tubman; 05-16-2018 at 06:11 AM.
tubman is offline  
Old 05-16-2018, 07:25 AM
  #9  
Panama 58
CF Senior Member
Thread Starter
 
Panama 58's Avatar
 
Member Since: May 2001
Location: Mint Hill North Carolina
Posts: 1,249
Thanked 53 Times in 52 Posts
Default

I have been running 26 all around since I got the car three months ago. With the warm weather here in NC I think this is as high as I plan to go. Thanks for all of the responses.
Panama 58 is offline  
Old 05-16-2018, 08:30 AM
  #10  
morly1963
CF Senior Member
 
morly1963's Avatar
 
Member Since: Apr 2012
Location: EHT NJ
Posts: 1,341
Thanked 120 Times in 103 Posts
Default

Just put air in mine this past weekend 24lb.
morly1963 is offline  
Old 05-16-2018, 11:39 AM
  #11  
SWCDuke
CF Senior Member
 
Member Since: May 2000
Posts: 9,894
Thanked 418 Times in 294 Posts
Default

Modern repro tires have a DOT- required placard molded into the sidewall that specifies maximum load at maximum COLD pressure, so that's the first thing to look for, and it's probably 35 psi.

Highway operation in hot weather will increase pressure by up to about 6 psi, and that's okay. The maximum pressure placarded on the sidewall is for a COLD tire, and pressure rise from operation is NORMAL.

Hot lapping a big race track will increase TP by 10-12 psi starting from 36 cold, and typical tire burst pressure is on the order of in excess of 100 psi. Tire cord is very strong.

The higher the cold pressure, the less rolling resistance, the lower the rate of temperature/pressure rise, the lower the wear rate, and the crisper the steering response, but you may notice increased high frequency ride harshness.

The OE tire pressure recommendation for my SWC of 24 psi was a joke. It was like driving on slim, so I increased cold TP to 35. There was no max load @ max cold pressure placarded on the sidewalls back then, but that's what my dad, an engineer (BSME U. of Wisconsin, 1927) who was in the Pontiac sales an service organization pre-War and owned a dealership post-War, ran in his cars.

So it's an individual choice between the original 24 psi recommendation and the maximum cold pressure placarded on the sidewall. Experiment and choose what works best for you.

Duke

Last edited by SWCDuke; 05-16-2018 at 12:16 PM.
SWCDuke is offline  
Old 05-16-2018, 12:03 PM
  #12  
GUSTO14
CF Senior Member
 
GUSTO14's Avatar
 
Member Since: Sep 2003
Location: eastern NC
Posts: 6,680
Thanked 653 Times in 592 Posts
Default

I would agree with those that suggest 32 psi as a good starting point. (Or at least start with the placard found in the door jam of most new cars.) However, because every car, including similar make and model cars, are different it isn't particularly precise. The following method is a more precise way to determine (or verify) the correct psi to run in your tires and one I've used for years.

First pick a psi to start with and monitor it so that it will remain constant over a period of time. Then, using a tire tread depth gauge, check the tread depth across the face of the tire. At the very least 3 places across the tread, outboard edge, center and inboard edge and write these numbers down. This is the starting point and of course works best on new tires, but can be done really at any time.



Then, at about every 4-5k miles take a new set of readings. If the tread depth remains constant at the outside, center and inboard side of the tire the pressure you are using is good.
If the center starts to wear more than the outboard edges, then you have a bit too much air in the tires. Lower the pressure a couple of pounds and check tread depth again in 4-5k miles.
If the outboard edges are wearing faster then the center your pressure is too low, so add a few pounds and check again in 4-5k miles.

This method is a much more precise way to determine the correct PSI you need to run and takes into account factors such as non stock tire sizes, mods to the car that have changed it's weight from stock and even different tire compounds.

What ever psi you settle on, be sure to write it down and keep it in a handy location so you can refer back to it, such as the glove box with the owners manual.

Good luck... GUSTO
GUSTO14 is offline  
Old 05-16-2018, 12:34 PM
  #13  
Mike67nv
CF Senior Member
 
Mike67nv's Avatar
 
Member Since: Apr 2010
Location: Northern Nevada
Posts: 1,918
Thanked 168 Times in 134 Posts
2018 C2 of Year Finalist
2015 C2 of the Year Finalist
Default

Originally Posted by Panama 58 View Post
Following the thread on radials tire pressure, what pressure are people running on reproduction bias ply's? Some of us idiots haven't converted over yet.
Take a look at your tires. My Kelsey Goodyear Power Cushion redlines (manufactured 52nd week of 2015) say ď32 PSI MAX. PRESS.Ē I talked to John Kelsey when I bought the tires and he said they were designed to be inflated to the OEM recommendation (24 psi).

I have tried different pressures and like 24-26 psi. Higher pressures give a harsher ride. I donít road race my car and I canít tell any difference in cornering traction at normal speeds.


Last edited by Mike67nv; 05-16-2018 at 12:36 PM.
Mike67nv is offline  
The Following User Says Thank You to Mike67nv For This Useful Post:
DansYellow66 (05-17-2018)
Old 05-16-2018, 12:59 PM
  #14  
AZDoug
CF Senior Member
 
AZDoug's Avatar
 
Member Since: Oct 2005
Location: Camp Verde AZ
Posts: 9,927
Thanked 351 Times in 265 Posts
2017 C1 of Year Finalist
Default

One thing taht hasn't been brought up is tire gauges.

I have oh, maybe 20 gauges, three on-hose type gauges, one digital gauge and 15 or more pencil type gauges.

They all read different, by up to 12 PSIG max spread at 30 PSIG. (readings from 28-40 on the the same tire)

Even the on-hose, service station type, supposed to be good quality plunger gauges are off by 5 PSIG between the two.

How am I supposed to know which ones are correct? Without buying a NSI certified dial pressure gauge for $100 or more and adapting it to a tire valve?

I have been thinking about using the in wheel pressure sensors from my '16 Z06, which has in dash readout of tire pressure, and using that as my standard and tossing any gauge that doesn't match that reading.

Doug
AZDoug is offline  
Old 05-16-2018, 02:02 PM
  #15  
SDVette
CF Senior Member
 
SDVette's Avatar
 
Member Since: Jan 2000
Location: Poway CA
Posts: 3,754
Thanked 272 Times in 209 Posts
2016 C1 of Year Finalist
Default

As you increase the tire pressure, you are increasing tire stiffness while reducing the contact patch with the road.

Racing vs. pleasure cruising: Very different goals.

Last edited by SDVette; 05-16-2018 at 02:03 PM.
SDVette is offline  
Old 05-16-2018, 02:19 PM
  #16  
6T5RUSH
CF Senior Member
Support Corvetteforum!
 
6T5RUSH's Avatar
 
Member Since: Nov 2000
Location: Clinton Township MI
Posts: 4,738
Thanked 96 Times in 78 Posts
Cruise-In III Veteran
Default

Originally Posted by dplotkin View Post
I run 35 in the front.

Dan
dplotkin,

I know you've heard this before but, THAT Plymouth is just badass!!

:thumbs!

Jim
In God We Trust!

Last edited by 6T5RUSH; 05-16-2018 at 02:20 PM.
6T5RUSH is offline  
Old 05-16-2018, 02:36 PM
  #17  
GTOguy
CF Senior Member
Support Corvetteforum!
 
GTOguy's Avatar
 
Member Since: Apr 2015
Location: Fresno California
Posts: 5,767
Thanked 803 Times in 668 Posts
Default

26 psi cold front, 28 psi cold rear, on my '61 Corvette with the stock size bias ply tires.
GTOguy is offline  
Old 05-17-2018, 03:45 PM
  #18  
tuxnharley
CF Senior Member
Support Corvetteforum!
 
tuxnharley's Avatar
 
Member Since: Aug 2004
Location: NorCal: So SF Bay Area CA
Posts: 9,960
Thanked 516 Times in 432 Posts
Default

The OEM tire pressure recommendations for my ‘67 - still on the original sticker on the inside of my glove compartment door - are 24 psi cold and 30 psi hot on all 4 corners.

Your preference may vary..........

Last edited by tuxnharley; 05-17-2018 at 03:47 PM.
tuxnharley is offline  
Old 05-17-2018, 04:32 PM
  #19  
MOXIE62
CF Senior Member
 
Member Since: Aug 2011
Posts: 2,566
Thanked 137 Times in 122 Posts
Default

30 cold or hot. Max tire pressure for my tire is 32.
MOXIE62 is offline  
Old 05-17-2018, 05:07 PM
  #20  
MikeM
CF Senior Member
 
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 21,798
Thanked 708 Times in 605 Posts
Default

32 PSI in every bias ply tire on every car I've driven since 1958.

Except Corvair.

For whatever reason, never had a bias ply tire fly apart like some of the brand new steel radials I've had.

Last edited by MikeM; 05-17-2018 at 05:08 PM.
MikeM is offline  


Thread Tools
Search this Thread
Quick Reply: Tire pressure on reproduction bias ply's?


Sponsored Ads
Vendor Directory

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: