Re: Radial Front Bias Ply Rear Staibility?
[Re: RyanJ]
#451846
08/27/09 11:29 PM
08/27/09 11:29 PM
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Joined: Aug 2003
Posts: 43,748 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,748
Bend,OR USA
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My Duster DOES NOT like mixing bias and radials, either front or rear combinations It(me ) does like bias with bias or radail with radials, bias in the front with radials in the rear isn't to bad, radials on the front with bias on the rear makes me think I've went back to drinking I don't run a big, fat front tire on either set, 26x15 ET fronts or 165x15 radials on the front, both sets are on 4 inch rims this is only on the street, at our local 1/8 mile track the car deosn't talk (act up)to me at all with mixed tires 6:90 at 100 MPH
Last edited by Cab_Burge; 08/28/09 02:28 AM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Radial Front Bias Ply Rear Staibility?
[Re: Triple Threat]
#451847
08/27/09 11:48 PM
08/27/09 11:48 PM
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Joined: Jan 2003
Posts: 21,123 Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,123
Niles , Ohio
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Ny 65 rides just fine with rads on frt and bias rears.Its street driven and at the track its been to 114 and still tracks straight.Now when I had the MT Sportsman bias on the front it was a total piece of crap street or strip.Rocky
Chrysler Firepower
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Re: Radial Front Bias Ply Rear Staibility?
[Re: RyanJ]
#451850
08/28/09 06:46 AM
08/28/09 06:46 AM
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Joined: Jun 2005
Posts: 2,776 Ontario Canada
MattW
master
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master
Joined: Jun 2005
Posts: 2,776
Ontario Canada
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Quote:
I can't remember, but I don't think I have ever ran a car down the track with Radial front, Bias rear until last week (at least a fast car) & am wondering if the majority of my top end wandering issues is from the mis matched tires?
I've ran several cars on the street with Radial front/Bias rear combo's & never really had any ill handling issues, but those are generally stiff sidewall bias plys like a M/T INDY Profile.
My Road Runner now has 235/60 BF Goodrich Radial TA's up front & 26 X 11.5 Hoosier Quick Time Pros on back for track use.... Last week had rear pressure @ 18PSI, car went 118.4 MPH & was wandering all over the place from about 1/8 mile on, & then decides to do some wicked diving around when I let off after the stripe. I thought I'd make it a little better by trying 24 PSI since junk converter was'nt allowing it to hit tires hard on launch anyhow.... needless to say I let off around 1100' as I was wandering towards the timing boxes @ the traps. I only have a 7" wheel & with the 11.5's with more air actually reduces contact patch....
I ordered a set of 275/60/15 Hoosier Drag Radials this AM & will try those this weekend if weather cooperates. I have a new 4000 Stall PTC 9.5" verter coming at beginning of week, & am hoping I can get car to hook with the DR's once it is in.
I've had the car to around 110 on the street with the Hoosiers on & it feels way better stability wise, than it does at the track?? Dunno what is into it... Buddy of mine has a mid 11 sec '70 Chevelle that runs Radial fronts & M/T ET Streets on back & said his does similar wandering around, but he said his really only does it on deceleration...
I did'nt really want to try a bias front tire since I drive car every day on street I'd like to keep the Radial TA's on it, because they work well in the rain & taking corners @ speed..
Just wondering what everyone's experiences have been like trying to run 110+ MPH with radial front/Bias rear, especially with a wrinklewall rear tire....
Just feels like rear end is wandering from side to side real bad @ speed & I'm constantly trying to chase it with steering wheel. Not happy with it at all....
Keep in mind that at full trottle the front end is not is the same place as cruising speed. The wide tire sure doesn't help but if it is set up right I don't see problems with mixing tires. In my opinion, most front end wandering is due to poor setup or driving technique. Matt
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Re: Radial Front Bias Ply Rear Staibility?
[Re: MattW]
#451851
08/28/09 07:13 AM
08/28/09 07:13 AM
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Joined: Jan 2003
Posts: 10,092 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,092
Frostbitefalls MN (Rocky&Bullw...
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In my opinion, most front end wandering is due to poor setup or driving technique. Matt
Generalizations can get a guy in lots of trouble. The faster a car goes, the worse any particular problem becomes. Based on the fact that as a group we tend to go faster as time goes by, we WILL find problems getting worse. Mixing types of tires is not recommended for a reason, and band aiding the problem with more pressure, wider rims etc is just hiding the problem, and looking for trouble. Case in point, drag slicks of radial construction are so prone to sway at speed Goodyear is coming out with a new radial drag slick with a sidewall construction just to address this issue. The tech guy at Comp Tires west said it will be out in January, roughly. I first had issues back in 2004. M/T radial slicks, 14.5 33 15. Car would swing back and forth so bad I was aborting half the runs I made. I know some will say this is about FRONT radials vs Back bias, but the fact remains, they drive differently and allow the car to move left or right differently based on tire construction. My scenario just amplified the problem into the extreme. I will not mix tires like this again, been to close to putting the car on its' roof more than once.
8.582, 160.18 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Radial Front Bias Ply Rear Staibility?
[Re: quickd100]
#451856
08/28/09 09:28 AM
08/28/09 09:28 AM
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Joined: Jan 2003
Posts: 21,123 Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,123
Niles , Ohio
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My 65 I can just about let the wheel go at 100 and it still tracks straight.Never felt the rear move at all.Now when i had the MTs on the front I was fighting it all the time.I knwo the alignment is right as I did it and rechecked it twice after I set it up.Rocky
Chrysler Firepower
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Re: Radial Front Bias Ply Rear Staibility?
[Re: RyanJ]
#451857
08/28/09 09:36 AM
08/28/09 09:36 AM
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Joined: Nov 2008
Posts: 660 San Diego
formula S
mopar
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mopar
Joined: Nov 2008
Posts: 660
San Diego
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Quote:
Well I'm going to find out 1 step at a time what is causing it. Hopefully if weather is OK I will run it Sunday with the new Drag Radials & see what change that made. If it still is not good, it's going for an alignment next week & will then run it next weekend to see what that does.
The front end is not "worn out" etc, I drive it every day & it drives/steers better than any old Mopar I've driven to date.
You can hold wheel straight going down the track but the rear end "wanders" around & acts like IT is doing the steering...
Ryan make sure when you align your front end that you get as much positive caster as you can, this will help it go straight
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Re: Radial Front Bias Ply Rear Staibility?
[Re: RyanJ]
#451858
08/28/09 01:01 PM
08/28/09 01:01 PM
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Joined: Oct 2003
Posts: 7,506 Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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The only reason I posted on this thread is because I run similar speeds, have a similar size car with similar tire set up as the original poster - and have had similar wander issues in the past. Trying to compare my issues with some one who has a dedicated race car running in the 140 and above mph range is almost meaningless. My car was never designed ( reads aerodynamic as a box of velveta cheese ) to do what I am asking it to. I think some older cars catch a lot of air under them at speed and this alone creates handling issues. Ride height changes and in old Mopars this often changes alignment specs, aspecially in the camber and toe areas. Pulled the front sway bar off my car earlier this year to try and cut an ugly 40 pounds off the car. Big mistake. Ran in a moderate cross wind and just about saturated my depends. Put it back on. I guess my point is that there is a lot more issues with handling than just tires - although tires obviously play a major roll. Just changing rear tire pressure 5 psi makes a handling difference. Making sure your rear suspension is tight and properly aligned ( to the frame ) is often over looked and Ma Mopar didn't do too good in this area from the factory with old iron.
Fastest 300
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Re: Radial Front Bias Ply Rear Staibility?
[Re: RyanJ]
#451861
08/28/09 09:48 PM
08/28/09 09:48 PM
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Joined: Jan 2003
Posts: 6,266 Renton Washington
Triple Threat
master
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master
Joined: Jan 2003
Posts: 6,266
Renton Washington
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Yeah, you've got to be pretty brave to drive the Hoosiers in the rain. But they hook well.
-Dustin 67 Dart, 9 second, 392" G3 Hemi 68 Barracuda 340 F/SA
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