bias ply vs. radial for poor prepped track...

Hey guys,

Our local track owner is a tight wad when it comes to track prep. Trying to seek better traction on the launch (like who isn't).

I just checked their site and see that MT now has a 28x11.50x17 ET Street R series bias ply available. I am currently running the ET Street R series Radial 305-45-17 (28x12.50x17). The Radial is an R2 compound while the Bias Ply is M5.

My setup puts about 550RWHP to the ground through a completely stock 6R80. I have the typical BMR )LCA/UCA/Drag Spring mods along with Lakewood 50/50 rear drag shocks. Front is soon to receive STrange single and BMR GT500 Drag springs and removal of the front sway bar which will hopefully help make the car more repeatable in the 1.6X range. I have cut 1.62 best and avg 1.68 normally on the setup and the ET Street R series Radials.

The car transfers weight respectively according to people watching it leave, but traction off the line is where it loses it if it is going to spin. The car goes straight.

QUESTION??? Would going to this Bias ply benefit any over the existing radial tire on poor to no prep scenarios which I can expect every week at TT at my local track? Or would I gain more by selling the 17" setup and going to a 15" wheel and running a 28x11.50x15 bias ply? I am seeking 1.5x consistent on a no prep/ poor prep track with a street legal DR. Hauling slicks in the back of a Mustang (no trailer) and swapping back and forth at the track sux.

Thanks. Tried to provide all information possible.

Don't believe there is a thread for this. Feel free to point it out and scorch me if there is.

I would switch over to a full set up of big and littles. They will be lighter overall, less rotating mass is a big deal and the 15" wheels with life a 28x15x10.5 is probably the most popular combo for drag racers here.

I used to use that tire you're speaking of only in a 26x17x11.5. I still have them actually in really good shape...but anyways, I got great 60' times of 1.48 and they were more consistent than the radial tires.

I switched over to the big little combo and love it much better than trying to make the other tires work on the track.

Great information. Thanks.

I race at an 1/8th mile track with an uneven-somewhat broken up concrete pad (and 4500 ft elevation to boot) and also at an airstrip and I have just recently found some success with hooking up. My car is a single turbo 3V that dyno'd 488/447 with 8 lbs of boost and 4.10 gears, I now run 10 lbs of boost and have tweaked my boost curve with the electronic boost controller so I figure it is making much more torque than it did on the dyno.

I am using a 325/50 15 ET Street Radial with a manual transmission. I have to use the lowest hole on the BMR brackets, loosen the struts (Tokico D-specs) up 6 3/4 turns (max is 7) and loosen the shocks 6 turns out. I had 5 runs in the high 1.5's in the same night and can do low 1.6's at the airstrip but the consistency is not as good on the airstrip.

I set the 2step (WOT box) at 5400 rpms and it is making about 3.5 lbs of boost at that RPM. I adjusted the TPS voltage setting on the WOT box until having the throttle about half way would activate the 2 step, that allows me to come off the clutch without the throttle being pinned and feed it in as soon as the car started moving rather than having to pedal back from having it pinned.

Prior to changing the LCA to the lowest hole, my best 60' at the 1/8th mile was 1.86 at that track, it was spin city or I'd drop my launch RPM and it would bog. I had never been under 2 seconds at the airstrip prior to this either.

I still wonder whether just going to a bias ply tire is the way to go but in your case with the 6R80, I would continue to try and make a radial work. A 15" radial would probably increase your chances for success but with some work, you may be able to find the sweet spot for your current setup.
Maybe it's time to get a converter?

^^^ Thanks for the 411. I have Strange single adjustable from struts and BMR 165lb/inch GT500 front springs ready to go in tomorrow night. While under there I am going to remove the front sway bar as well. I wish to see if there is any improvement with hopeful increased weight transfer (struts set full loose) with these changes. I have the relocation brackets by BMR on the car as well and have them currently in the center hole. If I see improvement with the front end mods I will then relocate to the lower hole on the rear LCA's to see if that helps even more.

I appreciate the feedback RED. Most people at my track that have any real knowledge on suspension and setups are running foxbody or Edge body cars. Good to get some feedback from someone running a similar body. Thanks for the effort.

Oh yeah, forgot to mention that I also remove a front swaybar link at the track as well.
Good luck with it.

Did that lower your 60s any or is it more for consistency?

Made a few changes at once but the combination of changes definitely worked for my car.