Author Topic: tire sudder  (Read 327 times)

Offline spookie

  • Jr. Member
  • **
  • Posts: 51
    • View Profile
  • Your Best Time: 9.02 1/4 5.62 1/8
  • Your Track: Quarter Aces drag-o-way
  • Your Vehicle: F.E.D.
tire sudder
« on: September 26, 2020, 07:39:21 AM »
Iam running hoosier 32x12-15 do5 without tubes.I get tire shake when track prep is not so good,even on trans shift.Have not played with presser yet.Would putting tubes back in help? This tire has worked just fine with cold or hot track for last two sets of tires.This is first year without tubes.Maybe Tubes were covering for wrong tire,or should I play with air setting more.My FED will 1.22 60ft and run 5 60s.

Offline THE FRENCHTOWN FLYER

  • Sr. Member
  • ****
  • Posts: 251
    • View Profile
  • Your Best Time: 8.28@168 door; 9.00@147 6-cyl alt; 8.53@160 RED
  • Your Engine: 300 Ford six NA w/ crossflow and prod. heads
  • Your Track: Milan, Thompson
  • Your Vehicle: Advanced Chassis altered , The Last Logghe altered, '30 RPU
  • General Location: North Coast
Re: tire sudder
« Reply #1 on: September 28, 2020, 11:55:38 AM »
I do not think putting tubes back in will help the shudder / shake. It will add rotating mass and likely exacerbate the situation. I've use those same tubes in my altered that runs the same e.t.s as you - tubeless - w/o a concern. I recognize the differences between a (suspended) altered and a FED. Nevertheless I would look to optimizing your converter, tire pressure, and launch RPM until you get it straight. Good luck.
« Last Edit: October 15, 2020, 06:04:38 AM by THE FRENCHTOWN FLYER »

Offline JrFuel Hayden

  • Hero Member
  • *****
  • Posts: 592
    • View Profile
    • Hayden Enterprises Speciality Wheels
  • Your Best Time: 6.02, 236 mph, 1/4 in 1973 Div 3 TF Champ
  • Your Engine: SBC, Alky, 403 ci, Best 6.99 @ 190 & 409 Hemi
  • Your Track: Bakersfield
  • Your Vehicle: 225" FED NHRA Heritage Jr Fuel
Re: tire sudder
« Reply #2 on: October 03, 2020, 12:18:29 AM »
one problem may be with the 32x12x15 Hoosier , when Goodyear stopped making for inventory a number of part numbers , one was the designed for JrFuel racers 31x12x15 light weight [ 26lbs] tire and since the JF rules and A/ND & B/ND Comp rules are 12" max wide tires , I called all the slick makers to see what they have. Hoosier said they had 31, 32and 33 tall 12" tires, BUT the 32 tall may not work for 2 speed dragsters , because Hoosier mad that tire with a softer compound for heavy door cars where they deadhook, shift, deadhook, shift, deadhook, not getting some tire speed like FED to keep the egine RPM in the power range. Also tire shake seams to come with not enough power or too much bite. Which a couple of slick makes agree that the trend of tracks spraying too much VHT, so that makes the tires dead hook and shake. Don Enriquez engine builder/tuner asked one ot our Heritage tracks to not spray any more VHT before JF races, it worked and A/F liked it better too.
One of the quickest running A/ND & B/ND Comp cars runs a 29x10.5x15 MT and just ran a 6.79 in St Luis. On our JrFuel car I'm about to try M&H 30.5x10.5[ 11.25] x15 on 12" rims next season. M/T, Hoosier, M&H all have stiffer sidewalls and are at least 32 lbs . Rotating weight takes more power to turn.
You could try lower tire pressure , it help getting more tire speed. With our Goodyears we have run as low as 4 3/4 lb on 12" rims. We started out on 10" rims then when we added power we needed more bite , so 11" then 12".
I hope this helps.     
Jon C. Hansen

Hayden Wheels

Offline spookie

  • Jr. Member
  • **
  • Posts: 51
    • View Profile
  • Your Best Time: 9.02 1/4 5.62 1/8
  • Your Track: Quarter Aces drag-o-way
  • Your Vehicle: F.E.D.
Re: tire sudder
« Reply #3 on: October 09, 2020, 03:17:58 PM »
Went to track 10-4-20,stable air day.Ran 5.75 lbs,raised stall rpm close to stall[less hit to tires]. With less air softer hit ran 5.6351 first run.Two hours later,same set-up ran 5.6309.Did not get to play with air for third run due to rain.With 60ft times within .005 I think I have found a winner.Thanks for input.Season is over at my track.