Technical > Roo Man's Room

Tubes or no tubes in slicks.

<< < (3/3)

JrFuel Hayden:
1'st of all most racers don't know the 10.5 M/T's are designed for 2500 to 3000 lbs door cars. So I think the inner tube suggestions are mainly because of the 16" wide rims.  Now the big reason they are working is they have much stiffer sidewalls. Also higher tire pressures. Mostly the difference is the much lighter weight of dragsters.  Oh Ya, you should not need inner tubes, I don't know of many if any FED that run tubes.
Now, Craig Bourgeois, 2015 NHRA Comp Elim Champ is an interesting combo. 1'st of all the MT tire is 29x10.5Sx15, the code of the size is "S" is stiff, your 33x10.5Wx15, is "W" is wide, which is actually 11" wide, and allot heavier, than the Goodyear D2585 31x12x15 22.6 lb tires. Max wheel width rule in JrFuel and A/ND & B/ND is 12". The Goodyears grow more, because of the MT stiff sidewall tire. Don't get me wrong I have a set of MT 33x10.5x15, I just need to try them, but they are over 10lbs heavier PER tire.  OK now back to Craig's combo, I think he wanted to run a rear gear in-between options because his 12bolt drop-out has allot fewer choices, so he tried the 29" tire. Craig runs 7-7 1/2 # of pressure. Again to back-up the higher pressures recommended, because of the heavy door car difference. Another thing is Craig runs allot more RPM, he tends to run 10,600 rpm high rpm chip, and I think he he runs that at about 1000-1100'. You see Comp elim is all about finish line racing, because no racer wants to hit the index. Craig has one of the faster cars/classes, so he chases most cars, so he has a better idea how hard he needs to beat his competitors. Another idea Craig had is a few years ago is I built a set of 21" wheels, not the normal 17" wheel. It is only an advantage in Comp , full tree, with the increased roll-out, because of the 27.5" tall tire. It multiples the affect with the 2" axle offsets. The 21/27.5" wheel gets you a 4" head start on the start line, but again ONLY in Comp, any heads-up or bracket racing with a Pro Tree = no advantage.
Most 7.60 dragsters I know run either 31x12x15, or 33x12x15 Goodyears or Hoosiers, you may need the 33" tires because you are running 565 ci motor = more torque. Depending on rear gears. But if you are looking for better 60' times, you'll want more gear, and shorter tires. Most all Heritage JrFuelers run the D2585, 31x12x15, a few run 33x12x15 because they have their engines out 52-60" and have less rear static weight. Can JF be all wrong running 6.90's to 7.10's, 185 to 195 mph.

Feel free to call me 805-444-4489 cell
Jon

Navigation

[0] Message Index

[*] Previous page