To screw tires to rim or not and more tire questions... for a 3900 lb truck with a 15 by 10 rim......

I got to go test on saturday and bracket race on sunday and got mixed results. Truck went faster than it ever has after the 60 ft. so no doubt we are making more power which is cool. My best 60 ft ever was 1.77 two years ago. Now last weekend my best 60 ft. was 1.79 and change but mostly varied between 1.82 and 1.89. I can't go rounds with this inconsistency. I got a new converter from Lenny @ UCC and so far I am very pleased with how everything is working in that department. I don't have any video and I'm hoping to get some next weekend. I'm currently running 275/60-15 Hoosier drag radials and they are over half gone so I will be in the market for some new rubber soon. One question I have is I can't really feel the truck slipping/spinning at launch so I'm wondering if I'm spinning the tires on the rims since I haven't marked them to check. Guess I should mark the tires for next weekend and check. After what 60 ft times should a guy have the rims screwed? I'm wondering if I'm at that point already? I've been told by my racing friends at the track that the truck plants the tires very well and has good weight transfer at launch so I'm kinda reluctant to change much on the suspension since it is still a street truck and pulls a trailer from time to time.

Other Question is which tire should I buy? I'm concerned I won't be able to get the drag radial to stick with the new found power and I'm looking to go to a full on drag slick since I can run them now that I jumped up a class at my local track. Only concern I have with this is I tried running M/T 26-11.5-15 ET streets one night and truck was kinda loose on big end of the track, seemed to wiggle some. Wondering because of the weight of the vehicle and not having tubes in the slicks caused this? Should I buy tubes at the same time I buy tires if I go to bias-ply type of tire? Should I get a slick designated as a stiff sidewall to help this also?

Sorry for all the questions, but just want to get a handle on this thing asap so I can enjoy bracket racing and go some rounds.....

I don't run tubes but with your heavy truck I think that I would. For a bracket racer, I would go with the slick. As far as screws, you can either go that route OR you can glue them. I remember the name of the stuff but it works very easy and is not really that difficult to break when changing the tires. With the bigger slicks it will not move around as much on the big end.

Dump the drag radial stuff & just go with something simple like a conventional M/T or Hoosier drag slick. M/T's are probably the best bang for the buck with a decent tread depth & a compound that often seems to last damn near to the end. Don't over do the burnouts & don't run too little air pressure & they should last quite a while. Screw them to the rim & forget them.

one of the biggest mistakes people make is running too little air pressure. We were at 14psi in our 28x10.5s on 12 inch wheels. good contact patch but we also only weighed 3250lbs.

So do you guys think a M/T stiff sidewall is in order for my heavy tank or just the standard M/T ET Drag? Guessing I'm gonna want to start out around 15 psi for tire pressure or maybe 20 would be better? Just want to be as safe as I can. I don't want to experience the wiggle on the big end of the track again. I'm also torn between the 29 inch tall tires or the 28's. I know theres going to be a little more contact patch with the taller tire and I run a 29 inch tire on the street to help bring the cruise rpm down a bit. Guess I should just go for broke and go big and be done with it? Thanks guys.

whatbumper wrote:one of the biggest mistakes people make is running too little air pressure. We were at 14psi in our 28x10.5s on 12 inch wheels. good contact patch but we also only weighed 3250lbs.

This is what I saw with my car.

I ran a 12 inch rim 28 x 10.5 Micky's with tubes at 13#'s of air, screwed, and have pictures on the leave with the rim only an inch off the pavement. There is only so much power you can have on the leave with the small tire. You can go fast with them if you add power down track.

With the big block on the nose of a short wheel base car , it's tricky to get it to hook and get the weight transferred and keep it hooked that first 2 feet. I feel that's why the small block cars seem to 60 ft better . I think I finally got mine to 60ft 1.29 one time. Usually 1.30 -1.31 .

bluef100fe wrote:So do you guys think a M/T stiff sidewall is in order for my heavy tank or just the standard M/T ET Drag?

Trucks are a tough call when it comes to sidewall & compound choices because of their nose/tail weights & wheelbase.

I know way back when I had my 70 Ranchero/351-C with Firestones, Firestone stopped making their "like magic" #2 compound slick (an amazing "middle of the road" compound that was always super, super sticky, but not too hard or too soft of a compound) the Firestone guys said their "soft" compound was better for trucks anyway because trucks are nose heavy/tail light and that you need a soft compound & soft sidewall slick to hook because of the lack of weight back there. But all their crappy "soft" slick did was spin it's nuts off as it ripped-up/ocean waved the living siht out of the slick tread surface.

On the other hand I have heard other slick makers say a truck needs a hard compound slick because a truck is by nature heavy & the hard compound is needed to stand up to the abuse without ripping-up the tread surface. But that hard compound slick can zing it's ass off too if you don't hit it hard enough.

So without factoring in engine power & just looking at the fact that it's a "truck" in my mind a rubber compound somewhere in the middle is probably a good starting point for the average truck. But unfortunately deciding correctly on regular or stiff sidewall sill can be a coin flip without being able to actually test them both to see which one a given combo will like best.

Guys I don't know what kind of percentages big block fox body mustangs have? I only mention them because they seem to be the most popular platform choice on this site. Maybe a few members have had their cars scaled and could enlighten us? The last time I had my truck on my friends stock car scales we were looking at, and I'm going from memory here, 44.5% rear and 55.5% front. That was before adding the trailer hitch, and I still don't have the rest of the exhaust out the back yet either, and I don't remember if the gas tank was full. I honestly thought the percentages weren't to bad for a pickup truck. Maybe after I get the exhaust done I will see if my friend will let me scale the truck again.

As for power I'm guessing the engine is around only 400 hp and 450 tq. Right now I'm still foot braking from about 2200 rpm with my new UCC converter which seems to flash to about 4200-4400. 90/10 shocks on stock front truck suspension and stock but cut rear leafs with the stock overload spring and 2 inch drop shackles on the rear. I relocated the rear shocks behind the axle.

In the back of my mind I'm still thinking I'm spinning the tires on the rims and I'm still irratated with myself for not checking last weekend. Reason I keep thinking this is happening is I've never had to add air to my drag radials between rounds, usually had to let some out as the temperature went up (morning race) was the norm but not last weekend. Does spinning the tires on the rim usually cause a pressure loss? I would think it would

Sorry for the novel again

I don't know about the bb guys but that is a better weight bias than I had with my sb nitrous combo last year. I will post the exact numbers tomorrow as I will be scaling and testing today.

We have to test when we can being farmers and all. Busy time of the year.

My car scaled 37% front 63% rear .................. that sucks.

IDT-572 wrote:My car scaled 37% front 63% rear .................. that sucks.

Blake I'd say that is quite good???? Or do you mean 37% rear and 63% front?

bluef100fe wrote:

IDT-572 wrote:My car scaled 37% front 63% rear .................. that sucks.

Blake I'd say that is quite good???? Or do you mean 37% rear and 63% front?

Dyslexic problem huh ? yes 63% front and 37 rear........... quite bad

Thats with aluminum heads and a tubular K frame and A arms.

I've seen worse.

IDT-572 wrote:

bluef100fe wrote:

IDT-572 wrote:My car scaled 37% front 63% rear .................. that sucks.

Blake I'd say that is quite good???? Or do you mean 37% rear and 63% front?

Dyslexic problem huh ? yes 63% front and 37 rear........... quite bad

Thats with aluminum heads and a tubular K frame and A arms.

I have that same problem with numbers. Boss really gets bent when I accidently change numbers around on part's sizes at work and make scrap. Wish I had aluminum heads, Mustang II front suspension on my truck, and about another 400 hp lol. Someday my truck will be fast......