Get yer minds outta the gutter already. Any tips or tricks on drilling a set of mags for screws? Anyone running slicks tubeless? Local guy swears the car will be quicker.
Ya screw the rim so the tire won't slip and ruin your tube, or on an older tire so it won't grow and come off the rim. Takes a lotta mill to make one do either. Summit raceing has a template to lay on your rim and make 16 holes evenly spaced. Its a cheap tool, way cheaper than a rotary table for your bridgeport. The holes in the rim don't want to be tapped, so make them big enough for the screw and thread the screw into the bead in the tire.
there is no need for it unless the tire is spinning on the rim. my 64 corvette ran 9.80 with a 10" slick 1.38 60 foot times and no problems with out them screwed on even with 16lbs of air
So, what's a good starting point for air pressure for a 1200-1500 pound car on a set of 30x9x15 slicks?
It is all going to depend on how your suspension works, launch rpm. slicks with low pressure get scarry at the top end when you let out of it
I didn't know the M&H would run tubeless. What I've always done for air pressure is start out a little hard and let a little air out at a time until I achieved the desired effect. One thing to remember is that when you're wadding up the side wall you're looseing ground, it takes a lot of torque to wad 'em up. The other thing to remember is that a low tire gets a squirrely as hell on the big end. Its a trade off, sometimes you have to give up a little traction to get the desired effect. you might have to feather it off the line a bit, that's part of the reason the high buck guys have gone to control boxes or stepped rev controls. it makes getting out of the hole a little easier.
This individual is running M/T drag slicks. That's why I was wondering if anyone had run M&H tubeless.
This may sound strange, but I read where rubber cement works better than screws. The reason is because rubber cement is very strong in "shear" -- like when two surfaces try to slide across each other -- but weak in tension -- like when you try to pull those surfaces apart. What that means is that if you glue the tire on with rubber cement it won't slip on the rim but can be dismounted fairly normally. I think this was discovered when the Army was testing a wheeled scout vehicle at Ft. Knox back in the early '70's.
Also, dont cheap-out on the screws if you do it. The ones made for it from Moroso are the ones to use. Brett
Stevie - Take Squirrel's advice. "mark the tire and rim and see if they're turning...if not, don't do it" It's the best tip on this thread. Don't assume the procedure is needed. I'd guess at least half of the guys doing it have wasted their time.
Resurrecting this thread I found using the search feature. If there's a newer one, I couldn't find it. Today, my new TTs arrived. They will be dedicated drag slick wheels for the Chevy. The plan was to drill 'em, but now I'm holding off until some actual drag racers can weigh in. Opinions, please! The combo: Blown 490 bbc, Autogear Super 22 4 speed and 4.11s in a 9'' with Detriot locker. Thanks all.
What tire?? What size tire and rim?? What's the rig weigh?? A lot of the guys I know running drag radials just glue them, Permatex High Tack either brushed on or from the aerosol can, or Edelbrock Gasgasinch(which looks just like rubber cement. I've also heard of use of 3M contact cement, like the upholstery guys use for headliners and such.. If that don't do it, then bead locks.(there are a ton of guys running bead locks who don't actually need them) The smart guys swore off screws years ago. M/T warns you not to screw the tires to the rim, the screw could sever one of the bead wires and generally just tears up the bead surface on top of that.
What squirrel said above^^^^^^^ TEST first, let the results dictate the next move............ I thought the same once ago...... BUT- I could throw the kitchen sink at it, leave on the brake at 4600, with a higher pressure, and still banged a low 1.31 60 ft time............Results may vary.
Thank you for the replies so far! Haven't weighed it yet, 3200# perhaps. Hoosier drag slicks, unsure of height. 15x10s I would love to hear suggestions for tire height, 6800 is where I set the rev limiter.
I'm running tubes ( no screws) on my 31' with Hoosier Quick Time Pros ,29" tall . Car ihas a short wheel base and feels like it wants to move around near the stripe. I did use screws on my 64' Polara with M&H cheater slicks . I have the same wheels as you, you will need to drill out the hole larger for the valve stem if you run tubes , no big deal.
There's several calculators here, but one is for figuring out rear gear to rpm. http://www.wallaceracing.com/Calculators.htm
I haven't used screws in years. My car weighs 2950 with me in it. 1.14 60 foot 6.8 in the quarter. As far as tire pressure the higher the better for lower rolling resistance. Have you ever tried to push a car with a flat tire? My mh tires run 12.75 lbs. with tubes. Slicks can be run tubeless. It realy matters what the weight of the car is. The heavier it is the more sidewall stiffness it needs. If the car can be run tubeless it will go faster because it will have less rotating weight. When buying slicks pay very close attention to the sidewall construction. Talk to the tech guys about your car and have a honest weight of it. Not all tubeless cars can launch and get down the track. A question like you are asking can't be answered here. Its answered with a time slip. You have to experiment. Tires will never fix a bad suspension so make sure the chassis is right before you worry about tires. After tires are mounted a measurement of the circumference is critical. Mh sells only in matched sets. If the tires don't match the car will always pull to one side. Over inflating ( like 30-35 lbs) a small tire and leaving it in the hot sun can stretch a tire larger. I have done that. Stock car guys do it to. I know of a guy that has a tire oven to stretch tires.
just for your entertainment, I run 20 psi in the 9x15 M&H slicks on my Chevy II. It's dipped into the 9s.... tubeless, no screws.
Thank you, guys. I intend to weigh the car prior to track day. I really appreciate the advice, asking questions will hopefully keep me from making wrong choices. Hoosier has a store nearby. Next week I'll stop in.
I just used the Wallace calculator for my new combo. I put in 4 different combo's with one h.p. rating and the e.t. and mph within stayed the same within hundred's as I changed from 6000 rpm at the end of the 1/8th mile to 6600 rpm's in the traps. It just told me the gear I needed to turn that desired rpm. I ran a big block 1970 O/T Malibu SS with a 468 big block and a 4.10 gear it ran 7.0 almost every pass in the 1/8th mile. Tried a 4.88 and it ran 7.00 every pass so I went back to the 4.10 so I could still run 1/4 mile stuff. So don't over gear your set up. I am running Moroso screws in my slicks . I am running a spec 29x7 slick on a 7 inch steel wheel. You can make your own wheel screw pattern without spending the money for a store bought one. Just take a piece of cardboard and trace the wheel pattern lay it on the rim and find the exact center and draw a line across the wheel and use some math to figure the spacing between the screws and draw your lines mark the wheels and start drilling . Flip the wheel and find the same starting point or your slick will distort when you launch it. I probably don't need to put screws in the slicks , but it looks era correct for the car and it is a 4 speed car.
Good luck with the Hoosiers. I have never been able to get them to work. I was using Goodyear's for all my cars until I tried MH. It's the best that I have found to work on all tracks. I use their front tires also.
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