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Discussion Starter · #1 ·
About to order rims and Quick Time Pros.

Want to know, given a similar width/height tire and an identical width/offset rim, which is better for rear dragstrip traction--a 14" or a 15" rim?
 

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Discussion Starter · #3 ·
The rims I want are available in both so that is not a problem, but I will certainly consider tire availability in my final decision.

I have a matching pair of 14" front rims already and was just tossing around as to whether there was a theoretical performance advantage in one or the other.

I'll restate my question differently:

Will an equal height/width DOT bias drag tire work better on a 14" or a 15" rim? (What affect does the additional side wall height play with drag type tires, given that everything else is equal?)

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Dennis

65' STANG, 3160 lbs

393W, 2.78 Toploader 4 Spd, 9" 3:70 Posi
Pro Comp Heads, Vic Jr. Intake, 750dp, 236/561 Solid Cam, 9.6CR, 1 3/4" Headers, Lakewood, Subframes, Caltracs




<font size=-1>[ This Message was edited by: dennis111 on 8/11/06 6:46pm ]</font>

<font size=-1>[ This Message was edited by: dennis111 on 8/11/06 7:54pm ]</font>
 

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Hey Dennis, I'm sure you've seen as well that the slicks say they have
or require tubes in the summit listings, do you know anything about tubes?
Do you really have to use them? I thought I had heard guys say they just take the tubes out. I just honestly don't know...
 

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Discussion Starter · #5 ·
On 2006-08-11 05:19, ga289stocker wrote:
Hey Dennis, I'm sure you've seen as well that the slicks say they have
or require tubes in the summit listings, do you know anything about tubes?
Do you really have to use them? I thought I had heard guys say they just take the tubes out. I just honestly don't know...
Good question as I have heard the same thing--I really don't know but I don't think I want to risk a possible week to week leakdown-especially if the are on the car and not being used. If I don't spring for the race tubes, I will probably go with a standard passenger car tube instead. They are around $10-$15 where as the Drags are around $55 each.

Hopefully someone can set us straight.

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Dennis

65' STANG, 3160 lbs

393W, 2.78 Toploader 4 Spd, 9" 3:70 Posi
Pro Comp Heads, Vic Jr. Intake, 750dp, 236/561 Solid Cam, 9.6CR, 1 3/4" Headers, Lakewood, Subframes, Caltracs



<font size=-1>[ This Message was edited by: dennis111 on 8/11/06 9:47pm ]</font>
 

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Well I'm sure you are closer than I to getting tires as I still have some live left in my little dr's. Which every tire you go with please let me know. I'd also like to here from other's on the whole tube thing...
 

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The drag tubes are for safety - you can run without them if you wish. You will have to drill your rims to about 5/8" to install the tubes. Drag tubes are MUCH heavier than regular tubes. If you're an occasional racer, probably the regular tubes will do you. If you race a lot and you want to run tubes, get the real deal becuase they have to put up with a lot of abuse. I just fixed a hole in one of my drag tubes - with no corresponding penetration in the slick. If you make enough torque, screw the tires to the rims especially with tubes - if the tire turns on the rim, it'll tear up the tube.

Regular slicks will hold air for a while, after being used a while they will leak through the sidewall. Some people put a little dish soap in them. I prefer the tubes - it about doubles the weight of the tire which costs HP but I don't spend a lot of time worrying about how much air is in the tires.

As for traction - the taller the tire, the bigger the footprint. The sidewall is part of the shock absorbing system of the tire. If you have a lot of power and a small sidewall, you're going to bounce the rim off the track unless you run a lot of air in the tire. Also, bigger tires typically run less air pressure - but you should run as much as possible and whatever it takes to get a consistant pattern across the tire.

I personally ditched all my rear 14" rims. The tire choices are just not there. Run 15s if you want to pick and choose.
 

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If you have to buy rims anyway 15's would be a better choice due to a better tire selection.The 14's will probably work the same though if rim width,tread width and diameter is the same as an equivalent 15 (26x8x14 vs 26x8x15 both on 7 inch rims).

Tubes aren't really needed. The 26x10.0x15 Hoosier slicks on my Morris have no tubes and rarely require air.There are no tubes in the 26X11.50x15 MT ET Streets on my Falcon and they leak more than the Hoosiers but not really enough to be a concern. The trick is to coat the inside of the tires with liquid dish soap prior to mounting to fill in any small holes and prevent leaks. I didn't do this but it wouldn't hurt. If tubes are used then rim screws will be required if much less than 15lbs is used which might cause the tire to spin on the rim and tear out the valve stem of the tube.

 

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Id go with the 15's. I did.
Tire choice and stance were the factors.
I also do not run tubes.
 

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The quick time pros hook pretty good and don't need tubes if mounted correctly. Always check them regularly but I have found that they don't leak that fast. I get by every couple months without adding air. You will need to experiment with pressure. I'd try about 12lbs. and go from there. Can't help with the size for your car, but go as large as you can fit under there. 7Dmach recommended me to use 28X11.50X15 for my393 car and they fit. If they will fit under your car I'd say that is minimum width for your car and power. They really only measure about 10 in. tread.
 

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Discussion Starter · #11 ·
Thanks guys.

As usual, you've help me a lot. I'll be ordering the 15's and reconsidering whether to go tubeless or not.
 

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The larger the tire, the less air pressure it needs. A huge slick might run around 4 psi, where a 26 x 8.5 might need 14 -16 psi depending upon the car's weight. 12 is definitely on the low side for a 26 x 8.5. I'd stay around 14 -15.

From my experience, the treadlife on the Hoosiers is better than the MT's.

Academically speaking, a slick mounted on a 14" wheel will have more sidewall. This will give it a little more shock absorbtion. The 15" slick, with it's shorter sidewall won't absorb quite as much shock, but will feel a little more stable.

Good Luck!

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302 4-speed 289 heads, 10.63 @ 129.3
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220


<font size=-1>[ This Message was edited by: n2omike on 8/12/06 11:47pm ]</font>
 

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Discussion Starter · #13 ·
I just pulled the trigger and ordered a pair of the Hoosier Quick Time Pro DOT's, 26 x 8.5 x 15 which is equivalent to a 235/60 in size and a pair of 15 x 7 rims with 4.25" backspace. I haven't heard a single negative word (except the "billboard sized" Hoosier label on the sidwalls) about the QTP's, but lots of positives. Good traction, good wear, and they are available in sizes that best fit a 65/66 wheel well.

Still considering using passenger car tubes as they are light and inexpensive insurance.

I should have some results and impressions after next weekend. Hopefully the QT's will help me tame the torque monster and I'll see what the car is actually capable of.

Again, thanks for all the help.
 

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I think you made a good choice Dennis. I am running the same sized wheels and tires on my car. I have the MT drag radials though.
Get ready to watch your et's plummett!!
 

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FWIW - the last set of Hoosiers I had went 100 passes without much air loss, then after one night with great air and good 60's they wouldn't hold air for more than two days. Switched to tubes after that. I go through two sets of slicks a year and standardize on M/T.

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1967 Falcon 4 door w/351C - Owner built, owner abused.
70 Mustang 302 / 06 Ranger, 04 SuperCrew parts hauler
http://raceabilene.com/kelly/hotrod

<font size=-1>[ This Message was edited by: ckelly on 8/14/06 11:04am ]</font>
 
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