I saw some posts on the drag radial topic indicating that perhaps a 305 or even 315 would fit on our wheels. Would an increase in the width of the tire increase your chances of popping the tire off the rim under heavy stress? What are the drawbacks to an oversize tire?

There is a competition tire available in a 305/30ZR18 that only costs $244 and I think that would make a perfect track tire if it will fit.



[This message has been edited by Nathan (edited 12-21-1999).]

 

Nathan, Yes it would increase the chances of popping the tire off the rim (bead seat). And I may also increase the level of stress your wheel could see. Granted it may not be enough to effect your wheel.

[This message has been edited by 2000Silverbulletonorder (edited 12-21-1999).]

 

I have to dissagree. ive squeezed a 295/50/15 on a 7 inch wheel before.if you can get it to seet right then it shouldnt hurt anything. i certainley dont think any size "tire" is going to have an effect on the wheels! they might not work as expected or perform good but you can basically put any size on a wheel if it would seet. now i am not saying to put a 215/70/15 on a 15x10 wheel, but i certainly dont think a 315 is going to in any way affect a 9 1/2 wheel.you might notice a slight outside wear pattern but i dont think with such a little difference you would notice anything but more rubber on the road.

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1999.5 LIGHTNING
WHITE #3700
DOB:8/99
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98.86MPH
NE DRAGWAY N.H.
SOON TO HAVE A SUPERCHIP AND FILTER HOPE TO RUN 13.49 THEN I WILL LEAVE IT ALONE

98 YAMAHA BLASTER
97 HONDA 600F3 WHT/BLK
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USED CAR DEALER
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N.H.

 

BADASSSVT, you're wrong, it does.
Likely not enough to matter, though.


[This message has been edited by 2000Silverbulletonorder (edited 12-21-1999).]

 

Just some information. Yes you can put a large tire on a small wheel. Will it work - yes. Will you gain performance - not always. What you have to worry about is getting proper tire patch contact and side wall deflection. I know this from both theory and also first hand. I ran B.F. Goodrich Drag Radials on my Cobra,(17x315 on 17x 9 wheels). They only worked OK at the drags (still had too much power hook)but on the street the **** end of the car was squirrelly as can be. The side wall was just too constrained on those wheels. I sold the tires to my friend, he put them on his ZR1 vette which has a 10 inch wheel.
PS. There are a lot of things that you can do and many times they even work. But an oversize tire on a small wheel (width) will get you into trouble.

I edited this post since I stated an 18 inch wheel and tire and should have said 17. I've been thinking Lightning wheels so much that I've got 18 inches on the brain.
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BABolt
SVT#290



[This message has been edited by BABolt (edited 12-24-1999).]

 

Hello!
I know that we have a Goodyear Engineer in our group and maybe he could offer up an opinion. (not tring to put anyone on the spot) Thank you.

 

Hey Nathan, The only time I ever popped a tire from the bead,was from running REAL low air pressure(8psi on a 38.5 mudder).I never have lost a tire on the road,auto-x'n,but on the street I don't run low psi. A general rule of thumb,for tires and rim width's.If the tread width of the tire is 10inch the rim width should be 10 inches.It is known that you can run with a plus or minus 1inch on the rim from the tread width. O.K. the overall width of are 295/45/18, is 11.5 but the tread width is only 9.5. So if you look at a 315/40/18, overall width is 12.4 and a tread width of 10.4 you are still with in the 1 inch rule of the rim size of 9.5. For those who want to know how to measure a tire in standard inches here is how to do it. Take the section width(295)divide by 25.4 equals 11.61.Take 11.61 times section height(.45)equals 5.22,times 2 equals 10.44,Plus rim size(18)equals 28.44(tire height).Now you know the math so start looking for the perfect(max)size for the L's rim size of 18X9.5.A 315/40/18 maybe you do the math and let me know? Kevin

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JIGAWATT SVT#2698


[This message has been edited by JIGAWATT (edited 12-23-1999).]

 

JIGAWATT said, "Take the section width (295) divide by 25.4 equals 11.61. Take 11.61 times section height(.45)equals 5.22, times 2 equals 10.44.(this is section width)"...the section width is 11.61 (295/25.4) not 10.44 (10.44 is just 2 times the section height). Were you trying to imply that 2 times the section height is tread width?

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HotRodSix
'98 STX Flairside 4.2L
Best 1/4: 16.26 sec. @ 84.4 mph
Dyno: 180 rwhp / 228 ft-lb

 

you guys are gettig too technical , wow!!! i might be wrong and probally am but i say if the shoe fits WEAR IT!!!

 

BFGoodrich lists the TREAD WIDTH of its 315/35R17 tire as 12.0" and recommends 11.0-12.0 wide rims for the tire. Section width (overall width) is 12.4" on a 11" wheel.

For a 295/65R15 (which is what I run at the track on my '95 on a custom 10" wide Centerline wheel), tread width is listed as 10" and section width as 12.4"

Interestingly enough, a 315/60R15 is listed as being 10.9" wide at the tread with a 13.4" section on a 9.5" wheel.

Basically the shorter the side wall, the closer the section width and tread width are to each other and the close the wheel width needs to be to the tread width.

I'm sure you can find these charts for any brand (I know I've seen them for Goodyears, Dunlops, BFGs, and Firestones). You can see the BFG T/A DRs at: http://www.bfgoodrichtires.com/tires...dragradial.pdf

Note it's a PDF. It's about 200K so it'll take a few to download.

Later!
Jeff S.
SVT Lightning #74 in '95
11.92@115.2 on radials, driven daily
http://nloc.org

 

Just came in from the Garage and was checking the board and wanted to add this.
At work today I asked a friend to review this thread and the info that was shared. We did not agree with what was posted but tried to keep our mouths shut. I am glad that "FMOS Racing" posted. Also in another post I stated that I was widening my Lightning wheels and I am, to the stated 10.5" width. Could I have gone wider, yes but I was aware of the constrain, the sheet metal of the bed and the fact that I will never run a wheel spacer on any of my cars / trucks. The additional one inch that I am adding to the wheels is all to the back side and since there is approximately 2 inches of clearance now, I feel save in giving up a little over half of this(I've done it before plus I know how I drive).I am not making a recomendation here. I believe that I did my homework. I had checked with three of the major tire manufacturers back in August and waited a bit before I kicked off my plan. Good luck.

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BABolt
SVT#290



[This message has been edited by BABolt (edited 12-24-1999).]

 

Going from a 295-45-18 to a 305-35-18 shouldn`t b a problem. I have increased tires sizes on every vehicle I currently own with no problems. As long as the aspect ratio is the same the new tire will be the overall height. Scrubbing may or may not be a problem. For example the stock hotrocks on My 93 Lightning would rub when locked fully left or right. A 315-25-18 would have correct aspect ratio but I'm not sure if one is offered in that size. Maybe a custom wheel
could be fabricated for the rear of the 99.5 and really get some meat on the ground. might be worth a tenth or so. I know mine is breaking loose when I hit second and I ain't even mashed it. This cold weather down south is really making a difference.

Jeff C.

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Red 99 Lightning (Totaled)
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Silver 95 SHO