Link: Testing Proves 2016 Sprints On Dirt Tires Meet All Expectations

2016 SOD spec tires. 100/13-15 medium and 92/12.5-15 D15

 
 
 
They don't even know how to spell sprint car 
much less chromoly...http://www.ycmco.com

This should be interesting. Loosing 5" off the right rear cir. and 3" in width. So right rear will be 2.5" lower. Going from probably a 88 or 90 to 92" cir. 2" in width. So loosing 12 to 14" of stagger to 8" of stagger.

Can't wait to see if this helps passing in the heats or is it the wing that is the problem.

Otto

Ok.  So are you only allowed these two tires?  Can you change stagger?  I understand the right rear, but not the left other than width.  

There are not different sizes of LR so you will have to set up your car with the same stagger all night no matter the track conditions. Spoke with one of the drivers who did the test at Eldora and the lap times for a 360 and 410 were real close which means the narrow tires equal the playing field. You can have all the horsepower in the world but if you can't get it to the ground with the narrow tires you will be no faster. It will be interesting to see how this plays out in 2016 for SOD.

Just  maybe  SOD is on to something here ?  I like there rule changes , but easing it in , is possibly the way to go . I do know one thing costs  have to be cut somehow , these teams can't continue this way trying to keep up  to the WoO,
the smaller teams on there circuit got to have cost problems . I think more will jump to other groups ?

That may be the most beautiful pair of pics ever posted on this board. Would like to see at least one more option on LR size though.

Loose is when you hit the wall with the rear of the
car, tight is when you hit the wall with the front of
the car. Horsepower is how fast you hit the wall and
torque is how far you move the wall.

A step in the right direction, but will need at least 2 different size of each side in order to regulate some stagger for set up. This is exactly what Lance has been saying for years to help unhook the cars & equal the playing field without a huge price factor increase. There will still be a buyer for your killer 410 motor that will no longer be the major focus of speed factor!!!

Kudos to the SOD!!!!!

I actually am really excited to see where this goes. The results show it levels the playing field. Agree with most above me, there needs to be a variety of sizes so teams still have the ability to change the stagger and set the car up different. That is part of racing and should stay.

Hope this tire rule carries over to other major series and even local stuff for those of us that do this for fun.

I was thinking current right rears were around 103 cir.

Currently 105"

The 105/16-15 MED measures between 107 down to 103 depending on tire you get from the pile. At around 8 1/2 to 9 psi they are around 105 +/-. But you will need more stagger, 12" for alot of Smaller tracks 1/4 miles or so. So you will need an 88/12.5-15. That left rear looks like Late Model tire.

I wonder if they will still have the variations in the chalk mark?  Currently, while it says the tires are 105 overall circumfrence, you can get anywhere from 108-110 chalk mark which will change the overall circumfrence of the tire.  So if you get a 109 1/2 chalk mark it should come up about 105 1/2 (104 if you get a chalk mark of 108) when you are at race pressures.  The same goes for left rears.

If they still have the variations, you can still change the stagger but it might not be going from 13" to 9" in one night. 

It is an interesting set of proposed rules for next year with SoD, hopefully it works and can get expanded for everyone.

I hear ya,they probably wont want as much stagger with these smaller tires,we will see.I think it's a good step and may work well.I think they will get alot of attention this year as to how it's working.Hats off to them for having the guts to try this. 

personly I dont think narrow tires are the answer all together. Why make teams buy all NEW rear rims and tires. Why not try running harder compounds on both the left and right rear. No new rims to buy just tires, pluss the added benifit of tire that last longer. something harder than a d55 or d65, then you will see some racing.

A D55 tire is way too hard of a tire.  In theory, the current width of a tire provides such a large contact patch that they are simply just getting so much bite.  The less contact patch the less opportunity to have bite. 

Also the smaller diameter tires mean that the rotations will be more per lap, so you are actually going to be gearing the car alot less than they are now.

Knoxville 360 in 1980s and early 1990s used 13 in tires that had to duro 50 plus.  We did not know any better so we got along fine with them.  Hope it works out good for SOD, then maybe others will do it.

There is no need to buy new wheels.  All testing was done with 15" LR and 17" RR wheels.  Now DirtCar has introduced very similar tires for their crate division.  This is going to be the trend, and I think its a good thing.  A lot of thought has gone into this, and I anticipate a great 2016 for SOD.

I imagine they will find they want to run higher gears with these tires to keep wheelspin down also which will drop rpm's which is also a plus.

Not sure on this. We will see but I'm thinking this will make fresh rubber that much more precious and folks will use more.  We will see. 

There are a need to buy new wheels. For one the tire in the picture has the side walls waaaaay to wide , that tire is not recomended to go on a rim wider then 13" according to hoosier, furthermore any racer knows that you will not get any side bite with that combination. Plus the tire mounted on a narrow rim will be taller. Taller tire = less wheel spin. I dont think this series will take off , hell alot of the sod drivers I talked to are either running the nra or the great lakes region series, where will the cars come from?