tires and tire compounds

grumpyvette

Administrator
Staff member
now many of the older guys can skip this but for the newer guys it pays to read thru what Ill say here, ok, the obvious point should be that adding significant traction or grip between the tires and pavement will allow you to transfer more torque from the engine to the pavement, more efficiently, so the car will accelerate faster and waste less energy in creating tire smoke.
but a good experienced driver will be able to rapidly learn his cars handling and traction thresholds and run the car right up to but not over the limits, while a less experienced driver will, quickly get out of his control limits even with better tires, EXPERIENCE COUNTS,
Ideally you driving skills will be up to the level where you exert some meaningful control over the amount of tire spin during launches and hard cornering with the car and ideally you'll have enough power available to break the tires loose at will at lower speeds so you have the ability to run on the ragged edge of the cars potential during acceleration, cornering and braking.
if your engine and suspension are set up correctly you'll be able to choose and in most cases dictate to a large extent the degree of wheel spin your employing, or avoiding.
each manufacturer has his own system for grading the traction potential of each tire, softer compounds tend to get more grip but they wear noticeably faster also, so its a compromise, most guys get tires that were fairly well and use a liquid or spray compound on the tire surface to soften the surface rubber if they can,t get the needed traction by simply changing air pressure or suspension setting or air shocks
you might want to re-read this info

viewtopic.php?f=7&t=489&hilit=video

http://www.miata.net/sport/Physics/

viewtopic.php?f=34&t=483

OK, first the largest diam. and widest tire that will fit and run without clearance issues at all points in the suspension travel will usually be the better choice ,and you'll need to take into account the brake disc and suspension and clearance issues under the car and in the wheel wells and but the tires compound, construction and air pressure, wheel diam. and width will also effect your traction
keep in mind that tires have speed , and load ratings and that tires AGE, deteriorate, and become much more prone to failures after 6-7 years

20160902_205726_zpse3zfuybe.jpg

http://www.nexusracing.com/index.php?cPath=147_204

http://www.pitstopusa.com/SearchResult. ... oryID=1557

http://www.mrsmcnastys.com/racetires.htm

http://garage.grumpysperformance.co...-info-worth-reading-through.11528/#post-53210

http://www.hoosiertire.com/specdrag.htm

http://www.hoosiertire.com/specdrag.htm#DRAG RACING SLICKS

http://www.racegoodyear.com/tires/dragspecial.html

http://store.summitracing.com/egnsearch ... oview=prod

http://www.mickeythompsontires.com/strip.php

viewtopic.php?f=87&t=2031&p=5411#p5411
 
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Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
The tire can give a pretty good account of its life and health in several ways. One of the first things we recommend is to determine the manufacturing date found in the serial code on the tire. Generally it's the last four digits and represents the week and year of manufacture. Knowing the date is not the only key, but it establishes the lifeline of the product. A visual inspection of the bead area is strongly recommended to insure there has been no damage due to mounting, movement of the tire on the wheel, or improperly installed wheels screws. The tread can be a strong indicator. Inspect the entire tread looking for any cuts or potential punctures. Older tires tend to be "dryer" than those that are new. This is not to suggest the tire's condition is unfavorable, but can be a factor if the tires were stored improperly. Also, a close inspection of the tread and shoulder area can offer clues to determining the correct duration of your burnout. If tires are worked hard in the water box, there will be evidence on the shoulder's edge. Finally, a thorough history of the tires circumference measurement should be documented. The size of your tires, especially Bias Ply tires is critical to the entire combination as the roll out and growth of the tire establishes the final drive ratio. In most cases each inch of roll-out can change finish line by about 125 RPM. Also Bias tires tend to grow from their originally mounted dimension. Radial race tires are not generally affected with this trait. Because of the construction, Radial tires are almost always identical in size and do not grow during the run as do the bias constructed race tires.
  • Will a slick typically "go away" before getting all the way down to the bottom of the wear indicators?
Not in every case. We have had many customers bring their tires to our M/T Service trailer with the cords showing. They always brag about how well the tires worked right down to the cords!Honestly, there are so many different combinations at the drag strip that to attempt to predict the life of a Drag tire on any particular car is a real gamble. Too many factors weigh in. Also there are other components in the tire that can affect performance. Heavy cars with big power can reduce the resilience of the tire reducing its spring rate. Ultimately it's the measured performance that will tell the truth on your tires. Look hard at the incremental times provided on the time slip. Check the performance of your fellow racers. Track conditions and ambient temperature also weight heavily in the consistent performance of your car.
  • Will a bias-ply drag slick change rollout over its lifespan, or once it's taken its initial "set", does it only change due to tread wear?
As mentioned above, yes the tires can grow. Most often your tires will grow from 5/8" to over 1". Different combinations will yield varying growth. Typically the tire will be "set" after 3 to 5 runs.
  • Obviously, an Outlaw 10.5 car and an 11-second bracket racer put very different loads on their tires - what are the similarities and differences in how you'd "read" tires at those extremes?
Well, the 11-second bracket car should be a dead-hook program, but that's another topic! Really it comes down to understanding the conditions and the time slip. What you want ideally is consistency and efficiency. If you see your 60 ft. times going up and down then look to the track conditions and draw comparisons to your competition. If your 60 ft. times go down consistently then your tires may have lost their ability to hold your car or create enough grip. PS – other things in the car can cause the same problem...
  • Is there a difference in what you're looking for on an ET Street DOT-approved tire, versus an ET Drag?
I believe so. When shopping for a DOT tire, most customers have an option to go bias or radial. Since the majority of those with street based performance cars utilize automatic transmissions, the radials become an ideal choice for most in the DOT applications. Most "street based" clutch cars lack the high end adjustability required to benefit from a radial. If you run a clutch then stick to the bias ply ET Street tire. Most racers shopping for ET Drag tires have made their tire size choice based on what the car can fit. Most are looking for a certain roll-out to insure they retain the combination that they have. Others are looking for the ideal tire to achieve success. Bracket or Index racing depends on a high degree of consistency from all components. Some prioritize consistency over performance. Heads-up racers are performance driven. Smaller lighter tires will take less energy to turn so if the tires produce the proper amount of grip to hold the combination the performance/efficiency will be enhanced.
  • How do you know when it's time to rotate bias-ply tires?
Watching your 60 ft. times closely along with a visual inspection of the tread are your best indicators. Some applications will never see a benefit from rotation, while others will. If you notice the tread of your tires "feathering" (a unique texture that's much easier to show than describe) this could be indicating tire slippage. Rotation can extend the effective life of a tire, as some cars can establish wear patterns that reduce the contact patch.

  • Can you tell anything about which direction to go with your tire pressure by visually examining them?
I'm sure it's possible to get close to your ideal tire pressure by visual inspection but I believe that that time slip is the ultimate guide. Always consider the ambient conditions and try to develop an understanding as to how they affect your combination. Good data is very important.
  • Drag radials are a whole world of their own - what do they have in common with bias-ply slicks when it comes to reading the tire, and how do they differ?
The radial tire has a different shape in the shoulder area. Bias ply tires tend to be square at the edge and the radial is rounded. This makes "reading" the radial a little more challenging. There is no distinct edge. I'll go back to the good old time slip – it tells you what the car wants! Here is a general statement regarding the inflation of Radials versus Bias ply type tires. Radials require greater air pressure to perform optimally when compared to Bias tires and most of the benefit in performance comes from reduced rolling resistance.

TIRE TECH

Determining the Age of a Tire


When it comes to determining the age of a tire, it is easy to identify when a tire was manufactured by reading its Tire Identification Number (often referred to as the tire's serial number). Unlike vehicle identification numbers (VINs) and the serial numbers used on many other consumer goods (which identify one specific item), Tire Identification Numbers are really batch codes that identify the week and year the tire was produced.

The U.S. Department of Transportation (DOT) National Highway Traffic Safety Administration (NHTSA) requires that Tire Identification Numbers be a combination of the letters DOT, followed by eight to thirteen letters and/or numbers that identify the manufacturing location, tire size and manufacturer's code, along with the week and year the tire was manufactured.

"When it comes to determining the age of a tire, it is easy to identify when a tire was manufactured by reading its Tire Identification Number (often referred to as the tire's serial number)."

Tires Manufactured Since 2000
Since 2000, the week and year the tire was produced has been provided by the last four digits of the Tire Identification Number with the 2 digits being used to identify the week immediately preceding the 2 digits used to identify the year.

Example of a tire manufactured since 2000 with the current Tire Identification Number format:

Post_2000_Full_Dot.jpg

In the example above:
DOT U2LL LMLR 5107
51 Manufactured during the 51st week of the year
07 Manufactured during 2007
While the entire Tire Identification Number is required to be branded onto one sidewall of every tire, current regulations also require that DOT and the first digits of the Tire Identification Number must also be branded onto the opposite sidewall. Therefore, it is possible to see a Tire Identification Number that appears incomplete and requires looking at the tire's other sidewall to find the entire Tire Identification Number

Post_2000_Part_Dot.jpg


The use of a partial Tire Identification Number on the one sidewall (shown above) reduces the risk of injury to the mold technician that would have to install the weekly date code on the top sidewall portion of a hot tire mold.

Tires Manufactured Before 2000
The Tire Identification Number for tires produced prior to 2000 was based on the assumption that tires would not be in service for ten years. While they were required to provide the same information as today's tires, the week and year the tire was produced was contained in the last three digits. The 2 digits used to identify the week a tire was manufactured immediately preceded a single digit used to identify the year.

Example of a tire manufactured before 2000 with the earlier Tire Identification Number format:

Pre_2000_Dot.jpg

In the example above:
DOT EJ8J DFM 408
40 Manufactured during the 40th week of the year
8 Manufactured during the 8th year of the decade
While the previous Tire Identification Number format identified that a tire was built in the 8th year of a decade, there was no universal identifier that confirmed which decade (tires produced in the 1990s may have a small triangle following the Tire Identification Number to identify the decade).

And finally, hold on to your sales receipt. Most tire manufacturer's warranties cover their tires for four years from the date of purchase or five years from the week the tires were manufactured. So if you purchase new tires that were manufactured exactly two years ago they will be covered for a total of six years (four years from the date of purchase) as long as you have your receipt. If you lose your receipt, your tires' warranty coverage will end five years from the week the tire was produced (resulting in the tire manufacturer's warranty coverage ending only three years from the date of purchase in this example).




Author: Carl Robinson
Mickey Thompson

http://vexer.com/automotive-tools/1-4-mile-ET-HP-MPH-calculator

http://www.wallaceracing.com/et-hp-mph.php

http://garage.grumpysperformance.co...-info-worth-reading-through.11528/#post-53210

https://robrobinette.com/et.htm

http://www.ajdesigner.com/fl_horsepower_elapsed_time/horsepower_elapsed_time.php

http://www.tuneruniversity.com/blog/2012/03/power-to-weight-ratio/
17" & 18" rim size slicks are available
http://www.titanmotorsports.com/tires.html

http://www.mickeythompsontires.com/strip/et-street-ss/
 
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Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
TIRE TECH: TIRE SPECS EXPLAINED: MEASURING RIM WIDTH
https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=199
Measuring Rim Width

The measuring rim width is the industry standardized rim width upon which the tire must be mounted in order to confirm it meets its dimensional targets. Because the width of the rim will influence the width of the tire, a standard rim width for every tire size is assigned and must be used. This standardized measuring rim width allows all of the tires produced around the world to meet the same dimensional standards and therefore, be equivalent with regards to their physical size. The measuring rim width is sometimes referred to as the tire's "design rim width."

Tire Size Measuring
Rim Width

P175/75R14 5.0"
P195/75R15 5.5"
P215/75R15 6.0"
P235/75R15 6.5"
Tire Size Measuring
Rim Width

P225/75R15 6.0"
P225/70R15 6.5"
P225/65R16 6.5"
P225/60R15 6.5"
P225/55R15 7.0"
P225/50R15 7.0"
P225/45R17 7.5"
P225/40R18 8.0"
The assigned measuring rim width changes with the tire size's section width and with the tire size's aspect ratio. As tire section width increases, the measuring rim width increases proportionately in 1/2" increments. Therefore, relatively narrow wheel widths are assigned for smaller tires while wider wheel widths are assigned for larger tires.

Additionally, relatively "narrow" measuring wheel widths are assigned for taller profile tires (75-series sizes) which graduate in 1/2" increments to the wider wheel widths assigned for lower profile tires (40-series sizes).

(Lea en español)
Section Width

A tire's section width (also called "cross section width") is the measurement of the tire's width from its inner sidewall to its outer sidewall (excluding any protective ribs, decorations or raised letters) at the widest point. This measurement is made without any load placed upon the tire and after the tire has been properly mounted on its industry assigned measuring rim and has been inflated and reset to its test pressure after 24 hours.

Because a tire's section width is influenced by the width of the rim upon which the tire is mounted, the correct industry assigned measuring rim width for the tire size being measured must be used.

The width of a tire mounted on a narrow rim would be "narrower" than if the same tire was mounted on a wide rim.

Note: The overall diameter of a steel belted radial is determined by the steel belts, there is little, if any, change to the overall diameter of the tire due to differences in rim width.

The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10".

For example: a tire in the P205/60R15 size is measured on a 6.0" wide wheel and this size tire has an approved rim width range from 5.5" to 7.5" wide. The tire has a section width of 8.23" (209mm) when mounted on a 6.0" wide wheel. If that tire were mounted on all of the rims within its approved range, the tire's approximate section width would change as follows:

Difference from Measuring Rim Rim Width Approximate Tire Section Width
0.5" narrower 5.5" 8.03"
Measuring Rim 6.0" 8.23"
0.5" wider 6.5" 8.43"
1.0" wider 7.0" 8.63"
1.5" wider 7.5" 8.83"

Because of the different wheel widths used in the above example, there is a 8/10" projected difference in tire section width when comparing a tire mounted on the narrowest rim to the widest rim within its range. This may affect fenderwell and frame clearances when selecting optional aftermarket wheel and tire packages.
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
(Lea en español)
Measuring Rim Width

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=199


The measuring rim width is the industry standardized rim width upon which the tire must be mounted in order to confirm it meets its dimensional targets. Because the width of the rim will influence the width of the tire, a standard rim width for every tire size is assigned and must be used. This standardized measuring rim width allows all of the tires produced around the world to meet the same dimensional standards and therefore, be equivalent with regards to their physical size. The measuring rim width is sometimes referred to as the tire's "design rim width."

Tire Size Measuring
Rim Width

P175/75R14 5.0"
P195/75R15 5.5"
P215/75R15 6.0"
P235/75R15 6.5"
Tire Size Measuring
Rim Width

P225/75R15 6.0"
P225/70R15 6.5"
P225/65R16 6.5"
P225/60R15 6.5"
P225/55R15 7.0"
P225/50R15 7.0"
P225/45R17 7.5"
P225/40R18 8.0"
The assigned measuring rim width changes with the tire size's section width and with the tire size's aspect ratio. As tire section width increases, the measuring rim width increases proportionately in 1/2" increments. Therefore, relatively narrow wheel widths are assigned for smaller tires while wider wheel widths are assigned for larger tires.

Additionally, relatively "narrow" measuring wheel widths are assigned for taller profile tires (75-series sizes) which graduate in 1/2" increments to the wider wheel widths assigned for lower profile tires (40-series sizes).
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
https://www.tyresizecalculator.com/tyre-wheel-calculators/wheel-rim-size-calculator

https://mechanics.stackexchange.com/questions/39613/standard-tyre-width-vs-rim-width-chart

http://garage.grumpysperformance.co...c4-corvette-wheel-tech-info.12099/#post-75335

https://www.budnik.com/helpful-tire-info

e9f66ca5b09f2a7dbc1c71d74e88feadx.jpg

https://www.journeysoffroad.com/wheeltire-sizing.html

A good rule of thumb is that your wheel needs to be a bit narrower that your tires, so that it squeezes the tire's bead area against the wheel's outer lip.

Your 7 inch wide wheels, in metric, come out to just under 178 mm. Therefore, any tire that has a width of more than 178 mm at the bead (the width stated in the tire size is at the tread) would fit nicely.

I've found this table to answer another user's question about tire width and rim width:



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answered Dec 9 '16 at 23:08

tlhIngan

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  • I've seen this table too, I think it more or less replicates the one I linked in the post. At least they match for my situation. However, this is yet another table derived by some nice guy from some unknown information sources, rather than a standard (as in ISO or ANSI) chart. So while your rule of thumb makes sense, I wonder where to find the official data or, alternatively, why it doesn't exist. At least I would expect the tyre manufactures to care about it, but I couldn't find anything on Dunlop or Michelin sites. – texnic Dec 9 '16 at 23:21

  • As you mention yourself, the rim should be narrower than the tyre at the bead, while the tyre width is specified at the tread. So the application of the rule of thumb is not very straightforward. – texnic Dec 9 '16 at 23:23
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Tyre manufactures list the range of acceptable wheel rim widths for each tyre type and size. On the narrowest allowable rim width the tyre will be more comfortable; on the widest allowable rim width the tyre will handle better. They usually specify a rim width in the middle of the range an an ideal compromise and this is what most manufactures on most models choose.
 
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