Tires

On This Page:

Reading Tire Sizes

Speed Ratings

Wheels

Changing Rim Sizes

"Dimple" on Sidewall


Tire Size & Rim Width Guide
(From: http://zhome.com/ZCMnL/WheelSizes.html )
Tire SizeRim Width RangeOverall DiameterTread Width
185/70/14 BFG Radial T/A5.0"- 6.5"24.2"5.5"
195/70/14 BFG Radial T/A5.0 - 7.024.75.8
205/70/14 BFG Radial T/A5.5-7.525.26.1
185/60/14 BFG Comp T/A HR45.0-6.522.85.8
195/60/14 BFG Comp T/A HR45.0- 7.023.26.2
215/60/14 BFG Comp T/A HR46.0 - 7.524.26.8
225/60/14 BFG Comp T/A HR46.0 - 8.024.77.0
205/60/15 BFG Comp T/A HR46.0- 7.524.76.1
215/60/15 BFG Comp T/A HR46.0- 7.525.26.8
205/50/15 BFG Comp T/A ZR5.5-7.523.16.2
225/50/15 BFG Comp T/A ZR6.0- 8.023 96.8
225/50/16 BFG Comp T/A ZR6.0- 8.024.86.8
245/50/16 BFG Comp T/A ZR7.0 - 9.525.77.5



• most major tire manufacturers put a marking on each new tire to indicate the "heavy spot" on the tire.

• A general rule is to match the tire's mark to the wheel's valve stem, however, many wheel manufacturers drill the valve stem hole at the light spot of the wheel.



[Bias tires]


[www.mickeythompsontires.com/faq_offroad.html#faq3]

Q: What are the differences between a radial and a bias belted tire?

A: The body plies are perpendicular to the bead on radial tires. On bias and bias belted tires, they are at an angle (bias) to the bead, which greatly increases sidewall strength and durability. The belt on a bias belted or radial tires improves tread stability and helps reduce rolling resistance which is the radial tires main feature. M/T's construction sandwiches the belts between the body plies, which improves ride and virtually eliminates belt and ply separations. Sandwiched belt construction is unique to M/T tires only.
--------------------
[ www.rsracing.com/tech-tire.htm]

Bias ply tires differ from radials on the following items:

Static negative camber requirements are less, usually about 1 to 1 1/2 degree negative is sufficient.

Rim width selection is more critical, because the tread face is flexible, the rim helps support the tire. The rim width should be as large or larger than the section width of the tire.

Air pressure can not be used to reduce sidewall flex (rollover). Excessive air pressure will cause the tread face to bulge, reducing the contact patch.

Bias ply tires give more warning (than radials) about traction limits and have excellent feedback of what the contact patch is doing.

Bias ply tires operate at larger slip angles than radials. This larger slip angle is what makes bias tires feel sloppy on initial corner turnin. What this means to the driver, you have to 'lead' the corner more to account for the slip angles.

Because of how bias tires react to cornering loads, the tread can be thicker than radial tires.


Radials differ from bias ply on the following items:

Radials generally need more static negative camber than bias tires.

Radials generally provide more breakaway grip than a bias tire.

Radials give less warning before 'breaking away'. This causes radials to be harder to drive at the limit.

Air pressure can be used to reduce sidewall rollover, without having the tread bulge like a bias tire. The may allow you to use a larger sized tire.

Radials are usually heavier than bias tires due to the overwrap plys.

Radials operate at lower slip angles than bias ply tires. The is the main reason Radials have better transient response than bias tires.


Most racing radial tires are closer to a belted bias ply tire than a passenger car radial tire. This gives the racing radial tire traits from both bias & radial tires (good feedback & higher breakaway traction). Which tire is best for you, it depends on your needs. The bias tire is good for applications where negative camber is limited, but only if a wide enough rim is available. Radials are good where transient handling is primary concern, and adequate negative camber is available.



General Info: 205/70r15: Rim width: 5.5 - 7"; Diameter: 26.3"; Revolutions per Mile: 767; Tread Width: 5.8"

BIAS: E70-15 Rim width 6"; Diameter: 26.4; Revolutions per mile: 764; (Tread width not shown)



[ www.barneymc.com/toy_root/techtalk/whls_hub/tires.htm ]

...I hate the road steer, the ride, flat spots in cold weather and everything else "bad" about bias tires...



Matching Tire Sizes


[www.nebraskatire.com/tires_101/size15.htm]

Original Size: P205/70R15 Appropriate Substitutes: (Doesn't take into consideration the vehicle's wheel well dimensions - RJ) 205/70R15, P215/70R15, P205/75R15, P215/65R15, P225/60R15, 235/55R15, P245/50R15


----------------
{Replacements: 14" replacements for 15" P205/70r15 http://amsoft.ru/tiresize/index.html?ws14=1&]

205/75-14 ; d=26.11; w=6.05

(Diameter of p205/70r15 is given as: 26.30", so the 14' "75" ratio tire is essentially the same at "26.11". The Wall sizes: 75 @ 14":6.05"; 70 @ 15": 5.65", about a half-inch higher. A 205/75R14 is d= 26.91 w=6.46)
-----
[Goodyear Brand Types]

P205/75R14: & P205/70R15:

Ultra Grip
Severe Winter Traction Radial Pinned For Studs
The Ultra Grip offers an outstanding combination of features. With characteristics such as a unique polymer blend and an advanced tread design, Goodyear Ultra Grip is one of the toughest traction tires on the road. ("Special polymers" looks like softer rubber for gripping, hence high wear. Also bad "dry traction". - RJ)

P205/75R14 & P205/70R15:
Regatta 2 (The only model described as "durable" in the blurb- RJ) Durable, All-Season Touring Radial
This durable, all-season touring radial offers durability, excellent traction, responsive handling and a comfortable ride. It is designed to meet the most demanding needs of today's touring sedan drivers. (Tire Rack - $59, cheaper than Aquatread 3 @ $63{which wasn't described as "durable"; "Integrity" was the only other Goodyear brand offered in that size, was cheapest $51]
--------------------
[www.goodyear.ca/tires/tirecatalog/LighttTruckLighttTruckWKHXGRADTL.html]

Goodyear REGATTA 2: 2 STEEL BELTS, I POLYESTER BELT;

Goodyear WORKHORSE Info:

[www.geocities.com/Baja/Dunes/6087/techlowtire.html]

GOODYEAR: Goodyear offers the Workhorse Radial, an all-terrain tire with two steel belts and a polyester cord radial ply construction for light-truck applications. The self-cleaning tread voids provide good traction and handling in mud and snow. The Goodyear Workhorse Radial and the Workhorse bias-ply tire are aimed at the price-conscious buyer who wants Goodyear quality. Information: Goodyear Tire & Rubber Co., Dept. 4WOR, 1144 E. Market St., Ste. 702, Akron, OH 44316, 216/796-2121.
--------------------
[From Goodyear site: www.goodyear.ca/tires/tirecatalog/LighttTruckLighttTruckWKHXGRADTL.html]

WORKHORSE "RADIAL" (Regular version)
(LT235/75R15 is the smallest size available in the WORKHORSE "RADIAL" designation {Smaller sizes are "P" designation})

Two-ply radial polyester cord body Comfortable driving and positive steering response
Optimum tread rubber distribution Uniform treadwear

Dual steel belts Added strength, puncture resistance and durability
Continuous center rib design Smooth ride and long, even wear

(LT235/75R15 is the smallest size available in the WORKHORSE "EXTRA GRIP" designation)

WORKHORSE EXTRA GRIP:

Rugged tread design and tough tread rubber compounds; Excellent tread block resistance to chipping, chunking and tearing, especially on gravel or rocky roads

Natural mold shape, efficient footprint gives Long-lasting wear

Dual steel belts: Outstanding puncture resistance and durability

Two-ply radial polyester cord body Comfortable driving and positive steering response Pinned for metal studs Increased traction in rugged terrain
----------

BF Goodrich


P205/70R15 Radial Long Trail T/A:
TWO KINDS: The "2Q" version: MSPN: 67753; Stock No.: 481-658 Service Disc: 95T (118 MPH) (Higher speed)
The "1Q" version: MSPN: 63349; Stock No: 215-658 Service Disc: 95S (112 MPH)

According to the site, these are "A Traction Rated"
(Same For Both:) 2 Steel Belts, 2 Ply Polyester Carcass; "High-strength Bead Construction" ; 1363 lbs @ 35 psi;
-----------
{epinions Review BF Goodrich Long Trail: http://www.epinions.com/auto-review-2C6E-DEBD111-39EA8B0A-prod1]

Pros: Wonderful wear characteristics. /

Cons: Awful traction and handling on-road; Bad off-road; Squeak and squeal like mad

Full Review:

If you are looking for a tire that will last, this is it. If you are looking for a tire with good traction (on and off road), this is NOT your tire. I have had BF Goodrich Long Trail T/As for about 25,000 miles, and they are wearing wonderfully. That is due (in part) to their very hard compound rubber and the tread design. That very hard compound rubber has some very bad side-effects, to say the least.

At first, the bad handling characteristics of these tires were not apparent. But, after about 10,000 miles, they began to behave differently. Here are my experiences:

In any sort of adverse weather, these tires are VERY slick. Driving in some light rain becomes an adventure, especially with a rear-wheel drive vehicle. I was almost tempted to put my Xterra in 4-Wheel Drive because I was slipping so much. That slippage also translates into bad braking. My Anti-lock Braking System went crazy when I tried a moderately hard stop in the rain. That is not what I want with 4000 lbs. of SUV behind me.

I have also found that these tires are awful in any sort of dirt, sand or mud. The treads quickly fill with mud and dirt, making them slick and unusable. Sand just runs right through them, giving no traction. Definitely something undesirable in an off-road vehicle.

Another unwanted feature that these tires exhibit is the squeal they make. Want to pull into a parking spot? Be prepared for a shrill squeal. Expect the same when you are pulling out of the spot, going around a parking garage, and even when cornering (at almost any speed). That, while annoying, is at least not dangerous.
----------------------------
[http://www.epinions.com/content_59425721988 ]

I think the one negative about this truck is the tire selection. The OE (original equipment) tire size is P205/70R15 95S, which is great if you need a passenger car tire but not so great if you need more off-road performance. After rough roads took two of the five Bridgestone tires that came with the truck, I did a lot of research and decided that I would be better off with more of a light truck/SUV tire. Problem is that very few such tires are available in this size. Fortunately, I found a good one, the BF Goodrich Radial Long Trail T/A, but it took special ordering to get this size. I would suggest that Honda look into getting the tire size upgraded for those of us who actually take our SUVs off the pavement -- a minority among SUV owners, I know, but there are a few of us.
--------
[http://www.carreview.com/Tires/BF,Goodrich,Radial,Long,Trail,T-A/PRD_955_1577crx.aspx }

PAY ATTENTION TO THIS: If you get these tires (BF Goodrich Radial Long Trail) rated with a B traction rating (printed on the sidewall) I understand that they do not handle well on wet roads. (get the A Traction types)
My originals were A traction rated and handled very well (until they hit 55,000 miles and had little tread left). I'm almost to 59k miles and I'm having the same kind put on my truck. The tire dealership ordered my tires and the B traction rated kind showed up...I told them I didn't want them, so now they're getting me the other kind directly from BF Goodrich.
----------
Weaknesses:
SE V6 4x4 trucks and Pathfinders chew up the right tire due to the camber & caster limitations(Note the extra heavy weight on the right front tire of the Trans sport...).
------
[www.nebraskatire.com/lt_truck/bfg_longtrail.htm]

[BF Goodrich describes Long Trail: Superb traction and control, precise steering response and good bruise and puncture resistance provided by two full-width steel belts. ]

"All Terrain T/A" a step up
-----------------
[www.tiresafety.com/construction/const_nav2.htm.]

Passenger Tire vs. Light Truck Tire Construction

Differences between passenger and light truck construction are due to the different uses and operating conditions of light trucks versus automobiles. Light trucks are usually designed to operate in more severe conditions, such as carrying greater loads more of the time and going off-road. Light truck tires may have an extra casing ply, an extra belt, a stronger belt steelcord and/or a larger bead with more sidewall rubber. This is why light truck tires tend to be heavier than passenger tires. Some light truck tires are also capable of higher air pressures and load carrying capacities.
--------------
( "on/off road" designation seems to be best)

Sipe:
To cut across a tire tread to produce biting traction edges.
Revolutions Per Mile (R.P.M.): The number of revolutions that the mounted tired will make in one mile, at rated load and inflation.
_______-
{www.tiresafety.com}

All-Season Tires:
One of the most popular types of tires sold today, all-season radials, are designed to handle dry and wet surfaces, and some amounts of snow.

Performance Tires:
These tires are designed to provide more grip. They let you "feel the road" and drive with confidence. The trade-off is that these tires are generally more expensive, their tread may wear down faster, and some ride comfort is sacrificed. But for enthusiast drivers, performance tires are the choice.

All-Season Performance Tires:
This new breed of tire combines the features of performance tires with the features of all season tires. It meets the needs of high performance cars in dry conditions, but also handles rain and light snow.

Snow Tires:
These tires are specially constructed to grip snowy surfaces. Even the rubber is specially formulated to stay pliable in the cold and give you better traction on icy roads. However, this same construction makes snow tires prone to more rapid treadwear than other tires on dry surfaces.



Reading Tire Sizes:

Example Size: P205/60R-15 :

P - Passenger [Alt.: LT - Light Truck]

205 - Width between the 2 sidewalls in millimeters.

60 - Aspect Ratio - Sidewall height is 60% of the width figure above (60% of 205 in this case).

"R" = "Radial". It can be coupled with the following letter codes:

HR - H=Speed Rating         VR - V=Speed Rating         ZR - Z=Speed Rating

15 - Rim diameter in inches.



Traction Rating: "A". Anything less (e.g., "B") is too slick on wet surfaces.




SPEED RATINGS CHART:

Rating Symbol Speed (mph)
M 81
N 87
P 93
Q 99
R 106
S 112
T 118
U 124
H 130
V 150
W 169
Y 188
Z Over 150



What is the definition of a Light Truck Tire?
This is not as easy as it sounds. We define a light truck tire as any tire line or size which would typically be applied on a light truck vehicle (SUV, pickup, van). As such, it could be an LT-metric tire for use on a Ford F-350 or a P-metric 'light truck' size of a typical tire line such as the P235/75R15 on a Ford Explorer.

In order to properly select Passenger tires for use on Light Truck vehicles (mini pick-ups, mini-vans, recreational vehicles, SUV's, full-sized 1/2 ton pick-ups and vans), the load capacity of the passenger tire at any inflation must be reduced by 9% and the maximum load capacity molded on the sidewall must also be reduced by 9%.

LIGHT TRUCK & "P" PASSENGER TIRE CHARACTERISTICS:
Standard Load
P-Metric
Passenger Tire

BODY AREA: Monoply or 2 ply body
Standard body ply cord
Standard bead construction

BELT AREA: 2 steel belts
Standard steel cord

TREAD DESIGN AND COMPOUND:
Standard all-season pattern
Compound designed for traction and handling

CUSTOMER BENEFITS:
Smooth quiet ride, high level of comfort

Standard Load
P-Metric
Light Truck Tire
BODY AREA: Monoply or 2 ply body
Standard body ply cord
Standard bead construction

BELT AREA: 2 steel belts
Standard or stronger steel cord depending on size
Possible nylon belt edge strips

TREAD DESIGN AND COMPOUND: All-season or all terrain pattern with squared-off shoulder. Possibly deeper tread depth

CUSTOMER BENEFITS:Compound designed for increased wear and less chip/tear Maintains smooth, quiet passenger tire type ride with aggressive Light Truck appearance

Extra Load
P-Metric
Truck Tire
BODY AREA: 2 ply body
Standard body ply cord but with more cords per inch
Heavier, stronger bead construction

BELT AREA: 2 steel belts
Stronger steel cord
Possible nylon belt edge strips
TREAD DESIGN AND COMPOUND:All-season pattern with squared-off shoulder or all terrain pattern both with deeper tread depth

CUSTOMER BENEFITS: Compound designed for reduced chip/tear Offers customers same as above with the ability to increase air pressure for additional load capacity (e.g. towing)

Flotation Sized
Light Truck Tire

BODY AREA:2 ply body
Light Truck body ply cord
Light Truck bead construction

BELT AREA:2 steel belts
Stronger or light truck steel cord (heavy duty)
Possible nylon belt edge strips

TREAD DESIGN AND COMPOUND: Typically all terrain or max traction patterns with beefy shoulder elements. Deeper tread depth.

CUSTOMER BENEFITS:Compound designed for chip/tear resistance Wide aggressive appearance, good off-road capability

LT-Metric: Light Truck
Tire : / BODY AREA: 2 ply body
Light Truck body ply cord
Light Truck bead construction. Bead wire increases with load range

BELT AREA: 2 steel belts
Light truck steel cord (heavy duty) with increased cords per inch per load range

Possible nylon belt edge strips
TREAD DESIGN AND COMPOUND: Highway, all terrain or max traction patterns with beefy shoulder elements. Deeper tread depth. Compound designed for mileage (highway), chip/tear and stone drill resistance

CUSTOMER BENEFITS: Offers customer the ability to increase PSI for additional load capacity, highly cut resistant tread compound, designed for more severe service than P-Metric tires

[Tire Sizes for Trans Sport: http://www.tirerack.com]

LT = Light Truck / "HT" (Guessing) Heavy truck

GoodYear makes a "LT215/75R15" [www.henisetire.com/spec.cfm?model=WRANGLER%20HT&Ttype=LT ]

[www.goodyeartires.com/catalog/products/WRLHTSize.html ]

GoodYear "Wrangler" LT215/75R15 Load range:D Service description: 106Q Sidewall:BSL Rim Width: 5.5- 7.0 / Section Width: 8.5 Measured Rim Width: 6 / Outside Diameter: 27.6 / Max. Load: 2,095 @ 65
----------------

NEW INFO

[Sigma tires Msg]

[http://www.v6z24.com/jbodyforum/viewtopic.php?t=11720]
Posted: Thu Nov 07, 2002 8:17 pm Post subject:

Look for sister brand names, like Sigma tires, or Cavalier tires. Off names but are just sister companies to Michelin etc. I run Sigmas on my car a set of 205/50/15 for $75 Cdn. a piece, and they handle very well summer and winter.
-------------------


Wheels


Seizing Lug Nuts on Aluminum Rims
Changing Wheel Sizes



Aluminum Wheels and Seizing Lug Nuts


A common problem with alloy wheels is seizing lug nuts. The contact of steel and aluminum during the heat and pressure of driving somehow binds the two surfaces. This can leave you in a real spot if you have to change a flat in the middle of nowhere.

Though the manufacturers can't officially recommend the use of Anti-Seize on the lug nuts and posts, in the real world this seems to be the only remedy to the problem. Some comments I've come across on the subject:



www.rv.net/forum/index.cfm/fuseaction/thread/tid/16599255/gotomsg/16600923.cfm

Generally, it's OK to use anti seize, but you have to retighten the lug nuts after 300 miles, and then check every couple of months...

I always used anti sieze compound on them due to the galvanic corrosion caused by aluminum hubs/wheels and steel lug nuts. I have never had any come loose or really over tighten...

www.dieseltruckresource.com/dev/showthread.php?s=6a8b84c5eba14a7f66473c7aabaa9bb7&t=45232&page=3&pp=15

I have used anti seize in the past with no ill effects. I do re-torque my wheels after 300 miles and again 1000 later....

if you torque them down correctly, drive around a few blocks and do it again you should be ok... Just remember to recheck the torque a few miles after you put the wheels back on ... I have used anti-sieze on my lug nuts, torqued them properly, and never had a nut come loose, gall, or strip...I only use anti seize on alum wheels... aluminum based antiseize on the hub and threads is what i use on aluminum wheels, on steel wheels i use the copper based stuff on the hub & threads...As far back as I can remember I have used anti-seize on all my lug nuts. Not only do I use it on the threads, I also put a little on the tapered part of each nut and on any part of the hub that contacts the wheel. I also tighten the nuts once only. So far I have never had a nut come loose or had a wheel seize on the hub, not even after many Canadian salty winters...

For wheel studs I use anti-seize very sparingly because of the dust and mud. Just a little is all you need....Lube with what you want, you have to be a strong guy to twist off a dual wheel lug with a four way. Generally the four way will bend first. I carry a 1 inch T bar and socket to tighten mine if on the road. That is about a 3 1/3 foot bar...use it sparingly because it will attract dirt...

www.wmi.org/bassfish/bassboard/trailers_towing/t7067.htm

Lug nuts on alloy wheels require lower torque than do steel wheels generally...

www.gnttype.org/discus/messages/1/977.html?1014612378

[Freeing seized nuts:] Get a 6 point socket (not a twelve) that will fit the nut tight without the chrome cap. You may need a metric one. If you find one thats close but just a little too small drive it on with hammer. Use impact gun and either remove nut or break stud. You will probably need new studs anyway because of pulled threads. They are easy to change and cheap. It's a good idea to keep spare studs and lug nuts. Do not use an impact gun, especially on aluminum wheels!

www.wmi.org/bassfish/bassboard/trailers_towing/t7067.htm

I've had good results over the years using a propane torch to heat up the nut before going at it too hard with the breaker bar [a long-handled socket wrench] or impact wrench. Play the flame on the outer surface of the nut, keeping it away from the stud as much as possible. Heat for ~1+ minute before attempting to remove nut. When it's good and hot, take the breaker bar and go at it, using a pipe to lengthen the bar if necessary.

web.continuouswave.com/ubb/Forum3/HTML/007950.html

Galling is a cold welding situation. Once two parts have galled, disassembly is difficult or impossible. Galling can be prevented by using an anti-seize compound when reassembling nuts/bolts, and the selection of a gall-resistant alloy.

Medical peroxide works wonders on any exhaust bolts & coca cola is known to free up gallded bolts also.



Aluminum Wheels & Slow Leaks


http://www.trailerlife.com/cforum/index.cfm/fuseaction/thread/tid/17253247.cfm

Slow leaks are extremely common with aluminum wheels. I have a friend that actually got rid of the aluminum wheels on his Chrysler Town & Country van because no matter what the tire shop did, he could not stop the slow leak. So he ordered a set of OEM steel rims and he hasn't had a leak since then. The small leak you have now will probably result in a catastrophic failure in the future. Good 'ol steel wheels work just fine for me!

Aluminum wheels seem to develop slow leaks at the bead, where I've never had that problem with steel.
We have both steel and aluminum, prefer steel. Temp. change, salt and curbs all affect the aluminum.



STUD REPLACEMENT


[STUDS - REPLACEMENT]

http://forums.beyond.ca/showthread.php?threadid=79851
I just replaced my studs on my neon, its quite simple to do but might need some muscle work. first take off your brake calipers, no need to completely remove them just set them on something so they don't hang from the hose, behind the studs there should be a disk type thing with a nitch cut out on it, put that nitch behind the stud your removing, now you can hammer them out which might take awhile depending on how well there, just spray the studs with WD40 or something to loosen them up some. when putting the new studs on make sure the flat part of the back of the stud is facing outward. now use a washer that fits the stud and screw the lug back on the washer prevents the lug from doing any damage to the pad. its hard to screw the stud completely on by hand so get a pipe or something that your tool fits in and use that for more power. do this with all studs.

WOW that easy huh? NOT!!!!!!!!!!!!!!!!!
you have to basically pull the whole hub assembly.......press out the hub itself and then press the studs out.........if you haven't wrecked the bearing which you probably will in the process of removal you will have to buy a new one......and do this to all 4 if you're doing spacers on all wheels.......it's alot of work!!!!!!

It's not bad if you can get the hub assembly off. That's all I did and then I just banged 'em out with a hammer. Took me about an hour for each corner.

LINKS:

www.tundrasolutions.com/forums/tires-and-wheels/44792-anti-seize-lug-nut-studs/ - Message board

Google results: Anti-seize, aluminum wheels



Changing Rim Sizes


[www.birminghamauto.net/cams/news0301.html ]

Lots of Miata folks change wheel size from the original 14 or 15 inch to 15 or 16 inch. No problem if the new wheel/tire combination has sufficient clearance in the fender wells. But what about the new tire size? The speedometer is calibrated to the circumference of the rear tire. Let's say, for the sake of argument, that the circumference of our old 195/50 R15 is 71 inches. We want to go to a 16-inch wheel. That same size tire, 195/50, on a 16-inch wheel will have a larger circumference, which means the speedometer will not display the true speed.

Tire dealers have a chart that shows the size of a larger replacement tire to allow for the proper circumference. But, herein lies the rub. There is no industry or national standard for sizes from brand to brand. Let's say that you are replacing a set of Bridgestone 215/70 R14's with BFG 235/60/R15's, which the chart gives as a replacement to keep the circumference correct. Unfortunately, the BFG may be larger in circumference than the Bridgestone of the same size. The only way to be certain is to measure the circumference of the inflated old wheel/tire combination and find a new wheel/tire combination that, when inflated, matches as closely as possible.
--------------------------

Caravan: 15 inch rim diam, 6.5 inch rim width (2005 Caravan, for reference).

[Anecdotal stuff:] Put some smaller tires on the van so there is less of a load on the drivetrain.... there must be some reason why all those cars that aim for fuel efficiency have those tiny little 14" wheels... In the days of carburators, putting LARGER wheels lowered rpm & thereby increased gas mileage. The reason was that the wider opening of the throttle plates caused better mixing of fuel and air. With fuel injection, this is no longer a factor... larger tires have more friction on the ground, and it takes more energy to keep them going...

Q: Will putting large wheels on a car have any negetive effect? I know that the wider the wheel the beter but will a 16 inch wheel perform beter that a 21 inch wheel? or is there no difference?

A: The added unsprung weight and inertia of the larger wheels can have negative effects on handling, braking, and acceleration. Acceleration will not be as good as with the 16's due to the extra weight and intertia of the larger wheels....dyno tests have shown actual horsepower losses when changing to larger wheels. Handling will also be effected slightly because of the added unsprung weight.

But just bumping up one size, to say 17's, shouldn't effect things nearly as much...especially if they're light-weight rims. I switched from factory 14" steel rims to 15" aluminum rims and I was able to reduce understeer noticeably (due to the stiffer side-wall), but there is a little more road feel transmitted through the steering wheel...and not exactly in a good way. [Possibly no difference changing by 1" - rj]



http://autos.groups.yahoo.com/group/autorepair/message/5845

Steel rims are the only way to go with low- profile tires. She killed both of the front stock soft aluminum mags on very minor potholes at the tune of $400 apiece before we replaced the wheels and stock Goodyear TA's.

http://www.honestjohn.co.uk/forum/post/index.htm?v=i&t=35837

http://ask.metafilter.com/mefi/14728

[Anecdotal stuff:] Put some smaller tires on the van so there is less of a load on the drivetrain.... there must be some reason why all those cars that aim for fuel efficiency have those tiny little 14" wheels... In the days of carburators, putting LARGER wheels lowered rpm & thereby increased gas mileage. The reason was that the wider opening of the throttle plates caused better mixing of fuel and air. With fuel injection, this is no longer a factor... larger tires have more friction on the ground, and it takes more energy to keep them going... steel wheels don't leak as often as alloy wheels. ... What is the point of alloy wheels? They cost more, They break, They corrode, They leak air when old, People steal them.... a car's alloy wheels break on roads which a steel wheel would have survived...



PRICE DIFFERENCES BETWEEN 15" & 16" TIRES


[TIRES]

http://www.ntb.com/tirePricing.do

15 INCH: 215/65/15
Item #: Type: Description: Price:
SG00721655 Sigma Regent 91.99
SG00921655 Sigma Shadow 59.99
GY17321655TVB Gdyr Assurance ComforTred 94.99
FD00521655H Fulda Carat Assuro 66.99
UN00921655 Uni Tiger Paw AS-6000 69.99
SG00521655TOL Sigma Supreme TR 77.99
BF02321655RL BFG Rad T/A 82.99
YH16921655H Yoko Avid H4S/V4S 99.99
GY09221655TBL Gdyr Ultra Tour LS 106.99
MC01321655 Mich Symmetry 106.99
MC08321655 Mich Harmony 115.99
MC19521655T Mich HydroEdge 115.99
16 INCH: 215/65/16
Item #: Type: Description: Price:
SG00721656T Sigma Regent 78.99
GY17321656TVB Gdyr Assurance ComforTred 122.99
BF11921656T BFG Traction T/A 106.99
GY09221656TBL Gdyr Ultra Tour LS 110.99
MC01321656T Mich Symmetry 115.99
MC01721656 Mich MX4 129.99
MC19521656T Mich HydroEdge 139.99



"Dimples" (Undulations) on Sidewall

Edited from: www.tirerack.com/tires/tiretech/techpage.jsp?techid=32

Indentations in the sidewalls of radial tires are a visual condition that will not affect the performance of the tires.

Sidewall indentations (aka "undulations") are common on almost all radial tires. They are more noticeable in large tires with taller sidewalls, and tires using higher air pressure.

Tires are reinforced by encasing individual fabric cords in rubber. Radial ply tires feature one or more layers of cord (depending on the tire's required strength) that run parallel to each other from bead to bead (with each individual cord running up the sidewall, across the tread and down the other sidewall). Because of their "straight across" direction, the overlap where the sidewall cords are lap-spliced may cause a slight indentation.

When the tire is being cured, it is pressed against its metal mold. Then when the tire is mounted on a wheel and inflated, it expands. These overlapping splices may create slight indentations since the lap-splices cannot stretch as much as the rest of the ply material - the splices are the most reinforced area of the tire's sidewall. Since radial tires feature steel cord reinforcing belts under the tread to keep them flat, indentations only appear on the sidewalls.

Protruding Bulges

However, if protruding bulges - rather than indentations - appear on the sidewall of a recently installed tire, it reveals that there is an undesirable gap between some of the body ply cords inside the tire. The tire should be replaced under the manufacturer's "defects in materials and workmanship" warranty.

If a protruding bulge doesn't appear until later in the tire's life, it was usually caused by a road hazard when the cord was injured as the tire struck a pothole, curb or object in the road.


LINKS

NTB

Tire Rack

Town Fair Tire



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