tjkj2002 wrote:
onthehunt wrote:
Quote:
If you look a the big rigs they have been running "pizza cutter" tires for years,but now most are switching to "super single's" which increase load capicity and stability from a wider tire that the "pizza cutters" do not give them.
The reason for the switch is lighter weight and most importantly one less tire to pay Federal Excise Tax on. FET is around $30 a tire for class 8 semi tires. Figure in fleet munbers and it doesn't take long to save a whole lot of money.Also,you have more load capacity with two seperate tires instead of one.
Not true,go look at a semi truck with duals,they have 2 weights on them,one is for single tire use and the other is when used in a dual set-up.The single use lists more weight it can handle compared to super singles.Super singles are more expensive then 2 regular tires but has more load capicity and more contact patch then 2 regular "duals".
You both are wrong. 1) try driving a semi with super singles compared to duals. Stability is decreased in the SS rubber. 2) Doesn't matter if SS tires have a higher weight rating. You can only have 32K# on any set of dual axles unless they are spread. Whether you are running duals or SS, you are still limited by state laws on how much axle weight you can have. Only a limited number of fleets are running them, not "most" as you stated. The primary carriers that are doing the switch are those that do not tend to run "heavy" such as FedEx. Keim out of Sabetha, KS has run them for years (probably the first fleet to run them consistently), but not without problems. On a spread axle trailer, SS tires get eat up faster than traditional duals.
SS offer decreased rolling resistance compared to duals, and therefore a little bit in fuel savings which is the primary reason they are being considered by some fleets. But they are not good for all applications. If you are doing over sized loads (I did not say over weight), the stability is less with SS. If you are doing off road hauling (i.e. rock and logs), SS will be a problem. Heavy haul application carriers are not switching to them at all.
For a traditional over the road application, they show promise. They are more cost effective, but require increased attention to avoid premature wear, and since most fleets drop and hook trailers around the country, tire maintenance tends to get overlooked. We have tried them on a few applications and have not had a good enough experience to justify switching totally. If they are so good, then why are they not offered as an option on a Dodge, Ford, or GM dually pickup rear axle? I have gotten over 300K miles (with a few 400K miles) on semi duals, but have never gotten beyond 250K on a similar equiped semi with SS rubber. They have to flex more than traditional 22.5 LP rubber and therefore generate more heat which is a tire killer.
I wouldn't make comparisons to what should be on a Liberty with what should be run on a semi. Heck, if the truth be known, ag tractors use a less wide tire and mount them in duals or triples. They do this to get two benefits in one... a smaller tire width to increase bite and mounting them in dual or triple applications to decrease the weight per square inch of ground pressure to reduce soil compaction The wider tire argument for flotation works well in some applications, but in general just is a fashion statement that offers no real benefit for the average driver and increases rolling resistance. Even wide mud tires have a place, but usually not for the average driver. I suppose if you are trying to imitate Nascar and corner at 80-100 mph, the wider tire would be of benefit on the road.
This is why we have so many varieties of tires... so many individual applications. Man.. What a Country!!
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Now I'm irritated that most of the tires I've bought (these included) are only rated for 50k miles! If the technology exists to make them last that much longer... We would have a lot less of a tire-disposal problem in this country!
