Archive for January, 2008

Chicken strips

Wednesday, January 30th, 2008
Chicken strips are also another name for chicken fingers.

A chicken strip is a sometimes derogatory term used to describe the width of unused tread on the edges of motorcycle tires, typically a sport bike.

A turning motorcycle must lean into the turn. The faster it is going or the sharper the turn, the farther the motorcycle must lean over. For a formula relating speed, turn radius, and lean angle, see Bicycle and motorcycle physics. As the motorcycle leans, the tires’ contact patches move farther to the side causing wear. The chicken strip is the amount of unworn tread caused by a motorcyclist being considered too chicken to go faster through a turn and thereby lean the motorcycle farther over.

This is frequently used as a derogatory term deriving from the term chicken. Hence, chicken strips mark an inexperienced motorcyclist who is afraid to lean a motorcycle far enough to wear the edges of the tire. It should be noted however that due to the handling capabilities of many modern motorcycles, and the vagaries of road condition, it is not advisable to exploit outer handling limits on public roads. On a closed race circuit, however, a rider is expected to use the edges of the tires on turns in order to stay competitive.

Lombard credit

Monday, January 21st, 2008

Lombard credit is the granting of credit by banks against pledged items, mostly in the form of securities or life insurance policies. The pledged items must be readily sellable. Lending is via central banks, in particular the securities ‘eligible for collateral’ which are registered on lists; as a general rule, the Lombard rate (interest rate) is more or less one per cent above discount rate. The pledging of securities means that the credit institutions have the opportunity of acquiring money in the short term from central banks.

One prominent role of “Lombard Credit” is in use by the Federal Reserve System of the United States of America. Traditionally, the Discount Rate, or the rate charged by the Fed to member banks in need of funds (ostensibly to maintain the required reserve ratio), was lower than the target federal funds rate, or the rate charged among banks for the same type of overnight credit. This meant that banks could borrow from the government at a lower rate than they could from each other, which contradicted the Central Bank’s role as a “lender of last resort”. The US was lagging behind many European central banks in this regard, as a Discount Rate lower than the rate typically charged by another bank opened the possibility of arbitrage and thus required extra scrutiny of potential borrowers. Thanks to the work of several bright and influential economists, the Federal Reserve Board of the United States switched to a so-called “Lombard Facility,” in which the Discount Rate is actually higher than the targeted Fed Funds Rate, thus creating an economic incentive for banks to look elsewhere before asking to borrow from the Fed.[1] It is believed that the term “Lombard Facility” refers to the traditional arrangement set forth by the Bank of England, named after Lombard Street.

In the minds of many bank executives and market participants there is still a stigma attached to borrowing from the Discount window, so while the vast majority of federal funds loans occur below the Discount Rate (at or near the Target federal funds rate), there have been instances when banks have paid above-market rates (particularly, rates at or even above the Discount Rate) for federal funds. Some economists speculate that banks take advantage of this arbitrage opportunity by borrowing from the Fed at the Discount Rate and then loaning that money as federal funds to other banks at a higher rate.

Tread

Saturday, January 19th, 2008

The tread of a tire or caterpillar track refers to the rubber on its circumference that makes contact with the road. As tires are used, the tread is worn down limiting their effectiveness in providing traction. A worn tire tread can be replaced using a process known as retreading. The word tread is often used incorrectly to refer to the pattern of grooves cut into the rubber. Those grooves are correctly called the tread pattern, or simply pattern.

Street tires

The grooves in the rubber are designed to allow water to be expelled from beneath the tire and prevent hydroplaning. The proportion of rubber to air space on the road surface directly affects its traction. Generally there is a tradeoff of tread friction capability; deeper patterns often enhance safety, but simpler designs are less costly to produce and actually may afford some roadway noise mitigation. Tires intended for dry weather use will be designed with minimal pattern to increase the contact patch. Tires without any tread patterns are known as slicks and are generally used for racing only, since they are quite dangerous if the road surface is wet.

Street tires will also include wear limit indicators in the form of small raised bridges within the grooves. When the tread is worn down enough that the limit indicators make contact with the road, the tire is deemed to be at the end of its service life. Brake pads use similar indicators in the form of notches on their surface that disappear when they are used.

Off-road tires

Off-road tires used in mud or dirt feature individual knob patterns to allow the tire to bite into the surface and leverage the sides of the tread to get a better grip. Given the smaller contact patch, these tires tend to wear quickly when used on asphalt.

Mountain bike & motorcycle tires

Mountain bike and some motorcycle tires feature tread patterns similar to off-road tires used on cars and trucks but may sometimes include an unbroken tread that runs along its center. This feature provides better traction and lower noise on asphalt while the bike is vertical while retaining its ability to provide lateral grip when the bike is leaning.

Caterpillar tracks

Caterpillar tracks such as those used on military tanks or construction machines have metal track segments which may be rubber-coated. They usually do not feature tread patterns, because these would offer little additional grip given the weight of the tracked vehicle.

Blowing Snow Advisory

Friday, January 11th, 2008

See Severe weather terminology for a comprehensive article on related weather terms.


A Blowing Snow Advisory is issued by the National Weather Service of the United States when wind driven snow reduces surface visibility and possibly hampers traveling. Blowing snow may be falling snow, or snow that has already accumulated but is picked up and blown by strong winds. A similar bulletin is issued by Environment Canada’s Meteorological Service of Canada but as a Warning.