How we build price tables and tire dates

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Posted-price tables

A few pages show prices that shops publish on their own websites: the out-of-province inspection price pages and the winter-tire changeover prices. They are built the same way.

  • From the shop’s own website only. A price goes in only if the shop states it on its own site for exactly that job. Nothing from other directories, coupon sites, reviews or phone calls, and nothing inferred from a price for some other job.
  • Copied as posted. The amount, whether it is a “from” price, and what the page says about tax. Where the page says nothing about tax, the table says “tax not stated” rather than guessing.
  • Dated and linked. Every row links to the page the price was read on, and the table shows the date the prices were checked. A price is only as current as that date; confirm it with the shop.
  • Lowest first, with a summary. Inspection prices are listed from lowest to highest, and the summary above the table gives the lowest, the median and the highest. The median, not an average, so one unusual price cannot move it much. The changeover prices are summarised as a range, lowest to highest.
  • Thin pages stay out of search. A city’s inspection price page with fewer than 5 posted prices still works for anyone who follows a link, but asks search engines not to index it and is left out of our sitemap.

Winter-tire switch dates

The winter-tire tool gives the typical day to put winter tires on and take them off. It is worked out like this:

  1. Take the monthly mean temperatures from Environment and Climate Change Canada’s Canadian Climate Normals 1991–2020: Calgary (Airport). The same station, Calgary (Airport), is used for all four towns, and the other towns’ pages say how far they are from it.
  2. Place each month’s mean at the middle of its month, and draw a straight line from one midpoint to the next (linear interpolation), December running on into January.
  3. Read off the day the line falls to 7 °C in the autumn and the day it climbs back above it in the spring. Below about 7 °C, winter tires grip better than all-season or summer tires, which is the rule of thumb Transport Canada and the Tire and Rubber Association of Canada give.

Monthly normals are thirty-year averages, so the date is a typical year’s. The tool pages also show this week’s forecast, because a cold snap does not wait for the average.

Quote prices stay private

When you ask for quotes, each shop’s price is sent to you, for your request. Quote prices are never published on any page, and never used to build the price tables above. What a shop sees about you before you book is in the Privacy Policy.

How these pages are written

Guides and price pages are drafted with AI assistance. Every fact is then checked against the source the page cites, and the page shows the date that was done. Where a source does not say something, the page does not say it either. Data sources and licences lists what the site draws on.

Found a mistake? Email hello@garagemap.ca.