# Gas Prices: $4.15, $4.25, $4.35 **URL:** \ **Category:** Factual Questions\ **Created:** [March 17, 2013, 10:01pm UTC](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202 "2013-03-17T22:01:19Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![Gagundathar](https://avatars.discourse-cdn.com/v4/letter/g/a183cd/32.png) [@Gagundathar](https://boards.straightdope.com/u/Gagundathar)\ **Post date:** [March 19, 2013, 10:28pm UTC](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202/21 "2013-03-19T22:28:26Z")
My favorite station here in eastern rural Tennessee has two grades, 87 octane and 93 octane. What is genuinely odd is that 87 goes for $3.50 and 93 goes for $4.00. Back in Atlanta, the gas prices typically jumped by 10 cents per grade. Which makes no sense whatsoever. ---
**Author:** ![Delayed\_Reflex](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/delayed_reflex/32/3172_2.png) [@Delayed\_Reflex](https://boards.straightdope.com/u/Delayed_Reflex)\ **Post date:** [March 19, 2013, 10:42pm UTC](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202/22 "2013-03-19T22:42:56Z")
The differentials per grade are more like 5-7 cents per _liter_ here in Canada, which is more like 19-26 cents per gallon - again typically with 3-4 grades. If I were to guess, the price differential is probably more a form of easy price discrimination rather than reflective of the difference in refining costs. ---
**Author:** ![Fubaya](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@Fubaya](https://boards.straightdope.com/u/Fubaya)\ **Post date:** [March 19, 2013, 11:14pm UTC](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202/23 "2013-03-19T23:14:18Z")
To answer the original question, premium gas does take more effort to refine. When you refine gas, you get carbon chains that can be split to make different things like propane, butane and gasoline. Heptane contains seven carbon atoms in a chain and octane has eight. I’m not sure why heptane is used in gas but 87 octane fuel has 87% octane and %13 heptane while 93 octane has only 7% heptane. Octane compresses well and heptane doesn’t. I don’t know about the science of refining but octane supposedly requires more effort than hectane to produce and I guess you’re getting more of the good stuff and less of the junk with higher octane gas. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [March 20, 2013, 2:54am UTC](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202/24 "2013-03-20T02:54:27Z")
> [@Fubaya](#): > > To answer the original question, premium gas does take more effort to refine. When you refine gas, you get carbon chains that can be split to make different things like propane, butane and gasoline. Heptane contains seven carbon atoms in a chain and octane has eight. I’m not sure why heptane is used in gas but 87 octane fuel has 87% octane and %13 heptane while 93 octane has only 7% heptane. Octane compresses well and heptane doesn’t. I don’t know about the science of refining but octane supposedly requires more effort than hectane to produce and I guess you’re getting more of the good stuff and less of the junk with higher octane gas. Yeah, but like I said above diesel fuel is significantly \*less \*refined than all grades of gasoline, and yet it’s \*more \*than the most expensive premium grade! ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [March 20, 2013, 3:29am UTC](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202/25 "2013-03-20T03:29:30Z")
> [@Hail\_Ants](#): > > Yeah, but like I said above diesel fuel is significantly \*less \*refined than all grades of gasoline, and yet it’s \*more \*than the most expensive premium grade! Less refined, but diesel fuel still costs more than gasoline to produce and distribute. Deisel fuel has to be an ultra-low sulpher type in the US, much less is produced, and the fuel demand fluctuates seasonally because of it’s use as fuel oil. Gasoline also is produced in greater volume and is sold at a lower margin. As far as the prices, the margin on gasoline is so low that it’s just a convenient means of pricing. You set your price for regular, and just add 10 cents and 20 cents for the higher grades. It changes so frequently it wouldn’t be worth calculating to any greater precision. ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [March 20, 2013, 7:31pm UTC](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202/26 "2013-03-20T19:31:43Z")
Anyone know the percentage of vehicles in the US that use regular gas (87) vs vehicles that use Premium? ---
**Author:** ![steviep24](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@steviep24](https://boards.straightdope.com/u/steviep24)\ **Post date:** [March 20, 2013, 10:31pm UTC](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202/27 "2013-03-20T22:31:30Z")
I went to a Mobil today and the prices are 20 cents apart. $3.89, $4.09 and $4.25 Grades are 87 (regular), 89 (special) and 93 (super). Pumps are of the one hose style. ---
**Author:** ![steviep24](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@steviep24](https://boards.straightdope.com/u/steviep24)\ **Post date:** [March 20, 2013, 10:45pm UTC](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202/28 "2013-03-20T22:45:33Z")
And I notice a mistake in my last post. Price for Super is $4.29 [Previous page](https://boards.straightdope.com/t/gas-prices-4-15-4-25-4-35/653202.md?page=1)