Talk:Turning radius

Confused or confusing definitions word choice: "...curb-to-curb turning circle" IS NOT the distance traveled by wheels.

For the sake of those Wikipedia readers who come to this page not already knowing the right way to define the technical term "turning radius", please consider the meaning and construction of the second paragraph, copied here:

_{Two different measurements can be quoted for a vehicle. A curb or curb-to-curb turning circle will show the distance traveled by the wheels. The wall or wall-to-wall turning circle will include an allowance for the width of the whole car, including the overhang of the bodywork. For example, a van may have been quoted as having a turning circle (in meters) of 12.1(C)/12.4(W).}

My primary objection is to the definition in the second sentence--it is wrong--because it defines the turning distance as the one traveled by the wheels, which could only mean that the turning circle distance is the length of the arc that the wheels follow when turning the vehicle 180 degrees around. This is one of those misleading "sounds right but it is wrong" definitions. The distance measurement that this article needs to focus on is the straight-line distance to/through the center of the turning circle, NOT the curved line distance connecting the start and end points of the 180 degree turn.

My second objection is to the comparison between curb-to-curb and wall-to-wall turning circles. This could be a simple comparison that tells the reader what is the same and what is different between these two measurements of turning radius. As it stands, the definition of wall to wall is obscured by weak writing.

I've made these two changes to the topic text.

Hth,

Writealong (talk) 06:26, 22 November 2013 (UTC)writealong

What is Curb to Curb Turning Circle ???

If the Car Starts parallel to the right curb, almost touch the curb, and then turns its wheels hard left, it will be able to do ONE U-turn past the 2nd curb, ALTHOUGH if it continues to do a 360 degree turn, then its right front tire will bump the right curb, UNLESS the starting position of the car is not 1 inch from the 1st Curb, but 12 inches for example, and then the Car can do a complete 360 degree turn, with the front right tire being able to pass both curbs.

So... does Curb to Curb Turning Circle allow ONE U-turn, or a complete 360 degree turn ???

But in the U Turn, is the Diameter from the outside right wheel to the outside right wheel? In essence how far apart the curbs would have to be so that you do not hit them? Example, you have a car with a 30" curb to curb diameter and the curbs are 31" apart. If you start flush to the curb on the right side, you should be able to do U Turn with 1 inch to spare.

- Look for God —Preceding unsigned comment added by 72.220.62.110 (talk) 19:47, 10 December 2010 (UTC)

A list?

would it be useful to start compiling a list of turning radiuses on cars here?

No. Wikipedia is not an indiscriminate collection of information. Besides, such a list would be incredibly long, impossible to maintain and of limited encyclopedic value; and how would you propose providing references for each entry?

However, there may be a place for notable deviations from the norm if it can be referenced - for example, we all know thew cliché that oil tankers have a very large turning radius and I have read that London's Black taxis have a particularly tight turning radius compared to other vehicles on british roads. Astronaut (talk) 16:08, 19 April 2009 (UTC)

Is it true to suggest that the largest turn radius (on Earth) equals 10 Mm, or 5.400 NM? —Preceding unsigned comment added by 85.164.222.225 (talk) 13:50, 24 May 2009 (UTC)

turning radius equation for a bicycle

In high school, I formulated an equation that relates the distance between the centroids of the front and rear wheels and the "front wheel turning angle" of a bicycle. The equation explicitly gives the radius of the circular path. Should I include a section about regarding this? —Preceding unsigned comment added by Yoshi12 (talk • contribs) 03:37, 22 October 2009 (UTC)

Totally incomplete article, it only talks about cars, and completely ignoring other vehicles

Even when the discussion on cars is "adequate", and even mentioning "airplanes", the article does not contain ANY information on them!. Turning radius is a very important concept in airplanes and other aerial vehicles, specially in combat ones. Amclaussen. — Preceding unsigned comment added by 192.100.180.19 (talk) 17:03, 3 February 2012 (UTC)

Preferred Nomenclature

If "Turning Circle" is the more accurate nomenclature for Turning Radius, as is posited by this article (The term turning radius is a misnomer, since the size of a circle is actually its diameter, not its radius. The less ambiguous term turning circle is preferred) why does a Wikipedia search on Turning Circle redirect to *this* article, Turning Radius? Shouldn't Turning Radius link back to Turning Circle? Cyphoidbomb (talk) 04:24, 30 April 2012 (UTC)

It's very confusing that this article is titled "turning radius", when the more common term is "turning circle" and the article goes on to say that "turning circle" is more accurate. 203.59.152.230 (talk) 09:52, 16 June 2015 (UTC)

This may also have to do with language differences -- trunk, hood, and gas, vs boot, bonnet, and petrol e.g. Where I live -- western USA, I only have heard turning radius, which is incorrect mathematically, (see above) but is understood as a driver. GeeBee60 (talk) 13:43, 30 September 2016 (UTC)

I don't understand why the term circle more accurate than radius. If anything, circle is more ambiguous since it can refer to for example radius (r), diameter (2r) or circumference (2 pi r). What seems to be really important here is curb-to-curb versus wall-to-wall, or is there something I am missing? Sauer202 (talk) 11:01, 14 February 2021 (UTC)

Errors

I'm not sure there is anything correct in this article.

'Turning radius' seems to be a term used but I do not know what it means. My guess would be that it is the radius of a turn or curve and in the case of a vehicle, the distance between the theoretical centre of a curve and a point on the vehicle situated at half the vehicle width and aligned with the rear wheels.

Figures quoted in the text appear to be turning circle figures (i.e. circle diameter), not radius.

The diagram has a number of issues too. — Preceding unsigned comment added by 79.64.1.38 (talk) 00:26, 18 August 2017 (UTC)

Turning radius is an established term within the car world. The radius of a circle is mathematically defined as half its diameter. Radius is also used about the curvature of corners in general (not just circles) in various scientific and technological disciplines, i.e. technical drawings. As I mentioned above, I think radius is a more precise term than circle. Merely saying circle is ambiguous since since it can refer to for example radius, diameter or circumference. Sauer202 (talk) 11:06, 14 February 2021 (UTC)

Since these two articles are on the same subject I have performed the merge of Turning circle into Turning radius, and tried to give a short explanation of the difference between diameter and radius. Sauer202 (talk) 11:35, 14 February 2021 (UTC)

Turning circle merged into Turning radius

Since these two articles were on the same subject I have performed the merge of Turning circle into Turning radius, and tried to give a short explanation in the introduction about the difference between diameter and radius. Sauer202 (talk) 11:39, 14 February 2021 (UTC)

Requested move 15 February 2021

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: Not moved. (closed by non-admin page mover) -- Calidum 04:41, 22 February 2021 (UTC)

---

Turning radius → Turning diameter – From my understanding, turning diameter seems to be the more mathematically correct term of this measurement according to usage. If this is correct, it makes sense to move the article to Turning diameter. Anyway, I have edited the article to try to highlight the difference between radius and diameter, as well as the apparent confusion within parts of the auto industry. Sauer202 (talk) 18:20, 15 February 2021 (UTC)

• Oppose radius is the overwhelming COMMONNAME in print sources, according to NGRAMS[1] I'm guessing that more sources actually do talk about the radius than the diameter. (t · c) buidhe 18:52, 15 February 2021 (UTC)

While acknowledging that in British English "turning circle" is the dominant term. NGRAM here or that if we go back at bit to English Corpus 2009 then turning radius and turning circle are more or less equal [2]. GraemeLeggett (talk) 19:34, 15 February 2021 (UTC)

• Oppose. The current title of this article is presently the most common name for this topic. Rreagan007 (talk) 19:49, 15 February 2021 (UTC)
• Comment: Policies aside, I feel it is weird to call it radius when the measurement indeed seems to refer to a circle diameter? And turning circle, as laid out in the article, is very ambiguous, as it does not indicate whether the measurement is about the radius, diameter, circumference or anything else. Turning diameter seems to be more technically correct in all cases, and the word seems to at least be used by Audi.(p. 39, "Turning diameter, curb-to-curb") To me it seems common sense to use turning diameter (unless I have misunderstood the technical terms in this article). Sauer202 (talk) 21:32, 15 February 2021 (UTC)

Turning diameter may also immediately seem to be a more useful measurement. For example it tells how wide a road, parking lot, etc., needs to be in order for a car with a given turning diameter to be able to make a U-turn. Or the other way around: How little turning radius a car needs to have in order to be able to make a U-turn on a given road width (for example 6.5 meter wide road). The turning radius does not immediately seem as useful in practice. Sauer202 (talk) 21:40, 15 February 2021 (UTC)

Here is a policy from Wikipedia:Article titles which may be used to support using turning diameter instead of turning radius or turning circle: When there are multiple names for a subject, all of which are fairly common, and the most common has problems, it is perfectly reasonable to choose one of the others. Sauer202 (talk) 21:51, 15 February 2021 (UTC)

• Oppose. have never heard the target name used Cas Liber (talk · contribs) 11:44, 16 February 2021 (UTC)

This corresponds with the NGRAMS argument as laid out by GraemeLeggett. Turning circle and turning radius indeed are the most used terms, but each have their problems. What do you think about those arguments? I see this as a somewhat similar situation as with for example the data cap article - many refer to it as a bandwidth gap, but in reality it is the data - not the bandwidth - which is capped, making data gap the correct title. In the same manner, using turning radius as presented in this article is mathematically erroneous, and turning circle is ambiguous - what measurement does a circle represent? It can mean several, i.e. radius, diameter, circumference, all giving different numerical values. Using turning diameter clearly seems like the best option to me, and it seems to be used by at least one reputable source: Audi. Can we have an academic discussion about what the terms represent first? It appears to me that all three terms are used to refer to the turning diameter. Sauer202 (talk) 14:34, 16 February 2021 (UTC)

I would add that the turning circle is both the path that is swept in the manoeuvre and when a value is mentioned the size of the path. Generally circles are described by their diameter unless radius is specified. Compare "Cut a 4cm circle in the piece of wood" versus "draw a circle with a radius of 5cm". I would also be aware that limiting your sources to automobiles when "turning circle" is relevant to combat aircraft (eg the Spitfire having a tighter turn than a Bf 109) and ships. GraemeLeggett (talk) 15:48, 16 February 2021 (UTC)

@GraemeLeggett: I am not sure if I am understanding you correctly, but are you arguing that a "circular measurement" primarily should mean diameter? In my world and mathematically speaking, the size of a circular path is the circumference, so it is ambiguous if "turning circle" is used to indicate the diameter. The most important thing we do here on Wikipedia is to disambiguate, so in my opinion we should avoid ambiguous terms. Thus my recommandation to use turning diameter as the primary name, as well as mentioning other terms and their corresponding ambiguous meanings and natural misunderstandings that can arise due to conflict between mathematical definitions and automobile jargons. Sauer202 (talk) 17:17, 16 February 2021 (UTC)

• Oppose per common name Red Slash 19:41, 16 February 2021 (UTC)

@Buidhe: @GraemeLeggett: @Rreagan007: @Casliber: @Red Slash: No one is arguing that turning radius and turning circle aren't the most common names. However, I kindly ask for your input on the other arguments laid out for using turning diameter. Sauer202 (talk) 07:06, 17 February 2021 (UTC)

@Sauer202: "No one is arguing that turning radius and turning circle aren't the most common names" - then what is the point of this proposal? Article titles must follow the common name as used in reliable sources. From Wikipedia:Article titles: "Article titles are based on how reliable English-language sources refer to the article's subject". We cannot simply make up a name because we dislike the names used by reliable sources. A7V2 (talk) 11:54, 19 February 2021 (UTC)

• Oppose. Clear common name, whether it's accurate or not. -- Necrothesp (talk) 14:15, 19 February 2021 (UTC)

In my mind, Wikipedia should aim to mention common names, but also to be technically correct and to disambiguate. As I mentioned above, Wikipedia:Article titles also states that When there are multiple names for a subject, all of which are fairly common, and the most common has problems, it is perfectly reasonable to choose one of the others. Turning diameter is the only term which is sourced at the moment, and it is cited from an Audi brochure.

Overwhelmingly many here have defaulted to "oppose" without going into a discussion on technical correctness or ambiguity. The use of either turning radius or turning circle on the basis of being common names are valid responses, but I think is a bit lazy when other points and arguments have been laid out and remain un-answered. It does not move the discussion forward.

Normally Wikipedia should use common names, but not necessarily when common terms in everyday language are technically wrong. For example, weight and mass are used interchangeably by many in everyday talk, but have different technical meanings. That technical difference is important.

It seems like turning radius in the car world is code speak for turning diameter, but I like to "call it what it is", and guess others think so too?

What I ask is: (1) read the article as it stands now (as I assume everyone have done), (2) read the arguments for and against, and (3) please join in a technical discussion so that a common understanding can be reached about the topic. Only then it makes sense to discuss the name. So far, only GraemeLeggett has contributed with technical interpretations on the subject.

The article as it stands now is a bit messy and ambiguous. I've tried to contribute and clear things up, but my knowledge on the topic is limited. Sauer202 (talk) 16:38, 19 February 2021 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.