# Odd hub tubes on South American Semi wheels

**URL:** <https://boards.straightdope.com/t/odd-hub-tubes-on-south-american-semi-wheels/238403>\
**Category:** Factual Questions\
**Created:** [April 5, 2004, 6:41pm UTC](https://boards.straightdope.com/t/odd-hub-tubes-on-south-american-semi-wheels/238403 "2004-04-05T18:41:12Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\
**Post date:** [April 5, 2004, 6:41pm UTC](https://boards.straightdope.com/t/odd-hub-tubes-on-south-american-semi-wheels/238403/1 "2004-04-05T18:41:12Z")

</div>

[This thread](http://boards.straightdope.com/sdmb/showthread.php?t=249244) reminded me of a question I had in Brazil:

I noticed that almost all of the semis there have beautiful chromed tubes going from the body of the truck to the center of the wheel hubs. What are these for? Why don’t North American semis sport the same tubes?

---

<div class="post-metadata">

**Author:** ![Earthling](https://avatars.discourse-cdn.com/v4/letter/e/90db22/32.png) [@Earthling](https://boards.straightdope.com/u/Earthling)\
**Post date:** [April 5, 2004, 6:57pm UTC](https://boards.straightdope.com/t/odd-hub-tubes-on-south-american-semi-wheels/238403/2 "2004-04-05T18:57:58Z")

</div>

Brazil!

I had the same observation and question while I was there. The engineer I worked with told me it’s a central tire inflation system. Evidently Hummers (at least the original, military-issue ones) also [have them](http://www.lynchhummer.com/componentpages/CTI.html). Don’t know why American semis aren’t so equipped.