# Why doesn't anyone use inboard brakes anymore? **URL:** \ **Category:** Factual Questions\ **Created:** [May 27, 2008, 11:15pm UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829 "2008-05-27T23:15:24Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Throatwarbler\_Mangrove](https://avatars.discourse-cdn.com/v4/letter/t/8c91f0/32.png) [@Throatwarbler\_Mangrove](https://boards.straightdope.com/u/Throatwarbler_Mangrove)\ **Post date:** [May 27, 2008, 11:15pm UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/1 "2008-05-27T23:15:24Z")
As the title states, inboard brakes were common on Jaguars, Citroens and Alfas in the past, but no one uses them anymore. Some reason for this? Partly related, here’s a guy in my home town who has a [Landrover with a Nissan 300ZX turbo engine, Citroen DS hydropneumatic suspension, Jaguar differential and inboard brakes in the rear and Nissan front differential.](http://www.citroen-ds-id.com/ds/Landrover_with_Cit_Suspension.html) ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [May 28, 2008, 12:41am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/2 "2008-05-28T00:41:49Z")
They’re more complicated to design and harder to service than outboard brakes. Combine that with what is probably precious little demand for them, and I imagine the decision-makers involved figured there wasn’t much point in keeping them. Subaru had a truck with inboard **drum** brakes. Boy, was that fun to work on. :rolleyes: ---
**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\ **Post date:** [May 28, 2008, 12:44am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/3 "2008-05-28T00:44:01Z")
I would add, expense: a rear brake job (pads only) on a Jaguar XJ6 ran to $900! ---
**Author:** ![Throatwarbler\_Mangrove](https://avatars.discourse-cdn.com/v4/letter/t/8c91f0/32.png) [@Throatwarbler\_Mangrove](https://boards.straightdope.com/u/Throatwarbler_Mangrove)\ **Post date:** [May 28, 2008, 12:57am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/4 "2008-05-28T00:57:48Z")
I understand that they were more troublesome to service, but surely for an expensive luxury car, it would have been worthwhile for the reduced unsprung weight and smoother ride? ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [May 28, 2008, 2:45am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/5 "2008-05-28T02:45:19Z")
[QUOTE=Throatwarbler Mangrove] I understand that they were more troublesome to service, but surely for an expensive luxury car, it would have been worthwhile for the reduced unsprung weight and smoother ride? [/QUOTE] My thought is that the reduced unsprung weight didn’t make a significant difference and most people didn’t notice a smoother ride. On paper and in testing it could be shown that there were advantages, but at the seat of the pants I’m guessing the great majority of drivers couldn’t detect said advantages. None of the customers or racing enthusiasts I knew ever even mentioned inboard brakes, much less praised them. ---
**Author:** ![onedayfishsale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/onedayfishsale/32/4398_2.png) [@onedayfishsale](https://boards.straightdope.com/u/onedayfishsale)\ **Post date:** [May 28, 2008, 2:55am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/6 "2008-05-28T02:55:31Z")
Also consider the forces that need to be transmitted during full braking. This would certainly require stronger axles and universal joints, since the brakes no longer act directly on the hubs. I seem to remember that inboard brakes are not DOT-approved (in the US), but don’t have a citation for this. ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [May 28, 2008, 2:56am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/7 "2008-05-28T02:56:23Z")
The axle serves as a torsion spring between the brake and the wheel. This is asking for a chatter problem. , especially at low speeds. ---
**Author:** ![onedayfishsale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/onedayfishsale/32/4398_2.png) [@onedayfishsale](https://boards.straightdope.com/u/onedayfishsale)\ **Post date:** [May 28, 2008, 3:02am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/8 "2008-05-28T03:02:31Z")
[QUOTE=One Day Fish Sale] I seem to remember that inboard brakes are not DOT-approved (in the US), but don’t have a citation for this. [/QUOTE] (Missed the edit window.) I think the reason I think this is because some 4WD enthusiasts use Rockwell-style heavy truck axles on their rigs. Many choose to replace the outboard drum brakes with a pinion disc brake which, from what I understand, isn’t legal for on-road use. This is, admittedly, quite a bit different than the inboard brakes the OP has in mind. ---
**Author:** ![Fubaya](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@Fubaya](https://boards.straightdope.com/u/Fubaya)\ **Post date:** [May 28, 2008, 3:04am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/9 "2008-05-28T03:04:39Z")
You can still get a vehicle with inboard brakes. The Hummer H1 has to use them because of it’s portal axles. ---
**Author:** ![R.P.McMurphy](https://avatars.discourse-cdn.com/v4/letter/r/7993a0/32.png) [@R.P.McMurphy](https://boards.straightdope.com/u/R.P.McMurphy)\ **Post date:** [May 28, 2008, 3:25am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/10 "2008-05-28T03:25:53Z")
CMIIW but IIRC the Audi 100 (the early Audi that was sold in the US) had inboard brakes. They used the “unsprung weight” as a selling point. Trouble is, although unsprung weight is a consideration, there are a lot of other engineering factors that determine ride characteristics. Unsprung weight isn’t the magic bullet to a sublime ride. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [May 28, 2008, 3:58am UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/11 "2008-05-28T03:58:41Z")
[QUOTE=ralph124c] I would add, expense: a rear brake job (pads only) on a Jaguar XJ6 ran to $900! [/QUOTE] No it didn’t, I worked at a Jag dealer in the mid 1980s, and a pad replacement was no where near that cost. IIRC the charge was 1 hour labor (same as the fronts) @$65/hour, and the pads were probably about $40. Just over a Ben Franklin and you were good to go. I did hundreds of these during my time at that dealer. Now if the discs went metal to metal, that was a bit spendy. Probably 5 or 6 hours labor. I only did this job a couple of times. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [May 28, 2008, 12:33pm UTC](https://boards.straightdope.com/t/why-doesnt-anyone-use-inboard-brakes-anymore/450829/12 "2008-05-28T12:33:34Z")
[QUOTE=Fubaya] You can still get a vehicle with inboard brakes. The Hummer H1 has to use them because of it’s portal axles. [/QUOTE] The H1 is no longer for sale.