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.
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:
I would add, expense: a rear brake job (pads only) on a Jaguar XJ6 ran to $900!
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?
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.
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.
The axle serves as a torsion spring between the brake and the wheel. This is asking for a chatter problem. , especially at low speeds.
(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.
You can still get a vehicle with inboard brakes. The Hummer H1 has to use them because of it’s portal axles.
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.
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.
The H1 is no longer for sale.