calliper placement

[rohitkj]

why are callipers placed on the side of the rotor...why not below....is there a specific reason to this....

[rohitkj]

why are callipers placed on the side of the rotor...why not below....is there a specific reason to this....

[PatClarke]

The calipers can be placed wherever you wish. There are benefits and drawbacks to each mounting position, but generally packaging determines the position.

Pat

[JT A.]

Its good to think about CG/Yaw moment of inertia effects, but what ends up being most important are the practical reasons for positioning. Things like packaging and bleeder valve access.

[Peter7307]

Some production cars have had calipers mounted at the lowest position when the brakes have been inboard. Citroen DS and GS series had them.

From a practical point of view they were not a great success. They collected water stones and road grit and were difficult to bleed when needed. In the Citroen case the cars also height adjustable suspension so as the car weight compressed the suspension after the engine was stopped the calipers became more and more vulnerable to any objects immediately below them.
The calipers were inboard next to the diff and fed cooling air from scoops under the front bumper. These also were often damaged when the car descended and so limited the amount of air available.

Technically very advanced but sadly difficult to live with in day to day ownership - speaking from personal experience!

Peter.

[billywight]

Draw up a free body diagram to see some interesting bearing load changes vs. caliper placement...

[Peter7307]

I forgot to mention the reason Citroen placed the calipers inboard was a direct result to do with the suspension geometry.

Citroen at the time used double arm suspension at the front and wanted to have the outer ball joints vertically in line with the tyre centre contact point which made packaging discs at the wheel end of the driveshafts difficult.
The solution was to move the brakes inboard.

Peter.

[windsoreng]

Like Pat mentioned, there are pros and cons to each location however packaging is often the greatest constraint. The packaging issue is often related to tie rod location. If you look at the vast majority of cars on the road today, if the caliper is mounted rear of the upright, the tie rod is forward of it, and vice versa.

Agreed with Billy as well...a free body diagram will also give you lots of insight into your question...

[onemaniac]

Brake calipers usually(not all) have bleeding valves on one or either ends of the length of the caliper. That being said, it's probably a practical decision to put the calipers on the side so you don't have to take off the calipers to bleed the brakes.

[wagemd]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by onemaniac:
... That being said, it's probably a practical decision to put the calipers on the side so you don't have to take off the calipers to bleed the brakes. </div></BLOCKQUOTE>

Almost an understatement. Can be a REAL pain in the butt...