How important is brake disc diameter as opposed to...

[DannyVTS]

.. the brand of the discs..

I have 2 Saxo VTS's.

One has 246mm Red Dot Grooved& Drilled discs
the other has 283mm Peugeot 307 HDi discs

I can't make my mind up on which to keep, they both look good under my alloys and feel about the same (to me)

What pro's and con's should i consider?

Thankyou
Danny

[OllieC]

i dont know anything about the specific setups in question, but i would have thought the effectiveness of the calipers are more important than the disk size.

Bigger discs would also help with heat dissipation, but what do you intend to do with the car ?

I wouldnt have thought youd need huge discs designed for the weight of a 307 on a light car like a saxo, unless you do track days etc ?

Edited by OllieC on Wednesday 27th October 13:55

[Whitean3]

DannyVTS said:

What pro's and con's should i consider?

Cost of replacement
Whether the larger discs require additional mods to fit (e.g. larger wheels)

If both sets of brakes feel the same to you (both when hot and when cold), and braking performance seems the same, then I would go for the cheapest option.
Which brakes are heavier? Lighter brakes = less unsprung weight = better handling.

Edited by Whitean3 on Wednesday 27th October 13:58

[Jonboy_t]

DannyVTS said:

.. the brand of the discs..

I have 2 Saxo VTS's.

One has 246mm Red Dot Grooved& Drilled discs
the other has 283mm Peugeot 307 HDi discs

I can't make my mind up on which to keep, they both look good under my alloys and feel about the same (to me)

What pro's and con's should i consider?

Thankyou
Danny

a) do they both stop you
b) Which one stops you best
c) Bin the one that fails either/or question.

Job done!

[GreigM]

The bigger ones should stop you better from higher speeds assuming all else is equal

[powerandtorque]

The 307 HDi setup is very heavy (comparitively) compared to the smaller setup, and that weight is all unsprung mass which is particularly bad. If the smaller, lighter setup works well, I'd be ditching the 307 setup without question.

I don't know if it's still the case, but the 307 HDi calipers had a very poor (and expensive) choice of aftermarket uprated pads available at one point, whereas I'd assuming that the original Saxo VTS setup has plentiful choice and much cheaper.

[alfa pint]

The drilled and vented disks I fitted on the Alfa aren't a patch on the solid Brembo disks it has on it now. Unless you're in a high performance car / track car, you're not really going to need the heat dissipation from drilled and vented disks.

[SDxsi]

You want to swap em both for the 206 challenge car brakes! They are by far the best you can put on it!

[acf8181]

Jonboy_t said:

DannyVTS said:

.. the brand of the discs..

I have 2 Saxo VTS's.

One has 246mm Red Dot Grooved& Drilled discs
the other has 283mm Peugeot 307 HDi discs

I can't make my mind up on which to keep, they both look good under my alloys and feel about the same (to me)

What pro's and con's should i consider?

Thankyou
Danny

a) do they both stop you
b) Which one stops you best
c) Bin the one that fails either/or question.

Job done!

Yeah, think i'd go with that approach myself....i'd expect the bigger brakes to be better, although as said will they fit under wheels, also worth considering will they lock up too easily (i.e. is there enough grip to make use of the better stopping power).

I'm also not a fan of drilled or grooved discs, maybe worthwhile on a heavy gt racecar, but i've never found any advantage on a road car. Suspect they're more a style statement. Pads make much more of a difference.

[oOTomOo]

The other thing to consider is the bigger disks will affect your acceleration.. Same as fitting heavier wheels..

[DannyVTS]

I am yet to test the other Saxo's brakes as i don't pick it up till tonight

Tested mine from over 100 leptons down to about 40 today and they performed very well, very even braking force with no bother (they would have been warm at the time)

[andy400]

Just a question, not a challenge - why do you have two of the same car?

[Mr2Mike]

Ultimately larger discs can dissipate more heat, whether or not that is important depend on how marginal the standard ones are, and it sound like they are adequate.

[Mars]

I think effective braking has more to do with both the pad area and piston area, coupled with heat dissipation.

[james_gt3rs]

Mars said:

I think effective braking has more to do with both the pad area and piston area, coupled with heat dissipation.

And tyre grip.