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View Full Version : Larger rear diameter brake rotors



gtntahg
09-12-2014, 12:29 PM
There's one thing that's always kind of bothered me about the looks of my Abarth (and I know some of you will think this is kind of petty, butů) I wish the diameter of the rear brake rotor were closer in size to the front one. Has anyone seen anything available to remedy this "issue"? :pride: I'm sure it would involve bigger calipers as well but that's OK. Who knows, it might even help with that crazy imbalance front to rear when you have to make a panic stop at highway speed.

ophidia31
09-12-2014, 12:43 PM
Like this?

http://www.gazzellaracing.com/product.php?productid=19587

Dont need a new caliper or anything. Just an adapters to move the stock ones out, longer lines and the larger rotors. These can probably be made locally (within the US) for cheaper than $1200 (w/ est shipping). Well, can also get the Wilwoods for cheaper too. But I think just a disc conversion that uses the stock caliper would be more than enough since all the Wilwoods are is a different looking caliper but still the same integrated parking brake single piston.

B3NN3TT
09-12-2014, 01:47 PM
This chassis is REALLY nose-heavy, so if you do anything to increase rear brake bias, you're asking for it. They are squirrely enough under braking as-is...

Horizontally-Opposed
09-12-2014, 02:22 PM
Wilwood kit may be your best move.

Eurowned
09-12-2014, 03:28 PM
There's one thing that's always kind of bothered me about the looks of my Abarth (and I know some of you will think this is kind of petty, butů) I wish the diameter of the rear brake rotor were closer in size to the front one. Has anyone seen anything available to remedy this "issue"? :pride: I'm sure it would involve bigger calipers as well but that's OK. Who knows, it might even help with that crazy imbalance front to rear when you have to make a panic stop at highway speed.

The inbalance in a hard stop on the highway is suspension upset from weight transfer and not inadequate brakes. The stock brakes are pretty impressive I have pushed them pretty hard myself. To counter this you want to do suspension that has 3 way (Compression, High/Low speed Rebound) coilovers and sway bars to better the manipulation of the handling characteristics of the car.

CCR#5
09-13-2014, 10:05 AM
This chassis is REALLY nose-heavy, so if you do anything to increase rear brake bias, you're asking for it. They are squirrely enough under braking as-is...

With the weight bias I'd actually prefer to have more rear brake bias to drag out(straighten) the rear under hard braking. BUT as Euro pointed out the main issue with squirrely braking is the weight transfer not the brakes. A larger rotor could cause the rear tires to lock up, but the abs system should automatically mitigate. This would certainly be a cosmetic modification, which is what I believe the OP is hoping to achieve. I certainly couldn't see any major negative impacts from doing it, assuming you don't go excessive with the rotor diameter increase.

ivmill
09-13-2014, 10:57 AM
Thinking out loud here but could you possibly find a set of front rotors/calipers and run them in the rear? I would imagine mounting points wouldn't be too much of an issue. As mentioned earlier it may cause too much rear brake bias though.

cy-clone33
09-13-2014, 11:48 AM
Im already working on making brackets to use front rotors in the rear . the only effect on bias will be the contact area of the pads being further from the center of the wheel making them more effective in ratio ( easier to stop a large spining wheel by holding onto the outside than a smaller diameter )

But I don't see it being an issue, its just cheaper to make the smaller parts and $$ is king in manufacturing, I think it will work just fine

gtntahg
09-13-2014, 02:11 PM
Thanks for all the replies! The larger rear rotors, as one of the posters has mentioned, is for cosmetic purposes. If there were performance benefits to be gained by making this mod then that's icing on the cake.

ophidia31
09-13-2014, 03:50 PM
Im already working on making brackets to use front rotors in the rear . the only effect on bias will be the contact area of the pads being further from the center of the wheel making them more effective in ratio ( easier to stop a large spining wheel by holding onto the outside than a smaller diameter )

But I don't see it being an issue, its just cheaper to make the smaller parts and $$ is king in manufacturing, I think it will work just fine

Front rotors wont fit in the rear caliper since theyre vented vs solid rear stock.

cy-clone33
09-13-2014, 03:57 PM
Front rotors wont fit in the rear caliper since theyre vented vs solid rear stock.

Thus why it isn't a simple swap , I have a set of used rotors to find an inexpensive way to do this, if it requires using the front calipers in place of the stock rears then it becomes a price vs gains issue still If you don't try then you never get anywhere

ophidia31
09-13-2014, 06:07 PM
Just have to see the size difference of the pistons in each caliper. If theyre reletively close, front calipers would probably be better with the larger surface brake pad. But then you lose p-brake ability.

Winston
10-07-2014, 08:52 PM
Squirrelly under braking at the rear can be mitigated by Neuf 28mm rear torsion bar, from Eurocompulsion !

bomba
10-08-2014, 06:59 PM
Squirrelly under braking at the rear can be mitigated by Neuf 28mm rear torsion bar, from Eurocompulsion !

This. The larger rear torsion bar makes a big difference with panic braking on the highway. EC is great and all the vendors seem to carry them.