SM GTS brake discs

conaero

Forum Owner
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34,582
There has been a lot of talk recently about alternative routes for brake disc so I thought it about time to show our hand.

After the success of our SM 4200 discs that MAF and I worked on, Zep and I have been working for about a year behind the scenes to bring not 1, not 2 but 3 options for the GTS.

Option 1:
Full set of solid (fronts not dual cast) vented GTS discs for £750

Option 2:
Full set of bells and rotors for £1500

Option 3:
Full set of oversized bells and rotors with calliper spacers for £2500

All discs are produced solely for us by a UK based manufacturer and come with full warranty, CE and indemnity.

The bells and rotors are undergoing testing so will be available Q1/2019 with the solids in Q2.

As we intend to stock these discs rather than group buy, it would be very helpful if owners could express which of the 3 options above they would be likely to go for?
 
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CatmanV2

Member
Messages
48,478
Bloody ****. Well done.

When I get a GTS I'll certainly be in the market, and would probably go for option 1
C
 

Zep

Moderator
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9,098
Just to confirm for option 3, this will be 380mm front and 356mm rear discs, retaining the original caliper with a modified mounting.

Option 2 is for standard size discs with bells and rotors. These will offer a significant reduction in unsprung weight.

Rotors are replaceable on both without buying a complete new kit.
 

GeoffCapes

Member
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14,000
As my technical knowledge is well, quite frankly, rubbish, I understand what the first option is. But what are option 2 and 3?

And how are they different to 1.
 

conaero

Forum Owner
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34,582
Bells and rotors are 2 piece. You have a central hub unit (bell) then the ring shaped disc (rotor) bolts to it.
 

Zep

Moderator
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9,098
Option 1 is for one price solid discs cast from a steel alloy. They will be the same high quality as the 4200 / GS discs.

Option 2 is for two piece discs in standard dimensions. The central bell (which is the bit that attaches to the hub) is custom designed and manufactured from a single billet of aluminium. The rotor is a bolted to this to form the complete disc.

Option 3 is the same as Option 2, but the rotors are larger, the caliper mounting is altered to suit and braking performance is improved a lot. They will also fill the wheels better.
 
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Doohickey

Velociraptor
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2,495
I'm with Geoff in technical knowledge but if I understand, option 2 is for front and back with less weight but no adjustment required to the calipers. In that case I'll be up for option 2 (but option 1 would be fine as well).
 

Zep

Moderator
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9,098
I'm with Geoff in technical knowledge but if I understand, option 2 is for front and back with less weight but no adjustment required to the calipers. In that case I'll be up for option 2 (but option 1 would be fine as well).

That is absolutely right Dave.
 

Moz1000

Member
Messages
820
Well done chaps and thanks for the effort. I'd probably go for option 1. However, what would the difference be between options 1 and 2 in terms of braking performance? If not a lot, then why did Maserati opt for the two-part fronts in the first place?
Moz
 

Zep

Moderator
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9,098
I think there are a couple of potential reasons why they went dual cast

Reason 1 - Weight. The dual cast disc is a bit of a boat anchor, but it will still weigh less than an equivalent in steel.

Reason 2 - They are awfully hard to have remade and so it protect their IP.

Reason 3 - Probably both of the above

As for the performance, any reduction in unsprung weight will improve reduce the amount of weight the dampers need to control so it will (whether these improvements are perceptible is not guaranteed) improve ride over bumps, improve handling and to a very small degree increase acceleration (I am not going into the benefits of reduced rotating mass - ask me in a bar). As for improvement in braking performance - there is probably a small difference based on improved heat dissipation of the alloy bell.
 

conaero

Forum Owner
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34,582
Thanks Zep. So will option 1 result in poorer performance compared to stock?
Moz

I would not agree that poorer is the correct term here. Additionally, option 1 would be less seseptable to wharping over the OEM that are almost designed to wharp.
 
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Zep

Moderator
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9,098
As Matt says, not poorer. Its different products for different purposes.

All steel should be considered as like for like with standard, bells and rotor and upgrade in terms of weight and to a degree performance and the big brake kit for those who really want a significant improvement in pedal response and stopping power.

If you look at the options available on the market they mirror our approach. An Italian firm will do you either a steel disc or a bell and rotor and another firm will do you a big brake conversion.
 

conaero

Forum Owner
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34,582
Also with the bells and rotors, you could go option 2 then upgrade to option 3 or vice versa. Hence if you have the bells it gives you greater flexibility and come replacement you only replace the rotor.

The Strads carbon ceramics are bell and rotor. If a carbon ceramic rotor was to become available you could potentially upgrade to this (pads would have to be changed too)
 

conaero

Forum Owner
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34,582
I would have no reason to believe that running the same pad in the same car there would be any noticeable difference in braking performance. They are a like for like replacement.

If it’s a braking performance upgrade that your after, it’s option 3
 
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Sam McGoo

Member
Messages
1,732
Being a 'soon to be' owner, this is good news. Well done to those involved!
So just to clarify, the bell for the OEM replacement option 2 and the bell for the big brake kit option 3 is exactly the same? So, swapping from one to the other is just a matter or swapping the rotor and adding or removing the caliper spacer?

I'd probably opt for option 2, and maybe get a set of over-sized rotors and spacers if I ever went on track.
 

Zep

Moderator
Messages
9,098
Being a 'soon to be' owner, this is good news. Well done to those involved!
So just to clarify, the bell for the OEM replacement option 2 and the bell for the big brake kit option 3 is exactly the same? So, swapping from one to the other is just a matter or swapping the rotor and adding or removing the caliper spacer?

I'd probably opt for option 2, and maybe get a set of over-sized rotors and spacers if I ever went on track.

The short answer is yes, but it’s a fairly involved process to swap the bell from one disc to another so I would say the normal route would be to have one or the other. Or for that matter a steel set for the road and the BBK for the track.
 

JonW

Member
Messages
3,259
Brilliant news... and thanks for the explanation for the less mechanically gifted!

I would be very interested - probably in Option 2, but possibly 3.