Rotors breaking like dinner plates
12-01-2010, 12:57 PM
#31
Originally Posted by krazik,Dec 1 2010, 08:57 AM
No. You have to include the cost of the BBK too.
So you need to factor that in too. Since it's your own time, you can determine cost/hr based on your salary. Time spent swapping stock rotors. Time spent swapping pads. Time lost on track due to swapping rotors (~$40 per session ballpark).
12-01-2010, 01:24 PM
#32
Former Moderator
There is only one case I can think of where it is suspected that an S2000 rotor cracked on track. It was that fatality in NJ. In that case, they suspected that one of the rear rotors cracked (and then came apart).
So if this floating nsx rotor is a direct bolt on, does the stock NSX rotors also work?
I'm a firm believer in RacingBrake 2 piece rotors. I was cracking stock OEM and Centric rotors every 2 or 3 track days--and losing valuable track time--so I made the jump to RacingBrake 2 piece rotors for the S2000 stock caliper. I got an entire season out of them--23 track days--before a small crack finally made it to the outside edge of the disk. The crack didn't cause any vibration, I just happened to see it when changing brake pads. I ordered a set of replacement rings and bolted them up to my RB hats. RB even includes new locking hardware.
When you do the math of all those cheap rotors, the lost track time and consider the peace of mind of the nearly indestructible RacingBrake rotors gives, the RacingBrake 2 piece rotors are worth every penny.
A couple of months ago I switched to the Accord calipers with RacingBrake's NSX 2 piece rotors. The NSX disc ring is even beefier than the S2000s so I expect it to last even longer. I switched to the Accord calipers to take advantage of the bigger pistons (move some brake bias forward) and larger, thicker brake pads. On my car new S2000 calipers will heat discolor after one or two track sessions but I now have about 7 hours of track time on the Accord calipers and they're still silver so I know they are running cooler. I'm getting about 80% more pad life with the Accord XP10 pads too. The only downside is the additional unsprung weight of the caliper and a slightly longer brake pedal caused by the larger Accord caliper pistons.
12-01-2010, 01:31 PM
#33
Registered User
Rotors get hot. Stock 1pc rotors do not allow the necessary thermal expansion of the rotor since it is connected to the hat. The S2K can generate some pretty significant stress on the brakes with sticky 255s up front (probably less brake stress/heat witch crappy 215s up front), that being said, the car brakes very well and makes a lot of heat the stock rotor can't support. It seems pretty consistent to crack rotors every 4-6 track days. I guess after that many heat cycles and thermal stresses, the metullurgy, design, cheap materials and piss poor cooling vein design of the stock rotors just can't take it anymore and eventually a stress reiser and weak point in the metullurgy of the rotor gives way to spectacular cracks.
A 2pc rotor allows the rotor to expand and contract freely without causing severe stresses to the rotor from being bound as a solid piece to the hat like a 1pc. ALMS/indycar quality metullurgy (PFC) also dosnt hurt to have premium rotor material that can handle the heat with less stress reisers as well as a high quality internal rotor vane design with more vanes, that pump more air through the rotor and lower the operating temperature of the rotor all help. That and keeping the heat off of the wheel bearing. But this dosnt come cheap. Yes it can possibly work out to less $ in the long run but time is $, wheel bearings cost $, convenience, labor, possibility of danger from a cracked rotor, and many other factors must be considered. A high quality 2pc rotor isn't for everyone and the initial price will probably shy many away at first. You have to look at how many track days you do, how fast are you, and figure out what's best for you.
Ever regretted not being patient and buying the cheaper set of suspension, hood, wheels, tires, etc... to save some $ all to regret it and wish you did it right the first time and spent the money up front rather than more in the long run by cheaping out at first? I know I have. Many times.
0.02
A 2pc rotor allows the rotor to expand and contract freely without causing severe stresses to the rotor from being bound as a solid piece to the hat like a 1pc. ALMS/indycar quality metullurgy (PFC) also dosnt hurt to have premium rotor material that can handle the heat with less stress reisers as well as a high quality internal rotor vane design with more vanes, that pump more air through the rotor and lower the operating temperature of the rotor all help. That and keeping the heat off of the wheel bearing. But this dosnt come cheap. Yes it can possibly work out to less $ in the long run but time is $, wheel bearings cost $, convenience, labor, possibility of danger from a cracked rotor, and many other factors must be considered. A high quality 2pc rotor isn't for everyone and the initial price will probably shy many away at first. You have to look at how many track days you do, how fast are you, and figure out what's best for you.
Ever regretted not being patient and buying the cheaper set of suspension, hood, wheels, tires, etc... to save some $ all to regret it and wish you did it right the first time and spent the money up front rather than more in the long run by cheaping out at first? I know I have. Many times.
0.02
12-01-2010, 01:50 PM
#34
Registered User
Originally Posted by robrob,Dec 1 2010, 02:24 PM
Mike, if this is referring to Cale's fatal crash we found it wasn't a rotor disintegration. The crash was caused by the stock, 8 year old brake line popping lose at the junction of the brake line and front right caliper.
Did the hose fail? The crimp? Or the fitting on the caliper?
12-01-2010, 02:07 PM
#35
Former Moderator
The hose actually popped out of the crimp. There was hose deep inside the crimp. I think all those heat cycles weakened the hose and it finally ripped loose under pressure.
The actual accident analysis can be seen here: http://robrobinette.com/cale_accident_report.htm
The actual accident analysis can be seen here: http://robrobinette.com/cale_accident_report.htm
12-01-2010, 03:04 PM
#38
Registered User
Originally Posted by robrob,Dec 1 2010, 03:07 PM
The hose actually popped out of the crimp. There was hose deep inside the crimp. I think all those heat cycles weakened the hose and it finally ripped loose under pressure.
The actual accident analysis can be seen here: http://robrobinette.com/cale_accident_report.htm
The actual accident analysis can be seen here: http://robrobinette.com/cale_accident_report.htm
12-01-2010, 03:12 PM
#39
Administrator
Originally Posted by Billj747,Dec 1 2010, 02:31 PM
Rotors get hot. Stock 1pc rotors do not allow the necessary thermal expansion of the rotor since it is connected to the hat. The S2K can generate some pretty significant stress on the brakes with sticky 255s up front (probably less brake stress/heat witch crappy 215s up front), that being said, the car brakes very well and makes a lot of heat the stock rotor can't support. It seems pretty consistent to crack rotors every 4-6 track days. I guess after that many heat cycles and thermal stresses, the metullurgy, design, cheap materials and piss poor cooling vein design of the stock rotors just can't take it anymore and eventually a stress reiser and weak point in the metullurgy of the rotor gives way to spectacular cracks.
A 2pc rotor allows the rotor to expand and contract freely without causing severe stresses to the rotor from being bound as a solid piece to the hat like a 1pc.
A 2pc rotor allows the rotor to expand and contract freely without causing severe stresses to the rotor from being bound as a solid piece to the hat like a 1pc.
-Ry
12-01-2010, 03:16 PM
#40
Administrator
Originally Posted by spdracerut,Dec 1 2010, 01:57 PM
Time = Money.
So you need to factor that in too. Since it's your own time, you can determine cost/hr based on your salary. Time spent swapping stock rotors. Time spent swapping pads. Time lost on track due to swapping rotors (~$40 per session ballpark).
So you need to factor that in too. Since it's your own time, you can determine cost/hr based on your salary. Time spent swapping stock rotors. Time spent swapping pads. Time lost on track due to swapping rotors (~$40 per session ballpark).
and no one is swapping multiple sets of rotors a day. if you plan a head you would never need to swap them at the track and they become a cheaper consumable not unlike gas, oil, brake pads, etc.You're not gonna win the argument it makes financial sense to buy a bbk to deal with this problem. As I said above 2pc rotors are a solution to cracking and they're somewhat less expensive than a bbk.
But in pure dollars, nothing is cheaper than just replacing the oem rotors every other event.