TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC

Racing Brake XT910 vs XT970

Discussion in 'Model 3: Driving Dynamics' started by beastmode13, May 23, 2019.

  1. beastmode13

    beastmode13 Supporting Member

    Joined:
    Aug 6, 2018
    Messages:
    342
    Location:
    NorCal, USA
    #1 beastmode13, May 23, 2019
    Last edited: May 23, 2019
    This is a comparison between RB XT910 and RB XT970 as daily driver pad.

    RB XT910 is part of the Racing Brake BBK upgrade I installed a month ago. You can read about the brake job here. The caliper is a 4-pot just like stock P3 Brembo caliper. Unlike Brembo with a pair of same-sized pistons, RB caliper has pistons of two different sizes, this will help reduce uneven wear of brake pad, but not much on the brake bite and modulation in a significant way. The bite and modulation are mostly factors of the brake pad. In this regard, the XT910 is a vast improvement over the stock P3 pad. The initial bite is distinct while the release is crisp. The modulation is very linear and predictable with slightest pedal travel converted to increase braking force. By feel, there is about 20% more braking force for the same amount of pedal travel. The dust level is slightly higher than stock, with medium grey dust. There is zero noise. With about 600 street miles on XT910, I would highly recommend this pad for better brake feel and performance if you don't might a bit more dust. I've not tracked this pad, but according to RB and review on GTR site, it is a capable pad for the occasional track days.

    Two days ago I swapped the XT910 for XT970. Wow! The stopping power on these is highly addictive in a similar way to the acceleration of P3. The bite is even more aggressive than XT910, but still very controllable once you learn the characteristic of the bite. With the stock pad, it is a whole foot operation, XT910 is a three toe operation, XT970 is a big toe operation. The most impressive aspect of XT970 is how fast and easy is to bring the speed down from 70 to 50 mph. This would be the pad that I use at the track, but I would not use XT970 as daily street pad due to its noise. The noise happens when you engage the brake from a creeping speed, but not above it. That is every traffic signal, parking lot, stop-and-go traffic, you will hear it. There is more dust with XT970, but it is not overly so. After close to 100 miles on XT970, I decided to swap back to XT910 for street, as I can not bare to hear the brake squeak on a daily bases, nor my wife asking me why the Tesla is so noisy. ;) I do plan to swap in the XT970 at the track since it is easier to change the pads on RB caliper than removing the wheel. A simple 5mm Allen wrench is all it needs.

    Read about track comparison of XT910 and XT970 please read this GTR thread. FYI: XT970 and XT960 have the same compound; the difference is only in the vehicle application.
     
    • Informative x 4
    • Helpful x 1
  2. beastmode13

    beastmode13 Supporting Member

    Joined:
    Aug 6, 2018
    Messages:
    342
    Location:
    NorCal, USA
    Quick brake pad change on RB Caliper with a 5mm Allen wrench.
    IMG_2187.JPG IMG_2186.JPG
     
    • Like x 1
    • Funny x 1
  3. destructure00

    destructure00 Member

    Joined:
    Mar 2, 2019
    Messages:
    505
    Location:
    Scottsdale, AZ
    Great info! Thanks for taking the time to share. I'm really curious how the 910s will perform on the track. I'm planning to run 910s with RB rotors full time, but if I start chewing through pads at the track or need more I'll probably revert back to stock for DD and 970s with RB rotors for track days.
     
  4. beastmode13

    beastmode13 Supporting Member

    Joined:
    Aug 6, 2018
    Messages:
    342
    Location:
    NorCal, USA
    BTW. I was tired when I made the OP. The dust level on XT910 is comparable to stock P3 pads, with no noise at all. XT970 is slightly higher than stock P3 pads, plus squeaking noise at creeping speed.
     
    • Like x 1
  5. Lunares

    Lunares Member

    Joined:
    Jul 9, 2018
    Messages:
    449
    Location:
    San Diego
    I have stock P3D brakes. What's your opinion on changing at least just the fronts for track and autox?

    I swap my wheels for those events so it's not really a big deal either way.

    At the least I'm going to upgrade to the 910's and castrol SRF pretty soon. Still on the fence for ventilated rotors
     
  6. destructure00

    destructure00 Member

    Joined:
    Mar 2, 2019
    Messages:
    505
    Location:
    Scottsdale, AZ
    Can't speak to autocross but here's how my stock brakes fared after one track day. Not so good.

    P3D front pads uneven wear after track
     
  7. beastmode13

    beastmode13 Supporting Member

    Joined:
    Aug 6, 2018
    Messages:
    342
    Location:
    NorCal, USA
    Both 910 and 970 have stronger initial bite than stock cold, and it gets progressively better with heat. I can see a benefit of autoX.
     
  8. Lunares

    Lunares Member

    Joined:
    Jul 9, 2018
    Messages:
    449
    Location:
    San Diego
    Oh I'm changing either way, I was more asking how difficult would it be to change the front pads every track day if I used 910 for daily and 970 for track. I take my wheels off every time for track so have the access

    And if it would even be safe to run XT970 up front and XT910 in the rear
     
  9. beastmode13

    beastmode13 Supporting Member

    Joined:
    Aug 6, 2018
    Messages:
    342
    Location:
    NorCal, USA
    I will be doing exactly that. 910 front, rear (when it’s available). Switch the front to 970 at the track, keep rear 910. Read the GTR thread in the first post, many of them use 970/910 combo. You will need to rebed 910 when you switch back it from 970 for street.
     
    • Informative x 1
  10. Lunares

    Lunares Member

    Joined:
    Jul 9, 2018
    Messages:
    449
    Location:
    San Diego
    What does "rebed" a brake mean?
     
  11. beastmode13

    beastmode13 Supporting Member

    Joined:
    Aug 6, 2018
    Messages:
    342
    Location:
    NorCal, USA
    Bedding the is a process of applying a thin coat of brake pad material onto the surface of the rotor. Much of the brake force is produced from the adherent friction of the pad material bedded on the rotor and rotor itself.

    970 is a aggressive compound that will remove the 910 and bed itself on the rotor with relative ease during the warm up lap at the track. 910 requires proper bedding process to remove the 970 and coat itself on the rotor.

    All pad material will benefit from proper bedding. This is the procedure I use for 910 and 970. All paddle application are quick stab action and release.
    3 x 40mph reduce to 25mph
    Drive without touching brake for 1-2min
    3 x 50 reduce to 35mph
    Drive without touching brake for 1-2min
    3 x 70 reduce to 55mph
    Drive without touching brake for at 5-10min

    Technical white paper on brakes.
    https://www.apcautotech.com/getmedia/b62c7705-ab5f-4a05-97a8-4a7390feedd1/Centric_and_APC_Technical_Whitepaper_C2-Bed-In-Theory-8-2018_1.pdf
     
    • Love x 1
  12. destructure00

    destructure00 Member

    Joined:
    Mar 2, 2019
    Messages:
    505
    Location:
    Scottsdale, AZ
    Once the wheels are off, I'd say it's an extra 5 minutes per side to remove the calipers and swap pads. Maybe 10 minutes per side your first time or two.
     
  13. beastmode13

    beastmode13 Supporting Member

    Joined:
    Aug 6, 2018
    Messages:
    342
    Location:
    NorCal, USA
    PSA - 6/10 ETA for XT910 P3 rear. :)
     
    • Like x 1
  14. bradhs

    bradhs Member

    Joined:
    Oct 14, 2013
    Messages:
    730
    Location:
    San Diego, CA
    Are there any 60-0 or 80-0 brake tests between stock P and the XT910?
     
  15. Knightshade

    Knightshade Well-Known Member

    Joined:
    Jul 31, 2017
    Messages:
    5,327
    Location:
    NC

    they'd be exactly the same.

    The brakes don't stop the car, the tires do.

    The only time you'd see a difference in pads is if you tested, say, 10 back-to-back-no-cooldown stops from 80-0 in a row.

    One set of pads, the braking distance would begin to get longer after fewer stops than the other.

    it'd never be shorter than stock though as brake upgrades can't do that- only tire upgrades can.
     
    • Informative x 1
    • Like x 1
  16. usofrob

    usofrob Member

    Joined:
    Nov 26, 2015
    Messages:
    174
    Location:
    Michigan, United States
    But with properly design brake pads, the dust could come off and embed itself into the tires, thus allowing the tires to stop better.
    Or the brake pads could disintegrate into a large dust cloud, thus increasing the wind resistance and slowing the car down faster.
    Or you could make the brake pads so massive that they warp space time to change how distance is measured.
    We just need some out of the box brake pad designers! :p
     
    • Funny x 2
  17. bradhs

    bradhs Member

    Joined:
    Oct 14, 2013
    Messages:
    730
    Location:
    San Diego, CA
    Thanks for that! Will a 245 tire stop faster than a 235 tire?
     
  18. jyalpert

    jyalpert Member

    Joined:
    May 8, 2019
    Messages:
    165
    Location:
    Oakland, CA
    Entirely dependent on tire compound.
     
    • Like x 1
  19. mact3333

    mact3333 Member

    Joined:
    May 24, 2013
    Messages:
    121
    Location:
    near Portland OR
    Hey Beastmode, did you install a BBK for the fronts and rears?????
     
  20. Knightshade

    Knightshade Well-Known Member

    Joined:
    Jul 31, 2017
    Messages:
    5,327
    Location:
    NC
    that's a really good question... generally? probably not in any measurable way (note the following assumes same tire compound just changing the width)

    Narrower vs wider trades off more pressure per square inch of the contact area (narrow) or wider contact area (wide).

    Increasing contact area with a wider tire will cause lower force of surface per square inch (assuming vehicle weight remains the same) and vice versa, skinny tire has less contact but must carry same load so pressure per square inch increases... and thus both will likely offer similar amounts of friction available.


    The exception would be if your car/tire combo is already at the limits of its load rating- because beyond that the tires coefficent of friction begins to decrease... so if say you added a ton of weight to the vehicle, to the point it was overwhelming the narrower tire and lowering coefficient of friction, then a wider version of said tire could resolve that. I've no reason to suspect this is true with the Model 3 by default, but I suppose if you were driving 4 linebackers around with heavy luggage or something it could matter.

    Pretty nerdy dive into tire load sensitivity here-



    Wider also may reduce range/efficiency, and generally not work as well in wintry conditions, though may offer some advantage in track/cornering type situations so there's trade-offs both ways there too.
     
    • Like x 1

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC