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Roadster - new options

Discussion in 'Roadster' started by bonnie, Mar 18, 2012.

  1. bolosky

    bolosky Member

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    I really don't get why everyone is so down on the brakes. I understand that they kind of feel weak, but as far as I can tell all that means is that you need to push them a little harder to get them to work.

    I periodically do hard braking just to keep the brakes clean, for practice, and because it's pretty fun. I never have any problem getting the ABS to kick in, which means that I'm at the limit imposed by the tires. Which means that better brakes wouldn't improve the stopping distance, even if they made the pedal feel like it was more responsive.

    If you never use the brakes, then they glaze over and don't work all that well. That's also going to be true with other brakes. You just notice it way more in the Roadster (and presumably Model S) because of the strong regen.

    On the other hand, lots of you who seem to know what you're talking about hate the brakes. So, am I missing something, or is it really just about the pedal feel and not the stopping distance?

    - - - Updated - - -

    Oh, and another thing that I don't really understand is why if they're planning on putting in something like the Model S power train (better inverter, motor, battery cells) why you'd expect better performance with a smaller pack. That's certainly not true with the S, the larger packs do better. Presumably this is because they have more power, which means that the place where the torque curve hits it knee is faster.

    Why wouldn't that be equally true on the Roadster?

    Now, if you're trying to build a great track car, maybe the reduced mass would be worth more than the increased acceleration because turning and breaking performance matter more than speeding up. But, I'd expect a larger Roadster pack would have a better 0-60 than a smaller one (until it hits the limit of the tires).
     
  2. W.Petefish

    W.Petefish Active Member

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    One major reason for wanting the Model S motor and PEM is the simple fact that they are liquid cooled. If you live in hot climates you can't always have your performance. (and alot of the time you get the Power Limited light.)
     
  3. daniel

    daniel Active Member

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    If you're never using the brakes, you're not driving the car like a sports car. If I drove the Roadster like I drove the Zap Xebra, I'd probably never need to use the Roadster's brakes. But I accelerate hard, and that means there are times I have to brake hard. I usually let the regen do the braking, maybe 75% to 85% of the time. But 15% to 25% of the time I get to the stop too soon and have to step on the brake pedal.

    I read on some thread here that the upgrade brakes have better cooling and so are beneficial on the track, where you're braking a lot. I've never been on a track. Maybe some day I'll take it to a track. But not as a regular thing, and never in a race. I always tell people, this is a sports car, not a race car. It goes way faster than any sane person would ever drive a car on public roads in the U.S. But not as fast as race cars go on the track.
     
  4. wiztecy

    wiztecy Active Member

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    #304 wiztecy, Sep 26, 2012
    Last edited: Sep 26, 2012
    The brakes are not up to par at all for that car. Unless you changed out to a different set of brakes to compare, you won't understand. My 1st observation of something odd was seeing all the roadsters getting in front end collisions. Two things for that... they accelerate quick so magically things jump out in front of them not knowing their hyper-speed sprints. But secondly, the regen is giving false confidence on the brakes and when you hammer them all you can do is clamp down on your teeth and hope/pray you slow down in time.... There's a thread on this. These brakes are not doing the physics that braking needs. Meaning the front end needs to dive and put weight on the front wheels and your tires have to be * squealing*, not just the ABS kicking in. I had the ABS kick in with the stockers, I never ever had the front dive on hard braking nor could I get the tires to squeal. All the inertia of the roadster's rear favored weight is going forward on a plane, not down. There's nothing out there except things to hit. Switched my pads and I've got bite, dives, and squeals on hard braking... thats what I wanted to see and have. Its my daily commuter and I have the car-pool lane sticker which is really a hazard at times, people will just pull into your lane when your going 40-70mph and you need really good brakes. You can say the stockers were glazed, but I don't think so, I feel they just sucked to be blunt. They generate too much dust, dust is not good since its like grease and marbles on your braking system. Braking systems need to be clean to work properly. The pads are also too small. My brakes never worked when I picked my roadster up used, it had only 3,800 miles on it. Lastly the pads didn't show any glazing it when I pulled them off.

    I'm absolutly happy about the brake upgrade Tesla is providing, I won't be going for it since I'm very happy with my brake pad swap results and don't track the car. I will every 5-10k pull the pads off, rough them up with sand paper, and brake clean / blow out with compressed air the entire brake system to remove any dust, dirt, and build up. I'll also clear out / clean the drilled holes in the rotors to help collect any accumulation of crap as well as well as inspect for any cracking (which drilled rotors are prone to do). That keeps my braking maintained at optimum performance.

    I also put braking up there as top priority, its safety for one thing, but also its protecting you, your roadster, kids on the street with runaway balls, etc....

    I'm running the CarboTech AX6's which are covered in the Brake thread. I'm seeing 1/10th the amount of brake dust from the AX6's vs. the stock Brembo's based upon the finger rub test on the front/rear rims. Dirt/Dust in and on anything is bad. Just look at the Roadster's PEM when it accumulates dust, it fails to provide proper cooling, and would eventually fail.
     
  5. Doug_G

    Doug_G Lead Moderator

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    +1 wiztecy.

    I have brand-new Carbotech AX6 brake pads sitting on the shelf in my garage, and will be installing them probably this weekend.
     
  6. frequencydip

    frequencydip Sig 100 - #52

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    There are several factors that relate to the roadsters poor brake performance, the brake upgrade will likely only solve one of the primary factors, initial bite at first application of brakes. Even with the AX6 pad the roadster still has poor bite when first slamming on the brakes. As the brakes heat up the braking becomes progressively stronger eventually geting the wheels to lock and some ABS to kick in. Allot of the improvement is to be had in that initial application of the brakes, larger pads, increased pad pressure, and lower unsprung mass will all help improve that initial brake application.

    The other major issue with the roadster is related to weight distribution and the lack of technologies like Electronic Stability Control and Electronic Brakeforce Distribution. As wiztecy pointed out the roadster does not properly transfer weight durring braking. Other sports cars solve this issue by selectively braking specific wheels (ESC) and or adjusting front and rear brake bias (EBD) to transfer weight from rear to front tires.

    Unless you have braked when traction control activated and therefore deactivated regen or braked while in neutral your missing out on why many of us complain about the brakes. Without regen the vehicle brakes very poorly and is still somewhat lacking even with regen when braking in an emergency.
     
  7. strider

    strider Active Member

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    Because you do periodic hard stops you are keeping the pads and rotors clean and so you have not experienced the problem. The stock pads and rotors work fine when they're warm and clean but if you don't use them much in your commute they won't work when you need them. It is not a matter of just pushing harder. When this happens the pedal remains rock hard, the car just doesn't slow down very quickly. I use my car strictly as a daily driver and through heavy traffic (25 miles on 237 and 101 each way) so I don't have an easy place to do hard braking. I guess I could do it first thing in my neighborhood but I'd spill my coffee. So over time "crud" builds up on the pads and rotors and then when I need them in traffic they don't work. Thanks to the early warnings here I've learned to leave some extra space and so haven't hit anyone but I've had a few moments where I didn't think the car was going to stop.

    I switched to the Carbotech pads a couple weeks ago and have been extremely happy. So far they bit early and hard every time. I'll give them a few more weeks of commuting and then see if they still work as well but I consider this issue closed for me. I don't track the car so larger rotors won't matter. Larger pads/calipers could improve stopping but with the Carbotechs I can squeal the front tires so my feeling is that they are sufficient.
     
  8. TEG

    TEG TMC Moderator

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    Part of the concern over the brakes is the fact that the Roadster makes it so easy to get going quickly without giving you a lot of queues. No roaring engine, no smoking tires. Some tall people can't even see the speedo very well.
    So, drivers are sometimes fooled into going faster than they would in ICE cars they drove before.
    You just make a quick stab at the "go" pedal and suddenly the Roadster is up to speed where you need some extra good brakes to slow back down quickly.

    Add this to the fact that the Roadster has attracted a bunch of drivers who previously hadn't considered a high performance sports car.
    They wanted a long range EV and ended up with something that has Ferrari like performance around town.
     
  9. garry753

    garry753 RoadsterS753 ModelS P1449

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    I'm with Jory and ViperDoc - don't need any more performance than I've got, but would love more range and supercharger capability. Looking forward to Model S in a couple months, but it isn't the same form factor as the Roadster. It would be nice to get to San Antonio and back, or to get to Houston/Dallas without a long charge time or on the same charge.
     
  10. samcarney

    samcarney Sam C

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    Amen!
     
  11. bolosky

    bolosky Member

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    The place I do it is on the freeway exit. I look behind me and if it's clear I just push the brake to the floor. It happens often enough to keep the brakes functional.
     
  12. daniel

    daniel Active Member

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    That's me, definitely.

    One thing that confuses me: I thought that the purpose of ABS was to prevent the wheels locking up, and therefore to prevent squealing??? Or is the squealing coming from the brakes, and not the tires sliding on the pavement?
     
  13. TEG

    TEG TMC Moderator

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    Maybe from the brakes. But tires can still make a lot of noise when ABS activates.
    ABS doesn't really come into play unless you are braking so hard that the wheels start to "lock up" and slip/slide on the road.
    Usually this happens in low traction situations such as on snow, ice, or heavy rain.
    The result is that the car pulses the brakes off/on quickly to make the wheel start spinning in fits and starts to keep control.
    It turns out it can brake better if it does it that way, and also maintains some of your steering control better. (Instead of just plowing forward in a straight line regardless of steering angle like it does when the front wheels aren't turning.)
     
  14. wiztecy

    wiztecy Active Member

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    #314 wiztecy, Sep 26, 2012
    Last edited: Sep 26, 2012
    The light squealing is coming from the tires. Its reaching the maximum stopping efficiency where the tires are beginning to break traction, some call it optimal squeeze point. This is the point where your tires' rubber is being twisted and contorted to a degree that only parts of your tires are actually skidding; this is the absolute limit of your tires' traction, and the quickest way to stop. When I hear this I know my brakes are optimum.
     
  15. jory

    jory Member

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    and

    i definitely fall into the category of someone who bought a sports car as a side effect of wanting a long range EV in 2010. i also live in the city so the model S is simply too large to be convenient. thus i am "stuck" with trying to civilize the roadster beyond its design intent.

    i added the sound insulation package, run my tires at the lower "comfort" pressure and have the adjustable suspension at its softest setting. (i would love to have additional range and supercharger capability to (be able to) use the roadster for slightly longer trips.)

    up until now i haven't noticed the brakes as a problem, though this morning while commuting i had to brake suddenly and definitely felt that i might not stop in time. i'll probably get the brake upgrade if it comes available but in the meantime the carbontech pads sound like a wise course.
     
  16. daniel

    daniel Active Member

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    So if I wanted the CarboTech pads, who would I talk to? Tesla ranger, or a local shop? And if the latter, how do I know who I can trust to do the work properly? Unlike some folks here, I've always trusted the dealership to work on my cars and I've never been disappointed. But a ranger visit costs close to $600 for mileage, and my next annual service is nine months away. I really don't want Crusty working on my Roadster. Or some kid the tire shop hired to remove and replace tires.
     
  17. ViperDoc

    ViperDoc Roadster 1305

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    Roadster wants Supercharger!

    Well, my wife's Model S came last weekend, and I don't want to have to take her car to take a long trip!

    :smile:
     
  18. frequencydip

    frequencydip Sig 100 - #52

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    ABS is primarily designed to allow the driver to maintain steering control when braking hard, other wise you would just skid and follow the path of least resistance. ABS is also for inexperienced drivers who do not know how to threshold brake. Threshold breaking will stop a car faster than ABS can. Threshold breaking used to be taught in driving classes but not really anymore. Its not hard to lean but does require practice and familiarity with your vehicle.

    The trick for threshold braking is to get as close as possible to locking up the tires, usually just before ABS engages. By doing so you can achieve the maximum braking effort. You will feel vibrations through the steering wheel, telling you where the point of locking-up is. If you feel you are about to lock-up the tires you should slightly reduce braking, while still applying sufficient pressure to remain in the threshold braking zone. You should hear the tires squealing a bit but not allot. The roadster is one of the harder cars to threshold brake in, there is very little modulation in the pedal.
     
  19. strider

    strider Active Member

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    If you haven't had the problem I would wait until your annual. Though I believe Doug in Canada said that Tesla wants to replace rotors along w/ pads and you don't want to do that. But you could ask if they would be wiling to do it when they're out for your annual.

    Replacing brake pads is bread-and-butter mechanic stuff and this is no different than a regular car. Is there a Lotus dealer in your area (doesn't look like it from a quick web search)? They could do it since the Roadster brakes are the same as the Lotus Elise. Else is yelp.com active? You could search there to find a shop that is good w/ brakes. There is a write-up in the Roadster section on brake pads and there are links to how-to's that you could give to the mechanic.

    Finally, I would go w/ the Carbotech 1521 compound instead of the AX6's. That's what I'm running and it works great for we daily drivers without the noise and dust of the AX6's which are an autocross pad).

    - - - Updated - - -

    My Skip Barber instructor said ABS stands for, Allows Braking and Steering.
     
  20. vfx

    vfx Well-Known Member

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    A new Roadster option needs to be a socket conversion to Tesla's new 2.0 plug. That way we can charge at any Tesla store, or service center. Not to mention we can share plugs with our Model S and Model X plugs at home and at friends houses.

    Then when Tesla puts an 2.0 plug HPC at the Supercharger sites for the 40kWh Model S' we can now do roadtrips with the Tesla highway options.

    Considering there are nearly no Roadster plugs left in the wild, the new Tesla 2.0 plug and the little J1772 adapter would be all we need.
     

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