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Braking on bumpy roads any better yet?

Discussion in 'Gen 3 Prius Main Forum' started by Emma7145, Dec 18, 2016.

  1. Emma7145

    Emma7145 Junior Member

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    A little bit of background… I had a 2011 Prius II and I absolutely loved it except when it came to stopping on bumpy surfaces. It would do the can't stop/shoot forward thing. The dealership said it was normal for the regen braking system but it would add btwn 5-10 extra feet of stopping distance. I always leave a lot of stopping room and this is why I never actually hit anyone but after moving to a city that gets a lot of snow and has a lot of bumpy brick roads, I decided to trade it in for an Impreza.

    The Impreza definitely handles better but I am very disappointed with just about everything else about the car. I loved my Prius and I want to go back. So my question is, do the newer models still have the same issue? If so, how new do I need to go? And is there any difference btwn the Prius and Prius v?

    I know there's been a lot of posts on the braking issues, and people whose Prii don't do this say either it's the ABS (which it's not) or break harder (which doesn't help) or leave more stopping distance (which is great until someone cuts you off and you have to stop unexpectedly and can't). So just to be clear, it's the issue where the car has gone over a bump, or series of bumps, so the regen system shuts off momentarily when the wheels disconnect with the road for a split second. If you haven't experienced it, it's really something!
     
  2. bisco

    bisco cookie crumbler

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  3. WilDavis

    WilDavis Senior Member

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    Welcome to PriusChat!
    I've noticed a similar behaviour with my 2009 Gen II, but have always put it down to my sloppy driving technique! (…shrug!) :eek: o_O :rolleyes: ;)
     
  4. Emma7145

    Emma7145 Junior Member

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    Bisco, what year do you have? I know a software update wouldn't be the solution - if we had a model year that had the problem, were basically stuck. But I was hoping for some eventual fix in the newer years!
     
  5. bisco

    bisco cookie crumbler

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    2012. you're right, i haven't read much from the gen 4 owners yet. maybe you should try asking the question there.
     
  6. David Beale

    David Beale Senior Member

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    It was worse with the GII than it is with the GIII. I never notice it with Pearl S (2012 with stock 15" wheels). Can't comment on the G4.
    If you hit the brake pedal fast it bypass's the regen. and you won't get the delay to switch between regen and friction braking. So if you panic the car will stop. It is an interaction of the regen -> friction braking and the antilock system. When a wheel hops off the pavement the antilock senses the slip and reduces the braking to that wheel. To do that it first has to switch from regen to friction braking. There is probably also some system in there to "protect" the HSD when in regen, that is, it tries to reduce the jolts from slip to traction.

    Heavy wheels/tires will make it worse (17" for example, especially with cheap aftermarket wheels). They hop better. ;)
    I would expect the independent rear suspension in the G4 would reduce it as well. The wheels should stay on the pavement better when they're independent.

    Take a G4 for a test drive somewhere you experienced it and tell us all what you find!
     
  7. Emma7145

    Emma7145 Junior Member

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    Heavy wheels/tires make it worse? I would have thought that the extra weight would help... I just had the standard tires on my 2011 but thought maybe a Prius v would fare better. More weight to keep it connected to the ground? Of course it could be a wash with more weight needing more stopping distance?

    In my old city I had several spots where I could guarantee it would happen but now I've moved. It's a tricky thing to recreate. Seems to want just the right bumps.
     
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  8. bisco

    bisco cookie crumbler

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    exactly.
     
  9. David Beale

    David Beale Senior Member

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    No, heavy wheels are harder to control. They do hop better. It's not the wheel weight that keeps it on the ground, it's the cars weight. The wheel weight introduces inertia in the suspension, so the wheel can't exactly follow rough ground. It "jumps over" a bump, leaving the surface once accelerated off it by a bump. If the wheel had zero weight it would follow the ground perfectly. Another way to think of it is the wheel interacts with the spring force, not the weight of the car.
     
  10. Emma7145

    Emma7145 Junior Member

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    Hmmm... The physics on all this is getting complicated. I was a French major so I'm just gonna go with it : )

    I did go out and test drive a 2016 Four and the breaking and handling was so vastly improved from my 2011. I found the worst road I could and tried to make it skip but couldn't. I guess I couldn't rule out that it could still do the shoot forward thing but I didn't even get a hint of that at all.

    Personally, I would feel safe in a 2016 or 2017. Now the question is do I try to get a preowned 2016 or, since I only want a Two, go for the new 2017 with the updated safety package? Decisions, decisions...

    Thanks for the input!
     
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  11. bisco

    bisco cookie crumbler

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    someone said there are a ton of '16's on the used market because they all traded in for the '17 with safety.
     
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  12. Raytheeagle

    Raytheeagle Senior Member

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    Is that the cause of the slow rollout of the 17's? I know the local dealer around here only had a couple of 17's and a glut of 16's( they even still have a couple of new 15 Gen 3's left).
     
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  13. bisco

    bisco cookie crumbler

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    idk, but that would make sense. judging by the incentives on the 16's, toyota may have backed off production.
     
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  14. liskipper

    liskipper Member

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    My 2010 was terrible with that braking problem. Just got a 2013 that is noticeably better, but it still has the problem.


    Posted via the PriusChat mobile app.
     
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  15. Emma7145

    Emma7145 Junior Member

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    Liskipper, sorry you still have the issue but appreciate the input! The dealer was encouraging me to look at a 2014, which would make a lot of sense from a financial standpoint (and I like the look of the Gen 3 way better). But, I know I'd be disappointed if it still had the stopping problem.

    I have only just started looking but I am seeing more used 2016's than I would expect. My guess was that maybe the dealerships had bought them for loaners because they were not selling because people were waiting for the 17's?

    It seems funny that someone would trade in a 16 for a 17 with the safety package... If they wanted it that much and have the money to trade in a year old car, I would think they would have just have paid extra for a 2016 Three with the safety package option. But, I say that as a person planning on trading in perfectly good Subaru so who knows!
     
  16. Prodigyplace

    Prodigyplace Senior Member

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    I voted for the 2017 for the safety & because I wanted a spare tire. I would need to get a 2016 Three with ATP, I believe to get what I have in my 2017 Two.
     
  17. Emma7145

    Emma7145 Junior Member

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    I ended up going with a regular 2017 Two. I looked at getting a new 2016 model with ATP but the price is got a bit high and it seemed like it was mostly for a lot of gadgets that I wouldn't use anyways.

    I tried to find a certified 2016 with ATP but they just weren't that many out there. And the few that were available seem questionable ( sold at auction, rentals, two owners and seven months… ). Also there wasn't that big of a price savings to justify the risk.

    So in a few months I'll be able to say whether or not the issue was resolved on my new Gen IV but so far so good!!!
     
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  18. bisco

    bisco cookie crumbler

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    congrats, all the best!(y)
     
  19. Emma7145

    Emma7145 Junior Member

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    Just as an update... I've been driving the 2017 for about 6 months now and it does handle much better than the 2011. There have been one or two times where it has been just a little bit jumpy with stopping but, for a car of its size/weight, it's probably to be expected.

    So the new model is clearly better than the last but I still find myself pining for my old one. The design, comfort, etc, was so much better. Everything but the braking! Oh well, maybe that's just how it goes with your first love! ;)
     
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  20. Tideland Prius

    Tideland Prius Moderator of the North
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    Yup. The Gen 2 was our first Prius and I still love it (even though we got rid of it last year).