Braking performance

[coldstart]

I'm somewhat concerned because (german) car reviews regularly seem to depreciate the Jazz because of abismally bad braking performance 

Examples (sorry about the german)

The Jazz bested several categories but was depreciated because of bad braking performance (again):
 https://www.autozeitung.de/honda-jazz-mazda2-renault-clio-toyota-yaris-vergleichstest-205320.html
https://www.auto-motor-und-sport.de/test/honda-jazz-seat-ibiza-und-toyota-yaris-vergleich/

My pet theory is that the Yokohama BlueEarth tyres are to blame for this (which is why I had my Jazz ordered with Michelin Primacy 4+ tyres and I feel quite comfortable with them).
I have to admit though that I've (yet) not been in an actual emergency situation where every inch would count - as I'm getting older, I'm tending to a more and more relaxed and defensive driving style 

My first car was a Citroën 2CV which rolled on measly 125/15 tyres but weighed only about half of a modern Jazz. My last car at about the same weight as the present Jazz was sporting 215/17 wheels and was "cornering like it was on rails" (to quote "Pretty Woman") - I had to severely cut back on my "cornering ambitions" when switching to the Jazz 

However, I still think that the quality of those few square inches of rubber which make the contact to the road make all the difference! (and the factury fitted Yokohama BlueEarths imho just don't cut it!)

What is your experience? (and what tyres have you fitted?)

[ahavoja]

What is your experience? (and what tyres have you fitted?)

I also believe that the traction of the tyres may be the limiting factor when braking, because I think the brakes on most cars are strong enough to fully lock the wheels even on dry asphalt.

I tried Yokohama Advan dB V552 tyres on my Crosstar (in size 195/65R15) before the winter came. It felt like they had more grip in tight corners on wet asphalt compared to the original Crosstar tyres, Dunlop Enasave. It also felt like the Advan dB required lower tyre pressures to achieve the same level of comfort. This could be because they have a higher load rating. The lower pressure must have increased the tire contact patch area, which could also have improved grip.

This link explains the the tyre load rating more: https://tiresize.com/pressure-calculator/

Another thing is that when you press the brake pedal on Jazz, at first the hybrid system only brakes with the electric motor, charging the battery. When you press the brake pedal further down, Jazz starts braking with the disc brakes. Maybe this causes a slight delay before getting full braking force?

[coldstart]

Another thing is that when you press the brake pedal on Jazz, at first the hybrid system only brakes with the electric motor, charging the battery. When you press the brake pedal further down, Jazz starts braking with the disc brakes. Maybe this causes a slight delay before getting full braking force?

Thank you for your response!

I'm assuming the testers know how to "put the pedal to the metal" and the Toyota Yaris e.g. is a hybrid car as well but performed far better in the comparison.

Regarding tyres: I understand that "Yokohama BlueEarth" seems to be kind of a brand that comes in a lot of flavours!
Unfortunately Honda seems to see fit to slap the cheapest kind onto our cars     

Honda is however not the only manufacturer to take this road - VW e.g. seems to hate the BlueGT (my former car) buyers...
The originally fitted Bridgestone Potenza 050 tyres were a disaster in the wet - moreover: They had all the usual performance indicators meticulously erased 

As I value my life largely over the price of a good set of tyres I had them scrapped after the first few thousend miles and bought Goodyear Eagle F1 Asymmetric 3 (later 6) and never regretted it! Wow, what a difference! Wet or dry: The car with these tyres felt like "glued" to the road!  (that's part of why I had to somewhat reduce my "cornering ambition" when switching to the Jazz) 

Pity Goodyear doesn't offer them in the measly Jazz wheel size  :'(

[ColinB]

My German language skills aren’t up to reading the two articles, but I assume they’re reporting road tests in which overall braking distance is measured under emergency braking conditions.

My understanding is that most modern cars, including the Jazz, have an ABS system. This acts to prevent the wheels locking up under heavy braking, which has two outcomes:
1. The car can be steered whilst braking.
2. It ought to reduce braking distance because the coefficient of friction between tyres and road is greater if the tyres are not sliding; static friction (“stiction”) is greater than sliding friction.

However there are opinions that under some conditions (eg a loose surface) ABS can actually increase braking distance. And it’s clear that the efficiency of the overall braking system under extreme conditions is dependent upon the details of how the ABS works (eg the frequency and duration of the on/off braking pulses).

So any road test of a car, and measurement of braking distance, is actually measuring the combination of tyre friction and ABS efficiency. You can’t blame poor emergency braking purely on the tyres.

Edit: And don't forget the automatic emergency braking, which detects that the driver wants to stop quickly and automatically applies maximum brake pressure. So that's another system, outside of the tyres, that may influence the overall braking distance.

[Lord Voltermore]

The German articles will translate  into English, but not the initial banner where you need to make one of several choices, one of which involves  monthly fee.  Can anyone advise which box I can safely press without agreeing to any  unwanted subscriptions and notifications  etc.  ? 
 

[Nicksey]

I like to think I drive within the limits of the conditions I am driving in. My Jazz stops as well as all the Renaults I have had, it holds the corners just as well too. A bit of understeer.. but my Capturs and Clio were just as guilty. As a motorcyclist, I have always driven defensively, and try to anticipate the road/traffic ahead.

[CB72]

Does the German review say which tyres the cars had on and the condition of the tyres, if not then the test is meaningless. Surely a braking distance test is all about the tyres not the car.

[ColinB]

Surely a braking distance test is all about the tyres not the car.

Disagree. If they measured the braking distances of cars, that tells us something about the overall performance of the braking systems, not about any component of the system such as the tyres. If you want to know about tyre performance you would use the same car with a range of tyres, or maybe some clever test rig.

Bottom line though, from Coldstart's original post, is that the tests seem to suggest that the Jazz's braking performance (ie the aggregate performance of all components of it's braking system) isn't as good as it's competitors.

[CB72]

Surely a braking distance test is all about the tyres not the car.

Bottom line though, from Coldstart's original post, is that the tests seem to suggest that the Jazz's braking performance (ie the aggregate performance of all components of it's braking system) isn't as good as it's competitors.

OK then, did they use the same brand and specification tyres on all the tested cars?
If they had the Yokohama BlueEarth on the Jazz and maybe Bridgestone Turanza on the comparison car that may explain the difference.
Also were the road conditions exactly the same?

I'm trying to defend the Jazz here!!

Whch? only give the Jazz 2 points out of 5 for braking, so maybe the Germans are right
Honda Civic gets 4 points.
Toyota Yaris gets 3 points.
But then again they don't give details of the test.

Maybe get some better tyres for the jazz rather than the supplied Yokohama BlueEarth to inprove the braking.

[shufty]

...The Yokos were fine on the Jazz.
Tried a few emergency stops originally and had no problems at all.
The were OK in the wet too.

Only downside was the wear. Shocking.
Nearly 16k miles before the fronts needed replacing. Which is terrible.
Other problem with the jazz was the range of tyre pressures you could have depending on speed and weight on board.

HR-V just sticks to one thankfully.

[Lincolnshire Rambler]

After I had done a few thousand miles in my new jazz I did a jump on the brake pedal emergency stop -along our empty country lane at about 40 mph in the dry … short enough stopping but more worrying is that the morons who drive 3m away from my rear bumper too many times have no chance of avoiding collision with me if I ever needed to do another emergency stop!  I like to keep a good distance behind the vehicle in front so I can see the pot holes I need to avoid -you can’t see them fast enough if you get too close and they are a major hazard !

[Jazzfan49]

My 23 reg Jazz SR has 12k miles on the clock and has Yokohama Blue Earth tyres since new, they still have 6mm of tread and I don’t drive gently or aggressively, as for braking efficiency never had a problem the car stops well even in wet conditions, when the tyres need replacing I will fit the same or equivalent to the car as I’ve never had need of an underwear change  but ymmv.
 

[Lord Voltermore]

I havnt been able to read the  German reports  but I agree with CB72.    It likely to be more about tyres.
Have Honda really fitted smaller brake discs  and callipers ,or found some other way of having inferior brakes to rivals  ?  I doubt it.
 
On the other hand they have chosen to have  185 tread width to possibly save a tiny amount of rolling resistance to improve  emissions and fuel consumption.  And have chosen Yokohama tyres, for better or worse.      On some dry road surfaces the narrower width might increase braking distance slightly.   But I understand that narrower tyres can actually have a  slight advantage in fresh snow and possibly puddles compared to wide tyres  .  They  cut through  down  to the road surface slightly better rather than aquaplaning over the top. 

You only need to read group test tyre reviews to see the difference  tyre brand can make.  A tyre of the same size, on the same car, on the same test track  conditions may stop metres sooner than other brands  . Why would anyone risk driving on anything but that tyre?    Because its often a compromise. A lower ranking tyre may be better in other weather conditions ,on some surfaces, and may have other advantages.   Sometimes if another organisation tests and compares the very same tyres on a different test  track  they get a different order of ranking for stopping distances.  Maybe also if they  test cars with different brands of tyre?

I am happy with the braking performance of my Jazz, both on  Yokohama Blue earth and Goodyear Vector all seasons.    . Maybe a McLaren with ceramic brakes could stop quicker, but I drive accordingly. Especially when tailgating a McLaren 

[coldstart]

OK then, did they use the same brand and specification tyres on all the tested cars?
If they had the Yokohama BlueEarth on the Jazz and maybe Bridgestone Turanza on the comparison car that may explain the difference.
Also were the road conditions exactly the same?

In the comparison test they tested the cars with the provided standard equipment (different wheel sizes and tyres for all four).
However we may assume that the road conditions where the same for all tests.

I agree that it is somewhat unfair to compare 215/17 with 185/16 wheels, but those are the choices of the respective manufacturers not mine - I have to (hopefully!) live with Honda's wheel choice but I can optimize the tyres.

[Hicardo]

An interesting topic.  Had my Crosstar nearly 3 years.  Thought several times that the brakes are not as "sharp" as i'd like them. 

But day to day it seems absolutely fine.  I think what seems to happen sometimes is the pedal feels a little initially dead, slow to get to the point where sharp braking happens. Mostly it feels normal under typical light braking.  So I wonder what's happening? Its never felt dangerous or made me think I should do something about it, but if I'm honest I have wondered about getting them checked a few times, and eventually done nothing. 

Btw my Crosstar is on Falken Euro All Seasons.  Generally like them and are better overall than the OE low rolling resistance summer tyres.  The braking feels somewhat more secure with these tyres.  .