Braking performance

[Lord Voltermore]

Despite my earlier comment about doubting Honda would fit brakes inferior to their rivals i have a couple of theories   

I have noticed on cars I have owned in recent years that my brake rotors (discs)  dont seem quite as bright and shiny as some other cars appear to have.   Still shiney, not rusty or scored, but  just slightly darker in hue.   This has applied not only to different makes of car   - Toyota Yaris, Opel Corsa and Renault  and the Jazz ,  but after many years of use both the Yaris and Corsa had replacment discs and  pads made by Brembo.  Or maybe its just my imagination  , the 'grass ' is always shinier on the other side of the fence.   

I suspect this is because I am habitually light on brakes , and the cars sometimes went  long periods without use  and get some surface rusting  to the discs.   The chosen brake pad material can make a difference.  .  Either they work immediately, but soft and  wear out very quickly  ,  or are harder and last longer but only reach full performance when hot.   These extremes are fine for  competition or sports use  , but for  normal road use  they try to find a compromise between the two.

Could it be  that because the Jazz hybrid  uses  regenerative braking  much of the time  (more or less depending on whether you use B or D )   So for some drivers  it will take longer  for any surface rusting to be cleared   or for the brakes to heat up enough for full performance.       

On the plus side the Jazz has  emergency braking assist  which in the event of you having to make a more rapid stop  than usual   increases the braking  effect.   This could be why Hicardo felt braking normally adequate, but sometimes improve.  It  may have influenced Honda in their prefered compromise in brake pad material.    Also the journalists comparing the braking of various cars may not have experienced this effect or misinterpreted it as poor braking.     You dont need powerful brakes  except for the times you do need them.   

Its helps  to 'derust' your brakes from time to time , and I have recently discovered the best way is to pull the handbrake  toggle switch up  on the move - somewhere quiet  . All four brakes apply so you dont lose control, and you can feel the rate of braking effect increasing. 

I remain happy with the performance of my brakes.     

[plasma]

+1 , I find the brakes top class

Plasma

[peteo48]

I can't find the link now but I saw a You Tube video by a tyre reviewer making a general point that OE tyres were never the optimal choice for any given car - in short he was saying you absolutely cannot trust the car manufacturer to put the best tyres on the car. Compromises would be made in all sorts of areas. One area was wet braking, another was tread depth (a lower original tread depth would result in marginal weight savings was the argument iirc).

I felt in absolutely no position to either agree or dispute this man's findings - I simply don't have the knowledge but, in the comments section there were people who had scrapped the OE tyres immediately on buying the car!

If I find the video I'll post it but I can see how a car manufacturer might not fit the optimal tyres looking to fulfill other criteria instead (not least cost).

[Pine]

Corrosion of disc brakes is common on hybrids of all makes because most of the braking is done by the retardation effect of regeneration.  The physical brakes only come into use when you get down to approx 5mph or brake firmly.  To get surface rust of the discs get up to speed, move into neutral to stop regeneration and brake hard.  Do this at your own risk only on a quiet road when there is nobody behind you.

[shufty]

I can't find the link now but I saw a You Tube video by a tyre reviewer making a general point that OE tyres were never the optimal choice for any given car - in short he was saying you absolutely cannot trust the car manufacturer to put the best tyres on the car. Compromises would be made in all sorts of areas. One area was wet braking, another was tread depth (a lower original tread depth would result in marginal weight savings was the argument iirc).

I felt in absolutely no position to either agree or dispute this man's findings - I simply don't have the knowledge but, in the comments section there were people who had scrapped the OE tyres immediately on buying the car!

If I find the video I'll post it but I can see how a car manufacturer might not fit the optimal tyres looking to fulfill other criteria instead (not least cost).

...Was it this chap?

www.youtube.com/@tyrereviews

[coldstart]

Thank you all for your thoughts and inputs on this matter!

A special thank you goes out to @peteo48 for remembering and @shufty for finding the Youtube-video!

(it confirms my doubts about manufacturers having our best interest in mind when choosing the OE tyres)

[peteo48]

Yes shufty - that's the one. Thanks for posting.

[Lord Voltermore]

Very interesting Video.

  I didnt realise OE tyres sometimes  skimp on tread depth to optimise rolling resistance  eco results  , dry braking and noise level.

  I had always  assumed a rule of thumb that new summer tyres had about 8mm and winter tyres had 9mm  . The first time I checked my OE Yokohama Blue earths after not very many  miles they were already  under 7mm  .   I checked my  Goodyear Vector all seasons before use and they had just under 8mm.   

[shufty]

...The Michelin Primacy 4 on the HR-V only came with 6mm 

[peteo48]

I guess the bottom line is OE tyres will be OK and certainly not dangerous but it did shatter the illusion I had to the effect that the engineers from the car manufacturer will try to find the optimal tyre for the car.

Being a bit of an old codger I very rarely get close to extreme driving scenarios - I don't corner at high speeds, I don't slam on the anchors in the pouring rain, I very rarely exceed 70 mph etc etc so I rarely get close to being able to say one tyre is better than another.

But - more powerful car, bigger annual mileage, more frequent driving in all weathers then I can see why some people will want tyres with better performance than OE ones.

[Hicardo]

Well, by chance, had to do a sharp piece of braking on the A1 today when  a driver cut in front of us and then braked fairly hard for some reason (I dont think he knew what lane to be in for upcoming junction), and obviously I hadn't had the chance to gap myself to him appropriately after his manoeuvre, so I had to hit the anchors quite hard.  The brakes were OK, just felt bit spongey when I stamped on them.  Left feeling non-plussed.  I'll do a rapid stop from speed, somewhere where its safe (not on the motorway!) to test them again, and see what transpires.  The road was damp and the temperature was about 12 degrees btw. 

Service is coming up soon anyway, so I can get them checked.   

[coldstart]

Being a bit of an old codger I very rarely get close to extreme driving scenarios - I don't corner at high speeds, I don't slam on the anchors in the pouring rain, I very rarely exceed 70 mph etc etc so I rarely get close to being able to say one tyre is better than another.

I tend to an anticipatory driving style as well (otherwise fuel efficency in the high sixties wouldn't be possible).

However, when push comes to shove I prefer the advantage of a truly good tyre!
(the cost of even the slightest "crash" will by far offset the difference in price of a cheap and a good set of tyres!)

Plus: As I'm getting older, I seem to increasingly value my life more than a few quid well spent.

[coldstart]

The brakes were OK, just felt bit spongey when I stamped on them.

And your brand of tyres is?

[Lord Voltermore]

I have another theory with no expertise or information. Yesterday I gave my brakes a derusting using the handbrake switch.  The car had been unused for a couple of weeks in damp weather and the discs had slight surface rusting.  When first driving off the brakes were grinding slightly. 

The handbrake stops cleared the rust almost immediately. In the interest of 'science' I did a few extra stops.   

The handbrake stopped the car very rapidly  .Initially the effect is slower, maybe in case of unauthorised application by a passenger  but quickly  becomes an increasingly  powerful stop. About as rapid  as it could get  without actually locking up the tyres on the dry road. (So powerful I had to abandon the tests as I was starting to get car sick    )    In this respect less is more. When tyres skid it reduces stopping ability .ABS actively strives to limit skidding. 
 
Professor ( )  Voltemores conclusions.
 Could it be that Honda have sought to increase braking in real terms by toning down how powerfully the brakes are applied in normal driving situations,  but retaining the ability for 100%  stopping ability in an emergency.  ? 100% in real terms  , with less requirement on the driver to moderate their braking  on certain road surfaces  to suit  the cars instantly powerful brakes.

Second finding was that all four brake discs got hot and were derusted  during tests.

Third finding   Dont do the tests immediately after a meal.       

[ColinB]

... retaining the ability for 100%  stopping ability in an emergency.  ? 100% in real terms  , with less requirement on the driver to moderate their braking  on certain road surfaces  to suit  the cars instantly powerful brakes.

In an emergency stop situation, both the auto emergency braking (which takes over from the driver to apply maximum brake pressure) and the ABS (which attempts to minimise stopping distance and improve control) will come into play. Attempting to second-guess these seems pointless: just put your foot on the brake as hard as you can, the car will stop just as quickly as it can.