Experience of StopTech Pads

[Stutopia 158]

Over the winter months I’ve noticed on motorway runs that the initial bite of the brakes really isn’t great. This tends to be when it’s particularly cold and wet (I do appreciate that cold brakes aren’t as efficient, but it’s more pronounced than I’ve ever noticed on any other car). The usual light dab to shave off a few MPH yields little stopping power, so I get on them a bit harder, this generates some warmth and then all is good. If I get on them hard straight away there’s a little, slightly disconcerting, pull to the right before returning to normal braking. Other than this, they perform very well when I’m driving in a spirited fashion or the weather is a touch warmer.

Naturally I asked my tech to check the braking forces across the wheels and he advises they are spot on, balanced almost perfectly left to right. This leaves the pads. Anyone else running StopTech pads (or even other brands) experienced similar results on the motorway in the cold?

Thanks, Stu.

[will300 812]

My Ferrodo DS2500 can be a bit like that when cold, they're fine once up to temp. I don't have any balance issue's with them.

[Church 209]

Hmm. Wait. You are using aftermarket track brake pads and complaining about cold bite?

[Deacon 1357]

My Project Mu's are also similar when cold. 

[Stutopia 158]

1 hour ago, Church said:

Hmm. Wait. You are using aftermarket track brake pads and complaining about cold bite?

Not as far as I know, I believe they’re street legal.

[Stutopia 158]

1 hour ago, will300 said:

My Ferrodo DS2500 can be a bit like that when cold, they're fine once up to temp. I don't have any balance issue's with them.

Hmmmm. I used DS2500s on my 350z and never experienced this, even first press in the morning in winter.

[surrey86 352]

I get this sometimes on Carbotech XP8 & Yellow Stuff. If I'm on a long motorway journey in the wet I occasionally dab the brake even if I don't need to, in order to get a bit of heat into them.

[Lauren 2259]

It's much the same with my DS2500's. Had the same with Stoptech, had the same with Project Mu HC800's. All are absolutely fine once you've actually used them. 

What's a 'tech'? Do you mean mechanic? 

[Church 209]

There are no pads good for everything and that imho should be end of story, as one should choose right tool for a job.

IF cold stops in colder weather matter more, choose more street oriented range of pads, meant for lower temps.

IF more track capability is wanted for pads to not get baked/glazed even at very high temps on longer track sessions, get pads made for that, while compromising "streetability" properties, such as cold stop/cold weather performance, better wearing of rotors, less dusting.

While track pads can be used for street purpose too, as often that cold stop friction might be on par on stock pad friction, just that they often brake much better (sometimes even more then twice better) when at designed operating temps, problems with race pads are that their temp range may make it hard to bed brakes properly while driving on public roads and withing legal limits. Unbedded brakes with worn off bedded layer from pads on rotors, may brake & wear worse and squeel at every stoplight making one feel like idiot :(.

I'd say, just choose which properties matter to you most and choose pads accordingly. One cannot fault in any way pads that are used outside purpose they are designed of. Best of course would have been two pad sets which get swapped according use, but some may find it too tiresome. But then one has to accept as is faults/deficiencies of misused pads. There are no pads that do anything well after all.

P.S.

I myself use DS2500 too (on stock brakes) all year round. These are certainly not proper race pads, but a bit better then stockers for track abuse. I guess, what is called "hybrid" pads. They indeed work a bit worse for first stops, but not unmanageably worse, but at least they don't squeel even in winter, even if i haven't tracked for long. They dust badly though

[Stutopia 158]

1 hour ago, Lauren said:

It's much the same with my DS2500's. Had the same with Stoptech, had the same with Project Mu HC800's. All are absolutely fine once you've actually used them. 

What's a 'tech'? Do you mean mechanic? 

Yeah, mechanic.

[br0wny 27]

Not noticed with the 86 as I don't use it much and have been lucky to not drive it in harsh conditions. 

My m135i was the same on the motorway even on stock pads. In the wet was sometimes scary how hard you needed to press the brakes just to shave a few mph haha! 

Changing pads on the 86 in a few weeks to project mu (sucker for the colour) so shall bear this post in mind 

[Varelco 211]

Got to say I've notice this on the stock pads over the past few months. Not sure if it's weather related or wear. They feel the same, just don't have the same grab, it feels like I have less brake assistance if that makes sense. 

[nerdstrike 186]

A poor bite when cold is very much par for the course for "fast road" pads. I felt similar on a set of Hawk HPS in my last car.

As Church says, pad composition is pretty scientific and little to do with the brandonium they're made of. The coefficient of friction of fast road pads falls away as temperatures go from warm day to cold winter, giving you a dead pedal on a cold wet rotor until enough heat builds up to get the compound working properly.

Indicative friction versus temperature graph

You can see that the Hawk HPS pad has half the friction of their random OEM pad at room temperature, and you don't get maximum stopping power until around 250 celsius. Sadly I cannot find a graph for stoptech pads, but you get the idea.

[Stutopia 158]

Thanks all for the info, much appreciated.

I’ve run performance/track pads before but never noticed such a pronounced drop off when cold, hence my question. Obviously I’m just used to the greater clamping force of bigger brakes or a compound that warmed up a fraction quicker. 

[Church 209]

Stutopia: take a look for this sample chart friction Mu vs temps:

Other vendors probably also have pads covering different temp ranges as optimal operating ones for them. This helps to see why those cold stops for some pads may have friction worse even twice or more for first stops in cold and why/how it differs for different pads designed for different uses. Luckily it's rare one needs heavy braking from car just started, as it's usually waiting a bit for engine to warm and slow moving in yard inner roads to normal ones ..

Check nfo in links / charts here for example.

[McDude 40]

I've got stock pads on my BRZ and never noticed this, however I ran various different pads on other cars. What is usually termed as a 'fast road' pad has been okay, so Mintex 1144 were fine when cold, but Mintex 1155 whilst better on track suffered from that initial loss of bite you describe which does create a confidence dip when cold. It's worse than a confidence dip though because you actually aren't braking for that time.

Church (and others) have got it spot on, you really need a more road focussed pad if you are on the road. I'd even argue that track pads aren't that safe on the public road because they perform poorly at cold temps.