Lamer question coming up.

I keep seeing this term in some of these brake posts, and I was wondering what it means.

Could anyone give a description of it and how you go about measuring it.

Cheers

Gary

 

I think the term you are referring to is the initial feel of the brakes when pressure is applied on the brake pedal.

Some performance brake pads only work at very high temperatures, and don't work well from cold. Thus, the initial bite of such a set of pads wouldn't be too good, since you would apply pressure to the pedal, but nothing much would happen for the first few moments until the pad warmed up. This can be a little disconserting!!

A good set of road pads will work pretty much from cold, and so when you stamp on the brakes, the pads will bite straight away - ie, the initial bite will be very good.

I don't think you can measure 'initial bite', as it is subjective - different people have different opinions on what feels 'good'.

Hope this helps. Oh, and I stand to be corrected if I'm wrong!

Dave

 

Cheers for that Dave,

To be honest though, I have used a high temp brake Pad (Pagid RS19 - I think thats the one, yellows I believe) and they certainly don't get up to temparature in the amount of time you are talking about. Much more like a good lap (well couple of corners) than just braking once.

I can't remember the figures, but the friction coefficient was about 30% less when cool as opposed to working temperature (again can't remember what that was for that pad - about 400 degrees I think).

This is why I thought it was maybe something more subtle ?

 

Gary, I think Dave has answered your question in that when most people refer to 'bite' they are talking about how long it takes higher rated 'track' oriented pads to work when you hit them hard from stone cold on a winters day. This is obviously a very important factor! Maybe 'delay' might be a better term?

I'm preparing a Brakes feature for the forthcoming ScoobyNews CD and have stacks of data from the likes of AP Racing, having spent a fantastic day there. Really fascinating stuff, but there's a lot to get your head around!

They have various measures for bite, including how the friction coefficient varies from the start of the stop to standstill, average friction, cold friction, friction consistency depending on load and heat...

Some measurements are very scientific and objective (a brake dyno test can tell you a huge amount) but some is subjective.

ScoobyNews should be out in a couple of weeks.

Richard Hopkins

PS One thing is clear. A braking system, especially pads, that works well from freezing as well at 600-plus degrees is asking a hell of a lot. Best to get road pads for road and track pads for track - they only take a few minutes to change, you'll get better braking all round and much better pad wear. Cheaper, better, safer.

 

Richard

Excellent ! that is exactly what I wanted to hear ! Sure some of this stuff is subjective (ie how adjustable the brakes - how easy to modulate the braking) fine, but I always wondered why things like Bite, working temparature, frisction when hot cold were not available. Excellent ! I will be able to make an informed decision next purchase.

Your point about compromise, yes I agree. I am specifically looking for cheaper pad with average friction that works at high temperatures. Couldn't care less about cold weather as these are for the track only, I just want to bring the total cost of a track day down and brakes / tyres are my major expenses.

Dave

Now that I think more about it, I think I do get this thing with the Pagid pads, I only notice it very first thing in the morning - don't know why I don't notice after a motorway run, maybe thats because I'm on the brakes harder so they heat up quicker.

You learn something every day etc

 

Gary, thanks for your positive response

I too want to reduce the cost of track days while extracting maximum fun, and wrecking a set of pads and discs is not the way to do it! (Been there, done that.)

The solution I've found involves heavy up-front costs, but almost zero costs on the day. AP Racing brakes (wanna buy my 4-pot 16in APR kit? 6-pots being fitted on Friday ), racing pads and part-worn slicks.

Richard Hopkins

 

Strangely enough I am supposed to be buying Stef's set of AP's of him !

But I'm not sure I can afford it at the moment, I am tempted in trying out the HiSpec big disk upgrade (on standard callipers) as a cheap interim measure.

I'll let you know if I change my mind / make a decision / Stef decides not too sell.

Gary