Front brake disc recomendations

[Defender 3,834]

On 22/11/2019 at 07:54, Tex said:

 

I suspect (but don’t ‘know’) that’s because of the changes in friction materials. Back when I joined the motor trade (late sixties) I replaced loads of pads but hardly any discs. Friction linings had a good dose of asbestos in them, were ‘soft’ and wore much, much quicker than the iron discs/drums. Actually about the only times I replaced either discs or drums was when a careless owner allowed the friction material to wear down to the backing plate/rivets and score them.

Now, of course, friction materials are sintered metal and are just as hard as the steel discs. The pads last a lot longer, but when they wear out they take the discs with them. They work bloody well though, no way would I want to return to sixties level stopping power. No way at all! 

I had a 1989 Vauxhall Astra, it was my first company car, it had a 9000 mile service interval, every service the brake pads had to be changed as the wouldn't last until the next service and that wasn't just down to me as we had another one in the company and that was just the same, every 3rd service, 27,000 miles it had a set of discs too. 

I'm in the process of changing the discs and pads on my 'Freelander, the slider pins on one caliper had got stuck so only one pad was doing the braking and was worn out and the other pad was almost as good new, I don't like sliding calipers TBH, but they are very popular as they are cheaper to produce so the manufactures like them.

My old Defender 100" Hybrid, had 1973 Range Rover brakes on both axles, which were opposed piston calipers, having four pistons on each of the fronts and two pistons on each of the rears, I never had a issue with them despite their age etc, they are a much better arrangement to my mind.

 

[MatBin 5,080]

4 hours ago, pjm said:

I have a recurring nightmare of not being able to get brakes to stop me, normally in a car. I never crash in to anything so assume it’s a self wind up. It could be the useless back brakes on most of the conventional bikes I have had over the last 8 years with the GS LC being the worst by far. 

In the old days bikes used to lock up the rear wheel just by looking at the break lever in the wet, so us old bikers hardly use the rear break these days anyway, just for settling the tail into/round a slow corner. :-)

[MatBin 5,080]

58 minutes ago, Defender said:

I know that dealership well, Ripoff & Scarper?

That was the bike dealer, sister dealer for cars - Bodgit and scarlet.

On that note anyone remember Pride & Clarke in S London, affectionately known as Pride & Sharks.

[pjm 6,041]

Yes but some old bikers like to be able to have all the brakes they can have if push comes to shove and although front brake takes the lions share its no good if your back brake is so weak it so t hold you on a hill start. Perhaps that's why BMW added hill hold as an option.

[Defender 3,834]

9 minutes ago, MatBin said:

That was the bike dealer, sister dealer for cars - Bodgit and scarlet.

On that note anyone remember Pride & Clarke in S London, affectionately known as Pride & Sharks.

I was told they were known as Bribe and Shark, that was in the mid 70's when I started to get into bikes.

[Defender 3,834]

16 minutes ago, MatBin said:

In the old days bikes used to lock up the rear wheel just by looking at the break lever in the wet, so us old bikers hardly use the rear break these days anyway, just for settling the tail into/round a slow corner. :-)

I use my rear brake a lot, I always have done, also having done some off road riding using the rear is second nature and also as my '12 NC700X has C-ABS so the rear brake lever also operates the centre piston on the front caliper. 

I'm not sure if I fit into the 'old days' thought, I've only been riding 45+ years and still learning!

 

[pjm 6,041]

I do recall the rear brake on my RD350 making the rear tyre "skip" as it at least had the power to stop the wheel revolving. That's when I seemed to just get on and ride without a care in the world. I don't recall ever giving a second thought to counter steering, how to brake, Hendon shuffle, best line for safety or anything like that at all. It was just fun. I have become so risk averse I am amazed I get out of bed.

[Tex 36,816]

 

1 hour ago, pjm said:

 

I don't recall ever giving a second thought to counter steering, how to brake, Hendon shuffle, best line for safety or anything like that at all. It was just fun.
 

 

I think we were all like that.  

 

I ‘discovered’ counter steering on my Norton Commando one night on the way home from the Norton Owners Club monthly meeting at Brighton. There’s a fast (80mph) S bend and to get it from the right over to the left needed a good shove on the left bar. That was the ‘penny dropped’ moment for me, the moment when I realised that riding was a science and not just luck. I began thinking about what I was doing (before that I just used to rush up to a corner and play with the bars until I got round). 

 

[MatBin 5,080]

1 hour ago, pjm said:

I do recall the rear brake on my RD350 making the rear tyre "skip" as it at least had the power to stop the wheel revolving. That's when I seemed to just get on and ride without a care in the world. I don't recall ever giving a second thought to counter steering, how to brake, Hendon shuffle, best line for safety or anything like that at all. It was just fun. I have become so risk averse I am amazed I get out of bed.

Agreed, long time since I heard "Hendon Shuffle". I still put my right foot down at a stop though. No idea if I counter steer. Best line for safety only seems to work if your fairing has 2 blue lights. I still ride by instinct (I think),  >45 years, seems to have worked so far.

[Andy m 23,472]

1 hour ago, pjm said:

rear tyre "skip" 

 

I assume on a drum? It's an odd phenonoma. The wheel locking up causes the temperature at the contact of shoe and disc to peak and expand out ot contact. At the same time the tyre has turned into a toboggan so the wind up in pivots, cams, back plate bearings, shocks and tie rods can relax. If its specific to a certain load and surface there isn't a subtle cure because harsher linings or turning the back plate just move the point it happens. If it does it every time it approaches the lock there are unsubtle cures. Fit a bigger actuator and the resulting hair trigger gets the ABS cycling so fast no one notices the clunking. The options on a rod operated drum are few though, cam profile might do it. There is a coffin corner on the charts though where you choose between having controllable braking and avoiding a bit of clunking. Squeal is even worse. 

 

BMW changing wheels is an ABS sensor issue. Sounds like they had run out. A couple of hours with a DTI and pack of shims required, or maybe just stopping the workshops pet gorilla throwing the wheels round while fitting. 

 

I was actually shown reverse steering on the CBT. The Hendon Shuffle wasn't called that but we did have end up on the back brake before setting off, so were shown how to recover if we ended up right foot down in the wrong gear. We also had to be in neutral at traffic lights. I'm guessing the tester was ex-plod and had a case of "foibles". 

 

Andy

[pjm 6,041]

I always thought it was the weight of the bike shifting forward and taking pressure off of the tyre allowing it to lock. It was a drum brake 1974 reed valve air cooled in purple. Loved it.

[Andy m 23,472]

Weight transfer is just a fact of life until the market accepts linked brakes or active suspension is legalised*. It leads to lock but the actual lock can be better handled. You shouldn't get judder and skipping if performing a full stoppie, the wheel just becomes stationary. Skipping along like something Barnes Wallis rejected as unworkable is a feedback loop you can try to break if it happens in regular use. Tractor units without the trailer are a laugh for it. Back in the day we'd offer a relay from the rear load sensing to change the front/rear balance to calm them down, some manufacturers would spend the money (and re-coop it in diagnostic work ten years later), some wouldn't. These days we just tick a box and the EBS is allowed more leeway in front to rear balance. 

 

*large bikes will get a form of electronic braking when they mandate collision mitigation. Once you have this you can let the rider decide to use whichever brake he likes so as not to annoy in normal use, but open the link electronically if Mr European Sportsrider never uses the rear or Mr U. S. Cruiserider never touches the front and **** happens. ETA IMHO, 2028.

 

Andy

 

 

 

 

Edited April 23, 2020 by Andy m

[MatBin 5,080]

Neutral at lights was/is my default gear. Except now out of 3 vehicles 2 are autos, so no longer really an option, although if in car and stop, stop, start traffic (M25 park and ride) I often throw the (auto) car into neutral if we're going to be stopped a long time, isn't a problem on the NC as it's always moving

[Defender 3,834]

Back on topic, I will check my discs thickness when I give the 'NC'X a going over, which is due very soon, along checking the pads for wear of course.

When I looked into front discs a little while back, I found you can get a 'Brand Named' disc rotor from just under £100, IIRC the ABS ring is mounted separately and isn't part of the rotor it's self?

 

[rjp996 1,091]

Yep the ABS ring is separate. I took mine off and the painted when I changed the disc - looked much better I will have to paint some of the other black clips and brackets now....

[Gerald 1]

75 k from your front disc whoa  mine was replaced at 6500mls as warped along with the rear  both under warranty, just replaced the rear again at 14000mls. According to honda dealer this is because I use the parking brake before the disc has time to cool down!!!!!!!!!

[MikeBike 5,005]

3 minutes ago, Gerald said:

75 k from your front disc whoa  mine was replaced at 6500mls as warped along with the rear  both under warranty, just replaced the rear again at 14000mls. According to honda dealer this is because I use the parking brake before the disc has time to cool down!!!!!!!!!

That's the first time I've heard that but know that my MOT has been close on pulsing probably due to the discs being warped a bit.

If it is a critical operational requirement to wait for a certain time before applying the parking brake, it should be stated clearly in the manual, especialy as a parking brake isn't something that most bikers have ever used.

[Gerald 1]

More likely just bullshit from the dealer. They didn't want to put in the warranty claim until I paid for the work upfront!! Unbelievable till I rang honda direct and they intervened. Main dealer for Suffolk, no names of course

[davebike 943]

Many BMW dealers fit that description ! I now recomend if you want BMW but new and sell when you can no longer extend teh warrentee !

we do a little BMW work and know of independant that will do more ! I still considering updating my GS911 coad reader and sets service light for more modern bikes but £££ for a dealer version not limited to a few bikes! From South Africa  so + import duty + VAT

only Apprilla and KTM are worse !

[Iron horse 121]

I've just changed my front OEM disc for a Brembo. The old disc was pretty worn and was actually dished. The new disc is noticeably chunkier. I'll need to get a few hundred miles on it  before I can really comment on performance, but all good so far. Paired with a set of EBC HH sintered pads, btw