How is “locking up” the measure of any brake for flip’s sake??

I’m kindof with you on this. I’m going to caveat the following with “I am not a physicist” however I see it like this:

When you apply the brakes what you’re trying to do is turn the kinetic energy of your bike moving forwards into heat …and in the case of Hope’s, lots of noise :-D.

When you lock a wheel all you’re doing is prove that you can very quickly turn the kinetic energy of a wheel’s rotation (but not the bike’s kinetic energy) into heat. It does naff all to disperse the kinetic energy of the bike (and more specificaly my mass perched upon it) as it hurtles towards a tree. In fact all that happens is that the kinetic energy of the bike is transfered into heat build up of the now-locked tyre scrubbing along the ground.

Now, are there any physicists in the room to tell me exactly how flawed my logic is?

Something about a plane on a conveyor belt?

When you lock a wheel all you’re doing is prove that you can very quickly turn the kinetic energy of a wheel’s rotation (but not the bike’s kinetic energy) into heat. It does naff all to disperse the kinetic energy of the bike

Yup, understood 🙂

It’s happened when ive come round a corner or bend and suddenly happened upon someone and their dog. A frightened sudden yank on the back.
At least it straightens me up.

I’ve got Magura, Shimano and Sram brakes on my bikes, no real issues with any of them.

🤷‍♂️

Might buy some hope calibers for the cross bike though. They’re very pretty. 😏

My road bike has shimano levers and hope calipers…

I noticed these new levers at ardrock, saw the guy who won the vets, lightning fast down stage 7, so had a sneaky look at his bike back in the event village front of the hope tent, difficult to tell without all the e4s on other bikes

You can put the bigger RX4 mineral oil piston seals in E4 calipers and mate then to Shimano master cylinders in theory.

That way you get a pretty caliper that won’t leak and a more grabby lever that will lead and randomly pull to the bars.

You can put the bigger RX4 mineral oil piston seals in E4 calipers and mate then to Shimano master cylinders in theory.

That is an interesting idea.  If my Magura callipers ever let me down I may investigate further.

a more grabby lever that will lead (leak?) and randomly pull to the bars.

Not experienced that so far but I do agree with whoever said the Shimano master cyclinder could do with a greater capacity.

How is “locking up” the measure of any brake for flip’s sake??

Your maximum braking power is achieved with the wheel right on the limit of locking up. If a brake is capable of locking up a wheel, then the limiting factor is tyre grip, not the brakes (this is irrelevant if going OTB is the limiting factor). When you get a brake that can’t even lock up a rear wheel, then you know there’s something seriously wrong. It’s not that you want to lock up wheels, it’s that being able to lock them up is a very simple test of whether the brakes are working properly.

Good brakes can apply more braking force before locking up.
Bad brakes lock up with lower braking force applied.
Really bad brakes don’t lock up at all.
Therefore ability to lock a wheel is nowhere near a reliable indicator of braking power.

Good brakes can apply more braking force before locking up.

simply impossible – basic physics.

You can put the bigger RX4 mineral oil piston seals in E4 calipers and mate then to Shimano master cylinders in theory.

Why not just use rx4 calipers.

@ofked needs to go back to school!

How did GCSE/O’Level physics go for you ofked? 😁

simply impossible – basic physics

Might be worth letting the F1 engineers know. They can save a fortune on carbon ceramic disks as some brakes from a Fiesta would lock the wheels up.

How did GCSE/O’Level physics go for you ofked?

I presume he is getting at the fact that good brakes allow you to feel where the locking up point is more accurately and hence allow you to get closer to the limit without locking up -ie modulation/sensitivity, which is what all the hope fan boys rave about, rather than saying that they increase the grip of the tyre – which is plainly wrong. it was Badly worded , but I think (guess) that was his point.

It’s not just feel. It’s how quickly you get there, how long and how sustainably you can hold it there, how repeatable it is, and many other factors. There’s a world of difference between good brakes and great brakes. Both can lock the wheels.

Why not just use rx4 calipers.

Because:
E4 have 2 large pistons compared to the RX4
E4 are a different caliper to E4 in terms of bleed port design (E4 needs no special tools)
MTB’ers with Hope brakes are more likely to have a complete set of E4’s already and not RX4 calipers

I didn’t say I was going to do this – I can set my E4’s up properly and have no issues with them on my bikes with them – just it was in theory possible for those who prefer no modulation combined with a lucky dip on whether the lever will hit the bard before the rakes come on, but not having to replace calipers al the time (while claiming it’s a bargain because they get free pads).

Good brakes can apply more braking force before locking up.
Bad brakes lock up with lower braking force applied.

No, they do not. How much braking force is required to lock the wheel is just a matter of tyre grip. Good brakes have better modulation. That makes it easier to judge how close they are to locking up but it doesn’t affect the actual braking effort required to lock up.

A Fiesta brake would not survive on an F1 car. F1 cars use carbon brakes and they glow red hot, that’s how much heat they have to dissipate. If you put Fiesta brakes on an F1 car, they wouldn’t last a single hard stop – the fluid would boil and the pads would glaze because they could not dissipate heat fast enough. An F1 car’s brakes are designed to dissipate probably 10 to 20 times the energy of a small road car’s brakes.

A Fiesta brake would not survive on an F1 car. F1 cars use carbon brakes and they glow red hot, that’s how much heat they have to dissipate. If you put Fiesta brakes on an F1 car, they wouldn’t last a single hard stop – the fluid would boil and the pads would glaze because they could not dissipate heat fast enough. An F1 car’s brakes are designed to dissipate probably 10 to 20 times the energy of a small road car’s brakes.

I totally agree that they wouldn’t be as good, but they would be capable of locking the wheels. The point is simply being able to lock the wheels is not a good metric.

No, they do not. How much braking force is required to lock the wheel is just a matter of tyre grip. Good brakes have better modulation. That makes it easier to judge how close they are to locking up but it doesn’t affect the actual braking effort required to lock up.

You are missing the time factor. If it takes 1 second to get to locking up then that is less braking force than taking half a second. If you are cadence braking then that makes a difference and you will get more braking force from the better brake

When I ride on ice I can lock up either wheel even if I spray WD40 on the discs. Can we please stop talking about being able to lock up the wheels being any kind of measure of how good a brake is?

Also, on the subject of modulation, I think there can be some confusion between lever travel and force applied. I’ve tried Magura brakes and hated them. It’s the opposite of what I’m looking for in a brake. What people describe as ‘grabby’ I just think is the sign of a good brake (the exception being if the piston is sticking and then suddenly pops out when you apply enough force).

I want a lever that I can set up close to the bar. I want the bite point to be as close to the bar as possible and then, once the lever is at the bite point, I want as little movement as possible. Braking force should be controlled by the pressure I’m applying to the lever, not the lever movement.

With the exception of Maguras I can normally get my brakes to work this way with some careful set up.

I’ve got 3 sets of Hope brakes in a box in the garage. 1 set of Mono Mini’s and 2 sets of Mono M4s. 2 of them are so old they have IS mounts.

From memory I think it was sticky pistons that relegated all the 4 pot brakes to the spares box and they have stayed there ever since

I’m quite tempted to try and overhaul them but flogging the calipers on Ebay is probably a lot easier. My worry is spending time and effort on them to find out I prefer a £40 set of Deore

You are missing the time factor. If it takes 1 second to get to locking up then that is less braking force than taking half a second.

Nope, you are misunderstanding the physics.

Lockup occurs when braking force exceeds tyre grip. With non-ABS hydraulic brakes, if you stomp on the brake pedal or lever as hard as you can, you will apply enough braking force to lock the tyre effectively instantly (yes, I’m sure engineers could measure the fractions of a second that it takes for the tyre to deform and lose grip, but as far as human perception goes, it’s instantaneous). The lag between applying pressure to the pedal/lever and braking force being applied to the wheel is too small for humans to perceive unless the driver applies the brakes so timidly that it takes time to move the pedal through the freeplay before the brakes start to apply.

The point about having brakes powerful enough to lock up a wheel isn’t that this guarantees they are good brakes, it’s that, if they can’t lock up a wheel, they aren’t powerful enough. It’s a necessary but not sufficient criterion for good brakes. A Fiesta brakes would not lock up the tyres on an F1 car at full speed, those things have more grip from the tyres than you would believe.

Sorry, but my Fiesta ST brakes are much better than your Shimano Deores.

But are they post mount or IS?

A Fiesta brakes would not lock up the tyres on an F1 car at full speed, those things have more grip from the tyres than you would believe.

If an F1 car found itself on a surface that had sufficiently low friction the Fiesta brakes would lock up the wheels just fine.

The point about having brakes powerful enough to lock up a wheel isn’t that this guarantees they are good brakes, it’s that, if they can’t lock up a wheel, they aren’t powerful enough.

I’ve had plenty brakes over the years that couldn’t lock up the front wheel. They were fine. Or maybe they could actually make it lock up. It’s not something I ever felt the need to check exhaustively.

The point of the above replies wasn’t really to go further down this rabbit hole, it’s more to say that being able to lock up a wheel has absolutely nothing to do with how good a brake is.

But if you can’t lock the rear how do you do mad skidz?

Cuz tha’s wot biking iz. Mad skidz

being able to lock up a wheel has absolutely nothing to do with how good a brake is.

It’s a crude indication that they have enough power to use all the available grip. It’s not the only consideration, but it’s not irrelevant in the way you seem to think. As described above, you aren’t going to lock up a front wheel on a mountain bike with a grippy soft tyre on a dry road anyway, trying to do that will end up with an OTB adventure.

If an F1 car found itself on a sufficiently sick flow trail could it schralp a berm and blow up the Gram?

But if you can’t lock the rear how do you do mad skidz?

Cuz tha’s wot biking iz. Mad skidz

Personally I carry a Hope stick with me (it’s purple). When ever I want to do a mad skidz I take my Hope stick out and jam it into the spokes of my Hope wheel (it’s also purple). The wheel locks up every time so my Hope stick is definitely the best brake I’ve got.

My Shimano stick is plain black. Not only that, it randomly changes length which means I’m not as confident when jamming my Shimano stick into my Shimano wheels (they’re also black). Sometimes my Shimano stick gets oily and slippy which can be quite dangerous when you’re trying to do a mad skidz in an emergency.

It’s a crude indication that they have enough power to use all the available grip.

Is this a thing people do to test their brakes? I mean, do people get a new set of brakes and then go out and check they can lock up the front wheel?

Not an extreme fanboy but I started using Hope 20+ years ago when their 4 pot DH brakes were the only reasonable choice for tandem MTBs. I did finally bin my first set quite recently – actually I think that’s a lie, I probably handed them on with the frame when I sold it. I think I’ve had 4 sets in all over the generations and the newest are very nice, plenty of power and good modulation though I’ve only had them a couple of years of light use so can’t speak to durability yet.

do people get a new set of brakes and then go out and check they can lock up the front wheel?

Whenever I bed new pads in, I check that they are powerful enough to lock up the back wheel and do a stoppie. I’ve never locked up a front wheel on a grippy surface, but if you can lift a back wheel off the ground, that’s as much braking as you’re gonna get. If they can’t do this, they need more bedding in.

IMO locking up a wheel is a bit of a red herring unless it is done under controlled lab conditions. There are just too many variables: surface, tyre grip, tyre pressure, brake temperature, disc size, pad type, rider/bike weight, gradient, environmental conditions…..etc.

Over the years I’ve had Shimano, Avid/Sram, Formula, Hayes, Magura, Giant and Hope disc brakes. The early ones were poor in comparison to newer models. I found Avid/SRAM a pain to bleed and I’ve had numerous piston swelling issues (including newish Levels). The lever reach adjust spring on Guide Rs also locked the front lever open whilst in the Alps – not fun. They had a nice feel but suffered from fade. I’ve had enough of SRAM brakes!

The last set of reliable Shimano brakes I had were some old XT M765. All the others since have suffered from calliper leaks. When working they are fine but grabby. Not an issue at speed but I prefer more modulation at slower speeds, particularly in techy/loose terrain. I’ve given up with Shimano brakes due to the leaks and throw away culture.

Having serviced a set of very old and neglected Hopes for a chap and ending up with brakes essentially as good as new I decided to drop the cash and get a set of Tech3/E4s a few years ago. I like them. Good, consistent, fade free power with great modulation and quiet operation. Easy and effective bleeding and a bite point adjust that actually does something. They also seem less prone to being effected by contamination, such as muck from being on the back of the car. Above all, despite being hammered they have been faultless and required nothing more than new pads and a precautionary bleed every year or so. If they do have an issue I can get the spares. And they are UK made! It would be nice if they were mineral oil though. Mine are black by the way! Having got on well with the E4s I recently got a set of Tech3/X2s and have been impressed by their power (loaded bikepacking trip and Lakes) and simplicity.

I understand people will have preferences over feel and looks but in my experience neither of my Hopes lack ultimate power. Those that say they have no power must surely have an mechanical or setup issue with their brakes? Anyhow, those new levers look good. Will be interesting to see what the real world difference is over the Tech3.

I’ve defended Hope in the past on the grounds that they’re not as crap as people say they are and that the reliability and consistency is preferable to the constant faffing needed to keep other brakes running on top form with their leaky calipers, plastic pistons and wobbly lever bushes. Even if there are more powerful brakes available the Hope’s are nice to live with.

I was quite happy with my E4’s for 4 years but now that they’re gone I won’t be rushing to replace them. I had a quick test ride on a bike with Code RSC’s and the difference is staggering. Straight off the shop floor they make so much power for so little effort at the lever.

I’m going to put all the Avid/Sram, Juicy/Elixir/Guide related heartache behind me and see what they’re like long term. If they flake out I might glance at Hope’s if the new versions look any good.

Reverse bleed – drain the master cylinder, squirt new fluid into calliper bleed port while making sure the hose is the highest point on the calliper. Drain master and repeat. Keep doing it until the fluid at the master cylinder is clean and bubble free.

Done with either a long hose on the syringe to the calliper, or with two people it’s an almost continuous process. Great way to teach your son how brake bleeding works.

that seems like more hassle than what I guess is the official way, open up the resevoir, loosen the caliper, pour in fluid while pumping the brake to push it through, catching the old fluid in a pot. Only done this once on my hopes, my old shimanos I was doing a bottom-up type bleed on a monthly basis, and the fluid coming out was black every month. lets also mention the shimano official bleed screw on thingy – not large enough to contain enough fluid to completely change the fluid in the brake, so you need to stop part way through, unscrew it and empty it, then carry on.

I was quite happy with my E4’s for 4 years but now that they’re gone I won’t be rushing to replace them. I had a quick test ride on a bike with Code RSC’s and the difference is staggering. Straight off the shop floor they make so much power for so little effort at the lever.

I wonder if old pads, discs or unbled Hopes. I’ve got Code RSCs on a newish bike and agree – they’re really good. But I just bled and changed the pads in my old E4s and still equally happy with them.

Job for later is to bleed the Guide’s on K’s bike as, despite being fitted new only back in May (and bled then) they still don’t feel quite right.

I had a quick test ride on a bike with Code RSC’s and the difference is staggering. Straight off the shop floor they make so much power for so little effort at the lever.

yep – agree. Code rsc are easily the best brake I’ve used out of hope e4, shimano 4 pot xt, magura mt5.

Currently on shimano across the bikes (XT and Deore) and they’re good. Had Hope X2s in the past (and some Minis) and they were good too. To be honest I don’t feel that passionately about either of them. They’re both fine. Yeah, they feel a bit different. But for an unfit old bloke bouncing down trails they’re much of a muchness. It comes down to price for me.

That said, I once had a pair of Magura Marta SLs and they were incredible. I swear, they could talk to me through the levers. It was as though there were angels on the discs singing feedback to my fingers. But I was drinking a lot back then, so who knows.

Looks like the tech4 is available in silver or black and just the mc cap, adjusters and bore caps on the caliper are in colours. Seem available in February looking at Evocycles site.