Hydraulic disks on ebikes

[GaRRy]

Just out of interest what about in the wet? The rims on a bike surely pick up more water than a disk would and so would take longer to clear and so get full brake efficiency ?.

 

[Old_Dave]

By a stroke of good fortune, centrifugal force and serrations in the rim can reduce any major worries,


Sent from my iPhone using Tapatalk

 

[flecc]

Just out of interest what about in the wet? The rims on a bike surely pick up more water than a disk would and so would take longer to clear and so get full brake efficiency ?.

Another correcting factor is that steel rims when they were de rigeur were useless for braking in the wet, hence the near universal change to alloy. But discs of course are still stuck with steel on bicycles, not so good as alloy in the wet. Carbon fibre is used on race cars of course.

 

[GaRRy]

Another correcting factor is that steel rims when they were de rigeur were useless for braking in the wet, hence the near universal change to alloy. But discs of course are still stuck with steel on bicycles, not so good as alloy in the wet. Carbon fibre is used on race cars of course.

Take your point about Alloy v Steel but as for Carbon Fibre Formula 1 and MotoGP definitely can use them but most other racing classes state ferrous brakes only to keep costs down etc.

 

[GaRRy]

Take your point about Alloy v Steel but as for Carbon Fibre Formula 1 and MotoGP definitely can use them but most other racing classes state ferrous brakes only to keep costs down etc.

Hmm after a bit more research found this: -

CARBON OR STEEL
MotoGP teams use disc brakes on their racebikes, technology which first emerged in the 1970s and has been in development ever since. Early versions of these discs were steel only and did not work very well in rainy conditions, but were later developed to produce progressive braking in both the wet and the dry.

Now, conversely, steel disc brakes are used by MotoGP teams only in the wet as they have a more modern and efficient solution to be used on dry tracks – carbon brakes.

Full article here motogp.com

As can be seen Carbon brakes are useless in wet as cant get warm enough.

 

[flecc]

Agreed, I should have said sometimes. Carbon fibre discs are used on heavy aircraft landing gear, Concorde was first, the C130 transport another adopter and they are now quite commonplace. I therefore doubt they are completely useless in the wet.

Maybe with time the prices for road vehicles will drop. They should be light enough for bicycle use.

 

[KirstinS]

My tuppence - I've been lucky enough to single track downhill from 4500m (yep!) all the way downhill to jungle at sea level. Took two days and would have died without control and power of large hydraulic disks

 

[JuicyBike]

Hi Bob...
A policy of component standardisation is a great move for Juicy, imo. Did you have any luck sourcing a cartridge-type bottom bracket for your latest designs?

Edit: it'd be worth updating your website with the Tektro info, otherwise people knowing the old spec may assume that this hasn't changed. Also, I'd say 20Kg is a touch too light for the weight; although it may have changed, it'll certainly increase with the higher-range batteries. My Sport 2010 (10Ah) was around 23Kg on the bathroom scales

Hi Jon
Yes, we now use a cartridge on the bottom bracket, preferred by LBSs but more expensive.
The weight of the bike is 19.4 Kgs without the battery and the 10AH battery that we use is a tad over 3Kgs.

The website will eventually show all the detailed changes... so much to say, so little time...
Kind regards

 

[JuicyBike]

Rim brakes are good, but wear out the rims of the wheel.... which is a bigger factor when the wheel is laced into a motor!
If a rider neglects the timely replacement of a rim brake and allows the pad to show its metal to the rim then the rim-wear is rapid and damage suddenly very likely.

 

[halfer]

Yes, we now use a cartridge on the bottom bracket, preferred by LBSs but more expensive.

Great stuff, a good change I think.

The weight of the bike is 19.4 Kgs without the battery and the 10AH battery that we use is a tad over 3Kgs.

Ah, that sounds about right, good stuff; mine came in circa 23Kg on the scales, with the 10AH

 

[SportRider]

I think my post about the Norton drum brake was misunderstood. Obviously the multi piston disc brakes on a modern sports bike are far superior, but then the performance of the bike is much higher. On the Norton, you did not have the problem of slowing from 180 MPH, and it is unlikely that you would have that problem on an ebike, unless youre bike performs better than mine.
What I was saying was that the Norton had excellent brakes without the use of discs or hydraulics, so we should be able to stop an ebike without discs or hydraulics. Hydraulic discs and cable Vee brakes both have their advantages and disadvantages. It is good that we are free to choose either.

It is indeed good that we are free to choose, Neptune, but as a motorcyclist of some 37 years' experience who's owned everything from pre-unit Triumphs to the latest litre sportsbikes I can tell you what brakes I'd prefer to be using - regardless of the machine or it's top speed capability.

My current bike is a GSX-R 1000, which, while being mind-meltingly fast is also able to travel at Norton Atlas speeds (and, indeed, below). Whether the motorcycle is travelling at 60mph or 20mph, if the need arises to stop quickly (maybe someone has pushed a pram into the road, as happened to me), you really want to be on a machine with decent disk brakes.

This was brought home to me when a friend let me have a go on his Triumph Bonnie recently (a bike I used to own many moons ago). I was approaching a roundabout on a dual carriageway, and instinctively went to brake at the same point I would have done on a more modern machine. (Foolish, I know...)

It was honestly as though the Bonnie had no brakes at all! A real 'new pants nurse' moment...

The difference was staggering, yet, like you, when I had my Bonnie all those years ago I was more than happy with its braking performance.

Similarly, I was happy with the performance of the V brakes on my first ebike. Until, that is, I tried a bike with hydraulic brakes. Quite simply, I was blown away by the difference, particularly with regards to feel.

Do try them if you get the chance. (Apologies if you have already...)

 

[Scimitar]

One thing I found with retro-fitting V-brakes to an older cantilevered system is not just the better action and effect of the V-brake upgrade, but the effect of not knowing about (and not fitting) the leverage reducer for the cantilever system brake lever.
The absence of it makes the V-brake incredibly effective. I suspect the reducer is there to prevent people losing the front under heavy braking because it would be possible to slide out by grabbing too much of a handful if you're so used to the cantis.
By this stage I'm well used to the improved feel and stopping power of the hybrid system though and it is by far the best bicycle brake I've ever had. I don't feel I need to put a disc on (nothing against discs, I use them on everything else, cars and bikes) as I doubt there's much to be gained.

 

[neptune]

@Scimitar, very interesting post, but not quite sure that I fully understand it. By cantilever brakes, I am assuming that you mean the type of brakes that are fitted with a "Straddle Cable" , that is a short cable that joins the two brake arms together. So if I am right, to upgrade to Vee brakes, it is just a matter of changing cantilever brake arms to Vee brake arms, using the existing mounting bosses on the fork or frame.
Now lets talk about the "leverage reducer". I had noticed that the actual brake levers on a Vee brake set up were short compared to the ones used for the old side pull brakes. I had assumed that this was because Vee brakes are very powerful, and the short levers were fitted to prevent wheel lock. But your post implies that the leverage reducer exists as a separate physical component. If this is true, where is it fitted, how does it work, and what does it look like?
I am interested because whatever type of brake is used, we have to strike a balance between efficiency, and its ability to lock wheels. But the ideal balance is a personal one, it would be useful to be able to adjust max efficiency for personal preference.
This would be useful to someone who, due to age or disabilty, had relatively weak fingers.

 

[Pedant]

If you look at the mechanical arrangement of a cantilever brake and compare it with a v brake you'll quickly see that the v brake mechanism itself has quite a bit more mechanical advantage than a cantilever. Brake levers designed for cantilevers have too much mechanical advantage for v brakes - they'll work but will lock the wheels with too light a pressure and will feel unprogressive.

That's why, when I fitted the kit to my bike including the levers with cut off switches, I had to change my cantilevers for v brakes - otherwise I wouldn't have been able to pull hard enough on the v brake designed levers to get the cantilevers working properly.

 

[Scimitar]

Now lets talk about the "leverage reducer". I had noticed that the actual brake levers on a Vee brake set up were short compared to the ones used for the old side pull brakes. I had assumed that this was because Vee brakes are very powerful, and the short levers were fitted to prevent wheel lock. But your post implies that the leverage reducer exists as a separate physical component. If this is true, where is it fitted, how does it work, and what does it look like?

It was designed for exactly this application - upgrading an old canti system to V-brakes, but keeping the original levers.
I came across it on the Wiggle site, or it might have been Evans, after I'd fitted the V-brakes and realised that it might have been useful. By that time I'd got used to the extra leverage the hybrid system gave me, so don't need it.
Iirc, it fits on top of the V-brake, but I don't recall the exact design of it. Driven by curiosity I recently had another look for it, but didn't find it.
The upshot anyway, is if you find a set of older cantilever levers and use them with V-brakes, you have a very powerful braking system. Just don't go ass over tit with it.

 

[neptune]

I wonder if any other members have come across these leverage reducers? I had a look at one of my old spare bikes which has cantilever brakes, and the levers are fifty percent longer than those on my Vee brake hybrid bike, so I can see for myself. Dave, the last sentence of your last post reminded me of a song we used to sing at school to the tune of "Oh give me a home, where the buffalo roam."

Peggy O`neal had a bike with one wheel.
The spokes were all ******ed and bent.
One day in the town, the bike let her down,
And base over apex she went.

 

[Scimitar]

Ah, found it...
Tektro In-Line Power Modulator > Components > Brakes > Brake Parts and Service Kits | Jenson USA Online Bike Shop
I suspect that there's a wasted-motion arrangment in there, so absorbing some of the effort from the cable.

And here it is at wiggle, now discontinued...
Wiggle | Shimano Power Modulator Kit | Brake Spares

 

[jhruk]

Now lets talk about the "leverage reducer". I had noticed that the actual brake levers on a Vee brake set up were short compared to the ones used for the old side pull brakes. I had assumed that this was because Vee brakes are very powerful, and the short levers were fitted to prevent wheel lock. But your post implies that the leverage reducer exists as a separate physical component. If this is true, where is it fitted, how does it work, and what does it look like? .

Many years ago when I changed a front brake from cantilever to v-brake I wanted to keep the original integrated levers so fitted a ‘Travel Agent’. This device effectively turns a short pull lever into a long pull one. It works well and is still on the bike.

And still available I see.