Disk O' Tech

indalo · Apr 5, 2011

I'm sorry lemmy but I have no idea at all about 2nd-hand values so I can't help you on that.

My interest in your posting though is your reference to rim wear. I've never given any thought to rim wear on my bikes but it must be something that happens.

My bike has internal brakes which are pretty feeble compared to the rim brakes and disc brakes on my other bikes. once used to them, however, they are consistent, wet or dry conditions and you ride within the bike's stopping capability.

I don't know yet how long internal drum brakes last but I suppose they must be pretty decent or they would have been superseded, (I'm not happy with that spelling!) with another type of braking. I have to say I think hydraulic brakes on a bicycle is a little OTT....or am I just wrong?

Regards,
Indalo

Conal · Apr 5, 2011

hydraulic front brakes

Hi

My eZee Forza has front hydrualic brakes and a rear cable disc brake.

The important factors here are weight and speed. I am heavy, and ebikes tend to be heavier than non ebikes, and they go faster. In my opinion my front brake is the better of the two, mainly because the disc is poor at stopping in the wet. It is certainly better than "V" brakes.

My original rear wheel had rims, even though they were not used. Last year I had a new rear wheel made up and was advised to use a rimless wheel as this is stronger than one with rims.

Interestingly (to me anyway) when I travelled down a steep hill near Chard, Somerset, a few years ago on the Ching Challenge with Nick (Tiberius) we reached over 50mph. I braked hard at the bottom and found out later that, after the burning rubber smell discappeared, I had warped my rear disc and had to replace it. I did no damage to my front hydraulic brakes other than having to adjust the pads.

There are a number of threads and comments on the Forum discussing rim wear - the experts point out that it can be measured by looking at the remaining depths of grooves in the rim wall.

Conal

Blew it · Apr 5, 2011

Lemmy

First consideration is, do the existing front forks have the cast-in disc caliper fixing points at the bottom of the near-side fork leg. If not, the forks would need replacing.

The front wheel would need to be re-laced with a new hub with disc rotor flange.

There are several examples of very powerful cable operated disc brakes from Shimano and Avid to name just two. On cable operated disc brakes, only the outside disc pad moves towards the rotor, deflecting it onto the fixed (but adjustable) inside pad.

Hydraulic disc brakes have dual pistons and operate in the same way as those on a car and motorcycle. That is to say, when the brake is applied, both outside and inside pads move towards the rotor in unison.

Which is best?.

As cable operated disc pads wear, compensation for this is made by advancing the pads using manual adjustments of the click-stop thumb-wheels provided. With hydraulic systems, fluid needs to be added as the pads wear, this is where bicycle hydraulic sytems differ from cars. On a car, there is a vented reservoir in the engine compartment which allows the system to be topped up as the pads wear. On a bicycle, which might be tipped upside down for maintenance, the system has to be sealed for obvious reasons, hence the need for occasional topping up/bleeding.

A correctly set-up cable operated disc brake is just as powerful as its hydraulic alternative, it's just a matter of personal preference. Unless of course, you are involved in extreme sports, in which case the hydraulic sytem will be preferred.

flecc · Apr 6, 2011

indalo said:
I don't know yet how long internal drum brakes last but I suppose they must be pretty decent or they would have been superseded, (I'm not happy with that spelling!) with another type of braking.

Regards,
Indalo

Your hub brakes are actually Shimano roller brakes. They work by rollers jamming progressively up ramps and are almost indestructible. It's possible to get a special Shimano lubricant that injects through an oil hole, but I wouldn't worry about that unless they ever start to squeak.
.

indalo · Apr 6, 2011

I'm liking my bike more every time I read stuff on this site.

Cheers flecc!

tillson · Apr 6, 2011

lemmy said:
I have a Kalkhoff Tasman, bought 18 montha ago with which I'm very happy.

Looking at the new bikes, the main thing different is disk brakes and the new 18ah battery,

Given that the battery can be bought as an upgrade, how hard would it be to convert the front brake to a disk? The rear brake seems less important to convert.

Maybe it isn't worthwhile at all, I'm thinking of rim wear long term. Any creative ideas?

Does anyone have any idea of the likely value of a Tasman, 18 months old, battery giving 27 miles on give and take going at 1:1 setting and in unmarked condition?

I have a few quid in a savings account which earns less than inflation - might as well spend it as save it

Are you experiencing any rim wear?

I think that I am correct in saying that the Tasman is fitted with Magura hydraulic rim brakes. I fitted these to my Pro Connect, replacing the original Shimano V brakes. The V brakes caused terrible rim wear, resulting in the need to replace / re-build the rear wheel after only a couple of thousand miles. Since fitting the Magura brakes, rim wear is virtually undetectable and I have done many thousands of miles since then.

For some reason, Magura brakes seem to be much kinder to wheel rims than the cable V brakes. If your wheels aren't showing any signs of excessive wear, I don't think that you will gain anything by swtching to disks. Unless of course you intend to use the Tasman for extreme off road downhill racing!

I can't praise Magura brakes enough. They are easy to adjust, change brake pads, stay in setup and they just work fantastically well. Perfect for an ebike.

As for a new bike. Unless I am missing something, I really can't see what there is in the latest range of bikes which moves things on significantly. They are all just essentially a frame, motor, wheels and a battery. Not worth £2000 to, "upgrade". The 18 Ah battery has possible performance advantages, so that might be worth a look.

NRG · Apr 6, 2011

I'm with tillson on this, if you have the magura brakes stick with them. I have them on my PCS and was considering changing them to the 2011 spec bikes hydraulic brakes but they work so well I've decided to stay with them.

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tillson · Apr 6, 2011

That's what I like about the setup. Panasonic drive, Alfine hub gears, Magura brakes, tough paint job, you can just ride and not worry about things wearing out or going out of adjustment. Wash it down and wipe over with GT85 and the bike looks like new It's perfect for high mileage commuting.

This is why I have absolutely no desire to replace my soon to be, 3 year old Pro Connect. It still looks like new and I fail to see what advantages a new bike will deliver.

flecc · Apr 6, 2011

lemmy said:
Yes, I agree. I wonder if there is any development left for the Panasonic drive bikes? Can't get faster (law), can't get more reliable (top notch cycle components).

So when you buy one, that's it, apart from tyre and battery replacements. Car and motor cycle makers change shapes, colours, up the power but where do pedelecs go?

A bummer for dealers if all sales are to new owners who don't buy again until the first purchase is knackered.

Very much the position of bike dealers for decades pre and post WW2, when the well built utility bikes from Sunbeam, Hercules, Raleigh, BSA etc just went on and on. Fundamental bike design had reached it's pinnacle so there was no point in changing.
.

theskip1 · Apr 6, 2011

lemmy said:
I have a Kalkhoff Tasman, bought 18 montha ago with which I'm very happy.

Looking at the new bikes, the main thing different is disk brakes and the new 18ah battery,

Given that the battery can be bought as an upgrade, how hard would it be to convert the front brake to a disk? The rear brake seems less important to convert.

Maybe it isn't worthwhile at all, I'm thinking of rim wear long term. Any creative ideas?

Does anyone have any idea of the likely value of a Tasman, 18 months old, battery giving 27 miles on give and take going at 1:1 setting and in unmarked condition?

I have a few quid in a savings account which earns less than inflation - might as well spend it as save it

i had an old powabyke euro ( now my grandsons ) for 12 years and has never had the drum brake pad replaced but it still good and shows no sign of failing.but i must admit since having hydraulic front disc 's on my whisper i wouldn't change them for the world.

z0mb13e · Apr 7, 2011

Hydraulic rim brakes

I had pretty much ignored hydraulic brakes as I thought the cut out switch would be a problem. Are there manufacturers producing hydraulic levers with cut out switches in them now?

As for hydraulic rim brakes not causing as much wear as other types, am I right in thinking that the brake blocks move in a linear fashion rather than pivot? If so I would expect that more of the brake block surface is making contact at the same time thus spreading the wear and increasing the longevity of the rim. Ideal for sandy conditions where a rear disc isn't an option...

mechaniker · Apr 7, 2011

z0mb13e said:
Are there manufacturers producing hydraulic levers with cut out switches in them now?

Check this, it´s from "tektro" but only to buy as a complete set with Disk as it is shown on this pfoto.

Have a good day
frank

tillson · Apr 7, 2011

z0mb13e said:
I had pretty much ignored hydraulic brakes as I thought the cut out switch would be a problem. Are there manufacturers producing hydraulic levers with cut out switches in them now?

As for hydraulic rim brakes not causing as much wear as other types, am I right in thinking that the brake blocks move in a linear fashion rather than pivot? If so I would expect that more of the brake block surface is making contact at the same time thus spreading the wear and increasing the longevity of the rim. Ideal for sandy conditions where a rear disc isn't an option...

Cut outs are not needed on Panasonic powered bikes because the motor cuts out at almost the same instant that the rider stops peddling or eases pressure on the pedals.

The brake pads do move in a linear fashion with Magura brakes. I would expect the pressure with which the brake pads are pressed onto the rim is higher with hydraulic brakes than cable V brakes. This would mean that sufficient friction can be generated using a less abrasive pad than with the V brakes, where the pad contact pressure is less. Magura brake pads do seem to be meatier and made from a softer material than the original Shimano V brake pads, so this probably explains the reduced rim wear.

deadmonkey · Apr 7, 2011

My Pro Connect has (I believe) the same Magura brakes and they've been brilliant.

It took me 5 minutes of confusion to reclip them the first time I used their quick release functionality to get the front wheel off, but as you say they just sit quietly doing their job. I hit 50k coming down a hill near my house and rain or shine they've never faltered.

Maybe lemmy should put that spare money aside for his next bike or a holiday?

z0mb13e · Apr 7, 2011

Thanks mechaniker the Tektro Agura eComp brake looks like what I want for the front and if they sold the levers separately then I could also add hydraulic rim brakes. The problem being is they are OEM only.

Oh well, no real problem as my cable brakes both work pretty well. The biggest problem (and it isn't really that big a deal) is the need to regularly adjust the brake blocks and front calliper. A hydraulic front floating calliper and hydraulic rim brake is the answer.

More of a problem for me is that the adjuster on the front calliper has seized up to the point where I am going to wreck the allen key recess if I use any more force (I've soaked it in WD40 as much as possible but still no joy).

mechaniker · Apr 7, 2011

z0mb13e said:
The problem being is they are OEM only.

I have a office in china and can order direct at factory

Problem is you need to order two set´s, so you must find a partner ;-(

Have a good day
frank

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