Nexave BR-im50-r (ezee sprint rear hub brake)

I have such a rear roller hub brake which is now very ineffective after probably 2000 miles use. Can anybody suggest how I might improve its performance? If it needs grease surely there will be some grade of high temperature grease I can use without chasing up "special grease". Will new grease improve things? What sort of life should I expect?

 

I have the angles right and cable in good shape but it needs a lot of pull for very little stop.

 

Hi to all,

 

Malcolm

Don't use any old grease Malcolm, the friction could cause it to burn. Shimano make grease specifically for these brakes which you can order from a cycle dealer, here's the details with part numbers, the small size is enough for consumer use:

 

Roller brake grease

 

10 gms Y-041 40020

 

100 gms Y-041 20400

 

Alternatively a dealer may have his own to lubricate your brake. In general though, I have a low opinion of these brakes on e-bikes, the extra bike weight plus the rider often pushes the total too close to their 100 kg maximum rating.

I have such a rear roller hub brake which is now very ineffective after probably 2000 miles use. Can anybody suggest how I might improve its performance? If it needs grease surely there will be some grade of high temperature grease I can use without chasing up "special grease". Will new grease improve things? What sort of life should I expect?

 

I have the angles right and cable in good shape but it needs a lot of pull for very little stop.

 

Hi to all,

 

Malcolm

 

As the miles of brake use get piled on, the brake shoe friction material wears down.

This means that the handlebar brake lever needs to be pulled further to achieve the same braking affect.

You don't notice this as it happens over a long period of time.

Try loosening the cable at the brake hub end, pull in the slack and retighten.

On mine, I actually pull on the brake hub lever too (not handlebar lever), as I am pulling in slack, to achieve a nice bite to the brake when operated.

Always check that the wheel free-wheels correctly after adjusting.

 

My rear servo hub's done well over 2000 miles, and the friction material is still quite thick and the operation is spot on.

Edited January 20, 201214 yr by Fordulike

Malcolm's brake doesn't have shoes and friction material Fordulike, it's braking action is all steel, roller and ramp, similar to the freewheels in hub motors.

Malcolm's brake doesn't have shoes and friction material Fordulike, it's braking action is all steel, roller and ramp, similar to the freewheels in hub motors.

 

Sorry, my mistake :o

 

Any chance of someone posting something, in piccy form, of how this type of brake works?

Just for future reference.

I have two bikes with these rear brakes and both have needed attention.

 

The first was stiffness as you describe and was due to water getting in the cable and causing inner corrosion where it loops under the crank. A new greased inner cable fixed this.

 

The second one became very noisy & abrupt after storage. I injected the special grease and this restored its previous mediocre performance.

 

Other than adjusting the cable I understand injecting grease is the only realistic maintenance possible with these. As Flecc says these are not ideal brakes for ebikes - but if you’ve got them they should last the life of the bike.

Any chance of someone posting something, in piccy form, of how this type of brake works?

Just for future reference.

 

Basically these operate by pushing rollers into a narrowing gap between ramps, giving the braking force as the rollers and ramps attempt to jam rotation. The grease prevents undue friction wear. Photos of the internals don't show very clearly how they operate. However, if you have a look at the top of the first photo below showing all the components, you'll see the three outer segments, the associated rollers and housing ring, and drum to get some idea:

 

http://www.zen157147.zen.co.uk/shimano_roller_brake.jpg

 

This diagram shows a complete brake with external parts (click to enlarge):

 

[ATTACH]3087.vB[/ATTACH]

 

and this next diagram shows on the brake the optional large finned cooling disc that's often seen attached:

 

[ATTACH]3088.vB[/ATTACH]

Edited January 20, 201214 yr by flecc

As Flecc says these are not ideal brakes for ebikes - but if you’ve got them they should last the life of the bike.

I find mine quite useful for not very fierce braking (e.g. going down a long hill), but am glad to have a rim brake on the front for quick stopping power. And being virtually maintenance-fee is nice.

Grease

 

I have such a rear roller hub brake which is now very ineffective after probably 2000 miles use. Can anybody suggest how I might improve its performance? If it needs grease surely there will be some grade of high temperature grease I can use without chasing up "special grease". Will new grease improve things? What sort of life should I expect?

 

I have the angles right and cable in good shape but it needs a lot of pull for very little stop.

 

Hi to all,

 

Malcolm

 

Called into the "Green Cycle Company" in Worcester this morning. Really helpful and ordered the special grease for me. I will post the results when i have tried it.

I must say I really appreciate the quality of help one gets on this site.

 

Thanks to all.

I've had some trouble with my rear roller hub brake. The thing is practically useless. I managed to tighten the front one very well, the lever is at least 2cm away from the handlebar when fully applied. However I can't seem to do the back one at all. I tried the barrel adjuster, and nothing really happened, I think the threads might be stripped.

 

I loosened the end of cable where it connects to the hub brake and pulled it tight and did the nut up again, it didn't work. I tried again and pulled the little lever slightly just so it engages and tightened the nut again. Still didn't work.

 

I would like to do this myself, otherwise I'll have to pay the bike shop to do it for me.

After that last adjustment, did the lever still pull all the way up to the handlebar Synthman?

.

Edited January 23, 201214 yr by flecc

After that last adjustment, did the lever still pull all the way up to the handlebar?

After reading the blogs I decided to just check the lever/cable. I found that there were alternative drillings for the cable anchor pivot marked v and c. Mine was drilled at the v, giving the least mechanical advantage. I have had it apart and drilled the c hole and reassembled which now gives about 30% more mechanical advantage. (The brake are still rubbish) I am surprised that Ezee did not pick up on this. Presumable V for v brakes and C for calipers. The cable and anchor bolt on the roller brake are obviously built to take a big load but I would not recommend anybody modifying their lever unless they have some mechanical skill you need to grind of the pivot pin and replace with a new one. Better some braking than suddenly none.

I have the nexave rear roller brake on my eZee Torq when I bought it second hand. It was rubbish so I bought my self a new one (not really knowing about them) and it is still rubbish. It is rubbish in the wet and rubbish the dry but better in the wet than my V brakes on my previous non e bike. Gradual breaking is the key to these puppies.

After that last adjustment, did the lever still pull all the way up to the handlebar Synthman?

.

 

It did yes.

It does still sound like a cable problem then, since there isn't any "give" within these brakes. Either that or the operating lever at the brake drum end or the outer cable stop there are not secure for some reason.

 

Best check those out for security first.

The brake itself is fine. I tested it by pressing the drum lever by hand while the wheel was spinning and it stopped the wheel rather rapidly.

 

Seems I can't get enough tension in the cable. I reckon even if I applied the brake more than half way and tightened the cable it wouldn't have any effect.

 

I was hoping that I could screw the barrel adjuster back in all the way, then pull the cable through at the hub and tighten, then tension it with the barrel adjuster. But it doesn't want to do anything. There's a screw by the side of the hub to adjust something but it didn't make any difference. I'm not sure if I'm doing it correctly but the front brake was extremely easy to do.

Sometimes there's a problem with outer cable terminations where they compress into the end cups as the brake lever is squeezed. Check if that seems to happen at either end as you squeeze the lever. It certainly seems to be a cable related problem, and most probably the outer or it's end stops.

I got to thinking about whether it might be time to grease my roller brake, but I found that what appears to be the grease nipple appears to be hidden behind part of the frame:

 

[ATTACH]3620.vB[/ATTACH] [ATTACH]3621.vB[/ATTACH](Apologies for the fuzziness).

 

Does this really mean that I have to take the wheel out just to grease the brake?

 

Also, since I have never yet had to mend a rear puncture on this bike (touch wood!), perhaps someone could explain the procedure for removing the wheel with this setup? It is not like any other rear mounting I have come across. The slot usually goes downwards and forwards, does it not? And what is the function of the small nut etc. to the right of the main wheel nut?

 

[ATTACH]3622.vB[/ATTACH](By the way, you can see that I have already rerouted the rather weird path of the wire to the rear light as shown in the first photo!)

There's a hole for applying the grease with a rubber bung in it (number 16 in this diagram from above).

 

It does look as though you'll have to remove the rear wheel for the greasing Roger.

I've had some trouble with my rear roller hub brake. The thing is practically useless. I managed to tighten the front one very well, the lever is at least 2cm away from the handlebar when fully applied. However I can't seem to do the back one at all. I tried the barrel adjuster, and nothing really happened, I think the threads might be stripped.

 

I loosened the end of cable where it connects to the hub brake and pulled it tight and did the nut up again, it didn't work. I tried again and pulled the little lever slightly just so it engages and tightened the nut again. Still didn't work.

 

I would like to do this myself, otherwise I'll have to pay the bike shop to do it for me.

 

I have found that grease does improve the efficiency a little. Also, I learned somewhere, cant recall where, that these complete assemblies can be bought new at very reasonable prices.

These brakes do require great force to work well but they do mean you are saving wear on expensive brake blocks.

Malcolm White

It does look as though you'll have to remove the rear wheel for the greasing Roger.

That's what I was afraid would be the answer! Now has anybody with an eZee Sprint or similar any tips for doing that?

Since the wheel only has to slightly clear the frame, just unbolting the brake torque arm and the two wheel nuts is all you need to do to slide the wheel out enough. You may have to undo ties securing the brake and gearchange cable outers to the frame if they impede the removal. Putting the wheel back means adjusting it for the chain to have about half inch of vertical slack in the centre of the chain run and making sure the front of the wheel is centred between the frame tubes before finally clamping the wheel nuts and the brake torque arm. If you are careful the gearchange adjustment won't be changed.

Thanks, Tony!

...just unbolting the brake torque arm...

Sorry to be dim, but that is the small nut to the right of the wheel nut in my photo, is it? It's just that I've not come across one of those before.