Disk Brake choice for new Nimbus hub

Any bicycle disk brake and rotor will fit the new Nimbus hub.

Recommendations? :thinking:

I have very little experience with disc brakes on a bike, having only used stock cheap mechanical disk brakes on one bicycle. I’m looking at getting the new hub because I need to rebuild my 29er wheel anyhow, and I’ve been craving more and smoother braking power than my current v-brake. I also really like the idea of a disc to not have to worry so much about the trueness of my wheel.

I’m initially inclined toward mechanical for easier maintenance and lower cost. Hydraulic seems like it might be more than needed for a uni? Pros/cons of hydro vs mech?

Also, what size disc? I assume smaller = lighter, but less braking power, right?

I’ve already started looking, first stop was the LBS to see what they think is the “best”.

First, I was told that Shimano is the easiest to bleed and Avid is the most difficult. Two shops told me this, as well I looked on line and the bleed directions suggested the same; it reqires bleeding all parts seperately.

Of the Shimano, it was all about price. I am running a Shimano m535, a generic caliper that came on my son’s jump bike. It was easy to bleed, has a decent feel, but I found out the hard way that some levers are more robust than others. This particular lever has a c clip that secures the plunger into the master cylinder. It poppoed out on the trail after a typical UPD and caused no end of problems on an all day ride in Colorado. Maybe there is a better design?

In terms of discs, you need an adaptor to match your disc size. I have run 180mm and 160mm, the difference in stopping power is negligible, but some feel like the bigger discs are better, I figure the bigger the disc the more the weight and the more liklihood of impacts.

Finding a lever that has the right feel in terms of pull, range, and positioing when placed under the saddle, I think that is key. The Nimbus Supplied Bengal is not a bad brake, I just don’t dig white :roll_eyes:

Search Ebay, get a set of “pull off brakes” that are new and have a return warranty, then you have one for each of your munis and they crossover if you ever need parts or one breaks…

I’m so excited about this hub, I have three builds planned!


Hmm Ben, your bad experience with the lever is exactly the kind of thing that I really don’t want to have to deal with.

Looking at reviews for BB7’s, it sounds like people have trouble coming up with anything bad to say. Anyone here have experience with them and thoughts about how they might work on a uni?

I run BB7’s on my trials bike and don’t have anything bad to say about them. I use 203mm rotors and would probably use 180mm on a unicycle, you can feel the flex on the bike, so I would think it would be very noticeable on a uni.

I have also got a set of Avid Juicy 5 brakes and they would be totally unusable on a unicycle. They are very sensitive to being held at any angle other than how they are normally on an upright bike. The bleed goes horrible when I put my bike in the car, ridiculously spongy and it takes a few minutes pumping the levers to get a decent feel again.

On my old bike I still use V-brakes and I have no experience with disc brakes. Is there any difference between front and rear brake? Which one can be used on uni? And can it be hydraulic or mechanic? I think there are no potential problems with mechanic, am I right? No bleeding, simpler mounting, I expect lower price…

Front and rear calipers are the same, line length is longer on rears.

The Avid issue is apparently a real deal, so I’m avoiding Juicys and the brakes that replaced Juicys.

Note, mechanical calipers will not fit due to clearance issues on a unicycle. I have tried to make them work and all mechanicals are wider by design than hydraulics, so they hit the spokes or the crank.

I just searched on Ebay and found a ton of “take offs” like the Shimano Deore and the higher end XTR.

You can read reviews on MTBR.

Thanks Ben. Well, I suppose there are some mechanical calipers you don’t know and they fit;) I’m afraid of hydraulics, especially bleeding :thinking: . Hope there will be some good tips for specific brakes in the forum.

[QUOTE=Nurse Ben;1507288]
Front and rear calipers are the same, line length is longer on rears.

The Avid issue is apparently a real deal, so I’m avoiding Juicys and the brakes that replaced Juicys.

Note, mechanical calipers will not fit due to clearance issues on a unicycle. I have tried to make them work and all mechanicals are wider by design than hydraulics, so they hit the spokes or the crank.

Actually not a great problem for Nimbus system. The cable model I tested fitted within the criteria of the Standard specification, and hence fitted… I guess you could find some that may not, but the one I looked for could not be called compact! This does not mean that I would recommend using it. Cable calipers are generally wider and are more likely to be caught by your foot during mounting or use. On the model I did my initial testing with 3 years ago it worked great, just nothing like as nice as the hydraulic versions.

Good advice on the Avid brakes, I had not heard this one and that would definately be a problem with unicycles.


Roger, if you found one that works, please share!

I ordered a number of mechanical brakes and not one was usable, I was really frusrated by this, so I would be very happy to know of one that will fit.

BB5/BB7 do not fit, I tried them, they are too wide, but feel free to try them youself and confirm my findings :wink:

Quad QMD-6

When previously researching options for the Mountainuni system, I wrote to the folks at Quad and asked them for dimensions for the QMD-6 mechanical brake caliper. They sent me the attached photo.
So, does it look like this would work on the Nimbus hub?


Just get a cheap hydraulic one (i use a shimano… dont know exactly what model :smiley: ). Works perfect :slight_smile: You’ll just need to replace the pads for some better ones (kool stop).

Need to ask jogi what brake it is… i think he got it off ebay…

@ Unishark: I’ll check when I get home. It looks wide, but without a basis of comparison…compare it to a BB 5/7 if you have one.

There is one distinct difference in the hydraulic brakes: DOT vs Mineral Oil.

Maguras rim brakes use mineral oil, it is non corrosive.
DOT is corrosive, same stuff cars use, I think Avid is DOT, Shimano is mineral oil.

I’m thinking about get some Magura disc brakes, I like how the hose angles downward.

Regarding the mechanical brakes - it is a disadvantage of outbound disc in Mountainuni system. Then the brake is the other way round it was designed to be used and that is why the broader side is on the spokes side.
With disc mounted on the hub, the caliper will be mounted as it was intended so there will be no problem with spoke clearance. As Roger suggested some of the bulkier ones may be in way of your foot (or maybe the crank), but I guess that most of regular ones may be used.


Take a look at the Quad QMD 5 and QMD 6, the 6 is like a BB5, might be thin enough, also the Hayes MX5.

I sent the tech guy at Niagracycle a message asking for caliper dimensions.

Why choose mechanical over hydraulic? Cost, durability, lever choice, and feel. I rode high end mountain bikes before going to muni and I rode BB7 exclusively, hydraulics are a PITA.

But, I have been down this road, and even though Roger says a mechanical will work, I have not found one that works, so I am all about “wait and see” on this…

Wow, this one is a bruiser. It looks like it is really close with the Venture cranks, but should fit easily with KH according to my layouts.


I’ve been looking at the Magura MT2s (http://www.wiggle.co.uk/magura-mt2-disc-brake-with-storm-rotor/#more) on the basis that they use mineral oil (like the HS33s I already have) and have a very similar looking 2 finger blade which will hopefully fit the KH spooner fine.

Sound like a good plan? :wink:

I wouldn’t want to have to explain a credit card purchase from “wiggle” to my wife. :astonished: :smiley:

Haha - I’d have to get a wife first!

Based on the good reviews I’ve seen so far for the MT series of brakes I’ve bitten the bullet and gone and bought one.
The MT2 model though - I don’t care if it weighs 2 grams more, it’s like a million quid cheaper than the MT>2s with apparently the same braking performance :smiley:

I went for the 203mm rotor as it’s going on my 29er and my thinking was that the larger the disk, the more disk moving past the brake for each bit of wheel rotation so modulation might be slightly better?
Ok I admit, I went for a big ass disk because I think it will look cooler. :stuck_out_tongue:
I don’t think the size will make much difference for a unicycle application and I know Paul has a big 205mm hope disk on his 36er so it’s kinda tried and tested.

Going to order the d’brake adaptor soon as my 29er colour scheme’s green so I might as well have it green and then if I can get new spokes ordered (trying to figure out if the length difference will actually warrant any new ones - emailing Roger…) the hub will be the only thing I’ll be waiting on and I can get it built up as soon as that arrives.

Use the regular spoke length for one side and 2mm shorter for the disc side. (This is from Josh at UDC.) You can also use the same length on either side and tighten the disc side 2mm more.