Ever deliberately put oil on a disc rotor?

I have a Skpke mechanical brake that I recently put on my Oracle 36er. I have used this brake on my 29er and it works great- I replaced a leaky hydraulic brake on that wheel and love it and have found it to be comparable in performance.

I have found that the braking with the mechanical (same 180mm rotor) on my 36er is not as linear as what I had with the hydraulic it replaced. What I mean by that is that when I apply the brake with a constant amount of force at the lever, as the wheel slows down the rate of deceleration increases, sometimes dramatically. This forces me to release some pressure at the lever, which causes the braking to be herky-jerky instead of the smooth braking modulation I am used to.

I thought one way to deal with this might be to put a tiny amount of hyraulic brake oil on the rotor- since I remember what this did to my rotor on the 29er. It seems counterintuitive to do such a thing- is this an unwise thing to do?

I’m not sure how the oil would affect the braking compound the pads are made of over time. Oil will most definitely decrease braking performance (as confirmed by a google search of “oil on disc brakes”)

You could try it and if it doesn’t work out for you, take the brakes apart and clean with rubbing alcohol.

There’s a good reason unicycles tend to have hydraulic brakes. They feel more linear and are easier to control, as you’re experiencing. They don’t tend to “grab” quickly either.

Before you try anything else though, take some alcohol and clean the disc itself. You may even want to check the pads and make sure they don’t have any particles in them and that they’re clean. Maybe a different brake compound would give you better performance.

I don’t run disc brakes. Grain of salt and all that jazz.

I have no experience with this (don’t you just love it when clueless people respond to your question?), but I’m interested to see where this goes, and I can appreciate why you’d want to try this. I have hydraulic brakes, they work too well, and they’re non-linear. Overall, I like the brakes, but it would be nice to have them work less well. Aside from a few limited situations, there’s almost no reason I need to brakes to be that strong, and I’d rather they just slowed down the wheel instead of easily locking it up.

I would wait for at least 15 rides with the new setup before even thinking about attempting it. Try and get used to it at first, break in the brake pads.

A little bit of oil will be gone quickly or attract dirt, as most bicycle brake pads are metallic, so they would not absorb the oil, and you wouldn’t want to lube your brakes before every ride, would you? Also, with not enough oil, you would probably achieve quite the opposite of the intended, with changing friction coefficients on the disk, you would get shuddery braking.

A different brake compound is what I would try, or a hydraulic brake. (I never used a cable diskbrake, but I am sure there is a reason why even budget oriented Muni builds feature a hydraulic brake). Maximum braking power is far less critical on unis than being able to dosate the power well.

It’s probably not going to ruin your brakes, but I expect it to not be a solution.

The reason I even have the idea is that when my brake leaked on the 29er, it made for a smooth drag in the braking that required more power on the lever to brake hard. I generally don’t need too much power, but smoothness is important since at high speeds and having to brake with a non-smooth setup I am likely to UPD.

I love the mechanical setup on the 29er- not sure why its different on the 36er- I thought it might be residual oil on the 29er rotor (even though I burned what I could off of it. Others on other threads seem to endorse the mechanical brake too.

What you were experiencing was probably air in the system, not residual oil on the rotor.

Maybe consider setting your pads further out or trying an avid speed dial lever.

Also maybe try organic pads vs. metallic.

I got a pair of cyclo-cross calipers, they are hydraulic calipers but work with a normal cable and lever. Advantages are automatic pad wear adjustment, power, cheap and easy lever replacement and you can adjust cable tension so it bites or just drags depending on your preference. I can’t see any disadvantages for unicycle use. I don’t know how to attach a link, but put mechanical hydraulic mtb caliper into amazon or Google and you’ll find them.

I don’t think oil on the disc is a good idea. It will not slow you down, will squeal like a stuck pig and it’s next to impossible to clean the pads after. Rotors can be cleaned but pads would need replacing. I’ve dripped oil on pads and rotors on b*kes accidentally when bleeding them. Admittedly a unicycle might be less of an issue since its assisting rather than your main source of braking, but I still say don’t do it!

Good thought, but no, I bled my line and know some oil got on the rotor. Even with maximal pressure on the lever, if standing and I leaned on the uni seat against the brake grip I could easily get the wheel to turn. Not the case with current brake.

Maybe I will try another brake pad. Have the avid speed dial lever already- partly from your posts on separate thread related to Spyke mechanical brake. Are organic pads expensive? Do they have GMO pads? :wink:

Update: So I decided to do it- i put a few drops of hydraulic brake oil on a rag and wiped my rotor and applied a tiny bit of the oil. The desired effect was achieved- my braking has the smoothness I was looking for. I did sacrifice some braking power, but so far I’m pleased with the result.

Adding air to brake system

Just added some air to my disc brake system. The braking was too harsh on my nimbus 26 disc. I opened the bleed valve released a bit of fluid and let a bit of air in. Much improved modulation. Obviously I can’t recommend it as it could go all wrong and require a full bleed - but it worked for me. Steeper hills have become easier to descend as modulation is more progressive.
Thanks for the advice.

Soft brakes

When I started making my own disc muni hubs back ln the early 2000’s I had several pairs of Coda hydrolic calipers stripped off of new Connondales because they were notoriously mushy. This turned out to be a good thing for unicycle braking, soft! I’m sure that many other cannondale owners felt the same and offer them cheap on ebay, even Cannondale switched when thier love affair with Skooks Coda ended. So maybe that would help.