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Discussion Starter #1
Some of the newer model bikes coming out have these petal type rotors or Wave rotors.
Even the dirt bikes have them too.

What benefits do these offer over standard rotors ?

Is this something that might show up in the Vstroms Future ? :wink2:
 

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They are supposed to be better at not warping when hot. My Tenere has them and I can not feel any difference. But to be honest I have never really used my brakes hard enough to matter I guess.
 

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They help keep things clean, the crud gets hit by the cut-outs and is thrown clear.
 

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You can buy wave rotors from eBay now m- I've installed them on two 650's. The big advantage of the more mellow ones was offroad where they cleared grit off the pads a lot better, they do work better than OEM pads all round though, particularly in wet conditions.

Downside, not recommended with sintered pads as they wear quickly. Off road with organic pads though they are noticeably better.
 

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Gotta think

Usually more rotor mass is better, especially for sporty street bikes where the brakes are likely to be used hard. On dirt bikes, I can see that they might self-clean better than solid rotors.

Moslyl I think they are for visual appeal rather than performance.
 

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Wave rotors originated in dirt bikes years ago for their self cleaning benefits and have since migrated on to other bikes for some practical but mostly styling benefit.
 

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+1 on the above.

We sell a lot of brake lines. It is an upgrade that results in tangible improvement. The upgrade does what is claimed.

The reps occasionally call me in an effort to market their brake discs. My response is always that i have owned over 40 motorcycles in my lifetime and never once needed to replace a brake disc.

That isn't to say that people don't experience warped discs, but with modern floating discs it is truly rare.

Wave rotors make a difference for guys riding true dirt bikes in muddy conditions. In the same conditions on a V-Strom you would not need brakes since that kind of mud would have already locked up the front wheel between the tire and fender.

I strongly suspect the greatest improvement a person can make to their V-Strom (unwarped) disc is to de-glaze it and the pads. I think it is overlooked because we are programmed from the moment we start watching TV that to get an improvement we need to buy something.

This video shows the deglazing the disc, but the pads can need deglazing as well.

 

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I agree that wave rotors score more points for styling than for the fractional physics gains. I have never put them on any of my bikes.

The only time I gave them any serious consideration was on that BMW K1200rs I had for a few years. It didn't suffer from a lack of power so the rotational inertia penalty didn't matter. That bike was genetically over weight and had the telelever suspension so saving 4 pounds of rotor weight, while tempting, was still no sale.

What made me think about getting wave rotors was brake fade when riding in the Sierra mountains. After 30 - 40 minutes of carving my way down a mountain the brakes would heat up enough that I'd have to alter my pace. At one point, I replaced the front pads with some boy-racer units which helped but they were really (yikes) bad when operating at more normal riding conditions. I even bought another 2 OEM pads and tried a combo of both street and race pads on the front end. Yes it proved to be a compromise _ at best. I could not find any definitive specs saying how much cooler wave rotors would run. I did not want to join that lottery so I sold the bike.
 

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The angled outside edges of the wave rotors create a continuous cleaning edge - helps clear the disc of dirt. Which is why they're so prevalent in the dirt world. As seen on street bikes, there's no real benefit other than that they look cool. Sometimes looking cool is reason enough.
 

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Among things that affect braking is "swept area". ie the actual area of disc that is swept by the pad. If the diameter was kept the same, the swept area would be less, leading to less braking efficiency. If the diameter is increased to compensate for that, then you have a change in rotational forces which has its own set of effects on handling and braking. Yes, modern rotors have grooves and holes but their positive (better cooling) more than offsets their negative. I would bet a beer that the main reason, on a road bike, is fashion/style/fad. Ask yourself this......how many motogp bikes have wave rotors? I would think that if they provided even a modicum of increased braking efficiency, they would all be running them, carbon ceramic or not.
 

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IMHO, the best bang for your "braking buck" is a set of EBC sintered pads. A noticeable improvement over stock.
 

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Sinterred pads stop you better, but wear faster/don't last as long and wear disks faster. That doesn't mean they are not worth it for some, especially those carrying a lot of weight on the bike (e.g., passenger and full luggage compliment or larger rider, or pulling a trailer (see my avatar)), but it's not a free lunch.

Galfer has sinterred pads as well.
 

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Question about wave rotors. I've not seen these on a bike so I have not been able to answer this question. Does the brake pad see metal, then the 'wave cutout' as the wheel turns? In other words, the swept area of the disc by the pad includes the 'valleys' of the wave?

Logically, the answer to my q is a yes, or what's the point. But if the wave form only sweeps the outside 1/5 of the pad, you are only going to be cleaning the pad of dirt and mud on that area. The wave has no effect on the unswept major portion of the pad. The wave cannot sweep the whole pad's area or the pads would collapse inward.

It's possible that the sweeping action of a fraction of the disk's area makes a difference, but I confess to being skeptical until I hear from a pro (who is not being paid by the mfr of rotors) that the improvement in braking is real.
 

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The disc spins inside the calliper so fast there is very little chance for the crud to penetrate then the discs have holes or slots to remove the rest.


When I had drum braked dirt bikes I could not stop the mud & crud getting in so I cut slots in my brake shoes, they were cat at such a angle that as the brake hub spun it pushed the mud out.

This was especially helpful with my son"s bikes as the smaller wheels collected more mud.
 
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Question about wave rotors. I've not seen these on a bike so I have not been able to answer this question. Does the brake pad see metal, then the 'wave cutout' as the wheel turns? In other words, the swept area of the disc by the pad includes the 'valleys' of the wave?

Logically, the answer to my q is a yes, or what's the point. But if the wave form only sweeps the outside 1/5 of the pad, you are only going to be cleaning the pad of dirt and mud on that area. The wave has no effect on the unswept major portion of the pad. The wave cannot sweep the whole pad's area or the pads would collapse inward.

It's possible that the sweeping action of a fraction of the disk's area makes a difference, but I confess to being skeptical until I hear from a pro (who is not being paid by the mfr of rotors) that the improvement in braking is real.
I have, and I've put them on two DL650's so far. And yes the swept area includes the valleys because the slots in the disc get what the petals miss.

And strangely it works better than OEM even with Chinese made rotors off eBay. You also drop the rotating mass by some margin which allows the bike to turn faster.

Frankly the two sets I've put on have been better made and assembled than OEM and both performed significantly better through their life than OEM as well. I wouldn't change them just for that, though the second set did get done earlier than the first because I had no reservations about using the eBay rotors the second time but in terms of replacing worn rotors they'd be my go to now and not just on cost.

I certainly notice the lack of squeal from the brakes and the more consistent brakes. They certainly work better on dirt and on wet seal, can't pick a difference on dry sealed roads.
 

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First bike, stock rotors lasted ~80,000k's and REALLY needed replacing. i.e. if the gouges on the rotor faces had been opposite one another the rotor would have parted. I sold that bike @120,000 and I think it made it to ~140,000 without the eBay rotors being replaced. (Cooling system failure supposedly killed it).

Next bike stock rotors lasted ~60,000's and would have been below the official service limit but were missing the deep gouges. I now have 130,000k's on that bike and the eBay replacements are starting to show signs of wear and I'd probably replace them now but the bike is just doing the commute. Yes I still need brakes on the commute but there's no hard braking from speed and near no wear.

One thing I have noticed, with the OEM rotors and a week of commuting I'd need several hard stops to get the brakes up to full function again (just build up of oily crap on the rotors I think), with the eBay rotors, one hard stop and they are back up to good again.
 

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Question about wave rotors. I've not seen these on a bike so I have not been able to answer this question. Does the brake pad see metal, then the 'wave cutout' as the wheel turns? In other words, the swept area of the disc by the pad includes the 'valleys' of the wave?

Logically, the answer to my q is a yes, or what's the point. But if the wave form only sweeps the outside 1/5 of the pad, you are only going to be cleaning the pad of dirt and mud on that area. The wave has no effect on the unswept major portion of the pad. The wave cannot sweep the whole pad's area or the pads would collapse inward.

It's possible that the sweeping action of a fraction of the disk's area makes a difference, but I confess to being skeptical until I hear from a pro (who is not being paid by the mfr of rotors) that the improvement in braking is real.
I think that with most wave and petal rotors, as one wave is leaving the pad area of the caliper, the next has already entered the other side. This allows the pads to stay in constant contact with the disc while enabling better cleaning and cooling. If the wave or petal were at any time completely free of contact with the pads, the caliper could potentially slam the pads shut enough to cause real damage and loss of control as the wave comes up against zero or negligible gap between the pads.
One argument (or rationalization) for wave rotors besides the effect on cooling, is less unsprung weight which aids handling. But I put a pair of EBC waves on my XZ11 just in case I had to make repeated hard stops some time.

Besides, they looked way cool. >:)
 
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