My bearing collection and testing methods
I use Kwik Ceramic, Qube Ceramic, Bones Ceramic Super Reds, ZJchao Ceramic,Yolo Ceramic, Bionic Ceramic, Mota Swiss, Crazy Skates ILQ9 Gold, Bones Super Reds, Bones Reds, Bones 6-ball, Bronson Raw, Bronson G3, Snyder Super Fafnir, Fafnir C7, Roll Line MAX, Kwik Zenith, Yellow Jacket ABEC 7, SEBA ILQ7, Oust MOC9 Arrr, Oust MOC7, Qube Juice, Qube 8 Ball, 3 types of unknown Chinese ABEC 7 608ZZ bearings, 2 types of unknown Chinese 608RS bearings, Mini Skater 608 Shieldless, and several more I’m forgetting (and over 100 spares). Yes, I’ve also tried old-school loose ball bearings (which are terrible).
To do roll-out testing on my bearings I use a half meter ramp and two lead weights which weigh a total of 33KG (half my body weight) in a skate boot with tight trucks. The test measures total distance.
I do spin tests with an 80lb load and a variable speed router (500-32k RPM). The test measures total seconds of roll after the target RPM is reached. I use a stopwatch.
I also use a set of stereo microscopes to examine the balls, races, and retainers up close.
So far, I've also tested 27 different lubricants. I'm an engineer by trade so I have the test equipment (such as the scopes and tension wheel). I plan to make several posts about bearings. As for me and my skating level: I'm a quad skater and I've skated for three years 4-5 sessions a week. I mostly do Rhythm and Jam skating, but I also do Park skating and Slalom on my inlines. I've been told my skill level is considerably higher than most folks with more years of skating, but if that's true it's just due to my frequent practice. I also do BMX Street and pro scooter, but nowhere near as much as roller skating.
I plan to make several posts about bearings, but I thought I'd first introduce my background with bearings.
Comments
This should be interesting and informative. Some swear by ceramics, while others say they cant tell a difference to their cheap Chinese bearings.
I don't think ceramics are always noticeable or better than steel (especially tight-tolerance "swiss" steel). I certainly have high quality steel bearings that can hang with ceramic ones. However, there are some areas where ceramics are superior. The balls do not expand as much as steel when they are hot. This means they perform better under speed and sprinting loads. If they are fully ceramic and have coated races, then they are functionally waterproof, too. However, you'd have the additional heading of using a heavy waterproof grease in that scenario, dragging you down. Where I'd avoid ceramics is for slalom. They tend to pit and chip the edges of the races or the contact points on the balls as they wear then they get chunky and ruined. It's easy to see under the microscope how they handle axial and torsional loads differently than the radial load most skaters bring to bear. If you are a slalom skater, choose a slalom specific bearing like the Oust MOC 9 and be quick with the metallic-soap based lubricants.
bearings on skates don't get hot, they wouldn't be bearings if they did. They would be junk bearings. Ive shot bearings/wheels with laser temp guns years ago. The wheels and bearing's temperature were generally the same. Usually the wheels and bearings are very close to room temperature or skate surface temperature.
If you have a hot bearing on a skate, it's pretty much junk. The same bearings are ran in electric motors. The bearings get warm from heat transferred from the rotor/shaft. Electric motors are inefficient, create heat.
I have a different opinion than you. I used a Bosch router and pushed the wheels to 7500 RPM (I can show the math if you'd like, but this is a good high-side figure for speed skater bearing RPM) while applying 80 pounds of hydraulic load on the test harness. I used an infrared thermometer (Fluke 62) and I've calibrated it enough to trust it's results using other thermometers. Most of my testing used Bronson Raw shieldless bearings so I could shoot temps on the balls themselves (the Fluke meter is that good). In my testing, the ball temperature would go from nominal (room level) to about 120-130 degrees in under a minute depending on the lubricant type and the amount applied. I'll grant that isn't very high, but it's certainly measurable. I've seen temperatures as high as 168F (that was on Mini Skater bearings). The reason I was doing this was to try and compute the viscosity temperature coefficient (VTC) of several lubricants I was curious about. Bearings definitely generate heat, even with low-load situations like skates. However, most lubricants don't break down or have viscosity problems until around 200F or higher, so I have more sympathy for the "it doesn't matter much" argument but not the "no heat is generated" idea, which is measurably false. Mechanical action on a bearing will always generate heat. Period. The question is how much, how measurable, and how much will it impact the application.
The retainers are the weak link besides lubricants. They are typically some kind of temperature "resistant" nylon or polycarbonate, though a few (such as a few Oust bearing types) make their retainers from steel. Oust bearings are frequently used by slalom skaters and their engineers specifically state they use metal to better handle heat. I actually have VTC viscosity/temp graph for MetOL and others and you can see similar results in this engineering test where the gentleman uses motor oil http://www.getrolling.com/orbit/F08_engineer.html which has a lot of great data including this line I wholeheartedly agree with "The downside is that a grease packed bearing has a noticeably higher traction torque."
So what is the temperature of a typical bearing or pair in a wheel at 25mph surface speed... 230# skater? Never ever seen a hot set of skate bearings. Seen worn out, never hot. If they were that hot, the heat would have been transfered.
With spacers or without? If spacers were imperfect in individual width/setup, I could agree that heat could be from angular loading of the races. Heat from the inner races could be transfered through contact/compression/tension on the axle/nut/bearing assembly and somewhat dissipated. Without spacers bearings are allowed to find the centers of their races and"run cooler". As with flip axles, there is no spacer to clamp inner races to. So less heat, at least none that I have measured. Typically the entire assembly is same temperature.
Now drag...
If you had perfect alignment, you would be loading in a turn, all bearings to one side of their races. If the bearings are allowed to be ran without spacers, typically you only load 1/2 of the races.
I am definitely interested in further posts about bearings.
I recently got a set of some cheaper ceramics and instantly blew out one of the ball bearings when I pressed an edge for an IB upright spin! I wasn't going to jump in them for fear of that happening but was pretty surprised the ball shattered from pressing a spin edge.
Welcome to ceramic bearings. Not uncommon for them to shatter.
Yeah that's the first and last time I go for ceramics. From what I felt for the minute before they shattered there was no difference anyway. I only weigh 150lbs and it's not like I was doing a travelling camel or anything, just a basic upright without any speed.
Interesting! I know that ceramic balls usually have about half the compression strength (or less) of steel balls. There is a guy on Youtube that does some crush testing and IIRC the ceramic was around 12K PSI and steel was around 23K. Can you share which brand you were using? I'm curious what type of ceramic balls they used. I do a lot of upright spins also and I weight the same as you but I have been lucky so far.
The claim by manufacturers is that ceramic balls deform less as they heat up. A materials science friend of mine agrees with that and also says they are also easier to manufacturer to ultra-tight tolerances. I use several sets of ceramic bearings but my favorites are Kwik Ceramic (the gold Nitride ones). I haven't blown up any ceramics while skating. I have blown up several different types of bearings with a high speed router, though, including ceramics. Ball failure happened in one case. I think I might even have some pictures of the ball under the scope. I'll look for those. On steel bearings, it was almost always a retainer failure.
In roll-out testing, Moto Swiss bearings and Yolo did quite well for me. Those are both 7-ball steel bearings. Moto Swiss bearings are also nitride coated and rather beautiful. The tolerances on them are gapless if you like that sort of thing. They are 608ZZ (single-side with fixed metal shield). So, you don't worry about shield drag. After testing so many, I'm not a ceramic bearing bigot. They work great for me but not any significantly better than some of the high-end Swiss bearings. I also always wondered if the lower compression tolerance would result in any ball-shearing or cleaving for someone landing a hard jump.
I was using these ones. https://rollskater.com/product/19681176/bearings-roll-skater-abec-9-ceramic
I can go find the rest of them and check the balls later, but they were white so I'm assuming ZrO2.
Our coaches have said they'd only use the ceramics for figures if they had to but otherwise would stick to something more durable even for dance. I'm pretty sure if I was pressing a deep dance edge the bearing would've shattered on that as well, definitely on jumps.
Also just as a side note I only use 7mm bearings as all my artistic skates and even the Labeda Proline I was using for fun on some low tops all have 7mm axles.
Have you tested out Hartford Gold bearings? They are supposedly extremely durable and roll for years but I have never tried them out. I am also interested in how the Roll-Line Speed Max bearings compare to some of the swiss type mid/high end bearings. Because all the guys I know doing high end freestyle stuff are using the Roll-Line stuff. A lot are sponsored by them but others like them regardless.
[quote]
I used a Bosch router and pushed the wheels to 7500 RPM (I can show the math if you'd like, but this is a good high-side figure for speed skater bearing RPM)[/quote]I'd like to see that math.
I did some of my own. I assumed a 59mm wheel and 25mph speed on a 100m indoor track. 25 mph would be sub-9 second lap times, and there are no quad skating records that low. Considering this is the quad forum, I think it's fair to say that's the high side.
59mm wheel has a theoretical circumference of .608117 feet, and 25 mph is 2200 fpm. That yields 3617.727 rpm on my slide rule. You'd have to be going 52 mph to hit 7500 rpm.
52 mph is world class outdoor inline speeds. Assuming a 110 mm wheel, that's still only 4036 rpm, and I'll bet the guys going that fast are on 125's.
Downhill longboard skaters could hit 52+ mph.
I diddo the math but knew that we weren't turning 7k+. Most electric motors turn only 1800 rpm. Some 3200 or so. Die grinders will turn higher rpms. Skaters, way lower rpms.
Wonder if I can get recommendation(s).
I'm a quad skater, outdoors. I posted in the evidently now defunct www.skatelogforum.com/forums asking about bearings and spacers. One poster recommended "100% stainless steel bearings with black ceramic SiN balls." People pretty much agreed to not bother with spacers (which I never have). I've never used ceramic bearings.
This evening at Amazon I ordered "Oldboy Premium Ceramic Skateboard Bearings (608RS ZrO2 at 8 x 22 x 7 mm) for Standard Skate Board Wheels - Good for Longboards, Quad Skates, Inline Stakes, Rollerblades and Scooters Too," but after starting a thread here today (as my first post here) was recommended to steer clear of ceramic bearings if I indeed wanted my bearings to not break down relative to others, so I just cancelled that order.
My predicament: I've been skating streets, sometimes sidewalks when the streets are too rough (which happens a LOT around here) for 30 years on quad skates. I'm on my second pair of uppers (basketball shoes) which I personally attached to Jogger trucks with bolts and broad washers. I've used exclusively Kryptonic 70mm urethane wheels. I have a new set of those wheels, which I plan to install shortly, but I figure I need buy and install new bearings, having no new ones now. My bearings have been nothing special, steel, and recently been rolling Bones Reds. I've sometimes tried to renew my gritty bearings by soaking them for a few days in acetone. I don't recall trying to lube them.
Less than a year ago a bearing seized up and I was forced to walk a few miles. I had another bearing seize up a couple days ago and luckily I wasn't skating down the hill I've been skating daily at probably up to 15 miles/hour or I could have been really hurt (I've been skating 6 times up/down a not-steep hill ~1/2 mile long).
So, hey, I'm not racing or anything, but I'm pushing myself, skating with a heart rate monitor on. Speed isn't the concern (although I'm skating pretty much as fast as I can if the situation allows that), I want a great workout and of course, I want to enjoy my skates. The hill I'm skating during the pandemic is pretty nicely paved, something that's kind of rare around here.
So, I want to buy new bearings that are least likely to break down on me, specifically not suddenly seize up and throw me to the pavement! I suppose being able to last a long time might be part of that equation, and would be convenient, but safety is the number one concern. Occasionally, I'll turn a skate over and spin the four wheels by swatting them and observe if they all spin a long time as a gauge of how the bearings are holding up. Unless I perceive a problem I just keep using them. Maybe I should pay closer attention to the health of my bearings and at least clean, maybe lube them once in a while??? I rotate the wheels around twice a year with a routine I've devised that I think balances the wear.
I should add that I'm not apt to skate when the streets are wet.
I do have an AmScope SE306R-PZ-LED stereo microscope, also an Amscope - 40X-2500X LED Digital Binocular Compound Microscope w 3D Stage. Maybe they could help?
So, is it true or false that ceramic bearings are to be avoided or preferred? I've been advised both ways now and don't know what to think. Specific recommendations, even a place to buy at least 16 bearings, very much appreciated.
Thanks!
Bearings from well-known brands are typically well-made and can handle the daily beatings of riding and cruising. It is a small price to pay rather than compromising the safety of your rides by settling for less. The key is to purchase a set that suits your needs and style and allows you to enjoy your rides to the fullest.
Muse, I have put Kwik Ceramic (the gold TiN coated ones) to work outdoors. The bearing cages have very tight tolerances. So, they work fine but need cleaning about every 10-20 skate hours in dusty outdoor conditions. You might like Oust MOC5 Street bearings. They are very very tough for use in outdoor skating (rockin stainless steel bearing cages!), downhill, and pro slalom skaters use these and the MOC9 Arr bearings in competition I've noticed.
Another one you might like is the Bronson Raw bearing. Those use tungsten races and no side shields at all. The design just grinds up crud and dirt and ejects it. They tend to be in heavy use by downhill skateboarders but work great in roller skates and have massive free-spin times and make a wonderful sound (if that appeals to you). I've seen skaters restore rusted balls in those simply by riding them out with a bunch of lube. They are so tough.
Also, check out my post about the really cheap nitride ceramic bearings on Amazon. Those are a steal for $18. They definitely smoke Reds on free-spin and feel much nicer. They are extremely weather resistant, too. I've had them under water in puddles and rainstorms with no damage (needed lube again, though).
I want to say congrats on those Kryptonics 70MM. I rock those on a pair of Sure Grip Fame boots with Arius Platinum plates (jacked up hardness cushions for outdoor), they ride high enough that it works well. Those wheels are so buttery. They aren't what I'd call trick wheels for doing park or any kind of dance/figure/rhythm etc.. but boy do they roll out over rough terrain with attitude and command. They also have terrific stopping power when wheel-braking.
You wanna use that scope? Check out your bearing scoring and perfectly tune your lubrication levels with it. I use a little 10x-30x sometimes when using white lithium grease and a sewing needle to apply miniscule amounts direct to the bearing. Your scope design will work even better for that. Grease is good when you need bearings to stay in service a long time, you weigh a bit more, or you need a bit more resistance to moisture. I mostly use Oust Met-Ol or Uncle Charlies for lube, though.
dvw, you want to see math? 4576 FPM is 52 MPH. I'll use your same units. 57mm diameter yields a circumference of 0.5875 feet. So, at 52 MPH the 57MM wheel would spin at 7788 RPM at 52MPH, well over 7500 RPM. Ain't cherry picking fun? Like you, I doubt many go that fast often on quads, but as an engineer you want to pad your metrics by at least 10% for safety reasons (20% for most safety sensitive engineering is more common in my years of experience as an engineer). So, that'd be around 33 MPH if padded for safety and that's a very reasonable speed for quad speed skaters. The world record for inline downhill is not 52MPH by the way. It's 77 MPH by Sandro Bovo and that is on the same 608 BEARINGS. So in that case, 6776 FPM is 77 MPH. The common 80MM inline wheel is 0.82457 feet in circumference. So, at 77 MPH the 80MM would spin at 8217 RPM on that same 608 bearing, again well above 7500. You mention downhill longboard. Those are 608 bearings too (usually with 70mm wheels) and the record is 91 MPH which just categorically destroys your doubts-substituting-for-an-argument. 608 bearings spin at 7500 in many skater/human-weight applications under load. Period. Fact. "Truth is not what you want it to be; it is what it is, and you must bend to its power or live a lie." -Miyamoto Musashi.
BTW, I also skate on inlines, but I'm no good on them for dance. I'm focused on quads mostly.
Been quad skating my 70MM Kryptonics with 2 sets of:
Oldboy Premium Ceramic Skateboard Bearings (608RS ZrO2 at 8 x 22 x 7 mm) for Standard Skate Board Wheels - Good for Longboards, Quad Skates, Inline Stakes, Rollerblades and Scooters Too, set of 8.
Basketball shoes with personally attached Sure Grip Jogger aluminum plates I bought in 1989 at a local skate shop.
I was, when I posted above, a year ago, street skating ~5.5 miles a day. I upped that to 6.5miles, then 9.2 miles and in early August to 10 miles/day. One of those Oldboy bearings seems to have gone bad and I replaced the bearings on that wheel with NMB Japan 608zz bearings a month or two ago.
I've doubled up on my 2x/year wheel rotation and now am doing 4x/year. I've also taken to lubricating the bearings after cleaning with acetone. I have a couple of tubes of bicycle bearing grease. Don't know if I should use that stuff, I suppose it's OK, but I bought some oil specifically to try on skate bearings, Valvoline Advanced Full Synthetic SAE 5W-20 Motor Oil. I put some in small bottles with eye droppers. I'm not sure how good it is, saw it recommended. I recently bought some Bones Speed Cream, used it last week to lube the cleaned Oldboy ceramic bearings as part of my scheduled wheel rotation.
Got some of those Kwik ceramics, also have a set of Kveni ceramics, but haven't used them yet. Also have that tube of very old NMB 608zz Japan bearings whose lube has gotten pretty tough, probably having sat in a warehouse for umpteen years. I cleaned some with acetone, they seem fine. I have a feeling those are probably great... well, maybe. I put them in a 2nd set of Kryptonics 7MM wheels, haven't used the wheels/bearings yet. But they're there in case I need a quick change! BTW, nothing beats a cordless screwdriver for quickly removing and replacing wheels on skates! Well, nothing I know of.
Skated late this afternoon. My first turnaround on my route (it's up & down one street, so two turnarounds, a total of 11 times up/back, to achieve my 10 miles), is at a park that has outdoor basketball courts that the city has recently resurfaced. They scheduled a couple of 5-8PM skating fests on the courts, and the first (I think) was today, so saw and heard (disco) the activity each time I made my turnaround at the park today. I figure skill skating, backwards skating is fun and all but every time I see people out there I get the feeling that they are all skating for each other, showing off. I'm all for the fun of it, of course, but I'm primarily working at increasing my fitness and aerobic conditioning, i.e. endurance skating. I always wear a heart rate monitor, with my cell phone in pocket. I wear gloves and a helmet. I haven't fallen in a long time but know that if and when I do, gloves are key to not getting hurt. The helmet? My PT talked me into wearing it on my bicycle, so figure may as well skating too. The street I'm skating daily is a designated "Safe Street" here, one of I think 3 in my town, has signs saying it's for cyclists and emergency vehicles only, "15 MPH," but obviously if you live on it you can drive on it. Drivers just ignore the 15MPH. Nobody's enforcing anything. I get the impression that many people honor the signs but that many don't at all, just don't care. Somebody has been engaging in vehicular vandalism and smashing the signs with their truck or something. Me and another guy have been restoring 2 of the signs every time they get flattened (last week or two, no damage, fingers crossed). The 3rd sign is gone entirely. It's a relatively smooth street, and it's only a block away from me, which is lucky. Also, depending on the time of day, there's not a lot of traffic, never a whole lot. The great majority of the streets around here are pretty impossible to skate because of the condition of the asphalt! I know of no roller skating rinks anywhere near me. I heard there's a park maybe 2 miles away where they skate, I should check that out one day, but my daily skate starting a block away is super convenient. It's kept me fit during the pandemic.
Muse, that's great that you've been able to skate your way through the pandemic. I've been lucky enough to do the same. I think your bearing setup sounds excellent and experimenting with different lubricants is fun. I'd say that anyone who goes over four months between bearing service might want to consider using grease. It's got a bit more starting drag, but under load it gives almost the same performance as oil and lasts a lot longer. When I use Oust Met Oil, which is the lightest lubricant I've found, I don't really find any lubricant left after about three months (@14 hours/week of skating). It's very thin, but also it's got those metal soaps in there that are supposed to protect the bearing a bit more under heat and load. I've had good results (esp freespin) from Met Oil, but it does tend to just disappear. I serviced a lady's skates that had white lithium grease in the bearings. They had crappy freespin but they rolled out okay under load and they'd been in service for four years!
Good luck with your crusade against the sign haters. I've got used to the skate-hate, but I don't understand it. I get why people absolutely hate bicyclists. I like to ride bikes and I still hate spandex bicyclists ass waggling at 15 MPH (on a 50 MPH road) in a big peloton. I guess it's probably the people who cut up pedestrians on skates or who zip in front of cars and ignore the signals etc... However, I've often had a darker suspicion when it comes to skate-hate that it's because some people just really hate watching someone else have any fun. That's different from bicyclists hate, where mostly it's because of how they act and look which makes people want them smashed. So, I consider the skate hate and the bike hate to come from different places, but maybe it's just because I'm a skater. 😉
Oh also, Quickstep, an engineer I work with and has forgot more about bearings that I'll ever even know told me that in a hydraulic press the chromium "swiss" style ball bearings tend to shatter at 80k to 110k (pounds) pressures. According to him the ceramic balls shatter at around 30k. So, that's one big issue, they are simply more brittle and there is no way around it.
His claim was that in all his testing, ceramics have the most problems with axial loads. Once the bearing faces become misaligned, the balls stop riding in the annulus of the bearing and one or both races can force the ball to ride on the edge of the annulus. This is what my genius buddy says is almost always the cause of bearing ball failure. He called it a "ball buster" configuration and described that as a "knife edge walnut press" for bearing balls. If you can force the bearing faces to remain parallel (or at least the bottom race) then you will force the load over all the balls and keep them riding in the annulus instead of having one or two balls riding the hard edge of one or both races. The way to do this is by using accurate bearing spacers. I weight about 150 pounds too. About 80% of the bearings I use are ceramic. I've never broken/shattered a ball. The spacers redirect the load onto the axle seat where it belongs, but doesn't change the fact that they are still fundamentally weaker in terms of load bearing.
I think you are probably a better, more demanding, skater that puts more load on your bearings when you land your jumps, for example. I can only land singles, but I suspect you go further/higher/harder. I also have noticed you are a smart person who knows a lot about skate mechanics. So maybe you were actually riding with spacers when you shattered the ceramics you had. I can also tell you that there is a very wide range in quality, even for ceramic bearings. The Kwiks are top notch, but I've had some cheap Chinese ceramics that were nowhere near as good. Everyone's mileage varies, and I have to also so that I have some Swiss bearings (Moto in this case) that outperform most of my bearing metrics on my ceramics. So, point is, they can be cool and extremely precise bearings (enhancing performance) but compared to really nice chrome bearings there is a very small delta, if any. The main two advantages are: it's easier to make the balls precise using ceramics and they don't rust.
The least expensive bearings produced from low-quality steel are typically labeled ABEC 1. ABEC 3 and ABEC 5 bearings are also affordable but fare much better than the previous classification. Because of the quality of materials and craftsmanship, ABEC 7 bearings run smooth and fast. Recommended for downhill riding, ABEC 9 bearings are ultra-fast, making them pricier.