|
|
|
| Bearing Reviews (4976 Posts)
|
| Bearing |
Review |
|
A Couple Thou
|
|
On 3/10/2006
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
Let's put it this way. If you were making hubs and spacers, I'd encourage you to make your hubs at no more than .400" (+0,-.002"), and your spacers at least .400" (+.002,-0). Having said that, your spacer can be over .005" wider than the hub spacing, and you may still have fine performance. I know some people who go all the way up to .420" spacers in their street wheels. I personally don't like the way that the wheel's bearing seats slide back and forth under a sideload. You can feel the wheels shift and make a click or a popping sound when pulling and pushing the wheels by hand. And although it's harder to detect it happening while riding, I still can't justify making spacers that wide. If you want a spacer like that, you can always put a washer between some Biltins.
Basically, you never want to make too narrow of a spacer, or too wide of a hub spacing. And since it's hard to hold tight tolerances with this stuuf, the safer thing to do is to cheat your hubs narrow, and your spacers wide. It works.
|
|
|
|
|
And another thing...
|
|
On 3/10/2006
JBH
wrote in from
United States
(70.242.nnn.nnn)
And I've often wondered about the spacer-measurement thing--but from the other side, i.e., is a slightly OVERSIZED spacer any better than a slightly undersized one? This question has particular relevance for me.
As some of you know, last summer I had a machinist make a small batch of slightly oversized spacers, because I was tired of having undersized ones that felt "bound up" when I tightened the axle locknut firmly, and frankly, because I didn't want to buy Biltins because I didn't like their shield design, which I felt let in dirt too easily.
I had my own spacers made because, for all practical purposes, NONE of the dozens of spacers I'd accumulated over 20+ years of skateboarding was worth a damn. Sure, maybe one out of every 20 or so was passable, but seriously, who has time to keep track of them? Not me.
A quick look at my various spacers from various manufacturers, including Powell (Bones), showed that some were "tilted", i.e. the edges of the spacer weren't parallel, which resulted in a "high spot" that caused the wheel to wobble.
Others, when measured with a dial caliper, were at or under .400", which almost always resulted in the situation that Chaput showed in his diagram.
So I had the seemingly brilliant idea of having a machinist make steel spacers that measured .404", + or - .001". (Also, a few prototypes he made went as high as .408".)
They worked like a charm to allow me to crank down the axle nuts rock-solid on all my boards and wheels, even my coreless park wheels. Surely it didn't hurt that I also rode only Radikal trucks, and a pair of "Geezerized" Randals with faced bearing seats.
But I had no reliable way of actually measuring each wheel's core. So I always wondered whether I had solved the inner-race problem but had perhaps created a new problem for the outer races.
Chris, what's your experience with the tolerances of the cores in your wheels? You've obviously invested a considerable amount of money that they're awfully close to .400" by making your Biltins meet that spec. What do your cores actually measure? And if I use a slightly oversize spacer, does it introduce a significant amount of slop by pushing the outer ring of the bearings slightly away from their seat in the core?
|
|
|
|
|
Slim's question
|
|
On 3/10/2006
Jonathan Harms
wrote in from
United States
(70.242.nnn.nnn)
Slim wrote: "For example, how much faster, in percentage terms, do you think a set of bearings set up with proper spacing are vs. the same bearings set up with no spacers and slightly loose nuts?"
I've wondered the same thing, Slim. It seems as though, as Chuck said, the bearings would be in a "pre-loaded" condition. Chuck, am I reasoning correctly that it's somewhat like constantly doing a hard GS turn? Even when going straight, the balls would be pushing against the side of the race rather than riding in the bottom of the groove? But even if that is correct, does that necessarily mean that setup will go slower than one that's set up all nice and perpendicular-like?
Whaddya say, Mr. Rocket Scientist? What's the answer, and why?
|
|
|
|
|
My Wheel
|
|
On 3/10/2006
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
Mine goes to 11.
|
|
|
|
|
Random Bearing Comments
|
|
On 3/10/2006 Chuck Gill
wrote in from
United States
(192.249.nnn.nnn)
The picture in CC's post below is actually how two-ball-bearing systems should be designed to ensure long life and consistent loading under all conditions. Obviously, this will result in somewhat increased starting torque requirements, and a very slightly increased running torque requirement. In "the real world" machinery is designed so that these additional startup and running torques are not an issue compared to the torques in the entire system.
Skateboards are not "the real world." The bearings we use are radically over-designed for what we do to/with them. Going along with this, the increased start-up and running torques from a properly loaded duplex ball system (using 608 bearings) are unacceptably high to skateboarders. We therefore do not preload our bearings, we do not mind crossover of the load path during use, and a Biltin-type system (yes, this also includes a trued/properly sized typical spacer set-up) is optimum *for how we use them*.
I we were to accept the maintenance requirements, tolerance requirements, and costs associated with a bearing designed (and not radically overdesigned) for skateboarding we would be using something that looked radically different and ran with a preload as in CC's picture.
In "the real world" you can find instances of bearings without any "slop" in them. It is called "negative internal radial clearance". The right lubricants will still perform under these conditions. This type of bearing is needed when high dynamic stability of a rotor is required (among other conditions).
I have successfully resisted the temptation to enter into the whole ABEC rating thing...until now anyway. ABEC ratings are not the be-all, end-all of skateboard bearing quality, usefulness, etc. Nor are the meaningless. True, there are likely marketers selling bearings under various ABEC ratings that do not really meet the requirements. That sort of crap shouldn't even enter into a serious discussion of bearings. Among accepted, quality vendors, however, ABEC ratings *DO* differentiate between various bearings within their own product line, but do not necessarily differentiate relative quality levels between different vendors. To put it another way, say, a Pleasure Tools ABEC 7 bearing will be better quality than a PT ABEC 3. But is a PT ABEC 7 better than, say, a Biltin ABEC 3? The numbers alone can not answer that question. Those who sell their bearings using ABEC ratings are certainly engaging in some degree of marketing hype. At the same time, those who choose to eschew ABEC ratings in favor of "skate-rated", "MOC", or other such "homemade" designations are equally guilty of some degree of marketing hype. Further, those invoke the speed ratings associated with ABEC ratings to somehow demonstrate that ABEC ratings don't apply to skateboarding are sterling examples of a little information being a dangerous thing. Yes, skateboards do not generate the speeds that even ABEC 1 bearings are rated to, but there is a lot more to the ratings than that. And in the world of bearings, .0007" can be a mountain. I am aware of applications where we control variation between individual rolling elements' diameters within a single bearing to within millionths of an inch. Don't think a number is small just because it has a few zeros in front of it.
|
|
|
|
|
Slop Is The Devil
|
|
On 3/9/2006
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
The only place that you want any "slop" is in the bearing itself. You need a certain amount of play between the balls and the races for the lubricant to do its job, but everything else just introduces harmful and unnecessary vibration, heat, friction, and noise. Everything flexes to a certain extent, but there's really no reason to pile on the imprecision. Wheels set loosely on an axle will chatter, scrub speed, and slide less predictably and ride with less control than a wheel that is properly secured. Even trucks that turn with greater precision provide greater TRACTION and control than trucks with slop.
It's not so much that you can always tell the incremental differences in speed from the bearings, but the increase in traction and control are undeniably present. It also tends to breed a type of confidence that indirectly leads to more speed. Like having rack and pinion steering instead of power steering.
Hard wheels and loose bearings SOUND fast. And you may be able to spin a loose bearing wheel with your fingers and have it rotate longer when there's no load on it, but that doesn't have anything to do with how the wheels will roll at speed with a 150 pound rider on top taking it through some turns.
And BTW, the only way to accomplish what Biltins do, is to machine the inner face of a steel locknut so that it is square and contains the speedring feature, to machine the end of a steel hanger so that it is square and contains the speedring feature, and to produce a precision steel spacer and put it all on a precision axle. Otherwise all of theses narrow pieces will simply tilt and adapt to the other crooked parts when tightened.
|
|
|
|
|
the difference
|
|
On 3/9/2006
slim
wrote in from
(71.146.nnn.nnn)
OK, anyone out there brave enough, and knowledgable enough, to tell us how much difference any of this really makes? For example, how much faster, in percentage terms, do you think a set of bearings set up with proper spacing are vs. the same bearings set up with no spacers and slightly loose nuts? If you also feel a benefit in stability, try to quantify that in some way.
Also, care to comment on the following? Let's say bearings are set up like biltins or another brand with proper spacers and "locked" into place. When one turns a skateboard, the wheels itself flexes, changing the relationship between the outer race of the bearing and its balls and inner race since the inner race can not move. Is this really a better set up than having all bearings being slightly loose on the axle so that the bearings inner race can move a little and perhaps stay more in alignment when the wheel is being flexed one way or another? If so, elaborate.
|
|
|
|
|
What He Said
|
|
On 3/9/2006
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
WT said: "So, let me see if I got this straight:
Before I tighten the bearings, the assembly looks like this:"
"And then after I tighten them down they look like this (very exaggerated):"
Yup. That is what happens with:
1. No spacers
2. Undersized spacers
3. Oversized bearing seats in the hub/wheel
4. Bearings that don't have their outer races seated all the way.
Add uneven locknuts, badly cast hanger ends, nominal axles, and cheesy little speedrings and Voila! You've got something that you can't tighten.
|
|
|
|
|
The Answer
|
|
On 3/9/2006 WT
wrote in from
United States
(152.163.nnn.nnn)
Thanks, Kevin and Chuck. That makes perfect sense. The bearing assembly gets twisted between the variance between the spacer and the hub. Simple enough to understand.
|
|
|
|
|
Spaced Out
|
|
On 3/9/2006
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
KMG, You won't catch any flak from me. If the hub spacing is two wide, it has the same effect as the spacer being too small. It will pinch and bind. Biltins are actually a good way to see if your hub spacing is wider than .400". As many of you know, after inserting the bearings into the wheel by pressing on the inner races and tightening the locknut down, you may still have to "seat" the outer races of the bearings by pulling and pushing on the wheels a bit before they nestle into place. Otherwise, it may appear that the hub spacing is too wide, when really the outer races aren't yet positioned directly over the inner races. I just ride the board a bit and turn from side to side and then they spin perfectly while tight.
Many street wheels don't have cores in them, and the different urethanes and different durometers yield different shrink rates when poured. These wheel molds have to provide the bearings seats as a part of the wheel, rather than having a "known good" hub already in them. Different wheels from the same wheel molds yield different spacings and as a result, the consumers just don't even bother with spacers. I've found that a speedring between two Biltin Bearings can solve the problem with oversized spacings.
|
|
|
|
|
all bearings
|
|
On 3/9/2006 john
wrote in from
United States
(24.247.nnn.nnn)
some people are just not smart enough to call a real bearing supplier and ask questions any bearing over a abec1 is not worth buying beacouse on skates or a board nobody can get up enough speed to use them where they are ment to be used and any cheep abec9 on ebay isnt worth the shipping cost japan can use our rateings and they dont have to comply with the usa on how they were tested the rateings are for fit ie bore,od,width and runout an abec1 is within .0007 allof your junk casted wheels arent even within .005 so if you really have money burning a hole in your pocket buy something that you really need
|
|
|
|
|
Binding
|
|
On 3/9/2006 Chuck Gill
wrote in from
United States
(192.249.nnn.nnn)
kmg got it right...although ideally your spacer and the distance between the bearing seats in the wheel core should be *exactly* the same.
I'll leave it up to individual interpretation how exact "exactly" needs to be...
|
|
|
|
|
re:
|
|
On 3/9/2006 dan@csu
wrote in from
United States
(216.17.nnn.nnn)
i used to keep my wheels just a little loose also but i have to say that if you get a proper setup and crank it down tight, then the bearing works how it was intended to, and it truly is faster.
|
|
|
|
|
it s all about momentum
|
|
On 3/9/2006 dt
wrote in from
United States
(68.5.nnn.nnn)
i know i'm probally in the minority on this one, but i prefer to keep my wheels slightly loose. enough so they can twist at an angle but with no side to side play. even with my builtins (i do prefer them in most my boards, they make wheel changes a snap and eliminate the need for washers in most trucks (floaters w/ center set wheels excluded)).
once you get it in your mind that your riding momentum and not a skateboard, little things like this cease to matter. a skateboard is merely a tool that enables one to ride, gravity its power, and your body is its main suspension and steering.
bogging a wheel down is only useful when showing beginners how to ride.
i still believe the built in s have a ways to go to truly accomplish what was set out.
i've seen plans that accomplish these, but cannot comment on them. hopefully they get their patents soon and are released for everybody to utilize. shoots.
|
|
|
|
|
bearing compression
|
|
On 3/9/2006
kmg
wrote in from
United States
(12.161.nnn.nnn)
WT,
I think you need to also consider that if the seating faces in the wheel hub are farther apart than the length of the bearing spacer, you will create a bind in the bearings. Or, to say it another way, the outer races would be forced outward by the seating faces in the hub while the inner races are being forced inward against the bearing spacer.
If the wheel hub faces are too far apart, even Biltins will bind. (I'm sure I'll catch some flak for that one........)
You can test this theory by adding an additional speed ring between one bearing and the bearing spacer. Then you should be able to torque the axle nut as tight as you want. The down side is the wheel will want to shift side to side, since now the bearings will be spaced too far apart.
See if you can accurately measure the distance between the hub faces on one of your wheels. If it is, for example, .410", then you should theoretically be using at least a .410" spacer in that wheel.
|
|
|
|
|
re:
|
|
On 3/9/2006 dan@csu
wrote in from
United States
(216.17.nnn.nnn)
i hope other people answer your question also, but one thing i know is that the picture you see in your minds eye only works when everything is absolutely precisely machined and fits PERFECTLY. this is usually not the case and i would bet that your dumb cheap speed rings (i hate those thngs) are coming on contact with the bearing shields. not to put in a plug but rather to illustrate, look at biltins- because they're precise and meant to work with each other you can crank those s.o.b.'s down as hard as you want.
|
|
|
|
|
Bearing "compression?"
|
|
On 3/9/2006
WT
wrote in from
United States
(205.188.nnn.nnn)
I gotta question about bearing compression. I use 8mm axles and 608 bearings. I put speed rings on both sides of the bearings. I put on a lock nut and tighten it down. Here's my question: what's getting compressed that causes the bearings to bind and spin slowly? Whenever I put on a wheel, I crank it down with the socket and then back off a 1/4 or more turn to get the wheel free spinning. There's a very fine line between binding, free-spinning and a loose wheel clacking around on the axle.
In my mind's eye I see the hangar face, a speed ring spacer, the inner race on the bearing, a bearing spacer, another bearing race, a speed ring spacer and the lock nut. It's all metal-to-metal. Nothing is touching the plastic shields, nothing is compressible.
Why is it that if I crank down too hard with the socket the bearings will bind? What's interfering with a free-spinning bearing? Am I really manly enough to compress and distort metal cylinders and alter the shape of the bearing race?
|
|
|
|
|
!
|
|
On 3/5/2006
Civ
wrote in from
Canada
(24.141.nnn.nnn)
he wont link the slalom skaterboarder site either. Scared of competition I think. To bad he already lost. This is just where i come for the drama.
|
|
|
|
|
this is stupid
|
|
On 3/4/2006
slim
wrote in from
(71.146.nnn.nnn)
ok, the reason it doesn't work is that the software on this ncdsa forum is changing the url! Why prevent links to silverfish? That worried about competition for ad click thru money? geez.
You'll have to cut and paste it yourselves or click on one of the links below and when it then says it can't find the server, change the underscore marks to dots so there is a dot after the www and before the com.
http://www_silverfishlongboarding_com/forum/viewtopic.php?t=21978
|
|
|
|
|
bad link
|
|
On 3/4/2006
slim
wrote in from
(71.146.nnn.nnn)
Hmm...that link didn't work. Please try this one
|
|
|
|
|
grease
|
|
On 3/4/2006
slim
wrote in from
(71.146.nnn.nnn)
Those interested in bearing lubes will like the following thread from Silverfish Longboarding:
all Greases are not equal.
|
|
|
|
|
dry lubes
|
|
On 3/2/2006 dan@csu
wrote in from
United States
(12.134.nnn.nnn)
i posted awhile ago aasking about dry lubes like graphite. whats the concensus on stuff like that?
|
|
|
|
|
hahahahahaha
|
|
On 3/1/2006 dan@csu
wrote in from
United States
(216.17.nnn.nnn)
u should buy them all, then do some tests like put a deck on a treadmill and then rig a bicycle rim and spin it and make a website showing us the results. imagine how much we would learn, and you'd be famous!!
|
|
|
|
|
good bearings?
|
|
On 3/1/2006 Slidey Mc.Slide
wrote in from
United States
(24.53.nnn.nnn)
Bearings not only need speed, the other very important thing about them is durability, what are the best bearings i can buy?
|
|
|
|
|
feel the speed
|
|
On 2/26/2006 herbn
wrote in from
United States
(205.188.nnn.nnn)
i get on a skateboard and roll,i have friends that ride together on hills and compare ,swapping boards ect ect. lots of other posts about various levels of bones unrated bearings, but it's fairly common knowlege that reds are much like abec 5 and swiss are kind of like 7's amybe a bit better. If the bearings are more precise on the outside then it seems that the insides(tolerences and polish)are also better,it may not be absolutely true especially with every ebay bearing guy claiming to be abec 7,but more often than not with major brands there does seem to something to the abec claim. It's been a long time but maybe i should try a set of abec 1's again just as a refresher. My favorite bearing has the best mark up,it happens to be rated at abec 7, it's pretty cheap (15 bucks re.) and LOTS of my customers agree, they buy them over and over again,or they come back to them after trying other types of bearings, they feel quick,quicker than lower rated bearing e.o.s.
|
|
|
|
|
