S k a t e L o g     F o r u m
Inline Skating and Quad Roller Skating
Forum Hosts: Jessica Wright | Kathie Fry

FOLLOW US: Our Blog | Facebook | Twitter | Email    


Home - Forum Index - Africa Skating - Asia Skating - Europe Skating - Oceania Skating - Pan America Skating - Roller_Rinks - Friend the SkateLog Forum in Facebook - SkateLog Forum on Facebook

Forum Administrators: Jessica Wright and Kathie Fry | Email Us
Access code for buying and selling subforums: "skates"
How To Get a User Account and Posting Privileges in the SkateLog Forum
Use Google to Search the SkateLog Forum

Go Back   SkateLog Forum > Special Interest Skating Forums (sorted by number of posts) > Quad Roller Skating Forum
FAQ Calendar Search Today's Posts Mark Forums Read

Quad Roller Skating Forum Discussions about quad roller skates and any other quad skating discussions that do not seem appropriate for one of our other forums.

Reply
 
Thread Tools Display Modes
Old February 6th, 2018, 03:48 PM   #21
Refresh
Junior Member
 
Join Date: Feb 2018
Posts: 7
Default

Connie is working on it for me now. Hopefully order today. Pretty much built Riedell 395 advantage skate but with cannibal wheels instead of sure-grip power plus.
Refresh is offline   Reply With Quote
Old February 6th, 2018, 06:29 PM   #22
fierocious1
Senior Member
 
fierocious1's Avatar
 
Join Date: Apr 2010
Location: Texas
Posts: 5,222
Default

Quote:
Originally Posted by Refresh View Post
Connie is working on it for me now. Hopefully order today. Pretty much built Riedell 395 advantage skate but with cannibal wheels instead of sure-grip power plus.
Great choice!
__________________
"Liberal Logic", not possible.... a phrase in conflict with itself....
fierocious1 is online now   Reply With Quote
Old February 11th, 2018, 04:21 PM   #23
dvw
Secretary of Skate
 
dvw's Avatar
 
Join Date: Aug 2007
Location: Hendersonville, TN
Posts: 4,391
Default

Quote:
Originally Posted by Sunnyape View Post
If the wheels really are measuring in B scale, then 87b equates to about 98a, which might be a bit too hard.
Be very careful trying to cross durometer scales. They do not convert. Period.

The durometer was invented by Shore Instruments and the scales are intended to act as a comparison between materials, not as a definitive measurement. They're an arbitrary 0 - 100 scale, and pair a spring load and a particular shape "indenter". The first flaw in the comparison between scales is that not all indenters are the same shape. That makes them react to the materials under test differently.

And although you will see skate wheels advertised with hardness numbers greater than 100, please understand that it's just marketing, as an indicator that it's a really hard wheel, as no such number is actually possible. Generally, skate wheels greater than 100 Shore A are measured on the Shore D scale. The indenters for the A and D scales are very different.
__________________
Find some roller derby girls. Don't try to romance them! That don't end well. okie 10/12/2011
Royals FTW! When only the shiny will do... Doc Sk8 05/19/2012
dvw is offline   Reply With Quote
Old February 11th, 2018, 04:28 PM   #24
dvw
Secretary of Skate
 
dvw's Avatar
 
Join Date: Aug 2007
Location: Hendersonville, TN
Posts: 4,391
Default

Quote:
Originally Posted by rufusprime99 View Post
I wonder if that has to do with older stock vs newer stock. Try checking with DVW. He is usually up on that sort of stuff.
The earlier purple Power Plus were sometimes listed as 97A, but they're more like 94-95 in real life, and I believe the marketing info has been revised. Those wheels were produced for many years and went through some transitions. I have some green ones that are a good ten years old and they're every bit of 97A and are some of the best wheels I own. There was a run of them ages ago where none of them hit their numbers and were all about 93.

Here's something that needs to be pointed out periodically. Selecting wheels purely by durometer numbers is somewhere between misleading and foolish. It isn't about the numbers it's about the chemistry. I have "93A" wheels that are slick as ice and "90A" wheels that out grip and out roll "97A" wheels. Why? Compound.
__________________
Find some roller derby girls. Don't try to romance them! That don't end well. okie 10/12/2011
Royals FTW! When only the shiny will do... Doc Sk8 05/19/2012
dvw is offline   Reply With Quote
Old February 11th, 2018, 08:33 PM   #25
Sunnyape
-- rufff --
 
Sunnyape's Avatar
 
Join Date: Oct 2017
Location: Sid-a-knee, Australia
Posts: 97
Default Maybe, but....

Quote:
Originally Posted by dvw View Post
Be very careful trying to cross durometer scales. They do not convert. Period.
I disagree on that particular point. The Shore scales are a measurement of material hardness based the response of pre-defined instruments. Provided the instruments are made to the specifications, then their results should be uniform and, therefore, predictable. If any measurement system is predictable, then it can be converted to another similarly predictable measurement system. IE just as inches can be converted to centimetres, gallons to litres etc. As long as you know the ratio between the two measurement scales, you can always convert between them.

HOWEVER, it's fairly well known that when the Shore hardness devices are measuring at the end of their respective scales, their accuracy gets a bit unpredictable, so a wheel measured as 95 on one Shore A meter might measure as 94 on another or 96 on another because they're all measuring in the upper range of their scales and sensitive to many small factors. That's why some wheel companies advocate measuring their skate wheels in other Shore scales like B or D, so that the measurements always fall closer to the middle of the scale's range, where the meters are more accurate.
Sunnyape is offline   Reply With Quote
Old February 12th, 2018, 07:00 PM   #26
dvw
Secretary of Skate
 
dvw's Avatar
 
Join Date: Aug 2007
Location: Hendersonville, TN
Posts: 4,391
Default

Quote:
Originally Posted by Sunnyape View Post
I disagree on that particular point. The Shore scales are a measurement of material hardness based the response of pre-defined instruments. Provided the instruments are made to the specifications, then their results should be uniform and, therefore, predictable.
True, except that the Shore scales are completely arbitrary. They are not traceable to any other standard. You would be correct saying that materials should react to different measuring devices if the devices were the same except for the scale ranges. Therein lines the challenge with the Shore durometer. The shape of the indenter is not uniform, and it only follows that the results would not be either.

Here's a little light reading for you.

Quote:
Originally Posted by Sunnyape View Post
HOWEVER, it's fairly well known that when the Shore hardness devices are measuring at the end of their respective scales, their accuracy gets a bit unpredictable, so a wheel measured as 95 on one Shore A meter might measure as 94 on another or 96 on another because they're all measuring in the upper range of their scales and sensitive to many small factors. That's why some wheel companies advocate measuring their skate wheels in other Shore scales like B or D, so that the measurements always fall closer to the middle of the scale's range, where the meters are more accurate.
Misconception. Shore durometers have better resolution toward the upper end of their ranges, much the same as other devices such as volt meters and other test equipment. The reason the results are "unpredictable" is that the device has the resolution to detect the difference. They're more uniform the the center of the range because of the lack of resolution. You are correct that as durometers reach a reading of 100 their accuracy appears to drop since the scale stops at 100. Which scale should be used above that is a factor of the material under test, and that goes right back to my comment above about the arbitrary nature of the test itself
__________________
Find some roller derby girls. Don't try to romance them! That don't end well. okie 10/12/2011
Royals FTW! When only the shiny will do... Doc Sk8 05/19/2012
dvw is offline   Reply With Quote
Old February 13th, 2018, 01:37 AM   #27
Sunnyape
-- rufff --
 
Sunnyape's Avatar
 
Join Date: Oct 2017
Location: Sid-a-knee, Australia
Posts: 97
Default

Quote:
Originally Posted by dvw View Post
The shape of the indenter is not uniform, and it only follows that the results would not be either.
Are you saying the indentors of the meters are not uniform when compared for one scale (manufacturing variations) or the they are not uniform when compared between different scales (specification difference)?

My original point wasn't that variation in the construction of the meter was a limiting factor in comparing scales. My point was that, assuming that the meters for the different scales had been manufactured to specification, then their results could be compared based on a known ratio.
Sunnyape is offline   Reply With Quote
Old February 13th, 2018, 03:04 AM   #28
dvw
Secretary of Skate
 
dvw's Avatar
 
Join Date: Aug 2007
Location: Hendersonville, TN
Posts: 4,391
Default

Quote:
Originally Posted by Sunnyape View Post
Are you saying the indentors of the meters are not uniform when compared for one scale (manufacturing variations) or the they are not uniform when compared between different scales (specification difference)?
They vary scale to scale. Indenters of a single particular scale are ostensibly the same.

Quote:
Originally Posted by Sunnyape View Post
My original point wasn't that variation in the construction of the meter was a limiting factor in comparing scales. My point was that, assuming that the meters for the different scales had been manufactured to specification, then their results could be compared based on a known ratio.
You would think so, but no. Materials react differently to the differing indenters. In particular the shape of the A and D indenters are intended to do different things. The A scale indenter is designed to depress the test sample, the D scale indenter is intended to penetrate it. They also react differently based on the amount of time the material is in contact with the indenter. ASTM D2240 specifies that Shore A should be measured at 1kg force, Shore D at 5kg, each with a tolerance of +10%, and the measurement should be for 15 seconds.

In pure theory, if you take one specific material sample - a skate wheel for our purposes - and measure it on five different Shore A durometers, your results should be relatively consistent. Likewise, if you measure the same sample on five different Shore D durometers, your results will be relatively consistent. The inconsistency comes into play when you perform the same test with an additional material sample. Because of the way the material reacts to the two different instruments, you could, for instance, have two wheels that measure the same on the Shore A but measure differently on the Shore D. It is that variability that precludes any sort of accurate conversion scale or ratio.



If anything, skate wheels should likely be measured on the Shore C scale after they top out the Shore A. Same indenter shape, different preload. But they arent.
__________________
Find some roller derby girls. Don't try to romance them! That don't end well. okie 10/12/2011
Royals FTW! When only the shiny will do... Doc Sk8 05/19/2012
dvw is offline   Reply With Quote
Old February 13th, 2018, 09:52 AM   #29
Sunnyape
-- rufff --
 
Sunnyape's Avatar
 
Join Date: Oct 2017
Location: Sid-a-knee, Australia
Posts: 97
Default

Thank you for making the effort to provide a more detailed explanation.
Sunnyape is offline   Reply With Quote
Old February 13th, 2018, 01:30 PM   #30
Refresh
Junior Member
 
Join Date: Feb 2018
Posts: 7
Default

Great explanations!

Im stoked to get my new skates.

395 boots will arrive tomorrow for fitting and then hope to be skating on them a week later!
Refresh is offline   Reply With Quote
Old February 21st, 2018, 11:21 PM   #31
RollerBones
Senior Member
 
Join Date: Jul 2010
Posts: 122
Default

When we measure what we call our 103a Elites, it really measures out to an 83b. Between the a and b scale, it's comparably about 20 points different between those two scales. It's not always the gauge that changes the reading by a point or two, it's the point of reference in which you are testing.


Cheers,
RollerBones is offline   Reply With Quote
Old February 24th, 2018, 10:50 PM   #32
Refresh
Junior Member
 
Join Date: Feb 2018
Posts: 7
Default

Skates came in yesterday and skated in them today. Love em!

Thanks Connie!
Refresh is offline   Reply With Quote
Old March 24th, 2018, 11:11 AM   #33
quantoo
Senior Member
 
quantoo's Avatar
 
Join Date: May 2009
Location: Australia
Posts: 4,371
Default This site has my go to off the shelf wheels

http://www.rollerskateusa.com/labeda...abstilered.htm
or they are still advertising them at least only available in slim worse luck.
quantoo is offline   Reply With Quote
Old March 24th, 2018, 01:12 PM   #34
fierocious1
Senior Member
 
fierocious1's Avatar
 
Join Date: Apr 2010
Location: Texas
Posts: 5,222
Default

Quote:
Originally Posted by Refresh View Post
Skates came in yesterday and skated in them today. Love em!

Thanks Connie!
So give us a rundown on your build..... what did you end up with?
__________________
"Liberal Logic", not possible.... a phrase in conflict with itself....
fierocious1 is online now   Reply With Quote
Old March 24th, 2018, 06:44 PM   #35
PRFunky
Member
 
PRFunky's Avatar
 
Join Date: Apr 2017
Location: Hales Corners, WI USA
Posts: 38
Default

Can't right now; too busy skating!
PRFunky is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 01:22 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.