Generally speaking: grooved or not for oil? Graphite?

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FatSebastian
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Re: Generally speaking: grooved or not for oil? Graphite?

Post by FatSebastian » Wed Oct 09, 2013 3:58 pm

xanthrum wrote:In plain English a properly prepped oil wheel will out perform a graphite prep
IMO results seemed to support (or at least did not deny) this.
xanthrum wrote:There are so many other factors that are so much more critical to a cars performance [...] a million other contributor factors that make a car fast...
A controlled experiment attempts to remove other factors for the purpose of isolating a singular effect.



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xanthrum
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Re: Generally speaking: grooved or not for oil? Graphite?

Post by xanthrum » Wed Oct 09, 2013 5:49 pm

A graphite prepped wheel - will spin longer and be slower than a oil prepped wheel (if done correctly) :idea: ... I think of myself as a fairly intelligent individual (maybe not rocket scientist) and I truly have no idea what you guys are referring to :scratching: ... actually I get it but - I am trying to relay on that my expeirence has proven to me that a grooved axel will out perform a non grooved axel. I also think that Derby Evolution -- makes a great axle that will perform at a very high competitive level. There is another couple places to get some of these very competitive axles - one from a placed that is not allowed to be name here; for some unknown reason to me... and many other Derby Product companies make and provide some excellent axles, such as Derby Dominator, Max V, Derby Monkey, Pinewood Pro, ABC Pinewood, Derby Champ & Derby Worx. Again I think there are some very awesome compelling theories out there that talk about weight distribution across a larger surface area vs a concentrated area and friction but the fastest cars are running grooved axles... The application is key.


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Re: Generally speaking: grooved or not for oil? Graphite?

Post by Stan Pope » Thu Oct 10, 2013 12:01 am

xanthrum wrote:In plain english a properly prepped oil wheel will out perform a graphite prep all day long -- but an oil prepped wheel - will not spin anything like a properly prepped graphite wheel. I am trying to relay on the notion that a spin test does not equate to speed. There are so many other factors that are so much more critical to a cars performance - begining with proper set up - if the rules allow rail-riding - placement of weight - the prep process and all the attention to a million other contributor factors that make a car fast.... Additionally a grooved axle will outperform in application... maybe not in theory but in application.
Lest newcomers to DerbyTalk misunderstand, Bob Barga's tests (2003-4) and Randy's tests (2008) were "loaded spin tests" in which the axle carried a weight comparable to that experience by the rear wheel of 5 ounce PWD car, and the total rotational energy of the weighted wheel was comparable to that wheel's share of a 5 ounce car's linear energy. Further, Bob Barga's tests of Nyoil II vs Hob-E-Lube indicated a substantial advantage for oil under all conditions that I reviewed.

These tests eliminate the effects observed when just finger spinning a wheel on an axle under almost no load. Under such low load, differences such as varying viscosity play substantial role. In Barga's and Randy's tests, the effect of viscosity is comparable to what a wheel experiences when rolling a car down a track!

Most have found that lower viscosity Krytox 100 oil is at least as good as Nyoil II AND is (a lot) easier to apply correctly. So, current opinions regarding comparative quality of graphite vs oil and grooved vs non-grooved are consistent with the results produced by Bob and Randy!

What I would like to do, but have not yet accomplished, is to translate the loaded spin data into coefficient of friction comparisons. My motivation is that we can be confident that, all else being equal, the wheel-axle combination with the lowest coefficient of friction wins. I know the equipment changes necessary, but still need to implement those changes and to understand the math/physics of the conversion.


Stan
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Re: Generally speaking: grooved or not for oil? Graphite?

Post by MaxV » Thu Oct 10, 2013 8:58 am

As Stan points out, the test were done with a weighted wheel spin jig, so the test simulates a wheel under real conditions.

Image

You can read the full article here:
http://www.maximum-velocity.com/pinewoo ... tm#feature" target="_blank

On this jig, longer wheel spin times(as shown in the tests) equate to a lower coefficient of friction for the axles and lube being tested.



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Re: Generally speaking: grooved or not for oil? Graphite?

Post by TimInOhio » Tue Jan 28, 2014 7:31 pm

So, do any vendors offer BSA axles with grooves? Thanks.



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Re: Generally speaking: grooved or not for oil? Graphite?

Post by FatSebastian » Tue Jan 28, 2014 8:10 pm

TimInOhio wrote:So, do any vendors offer BSA axles with grooves? Thanks.
Hodges H46.

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