MXA / J-Bone / DLC coating?

Ghost of Jabroni
Edited Date/Time 5/16/2016 12:18pm
In this month's issue of Motocross Action, J-Bone has a piece he wrote on the downsides of aftermarket DLC coating.

The general theme of the write up is that any aftermarket DLC coating is actually going to make your suspension work worse. (nevermind the fact that most riders out there wouldnt actually gain anything from the modification anyways but that is another topic)

He makes it sound like that for the only way for the DLC coating to actually work, is if it is applied during the manufacturing process so that the tolerances of the ID and OD of the tubes are not affected. When done AFTER the manufacturing process, he's saying that the tube actually gets too big a diameter and can add to the stiction.

This is pretty insightful and makes sense, but it's something Ive never heard said before. What are your thoughts?

Are we to assume that the A-kit stuff they sell has these coatings already applied from the Showa factory?

I just find it odd that some VERY reputable companies like PC or FC would offer DLC coating to customer forks, all the while knowing that it can actually make things worse.
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keeptwostrokesalive 5/15/2016 3:18pm
5/15/2016 3:18pm
I always thought that they stripped the factory coating and then applied the DLC coating to prevent expansion? I could be wrong on that though
Piston Slap
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Piston Slap 5/15/2016 3:27pm
5/15/2016 3:27pm
Jabroni,

It's about $$$$$

You want it, we got it......
JBernard_401
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JBernard_401 5/15/2016 3:35pm
5/15/2016 3:35pm
DLC is 2 μm thick. Do you have any idea how thick that is?
philG
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philG 5/15/2016 3:41pm
5/15/2016 3:41pm
DLC coating is very thin, the stuff i have been involved with is in the 0.003/0.008mm range which will put on 0.006/0.016mm on a diameter.. production forks dont run tolerances tight enough for that to be an issue, factory stuff will be tighter tolerances to get better build quality and repeatability, and will be made to the correct sizes to allow for the processes needed, thats why they cost big bucks over the production stuff.

I think he is talking out of his ass.

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Ghost of Jabroni 5/15/2016 3:49pm
5/15/2016 3:49pm
philG wrote:
DLC coating is very thin, the stuff i have been involved with is in the 0.003/0.008mm range which will put on 0.006/0.016mm on a diameter.. production...
DLC coating is very thin, the stuff i have been involved with is in the 0.003/0.008mm range which will put on 0.006/0.016mm on a diameter.. production forks dont run tolerances tight enough for that to be an issue, factory stuff will be tighter tolerances to get better build quality and repeatability, and will be made to the correct sizes to allow for the processes needed, thats why they cost big bucks over the production stuff.

I think he is talking out of his ass.
His argument is that these days, production forks are actually made to tight enough tolerances that the extra 3 microns of thickness actually could cause more stiction. Or at least, that was what I gathered from the article. It wasnt well written.
joe stanley
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joe stanley 5/15/2016 4:50pm
5/15/2016 4:50pm
An article in MXA wasn't well written........thats a suprise.......
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smoothies862 5/15/2016 4:58pm
5/15/2016 4:58pm
so more girth is a problemDry
dbrunski125 5/16/2016 4:40am
5/16/2016 4:40am
So what if you have a showa a kit and the ti nitride coatings start to wear? ..... don't bother re coating again because it's not during the manufacturing process?...
Slosh 112
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Slosh 112 5/16/2016 4:54am
5/16/2016 4:54am
philG wrote:
DLC coating is very thin, the stuff i have been involved with is in the 0.003/0.008mm range which will put on 0.006/0.016mm on a diameter.. production...
DLC coating is very thin, the stuff i have been involved with is in the 0.003/0.008mm range which will put on 0.006/0.016mm on a diameter.. production forks dont run tolerances tight enough for that to be an issue, factory stuff will be tighter tolerances to get better build quality and repeatability, and will be made to the correct sizes to allow for the processes needed, thats why they cost big bucks over the production stuff.

I think he is talking out of his ass.
Even then top level factory suspension wouldn't be that tight of a tolerance. Not very often do you see something mechanical that runs on tolerances that tight maybe a common rail diesel pump but definitely not a set of forks.

Chrome is porous and if it is left un protected by oil or not polished often enough you will see it begin to pit, DLC has a more dense surface with less blemishes and therefore has less stiction same thing as a ceramic bearing versus a normal bearing.
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hillbilly
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hillbilly 5/16/2016 5:23am
5/16/2016 5:23am
A lot of guys that coat just want the looks and a high percentage don't center the forks on the axle to prevent binding anyways.
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BobPA
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BobPA 5/16/2016 5:27am
5/16/2016 5:27am
philG wrote:
DLC coating is very thin, the stuff i have been involved with is in the 0.003/0.008mm range which will put on 0.006/0.016mm on a diameter.. production...
DLC coating is very thin, the stuff i have been involved with is in the 0.003/0.008mm range which will put on 0.006/0.016mm on a diameter.. production forks dont run tolerances tight enough for that to be an issue, factory stuff will be tighter tolerances to get better build quality and repeatability, and will be made to the correct sizes to allow for the processes needed, thats why they cost big bucks over the production stuff.

I think he is talking out of his ass.
I would be willing to bet fork tubes are manufactured with less than 0.006" deviation....that is actually quite significant
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C-Rock
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C-Rock 5/16/2016 5:36am
5/16/2016 5:36am
Jim Bacon and Jeremy Albrecht are two different persons.
Crush
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Crush 5/16/2016 5:42am
5/16/2016 5:42am
Isn't there a thing where they will try and cross-hatch the slider after it's back so it actually keeps some oil to help stiction? Otherwise it is so smooth it can vacuum?
philG
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philG 5/16/2016 6:19am
5/16/2016 6:19am
BobPA wrote:
I would be willing to bet fork tubes are manufactured with less than 0.006" deviation....that is actually quite significant
I am talking in mm.. 0.006" is 0.12mm which is a country mile. The cylindricity of the damper tubes I measured was 0.025mm over 400mm, and size was +0/-0.04mm
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zlowery 5/16/2016 6:49am
5/16/2016 6:49am
In my opinion and experience, .006 is huge. I turn down solid 4140 shafts to around 13.5" to 16" and have to be within .0015" on coupler fit diameters. Also do alot of bearing work from 2" diameter to 18". Again, all the seals i use, LER, lip seals, inpro, etc etc have much smaller tolerances than .006. Usually +.000 -.003 when im machining shafts. If someone told me then were increasing my fork tube diameter by .006 and expecting them to work with the stock seals and bushings - I would laugh and walk away.

But i know nothing about electroplating and stripping it. So there's a chance that it can be done without effecting diameter.
Sheriff245 5/16/2016 8:17am
5/16/2016 8:17am
zlowery wrote:
In my opinion and experience, .006 is huge. I turn down solid 4140 shafts to around 13.5" to 16" and have to be within .0015" on...
In my opinion and experience, .006 is huge. I turn down solid 4140 shafts to around 13.5" to 16" and have to be within .0015" on coupler fit diameters. Also do alot of bearing work from 2" diameter to 18". Again, all the seals i use, LER, lip seals, inpro, etc etc have much smaller tolerances than .006. Usually +.000 -.003 when im machining shafts. If someone told me then were increasing my fork tube diameter by .006 and expecting them to work with the stock seals and bushings - I would laugh and walk away.

But i know nothing about electroplating and stripping it. So there's a chance that it can be done without effecting diameter.
.006" is huge, but we're talking .006 mm here, which is less than 0.00024".
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cslacker 5/16/2016 8:19am
5/16/2016 8:19am
The article also discusses the methods used to remove the chrome and the possible damage to the tubes when removing the lugs as being big issues. I really think the main point of the article is simply that spending a bunch of money on DLC coating your forks isn't worth the hassle and could be a step backwards in many cases. I will take Bones' word for it...
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davistld01 5/16/2016 8:23am
5/16/2016 8:23am
smoothies862 wrote:
so more girth is a problemDry
Girth has always been a major problem for me.

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JBernard_401
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JBernard_401 5/16/2016 8:29am
5/16/2016 8:29am
philG wrote:
DLC coating is very thin, the stuff i have been involved with is in the 0.003/0.008mm range which will put on 0.006/0.016mm on a diameter.. production...
DLC coating is very thin, the stuff i have been involved with is in the 0.003/0.008mm range which will put on 0.006/0.016mm on a diameter.. production forks dont run tolerances tight enough for that to be an issue, factory stuff will be tighter tolerances to get better build quality and repeatability, and will be made to the correct sizes to allow for the processes needed, thats why they cost big bucks over the production stuff.

I think he is talking out of his ass.
BobPA wrote:
I would be willing to bet fork tubes are manufactured with less than 0.006" deviation....that is actually quite significant
ta-c dlc coating shouldnt be anywhere near .003 thickness. its in the micron level.
.003 is like CeraKote ceramic coating spray on thickness.

2um is 0.00007"
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OW38B 5/16/2016 9:00am
5/16/2016 9:00am
joe stanley wrote:
An article in MXA wasn't well written........thats a suprise.......
The OP never implied that......that is something you inferred without ever reading the article? Jeez,only the Vitards.
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zlowery 5/16/2016 9:03am
5/16/2016 9:03am
zlowery wrote:
In my opinion and experience, .006 is huge. I turn down solid 4140 shafts to around 13.5" to 16" and have to be within .0015" on...
In my opinion and experience, .006 is huge. I turn down solid 4140 shafts to around 13.5" to 16" and have to be within .0015" on coupler fit diameters. Also do alot of bearing work from 2" diameter to 18". Again, all the seals i use, LER, lip seals, inpro, etc etc have much smaller tolerances than .006. Usually +.000 -.003 when im machining shafts. If someone told me then were increasing my fork tube diameter by .006 and expecting them to work with the stock seals and bushings - I would laugh and walk away.

But i know nothing about electroplating and stripping it. So there's a chance that it can be done without effecting diameter.
Sheriff245 wrote:
.006" is huge, but we're talking .006 mm here, which is less than 0.00024".
Ahhhh, gotcha. Crazy how thin that is.
BobPA
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BobPA 5/16/2016 9:10am
5/16/2016 9:10am
BobPA wrote:
I would be willing to bet fork tubes are manufactured with less than 0.006" deviation....that is actually quite significant
philG wrote:
I am talking in mm.. 0.006" is 0.12mm which is a country mile. The cylindricity of the damper tubes I measured was 0.025mm over 400mm, and...
I am talking in mm.. 0.006" is 0.12mm which is a country mile. The cylindricity of the damper tubes I measured was 0.025mm over 400mm, and size was +0/-0.04mm
I swore when I read your post it had 0.003" instead of mm...who knows, I could be losing it
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philG 5/16/2016 10:12am
5/16/2016 10:12am
BobPA wrote:
I swore when I read your post it had 0.003" instead of mm...who knows, I could be losing it
we dont do inches over here ... its not 1957. LOL

just for reference.. 0.001" = 0.0254mm

the beauty of DLC is that it is so thin, so you can do it as a post manufacture process.


We have had crank pins, gudgeon pins, rocker shafts and rockers DLC coated , all made to tighter limits than suspension parts , with no issues .
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BAMX 5/16/2016 10:42am
5/16/2016 10:42am
BobPA wrote:
I swore when I read your post it had 0.003" instead of mm...who knows, I could be losing it
philG wrote:
we dont do inches over here ... its not 1957. LOL just for reference.. 0.001" = 0.0254mm the beauty of DLC is that it is so...
we dont do inches over here ... its not 1957. LOL

just for reference.. 0.001" = 0.0254mm

the beauty of DLC is that it is so thin, so you can do it as a post manufacture process.


We have had crank pins, gudgeon pins, rocker shafts and rockers DLC coated , all made to tighter limits than suspension parts , with no issues .
Haha... I did read your post the same as BobPA had. Since you used the / , it looked like you converted it for us. I think that is why a few are shaking their heads. .006 of an inch is a huge tolerance on a turning so your post came out as contradictory.
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FGR01 5/16/2016 12:18pm
5/16/2016 12:18pm
Funny, we are always told that the tighter tolerances of Factory suspension are what makes them so awesome. Then when we go making our tolerances tighter we are told it's not a good idea. Dry

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