How coarse is too coarse?

I’ll let Brian answer but I believe like on a cylinder bore its the stepping up in grit from your coarsest grit you plan to use to your finest
 
Plateau finish ?
So when you sand with a low grit, it cuts deeper grooves into the tire. Then when you hit it lightly with a higher grit, it knocks the peaks off and puts lighter grooves on top of and across the deep grooves. You typically want to cross hatch to get the best results.

As stated above, a lot like a cross hatch in a cylinder.
 
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Like that
 
So when you sand with a low grit, it cuts deeper grooves into the tire. Then when you hit it lightly with a higher grit, it knocks the peaks off and puts lighter grooves on top of and across the deep grooves. You typically want to cross hatch to get the best results.

As stated above, a lot like a cross hatch in a cylinder.
So you have to use a belt sander not disc to achieve this effext ?
 
I wouldn't say you have to use a belt sander. The key is using two different grits. Like using a low(100-220) grit then use a higher (200-320).

It all depends on your track conditions and the brand of tire as to what grits and whether or not you use one grit, or multiple grits in my opinion. But, 8/10 times I plateau finish all my tires.
 
Plateau finish ?
Same as you would finish an engine cylinder. Progressively finer grits at slightly different angles. It smooths off the high spots, or sharp edges, of the finish leaving more surface area while retaining some of the deeper grooves/scratches. Think "plateau" rather than "peak."
I use a belt sander. I don't don't how you would achieve the same finish with a grinder unless you stood on your head and ground backwards. :)
Not the best picture, I'll have to dig through my old computer to find a closer look at the finish. I'm sure I've posted one on here at some point in the past. I'll be working on tires today in the shop - maybe I can snap a few new pictures.
 

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I can get a tire sanded to look like that in about 2 minutes. One thing that sticks out to me is the hatching all the way across shoulder-to-shoulder. I keep the course sanding between the dots. Then get some 200 on an orbital sander and carry it out a little further. Then some 320 on an orbital sander and carry it out a little further. Finish is off by hand with some set 600. Gotta keep the tire wet the whole time and run a sponge over it to pickup the rubber crumbs that stick to the tire. It takes time but they come out looking glassy. Someone told me I'm good at it (I don't know about that), consequently I get to cut a lot of tires :(
 
So you got much better with the fine grind?
Yeah we did. And I noticed afterwards that the surface of the tires was brown, just like the track. I know now if the face of the tire stays black the tire is getting into the track. And now if I see a kart that isn't getting around the track very well its tires aren't very black.
 
This is a battle of the preferred methods, lol.

for whatever it's worth, I've had really good luck over the years running a belt sander with methanol spray to cool... I start with a 120 grit and finish with a 180. I used to do the whole two direction cross hatch but for whatever reason, I've come to prefer just the single direction hatches.

After reading everyone's posts, I'm tempted to try a 220 grit. I've had a lot of success with this current method though on burris, vegas and maxxis. Been doing customer tires like this for a while also.
 

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This is a battle of the preferred methods, lol.

for whatever it's worth, I've had really good luck over the years running a belt sander with methanol spray to cool... I start with a 120 grit and finish with a 180. I used to do the whole two direction cross hatch but for whatever reason, I've come to prefer just the single direction hatches.

After reading everyone's posts, I'm tempted to try a 220 grit. I've had a lot of success with this current method though on burris, vegas and maxxis. Been doing customer tires like this for a while also.
Keep in mind the finer you go (220+) on used tires, the more critical it is to keep the tire cool or it will gum and burn quicker than 120 or 180. You may want to mix methanol with another substance like windex that doesnt evaporate as fast and do them by hand on the machine. As you know, new tires are a little more forgiving.
 
Keep in mind the finer you go (220+) on used tires, the more critical it is to keep the tire cool or it will gum and burn quicker than 120 or 180. You may want to mix methanol with another substance like windex that doesnt evaporate as fast and do them by hand on the machine. As you know, new tires are a little more forgiving.
I've actually noticed that the Maxxis seem to make more rubber dust than Burris or Vega. I tried the windex thing (ammonia free) and just did not like it. it didnt evaporate that well and allowed the rubber dust to stick to itself and stick to the sanding belt. Perhaps I'll try again 75% methanol, 25% windex.

Maybe its the tire lathe or sander speed I prefer but methanol seems to cool it, keep the dust from sticking, open the pores a tiny bit and evaporates fast. I blow through about half a gallon of methanol on a brand new set of tires. lol
 
I've actually noticed that the Maxxis seem to make more rubber dust than Burris or Vega. I tried the windex thing (ammonia free) and just did not like it. it didnt evaporate that well and allowed the rubber dust to stick to itself and stick to the sanding belt. Perhaps I'll try again 75% methanol, 25% windex.

Maybe its the tire lathe or sander speed I prefer but methanol seems to cool it, keep the dust from sticking, open the pores a tiny bit and evaporates fast. I blow through about half a gallon of methanol on a brand new set of tires. lol
That's because maxxis being synthetic
 
I've actually noticed that the Maxxis seem to make more rubber dust than Burris or Vega. I tried the windex thing (ammonia free) and just did not like it. it didnt evaporate that well and allowed the rubber dust to stick to itself and stick to the sanding belt. Perhaps I'll try again 75% methanol, 25% windex.

Maybe its the tire lathe or sander speed I prefer but methanol seems to cool it, keep the dust from sticking, open the pores a tiny bit and evaporates fast. I blow through about half a gallon of methanol on a brand new set of tires. lol
It smells really bad when you get to sanding and grinding on the tire, but I put track tack tire wash in a spray bottle and keep spraying it on. Sticks to the tire really well.
 
I would think that the alcohol would NOT open the pores of the rubber, rather, it closes/tightens the rubber. It also pulls some oil to the surface of the tire, which you may, or may not, want, same with using degreasers.

I think that the key with finishing is to match the application and track surface. There can be times that a courser ground tire is an advantage, and times that a smoother ground tire is the ticket. Hard clean surfaces that bite up seem to prefer a finer finish tire.

When you plateau finish a tire, it's much the same as plateau finishing an engine cylinder for ring seal. You get the benefits of a smoother surface finish and the deeper sipes. Multiple grits at slightly different angles leave a smooth surface.

I wrote about this shortly after my previous post on here for our Facebook page for one of my Tech Talk Tuesday blogs on May 10th. Feel free to take a look at that article with additional pictures as well. Maybe I explain it a bit better on there.

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-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
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34 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
I think its actually kind of cool that everyone who messes with tires learns things a certain way and does things just ever so different from the next.

I'm tempted to take what I've learned here and try a "smoother polished/ finer grit method" cut on my lower duro "gumball" sets of tires.

What would be neat would be to find a way to test the cut profile differences exclusively. There's too many other variables like chassis, driver, weight, prep, etc-etc.

My tire sensei from a dozen years ago taught me much of what I know now with a belt sander, but he himself used an electric variable speed buffer when cutting some other customers tires who raced in other parts of NY. I tried it once many years ago and I wasn't able to replicate what I saw and what I had been using/ current methods was working really really well. I think its time to practice this on a few sets!

We cannot learn from what we do not attempt.
 
I think its actually kind of cool that everyone who messes with tires learns things a certain way and does things just ever so different from the next.

I'm tempted to take what I've learned here and try a "smoother polished/ finer grit method" cut on my lower duro "gumball" sets of tires.

What would be neat would be to find a way to test the cut profile differences exclusively. There's too many other variables like chassis, driver, weight, prep, etc-etc.

My tire sensei from a dozen years ago taught me much of what I know now with a belt sander, but he himself used an electric variable speed buffer when cutting some other customers tires who raced in other parts of NY. I tried it once many years ago and I wasn't able to replicate what I saw and what I had been using/ current methods was working really really well. I think its time to practice this on a few sets!

We cannot learn from what we do not attempt.
Oh yea, there's no "my way is right and everyone else is wrong" attitude from me, anyhow. I learn new things every day. Having a teachable spirit is key to getting better all the time.
You do what works best for you and your customers, despite what your competition, or even the guy pitted next to you, is doing. :)
 
Oh yea, there's no "my way is right and everyone else is wrong" attitude from me, anyhow. I learn new things every day. Having a teachable spirit is key to getting better all the time.
You do what works best for you and your customers, despite what your competition, or even the guy pitted next to you, is doing. :)
Very well put.

Ironically, 10 years ago, I would have naively been self-convinced that there was a "best way' to do each individual variable but with time I've come to learn that it's much more complex than that, and how things perform as a whole TOGETHER, in a sort of balancing act, is what is actually the gauge of "control".

It's a simplistic train of thought but I try to encourage myself and others the mind set of "never stop learning and enough is never enough"
 
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