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Track conditions, surfaces, wood, plastic. On wood the type of paint will make a difference. Air wheels work best for us and NSR rubber

Excellent guide but I think you should add some pics to help people visualise what you are describing as blistering.
I have started a thread not a long ago here. Very interesting tips there as well.
Personally my best tyres come from a very smooth finish even after treating the tyres with oil. My gut feeling (and I am surely wrong here) is that any "blistering" would cause the rear tyres to bounce and produce too much vibration. That is why I am really curious to see a close up pic of this blistering effect!

thanks for writing this.
 

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I round the tire edges so they dont catch the braid sliding over

Oops, I should have been clear that the conditioning oil is mostly dried out before the car is allowed on the track. Some race rules actually require that the car is placed on a sheet of paper, to test that there's not an excess of oils leaking into the paper, therefore no risk of contaminating the track. Of course, I'm talking about oils used to blister the tyre, to effect a permanent change in its physical characteristics, rather than on-track tyre treatments which are applied immediately before racing.

Bob, your recommendation to bevel the tyres to increase the contact patch as the car leans into the corners is interesting. I guess that the very slight convex bulging of blistered tyres might have a similar effect in increasing tread contact patch? I also understand that bevelling the tyres is advantageous if the tyre breaks free - tail sliding - as the rounded or bevelled edges will not give such a sudden side slip. It's a technique used on untreated tyres where you actually want to have controlled tail sliding. Whereas with super-grippy conditioned tyres, the tail breaking free too often equals "game over" with a catastrophic deslot. Is this correct?

Tony, Koala Claws is amazing stuff. We've a few New Zealanders who dreamily sniff it all night long http://www.slotforum.com/forums/style_emoticons/#EMO_DIR#/rolleyes.gif.

Thanks,
Rick
 

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You can use an NSR tire truer/juicer or make your own like I did to speed up the softening process

Gentlemen,
Agreed tyre dynamics is a complex subject, but my initial posting was never intended as a technical submission on tyre dynamics. It's actually about creating shape changing tyres. The simplified science bits are only there to give some contextual basis for discussing the little known benefits of shape changing tyres. Please don't read them as more than simplified 'supportive' material which is intended to explain how shape changer tyres help win races.

Let's start over. This post is about a technique that gives you a kind of "one size fits all" rubber compound racing tyre that works on all track surfaces.

When I say "one size fits all", I Do NOT mean you can have just one tyre that'll work in every possible circumstance. But this appears to be about as good as it gets in terms of adaptive tyres for slot cars.

Please note: this is not about simple 'tyre softening' techniques where oil is used to simply soften the outer surface of the tyre to give better grip; although the techniques are related. It is also not about 'tyre conditioners' which are applied immediately before a race, also to increase grip. What my posts were about is a process which causes separation in the layers of the rubber tread - so-called blistering - which results in a tyre which shape changes during a race.

As you know, a "tall" large-diameter tyre will run faster along the straights, as it effectively gives you higher gearing. Whereas a "squat" small diameter tyre gives an effectively lower gearing, and will be better for acelleration as well as fine throttle control. These are to diametrically opposed qualities we'd like to have in the rear tyres we fit to our cars.

Then there's the size of the contact patch, and whether it's wide or narrow. We could write a book on this one. But (for simplicity sake) let's agree that, in general, we want a big contact patch when braking, cornering, and during initial acelleration. Whereas, when we're running full-throttle along the straight (where we're not concerned with lateral grip) it'd be beneficial to reduce rolling-drag by having a smaller and narrower contact patch, as well as the aforementioned larger diameter tyres.

This is what the shape changing tyre gives you.

Creating such tyres is simple. Smear a small amount if 3-IN-ONE oil onto the treads of the tyres. Leave until next day, and repeat the oil application. This is the same thing we do to simply soften a tyre tread to increase its grip. But keep going, day after day, until the tread starts to rise up and form what's called a 'blister' right around the tyre. When the blister looks like the ones in the pictures l posted earlier, you'll have a set of shape changing tyres, and you're ready to race.

Tonight is race night, so Over-and-Out,
Rick
 

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And now with my tongue firmly in my cheek: what the **** is a "super expert"

QUOTE (LeMan1960 @ 7 Sep 2016, 14:08) <{POST_SNAPBACK}>
This is why experts - or, worse, a 'super expert'

Is he more expert than the expert? Or is he a "super guy" who just happen to be an expert?
But if the expert has a super expert more expert than an expert, how can he be an expert? Unless he is an expert at not being very expert?

Here is "my" definition of "an expert".

An "Ex" is a has been.

A "Spert" is a drip under pressure.

The Moral of the story...never take advice from a Has Been Drip Under Pressure.

I appreciate that I am somewhat late to this party but I hope my small piece of input helps.

Cheers.

Nik.
 

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Interesting topic, read the OP skimmed over most of the other post.

Firts of all let me say that the willingness to share information and taking the time to do it is something I will always applaud.
So kudo's to Rick for staring the topic, I know from experience how much time a good write up can take.
And I agree with Gary there is some good info given on the how too part.
I have disagree with Gary's opinion that 1:1 tyre science is not applicable for slotrace slotcar rubber.
I.m.o. there's alot that can be learned, because the same basic principles apply, the trick is to see what and where they apply and to which extend they can be used to improve your slotcar.

Rick starts his post with a very good example to illustrate the relation between a contact surface and the amount lateral force it can resist without slipping.
The observation is correct...but with his first conlusion "less rubber on the track equals more grip" he immidiately cuts one very big corner which makes him loose grip on his own reasoning.

As Kevan mentioned early in the discussion "Pressure is a result of force and contact area"
So the correct conclusion here should have been: With the same force applied, the pressure on a small contact surface will be higher than that on a large contact area.

Had Rick repeated the same experiment pushing with increasing force, he would have noticed that there would be a point where an eraser on its edge would start to slide earlier than one laying flat on the surface. He would notice that the eraser on its edge would start to hop....like in "Ninco hop"

As with so many things in our dear hobby, its always about finding the right balance.

My contribution to the discussion are a couple of images that illustrate the effects different forces have on the contact patch of a tyre under load.
Interesting to see what the replies will be

with kind regards
Tamar

gripcircle_transition.jpg
Force and the direction it is applied in

© farnorthracing.com

Slip+Angle+Leading+and+Trailing+Deformat
bhvrcpmgrtn.gif
Contact patch deformation under directional and lateral loads

image left: © 2.bp.blogspot.com, image right: © insideracingtechnology.com

deformation.gif
Rubber tyre on a Ninco track surface

© www.expeditionswest.com
Whilst the image does characterise the difference in tyre width on a 1:1 vehicle, I think the depiction of a 12.5 inch wide tyre on Ninco track would be slightly out of scale :)

What does happen is a slot car is always sliding the rear end, therefore the outer rear tyre is digging in (or trying to) and the inner rear is often lifting slightly, also spinning faster hence additional wear shows on the inside edge of the rears after a good hard run.

Rounding the edges reduces the risk of the car tipping and tyres do blister and in some cases it is necessary to clean the accumalated ball of rubber mid race, as the car bounces as if the tyre had come off the rim

That said, I have seen many racers take hours over the prep & set up of their tyres getting hammered by another that never touches theirs and the tyres look almost undriveable!

But that's slot racing for you :)
 

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I kind of wish I hadn't seen this thread. But I cannot read it and walk away without mentioning the notable late race engineer Carrol Smith's books for full scale auto racing, Tune to Win, Engineer to Win and Drive to Win. He talks in those books about the grip circle, also pictured in the above post. Now that may not be up to date scientific material, but it worked very well for him, with some notable engineering wins at notable races. Whoops, I've gone and referenced full scale racing which is not really similar to slot cars at all. But I believe there is a lot more to tyre grip than some of the simplistic views represented in this thread. One interesting thing about Smith's build approach is that he claims that a (full scale) car design should and must begin with the choice of tyre. He claims that the design of the entire car starts with tyres. Difficult to grasp in some ways, but his cars won notable races!
 

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Kevs Racing Bits
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I've got that book, bought many moons ago...a lot of it will need reading more than once.
 

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Bob Chapman
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This has certainly turned into more of a debate on the merits of various engineering principles , and preferred methodology.
It is far to complex of a topic to really garner any useable info for any one person. The variables are too many and the similarities of tire types far to different from each other to garner a true perspective of what will and what will not enhance performance of a tire as related to the chosen car. Every make of tire is different by way of material, urethane , silicone , rubber, foam, and each responds differently to thae variants of a race day such as track surface, temp and humidity, tire prep etc, all before getting into the contact patch.
Differing compound softness factors, and even how they are measured come into play, age of tire , style as per wheel fitting,mie air hub, solid hub etc. Truing is a real unknown as a tire may be perfectly round , but the truing process may have changed the tires hardness depending on the heat generated in the truing process. So many factors that can really have a profound relationship with the overall stability of the car. Low profile , tall profile etc. Unlike 1:1 tires which come with differwnt ply ratings, special designs for purpose specific use such as car , truck, trailer, and season have no equivalent in our scales.
I think a more useful and simple thread for newbies would be about the aftermarket tires available, what they are made of, what shores they have and the range of applications may be quite useful.
I see that the members here have a wide variety of choices, by preference, so lets not rehash the silicone , urethane, rubber or foam bit, and lets keep away from the dark arks of juices etc.
Just a simple chart of tire manufacturers their product line, what they are made from , shore rating , and perhaps intended application . Ie, LMP, F1, Sports car etc.
It should prove to be a very interesting list and offer the newbie a good place to start when looking to expand from rtr to aftermarket tires.
Bob
 
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Well put as usual Bob.

I look forward to the publishing of your new guide " Tag, you're it " hee hee

Actually, in all seriousness, much of the information is readily at hand. The original Slot.it tyre guide has intended applications for their various series of tyres, most of the makers put out shore charts
 

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Rich Dumas
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Last night we hosted a proxy race for cars with spec urethane tires, it was the 5th race in the series so the cars had a history. We had notice that for one of the top running cars the performance had dropped off a lot between the qualifying runs and the actual race for #3. By the qualifying runs foe #5 the car acted like it was running on ice. Note that we had been cleaning the tires all along. The car owner asked me to take a close look at the car, so I got to the track early and took the body off to see if anything had come adrift, but nothing seemed to be out of order until I looked closely at the tires. The tires has gotten glazed, a quick wipe with some contact cleaner on a rag removed the glaze and the car was the top finisher of the day. None of the other cars had glazed tires, all of the cars had their tires cleaned at the start of their heats. Since all of the cars were run on the same tracks and they all had the same brand and compound tires I can't figure why that one car suffered the glazing problem.
 

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Alexis Gaitanis
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I had a similar problems:

-with round 1 of IPS ,would track, 2 cars ,#25 and #170 ,urethane shod, felt like running on ice,despite cleaning the tires more than once and finished 25 &27 out of 32 whereas in round 4 they finished 3rd and 1st

-at London Scalextric club where i attended 2 races in may,Scalextric Sport painted track,they race exclusively urethane tires mostly Ortmans.My cars were fitted my own urethane tures.I was loosing grip after 3-4 laps and could not understand why.Finally i found the solution:i run 2 warm up laps then cleaned tires and problem solved.I seems that Ortmans dust affected my tires
 

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Room temperature sure does affect things. Even with treated soft rubbers, we notice on a cold night that our lap times are 1 or 2 tenths slower than a warm one.
 

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I too wish I'd not started with this thread as I had growing doubts about the validity of some of the points being expressed and then thought I was going mental with references to Maurizio but, backwards and forwards, could find no posts from the fella.

Did he go all Efferty-Geofferty and they get deleted?? ;o)

But, I'm taking heart from the fact I identified a flaw in the 'guide', early doors. Clearly, the guide is not for me. Clearly, I am not an idiot. Q.E.D.

That said, where are these 'Eraser' tyres available? I can't see them listed at Pendle's and they sound the dog's.
 

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David H
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That said, where are these 'Eraser' tyres available? I can't see them listed at Pendle's and they sound the dog's.
Over the years I've read numerous posts on SlotForum claiming that the best tyres are the dog's b***cks. Intrigue has finally got the better of me. Who is the dog, where can I buy his b***cks and, more importantly, how do I fit them to my rims?
 

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Kevs Racing Bits
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Over the years I've read numerous posts on SlotForum claiming that the best tyres are the dog's b***cks. Intrigue has finally got the better of me. Who is the dog, where can I buy his b***cks and, more importantly, how do I fit them to my rims?
You'll probably find it barking up the wrong tree
biggrin.png
 

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Coming in late on this topic; again...&#8230;..

Great post LeMan 1960! There certainly is a lot of complexity in properly preparing rubber tires. I have a question that is peripherally related to tire prep; I hope that it's not considered off-topic.

It relates to the picture that you showed in post #21; of the prepped tire on the airhub wheel. You mention the lines/grooves in the tire that are left by the tire truer. I find these same lines all the time when I true either rubber or silicone tires; somewhat less with urethanes. The lines on my tires come from the sanding drum on my Hudy tire truer. Up to this point, I have made efforts to remove them before finishing off my tires. My process for rubber tires, generally, consists of:

1. Hudy trueing down to within 0.2mm of the target tire diameter

2. Tire Razor sanding with 150 grit (dry) to remove most of the lines left on the tire by the Hudy (yes, I do use the back and forth motion option on the Hudy, by moving the outward pully in and out; but my experience is that this is not terribly useful; but, that's just me)

3. Tire Razor sanding with 220 grit (dry) to improve the smoothness of the tire surface / 220 grit (dry) profiling of the outside and inside edges to produce a somewhat rounded shoulder

4. Tire Razor sanding with 600 grit (wet) to start to finish off the surface of the tire / 600 grit (wet) as an initial finishing step for the tire shoulders

5. Tire Razor sanding with 1500 grit (wet) to continue the finishing process on the contact patch / 1500 (wet) as a final finishing step for the shoulders

6. Tire Razor sanding with 4000 grit (wet) to finish off the smoothing of the contact patch

7. Cleaning with 5 short cycles of lighter fluid (tire surface softening starts, roughly, after the third cycle, and continues through the 5th)

We are not allowed to prep tires with oil soaking or similar methods for most of our events, so, for me and in general, rubber tire prep stops here.

Reading the comments that followed post #21, particularly with respect to a larger or smaller contact patch and it's effect on performance in the turns, I'm wondering if the ridges on the contact patch left by the Hudy are a bad thing that should be sanded away, or a good thing that should be maintained. For me, without the 150/220 grit sanding steps, the ridges will continue to be present at some visually detectable level (although greatly reduced) right up through the lighter fluid step. Up to this point, as I mentioned above, I've considered them to be a bad thing and have made every reasonable effort that I can to remove them. .

My reasoning has been based on the observation that in some cases, new tires; particularly silicones or urethane, that are slipped on are faster than the same tires that have been glued and somewhat hastily trued. So, I have focused on the very smooth surface that these tires have coming out of their molds; which hastily trued tires do not have, and have tried to approximate that surface using my truing process. But, as I said, above, this may not be the way to go.

What do you do and what do you think about the negative/positive effect of the ridges and the quest for a super-smooth contact patch?

Allan
 

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Rich Dumas
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When you glue tires the thickness of the layer of glue may not always be uniform, so the glued tires will be less true than ones that have simply been slipped on. That tends to be more of a problem if you use a thick adhesive like silicone gasket cement. Slot Car Corner sells a neat tool for doing glued on tires that helps a lot to reduce this problem.

Even if you use a more sophisticated truing machine like a Hudy you may not end up with tires that are perfectly true unless you use the correct procedure. Each type of tire will require a somewhat different procedure. For a start you will probably have to vary the speed and grinding pressure as well as the grit of the sanding medium. With a machine like the Hudy changing sanding drums is not a great option.

Generally most rubber tires are the easiest to true, one exception is the very soft NSR ones that need a very slow speed. Urethane tire true about the same as the typical rubber tire, but the ones that I have done tend to end up with grooves that must be removed by polishing for the best performance.

Modern silicone tires by Super Tires and Quick Slicks are more difficult to true. They both leave a gummy deposit on the grinding media and renders that useless. You have to stop frequently to clean off the media or squirt on a soap solution to keep the deposit from building up. Both brands grind very slowly and if too much pressure is used the tire will be compressed a little, so the diameter will be reduced without actually eliminating the high spots. My Hudy is set up so I can move the wheel/tire from side to side. I grind without moving the tire from side for most of the time, but I finish each pass with about thirty seconds of side to side movement. Oddly that only seems to eliminate the grooves with Super Tires, there are still slight grooves with Quick Slicks that need to be removed by polishing. The Quick Slicks that I use are the same Shore value as Super Tires by the way, go figure.

If the tires need polishing I have never had any luck with fine sand paper. I run a car around a skid pad made up of Ninco track in alternate directions for as long as it takes.

Once you get the trued tires on the track you can run about a hundred laps and examine the tread pattern, if there is any pattern at all the tires need more work. On a wood track tires that are not round will make a drumming sound.

One clever person in my club has a few sets of glued and trued reference tires that he knows are good. If he is working on a car that does not seem to be up to par he can eliminate the tires as being the problem by trying the reference tires.
 
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