Indoor Tire Prep 101

Indoor racing has been a staple in r/c racing ever since I can remember. And ever since I can remember 99% of the indoor tracks  have some sort of “tire game” required to attain the fastest lap times. This changes from brand to brand, tire to tire, track to track, you get the idea.  I’m going to touch on a few basic things you should carry in your pit bag, how I decide on how to setup my tires inserts and wheels, and what to look for when making these changes. Fair warning, this is “general” and only my opinion. And we all know what they say about opinions; “Opinions are like %^&*(, we all have one.”

I’m not going to bore you with “how to glue” tires here. I will however give you a few tips you can use to tune your tire/insert/wheel setups however. There are a few tricks I’ve learned along the way you can try.

Venting is a pretty straight forward affair. In general I put 2 1/8” holes in my 1/10 buggy tires 180 degrees out from each other, and in general 90 degrees out from the wheel vent holes.  If the track is really bumpy or I’m running a softer insert I may increase that to 3 holes 120 degrees out from each other. The wheel vent hole isn’t super important so don’t sweat this too much. In my opinion anytime we’re using closed cell inserts the “closed” is important here. That means the insert doesn’t “breathe” like an open cell old school insert. So tire/wheel venting is important. I always vent the wheel simply because I look at it this way; If air is coming out of one hole, it’s coming in from another. Sure the opposing tire vent hole may allow it to breath, but if the insert is stuck against this hole during acceleration and the centrifugal force on the tire/insert and that causes the insert to plug that tire hole…Now you see why I choose to vent the wheel, always.  I carry the same idea into 1/8 but generally do 3 holes and up to 4, evenly spaced apart from each other.









I generally carry a 110v drill and arbor that fits my 12mm wheels along with a few different belt sander belts in various grits. Generally speaking 80 and 120 are in my bag. They’re cheap and the belt is stiff enough to control with support but will allow you to round it as needed on edges of tires, etc.


Don’t be a %^&*^&* here and not pay attention to what you’re doing. Yes you should be using a pair of safety glasses, make sure you have no loose clothing on, etc. Use some common sense here.

$40 drill and 2 belts in 80 and 120 grit.

If the track is not abrasive and can take many runs to break in tires you can accelerate this process with the drill and belt sanding belts. This is “scuffing” up tires and can be a pretty quick way to get tires on pace.  Remember that each tire will have a side on the car, so mark them on the inside of the wheel so you can track it. You’ll need to break in one for each side, and yes the direction matters. It’s always best to talk to the local fast guys if you’re visiting a track. They’ll have this procedure dialed and can tell you how far to knock down the tread, etc.

Inserts are just as important as the tread and compound of tires you choose. The faster and smoother the track the stiffer your inserts typically will be. Slower looser tracks with more bumps generally call for a softer insert.

Hard Insert:

Fast, smooth, high traction.

Soft Insert:

Bumpy, lower grip, slower acceleration.

Now of course there are ways to get a stiff insert to bridge the gap between a soft or medium insert. We often take the JConcepts Dirt Tech inserts and “tune” them. We can do this a few ways but the most commons is punching extra holes in the insert with your tire punch. The more material you remove, the softer the insert will be. Make sure you do this as uniformly as you can.

Plenty of patterns to try. More holes, less holes, spacing etc.

One specific SCT Truck insert trick is to glue the inserts to the wheel. Yes this maybe illegal depending on where you race but its common practice especially on high speed high grip surfaces we’re racing on today. Another trick is to glue the outer webbing of the tire to the wheel itself.  This has to be done before you glue up the entire tire, or if you’re using JConcepts wheels, there are little holes in the backside of the rim you can dribble thin CA glue into and accomplish the same thing, albeit without seeing your work. I’d do it before hand personally. This has a “HUGE[1]” effect on how the truck will enter corners and how much speed you can carry without having the tire folding over on the sidewall. Trust me on this.

Tire sauce is always a fun conversation to have. Purists will tell you the “hate it” while others could care less. Personally I’m on the “care less” squad simply because I don’t care as long as the traction and race track surface are consistent. This often means the racing is consistent, which is all I care about.  In general I sauce my tires 15-20 minutes prior to running the car. I often run MoGrip tire sauce but again check with the local track fast guys. Other options are WD40, Blue Liquid Wrench, etc.  I use either a tooth brush type tool or a bottle with a soft tip depending on tread height. Point here is stay consistent. Typically it’s not great to set your car down with wet tires either. As a former track owner I can tell you it does affect the dirt surface putting a layer on top. Don’t be that guy.  If you need to accelerate sauce getting into the tires quickly or if you’re breaking in your tires and want to be more aggressive you can “bag” them. This means saucing the heck out of them and inserting them back into their packaging bag and letting them “bake” for 15-20+ minutes.  The harder the compound, the longer you can cook them.

Make sure to remove the JConcepts decal from the bag PRIOR to baking any tires. Right Jason?

One of the biggest tips I can give you is stay consistent. Find what works for you and stick to it.  Tire prep can be a black art and a little cloak and dagger in the pits. The fast guys are fast for a reason but not all are forthcoming with their tire program.  I’m not fast so I’ll share as much info as I can with anyone asking me for it.

Once again as always if you have a suggestion for a “Tip of the Month” hit me up here!

[1] Donald Trump voice

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