What is the purpose of foam tuning Why do it, what is the theory.

[opek]

Are you trying to control contact patch or the way the tire bunches onto itself. Is sorting out the two what makes this difficult? Again searching has yielded not much general theoretical advice. This is one aspect of this sport that is significantly different than 1:1 and really limits the places I can find information.

The foam seems to have quite a bit more flexibility in tuning than air pressure. I see shorter foam insert discs can be used to increase lateral rigidity. Are people with something as strong as a rover sidewall running these to help with fold over when sidehilling? Or are these just to help out those guys who have thin sidewalls? Beyond something like that are we left to our sidewalls to control lateral go?

I see the hard rings to limit vertical compresssion seem to be popular and effective. Is this because people are running such a soft foam and carcass combo the tire will stick itself? Does this ring help prevent the tire from rolling over? Do people run the rings in the center or in the outer third of the rim?

Thanks in advance! If you don't want to answer because you have written about this or have read about it, I would really appreciate if you could take a second and think of some keywords that might lead me to those threads. I have tried with great enthusiasm to search all of this information out."thumbsup"

 

[TexasSP]

I have never seen this addressed deeply so having this thread is a good idea. I am sure Eddie with CI and others will join in.

My short answer is that foam tuning serves many purposes specific to a drivers wants and needs as well as terrain, vehicle weight, tire type and compound, etcetera.

I will say that with foam tuning it is important to have a specific goal in mind and be aware of how what you are adding or taking away will affect performance. You also must have a good bead on how you are as a driver and what your specifics needs are.

Personally, I buy good two stage foams leave it at that. I am not a serious enough competitor or driver to take the time to finely tune my foams. However, I am not taking away from those that do. I have great respect for people who can dial in a rig well.

 

[Jus]

I try to get to where the sidewalls have enough support without the tire being too stiff and call it a day.

 

[slowngreen]

This is the answer right here...

My short answer is that foam tuning serves many purposes specific to a drivers wants and needs as well as terrain, vehicle weight, tire type and compound, etcetera.

You dont "have" to do it, but its something that can fine tune your tire/rig setup and give you that much more capability's over a stock foam.

 

[Charlie-III]

To complicate the answer, tuning for flat ground is different than climbs which is also different from sidehilling (where you have side loads on the tires).:roll:

You have to look at your driving, terrain, tires, typical courses, rig strength/weaknesses, temperatures.......
All these variables affect tuning and how the tires perform. Fix one thing, mess up something else.
You could go nuts trying a bajillion things, or get something close and just deal with it.

Maybe go to a local comp and talk to the better guys with similar rigs & tires. They can give a little direction (how much depends on them and how good you are...) on what to do. The rest is up to you."thumbsup"

 

[Jeepkid]

Just use brown foams

 

[Meatwad]

... Personally, I buy good two stage foams leave it at that. I am not a serious enough competitor or driver to take the time to finely tune my foams. However, I am not taking away from those that do. I have great respect for people who can dial in a rig well.

+1 Couldn't have said it better myself, I'm in the same boat.

 

[Maxwedge]

from one newbie to another, here is my take on it...

I've been into scalers for a full year now- started with a used dingo and now have a totally custom built 1.9 comp-ready rock bug.
http://www.eparccrawlers.com/forums/showthread.php?1338-The-Bug-A-Boo
I have never bought foams, just something I haven't gotten into yet, but I have "tuned" or modified the stock foams that came with all my tires. Since you mentioned 1:1's I'll say this- think of full, uncut foams as 1:1 tires with full air pressure. Good on the road, but on rough rocky terrain 1:1 drivers "air-down" their tires to conform to the rocks better (squish or wrap around them). With beadlock wheels they can air down very low without ever breaking the bead. Airing down is what we are doing by cutting our foams. Many guys do a "star cut" (type it into the search bar). It still loosely fills out the tire, but the tire now squishes against the terrain for more/better surface contact. Personally I like to trim the sharp edges off the foams corners, rounding it out like a donut shape, with a modified star cut (trade secret). On one set I took my solder iron and melted holes thru the foams (swiss cheese) which softened it up nicely. Anyway..
Softening the tire like this has the side-effect of hurting your side hilling abilities. The softer the foams n sidewalls (more aired down) will allow the tire to roll under. The taller and/or skinnier the tire the more you'll see this. Also the heavier your rig (mine is 9 1/2 lbs) the more squish (duh!) so the less trimming you'll need for a given foam.

You have to experiment to see what works for your rig and driving. Take away a little at a time- you can always remove more. And while it doesn't have to be perfect, it doesn't hurt to try. Use a marker and draw out your star or whatever on the foams first (I use a sharpie, ruler and lego bricks to trace it out).

Hope this helped some, just my experience so far.

 

[Big Pitt]

Hello,
To reopen this thread I would have some questions.
I have a 2.2 MOA and I have some issues with my tire/foam.
I'm using 2.2 Losi Comp crawler tire and foam (memory foam).
I'm not doing comp and I'm driving on everithing I can find, so sometimes I take some inclined trajectory on a rock trying to drive in parallel with the ground.
Doing that my tires stick well on the rock but the side walls bent and my rig start to slide.
It also happend when I try to turn sharp on a adhering surface. My wheels turn allong with the tire but when I start to drive forwards it's like my back axle push everithing forward, my front wheels spin but the truck does not turn according to the turning radius. Instaed I see my wheels "pusshing" there way "trough" the tire and so it's completly misshapen.

I'm thinking of adding some stiffer foam ring on the side of my memory foam...
Would it solve some of my problems?
I would like to buy some stiffer foam insert that I could slice myself instead of buying already made rings ( more expensive I guess...).
Witch insert should I choose? Same diametre (?or bigger or smaller?) as the memory foam??
Once I would have cut the rings should I just glue (?with contact adhesive glue?) them to my memory foam?

I hope my problem is clear ennough to have some informations... :???:

Some help would be great "thumbsup"

 

[JeremyH]

Tuning foams is dependent on the tire setup that you are running. It becomes more evident when you are using a tire with a very soft sidewall.

I see the hard rings to limit vertical compresssion seem to be popular and effective. Is this because people are running such a soft foam and carcass combo the tire will stick itself? Does this ring help prevent the tire from rolling over? Do people run the rings in the center or in the outer third of the rim?

The ring does help with lateral stability (it is sandwiched by the foam and can keep them from sliding around), but I found them to be most important when you push the truck into an undercut. I ran the rings in the front and they would keep the front tires from completely collapsing in the undercut.

I'm using 2.2 Losi Comp crawler tire and foam (memory foam).
...
My wheels turn allong with the tire but when I start to drive forwards it's like my back axle push everithing forward, my front wheels spin but the truck does not turn according to the turning radius. Instaed I see my wheels "pusshing" there way "trough" the tire and so it's completly misshapen.

Memory foam? What temperatures are you running your truck in? I have found that memory foam becomes too hard at colder temps and, unless you have a tire with really thin sidewalls and carcass, then memory foam is not necessary.

As for the rear tires pushing, well that is just a negative side effect of having a locked front and rear axle. This is a good reason to use dig in that instance.

 

[AX10wannabe]

i've heard of many different ways to cut tire foams like star cut, cut a V in the middle of the foam all the way around etc..me personally i like to cut the sharp edges off my foams and to make them more round. im running TSL tires and they have a very soft sidewall i rounded and narrowed my foams and just enough so they form around the rock and but not too much that the rig is running on the rim all the time. this setup works well for me even without weight in the tires and i figure its just learning how to drive and pick out lines.

 

[Big Pitt]

So not really what I was looking for an answer so I'll ask an other way...

I would like to stiffen my sidewalls by adding some foam discs on the side of my memory foam inserts.

I know there is those discs fom Crawler Inovations:

But I would like to make mine, using foam stiffer inserts that I would slice at the proper thickness (wich is...???).
I assume that it would be less expensive 'caus I'm on a budget...

So where could I found 5 or 5.5" tall firm foam inserts with 2.2" inner diametre??? Or should I use sheet of foam ,and if so how could I found the right stiffness?

Some help would be great."thumbsup"

 

[Meatwad]

Do work. If you don't wanna pay and diy is the route you're choosing to take, get ready to experiment. There are plenty of different ways and plenty of different materials to make your own foams from.

Nova's Ark at CI has the formula down and has been playing with foams for years now.