Contact Rear tyres - chunking

[lordnikon]

Is there any way to help the rear tyres stop chunking ? It always seems to be the rears - body has plenty of clearance so dont think its that catching the tyres ...

Is there anything that can be done to help stop it or even help it occur less ??

[Karting]

Normally its contact with other cars bodyshells which damage the tyres

[reg]

Run some superglue round the side wall then stick the sticker on,I've been running 32s for 3 weeks with no problems,

[colin367]

Its normally the size that creates chunking, how big are you running them ? more tyre, the bigger the chance.

[lordnikon]

As they come out of the box ..... no tyre truer to make them smaller

[reg]

I've found it's hitting things the does it

[mark christopher]

check evey run to make sure there not torn or damaged, ask some one to true them down at a meeing if you can, then some apply a coat of evo stick to the sidewall. also make sure the side wall is rounded and not square.

[Allan1875]

Contacts are bad for chunking, it just seems to be the way they are.

If you glue the side wall you all alter the handling of the car as you lose a lot of roll which loses grip.

I personally use Pink Med rears and 46 fronts, work just as good as contacts in my opinon.

[racingben]

As stated above, crashing and chunking go hand in hand.

[reg]

Originally Posted by Allan1875

Contacts are bad for chunking, it just seems to be the way they are.

If you glue the side wall you all alter the handling of the car as you lose a lot of roll which loses grip.

I personally use Pink Med rears and 46 fronts, work just as good as contacts in my opinon.

i run 32s rears so loosing some side grip means it doesnt chatter when its pushed hard round the corners,but you get mega forward grip,i dont put any on 37s or 40s,thats when i notice it does take away to mush side grip,but as they are harder they chunk less,unless i crash more

[JimboJames1972]

Chunking:

Usually caused by one of several factors - snagging your shell, hitting something, over-softening the tire rubber or excessive loading through the corners.

On the whole, tires with larger diameter side walls are more prone to chunking than smaller diameters.

Over-softening the rubber is something that many people over look. Each time you apply additive you soften the rubber compound. If you apply additive several times each meeting you run the risk of over-softening the tire rubber because its effect are cumulative. It also depends on what additive you use. CS High Grip seems to be the most aggressive on the rubber compounds (but some say it also gives the most grip) while Nosram/LRP carpet additives seem to be the mildest on your rubber. Jack the Grippa is somewhere in the middle.

A common method to reduce both tire wear and the chunking risk is to run multiple sets of tires each meeting. I use 3 pairs of rears and run each set twice only each week (two lots of practice, three qualifiers and one final so six runs in total). I find that, on average, I wear approx 0.2mm off each pair each meeting. Some of the guys who run just the one set wear up to 1.5mm (or more!) off each meeting! Buying multiple sets costs more in the beginning but I get several months from my sets. I also handly ever chunk them, so they pay for themselves very quickly.

Another thing to make sure of is that your outer sidewall is well rounded off. A sharp edge can cause the tire to bend under itself and give you either grip roll or chunking.

In my experience, the Contact 32 or 35 tires are more prone to chunking than the Mardave Pink Mediums, especially if you glue and true your own donuts on the Mardave rims. The pink donuts come with one sidewall that is smooth and slightly toughened so have this on the outside. this, along with the lip on the rim of the Mardave tire will go a long way to help reduce the chunking risk.

Hope this helps,

James

[bally]

My advice would be to run a softer rear spring, i have found running anything stiffer than Yellow on the SupaStox and my tyres chunk!

[SlowOne]

The most common cause of chunking is being hit by another car, and clipping barriers. I find Contacts chunk less than others... go figure!!

Superglue on the sidewalls has no effect on chunking in the main. USe the wrong glue and you stiffen the foam making it come away from the rest of the tyre easier. Evo-Stik works better, and putting the tyre sticker on works best. Make sure that you put the sticker on the plastic bead of the wheel and then over the tyre, not on the tyre alone.

The sticker should be stuck to the plastic bead of the wheel and the foam, as this will strengthen and protect the tyre. You will have to cut the sticker in one place because when you get the sticker on all the way round, it will overlap - it's designed to go on the tyre only.

This is also a good way to help stop grip roll. Put the sticker on the front tyres overlap the wheel bead again) and after a couple of runs the sticker will be almost up to the top of the tyre. This stops the edge of the tyre digging in and reduces grip roll. Much better than using superglue, and it strengthens the foam tyre, not weakens it as with superglue. HTH

[mark christopher]

Originally Posted by SlowOne

The most common cause of chunking is being hit by another car, and clipping barriers. I find Contacts chunk less than others... go figure!!

Superglue on the sidewalls has no effect on chunking in the main. USe the wrong glue and you stiffen the foam making it come away from the rest of the tyre easier. Evo-Stik works better, and putting the tyre sticker on works best. Make sure that you put the sticker on the plastic bead of the wheel and then over the tyre, not on the tyre alone.

The sticker should be stuck to the plastic bead of the wheel and the foam, as this will strengthen and protect the tyre. You will have to cut the sticker in one place because when you get the sticker on all the way round, it will overlap - it's designed to go on the tyre only.

This is also a good way to help stop grip roll. Put the sticker on the front tyres overlap the wheel bead again) and after a couple of runs the sticker will be almost up to the top of the tyre. This stops the edge of the tyre digging in and reduces grip roll. Much better than using superglue, and it strengthens the foam tyre, not weakens it as with superglue. HTH

one of the good flexible supa gules does help and it doesnt crack also a read of jims tyre tips will do wonders on racechat http://rcracechat.com/vb/showthread....t-of-your-dosh

[GhostlyRock]

I had a suggestion from one of the 1/12 scale guys at the weekend at Plymouth, myself and Bob Hill both tried it, Bob in 1/12th blinky and me in GT12.
The idea was not to cover the whole of the rears with additive, but leave a small outer ring clear, thus not softening the outer edge and in some ways the tyre becoming a dual compound, harder outer and soft inner.
It seemed to work ok with my tyres, not one chunk all weekend and the car handled well.
I dunno if this is good idea or not, I'll leave it to the more experienced guys on here to work out the + & - of it. (Pete).

[reg]

I guess its "do what works for you"

We run on a big open track so dont smash into things,no problem with chunking for me when i do what iv said,it might be different on a high grip small track playing bumper cars