Keilor Tyre Choice – Which J-Concepts Products To Use And When


Technical Report By Ray Munday

July 2010


I have done a lot of tyre testing at Keilor for JConcepts and would like to share my findings. My role as a factory driver is to do the hard work for you-hopefully saving you time and $$ while making you faster!!!

When the Keilor track has been blown off and is mostly dry, the correct compound is more important than the tread pattern. Very worn tyres of the correct compound will be better than new ones of the wrong compound. You don’t need new rubber all the time!

I recommend stocks of the following JConcepts tyres for the following conditions:
  • Cold + dry/swept: Bar Codes (blue compound)
  • Warm + dry/swept: Bar Codes (orange compound), (white compound for 2wd front)
  • Damp or dusty: Double Dees (green compound), Groovy 2wd front (green compound)
  • Wet: Goose Bumps (green compound), Groovy 2wd front (green compound)

JC Compounds Refresher

  • Green : super soft (similar to proline m3)
  • Blue: soft (slightly firmer than proline m3)
  • Orange: medium (similar to losi red)
  • White: medium/ hard (similar to losi silver)
Bar Codes (blue compound)
Use when the track is dry, swept and cold (< 13C, but work best 8-12C) eg the last club race. They were 0.7s/lap faster than anything else in practice (which was a chilly 8C!!). Don’t use on a warm day as they will wear fast and actually grip less.

Bar Codes (orange compound)
Use when the track is dry, swept and warm/ hot (>15C, but optimal around 20-25C). Below 20c, these need a few laps to warm up (some burnouts and slides on the warmup lap will help!). Below 15C, these will feel too hard and skaty. I have run these as slicks on a 20C day and still had fast lap times in 2w mod (some of you may remember that at a club race in May vs. Matty G).

The orange compound really suits the Keilor surface well when it us warm and abrasive.

Double Dees (green compound)
Use when the track is damp or dusty. They will work best under 20C or so, but usually if it is warmer the track will dry out anyway. The round profile of the tyre makes it ride smoothly through bumps and the pins dig through into the base.
When the track is dry warm and swept, they will have high peak grip but feel a bit strange as the pins move around on the surface. They will wear much faster than orange bar codes in these conditions. At the recent ROAR nats some team drivers were making low profile flat versions by removing a few rows of pins and re-gluing. I'll try this soon and post results.

Goosebumps (green compound)
Use these when the track is wet / muddy. The large spacing between the pins stops them from clogging up while the long spikes dig into the surface.

Flip Outs (green compound)
These are a new tyre which look like a cross between the Goose bump and the Double Dee. I will be trying these soon. They should be good when the track has some damp areas.


2wd Vs. 4wd

The above notes refer to 2wd/ 4wd rear and 4wd front tyres. I try to use the same compound f+r on 4wd.

With 2wd, I often use a firmer front compound when it is really grippy. When warm, I usually run white compound bar codes on the front as this smooths out the steering. When it is really cold, I will still run blue fronts.

Alternatives: losi taper pins. These work well but have a much lower tread height which means more wear and they also lose grip with any dust on the track.

I very rarely use ribs at Keilor as they make the car hook, but if it is damp or very dusty I will use JC Groovys. If it is warm and dusty, Bar Codes will work. At the 2009 ROAR nats, they were using cut down Double Dees for the front and I will be trying that soon as well...


Inserts:

The inserts that come with JC tyres (the And-1 foams) are quite firm and as long as you have the correct compound, should work fine. However, I have found that when the track is grippy, 2-stage inserts (cut to 45mm width) help stabilise the car through the bumpy corners - they stop the tyre from rolling over and the rims digging into the ground. When the track has been recently rolled it isn’t an issue. I would say that this is a tuning option rather than a necessity.


Truck

For truck, basically follow the 4wd recommendations, but use the carver rib fronts when it is wet.


Other Tracks

Keilor is very hard and abrasive compared to a lot of tracks, therefore a harder compound is required. You may find the compounds are suitable at higher temperatures at other tracks (eg Blue may be suitable up to 20C at a track like Wodonga).


Actual Lap Times

The chart below shows some lap time results from a club race at Keilor in 2009.


On this day the track had very little dust but it was a very cold day. Note how much faster the Blue Bar codes were when it was very cold – they were amazingly good when it was really cold, but they didn’t get faster as the day warmed up. The Orange Bar Codes started to work at 13-14C, and will get much better as it warms up further, but were really slow at 8C. Double Dees were consistent across the temperature range but started to wear at 15C.


Keep An Eye On The Weather And The Track!

Biggest tip from all this? Keep an eye on track and weather conditions, choose the appropriate tyre compound and you will be faster!

I hope this helps you out with your racing. Feel free to contact me at ray@rccar.com.au if you have any further questions.


JC Tyre Selector

Here is a quick reference chart to stick in your pitbox: