Tire problems
 

I live in Thailand and a member if the Chiangmai model raceway club. We have an asphalt track and we all use composit foam tires made by GRP consisting of 40 and 42 compound. Most of us have HPI RS4 Racer 2 nitro cars. The problem is we go through tires every 20 minutes of racing. The foam tires do work the best but we use up to 6 sets of rear and 2 sets of front tires every race. This can get expensive plus we have to change tires when we refuel. The track temperature here can reach well over 100 degrees f. The foam tires are the best to use on our track and are used by racers throughout Thailand. My question is does anyone know of a composit foam tire that can last longer in this heat.:tire:

Re: Tire problems
 

Hi speedoo,

In Malaysia, we run 42 rear and 45 fronts and wear rate is pretty reasonable. UFRA tires which is also by GRP. The rears wear off about 2 to 3 mm after 2 to 3 hours of intermittent play (play 7 minutes, rest 5 minutes). I can't find rear foams that are 45 shore yet.

I believe the climate here in Malaysia is hotter than Chiangmai. Our ambient climate is already about the same as your track temperature:nod:

Is the track treated? Our track here is somewhat "smooth" untreated asphalt. Could be that the track is rough asphalt type that is not so condusive to foams... Just a guess.

i think that the tire wear is more affected by the type of surface
you guys race on than temp. you could go with a harder compound and should help.

Thanks guys for your quick reply. I will go with the higher 42 to 45 compound. The problem is not with the tire size as much as chiping off on the outer edges on the rear tires. The track is kind of like a parking lot asphalt surface. The problem is that when they made the track they put sand as a base first so fter a rain the sand comes to the surfce and we then have to sweep it down. We then add sugar water for better traction.

Has anyone tried the new (part number 4763) Advan A038 Belted Tire 24mm (33R - Hot Weather) tires from Hpi yet for their nitro car? We have 1 guy who used them during a race last sunday on his HPI RS4 electric car on our track and won by a large margin. While everyone elses tires were screeming in the turns his tires were quiet with loads of grip. I am wondering how they work on nitro cars before I purchase a set. :tire:

Side wall of the tires chipping out? I think you run the tires too thick. Stock foams are around 66 mm. To make the tires last lnger in order to avoid side flexing of the foams and chipping off, you need to true the tires down to 60 or 62 mm.

If you want to try rubber tires, then I suggest to go with 36R or 40R Sorex belted tires. Use a harder insert according to your taste. This is what we generally use here for a hot and humid climate country. They las the mongest and provides the best available traction. But then I must warn you that you will not have as much grip as what you can find on foams...

Thanks again guys. My rear tires are already 60 mm however my front tires are only 55mm and I don't get chipping on the front. I like the smaller front tires as I can make tighter turns. Since our track is very tactical with short straights and lots of hairpin turns the smaller front tires help a lot. I will try to trim my rear tires down to 55mm or so and then give it a try.
I have also designed a fender that covers the front and top of the left rear tire and attaches to the chassis plate and left rear part of the shock tower on my HPI nitro Racer 2. In long races when I have to fill up (2 or more times in some races) it keeps the fuel after the fuel pit stop from getting on my left rear tire. It also stops the exhaust oil from getting on the tire. When everyone is spinning out after a pit stop I am going full out with no tire slippage. It does not rub on the tire and moved freely with the body. I am thinking of going into production to make this option part for other racers to purchase. Would anyone out there be interested in purchasing this tire guard made with either high impact plastic or anodized alumunum? I had mine made here in Thailand out of alumunim from a local machine shop. I used it for the first time last Sunday. Works Great.

change cars
even in the us the hpi has strange effects on tire wear
some say it's the flex the car has and the slop in it's a arms

HPI tire wear
 

Speedoo;

One thing that I have found when running HPI Nitro cars is that they like to have little or no Camber in the Front and -1 deg or less in the Rear. With foams, adjust Rear Camber based on tire wear. (Usually around -1 to -1.5 deg) The Front seems to wear Ok at 0.0 to -0.5 deg. which is the same for rubber tires.

MOST other brands or Nitro cars will work better with Camber settings in the -1.0 to -2.0 deg mark at both ends.

Try a firmer compound Foam Tire or a Firmer insert on your rubber tires to improve the wear characteristics.