November 2024. The temperature is approaching 0°C and you still want to go to the track for a training session or a race?
How can you change and adapt your set-up for this change?
When the temperature changes, your whole car will behave differently on the track, as the material resistance (mainly plastics) changes. Plastics are stiffer, but also more brittle.
But fluids in differentials and shock absorbers will also change.
Before I start talking about these variations, I'd like to emphasize an essential point to bear in mind.
Before talking about adjustments, it's very important that you have quality equipment from reputable brands in your travel case, transport bag or toolbox.
This is particularly true for your car, but also for your peripherals and oils. There are many players on the market today, but the quality isn't always the best. For shock absorber and differential oils, I recommend XTR oils.
Rule number 1: you should always have only one brand in your gear. It's not necessary to have the same brand for differentials and shock absorbers, but for each component you must use the same brand (XTR for shock absorbers and Kyosho for differentials, for example).
Otherwise, if you want to optimize your settings and adapt them to your needs, for example by stiffening your car's suspension, you won't get the results you're looking for. In fact, each brand has its own way of producing and measuring its oils, and from one brand to another there may be slight differences in values.
WT or CST is a different measurement, and I invite you to read this blog post for a better understanding the differences.
Now let's talk about changes with temperature. Despite the high quality of XTR 100% silicone oils, which are far better than some of our competitors we won't mention, viscosity will vary with temperature.
In the case of differentials, viscosity doesn't really change with outside temperature, as the differentials are really enclosed inside the car. Their operating temperature will therefore be slightly different in winter and summer, but this will have minimal impact on your car's behavior.
Shock absorbers, on the other hand, are a different matter.
The rule I can recommend is to change the oil by 50cSt (about 5WT) every 5°C (10°F). For example, your magic setup has 500cSt oil at an outside temperature of 20°C.
If the outside (and/or track) temperature drops to 10°C, you should use 400 cSt oil, and conversely, 600 cSt by 30°C.
You need to keep this in mind, so you can enjoy the same dynamic car behavior on the track, and know how to react if necessary. Indeed, on a fine spring or autumn day with wide temperature variations, not changing the oil will have a direct impact on your car's behavior (too hard in the morning and too soft in the afternoon, for example).
Another thing to remember is to adapt the oil to the shock absorber pistons.
When you talk about your shock absorber settings, always think of the piston, but also of the car you're using. From one car to another, it's not possible to use the same oil with the same pistons. In fact, the geometry and tolerances of the pistons and bodies will influence the oil used.
So base your choice on the settings shared by other drivers, or directly on your car's manual.
Last but not least, for a 1/8 (or 1/10) off-road buggy, the categories in which I have the most experience, make sure you stay within a range of grades of around 300 to 800.
If you need to use a thinner oil than 300cSt to get “lively” suspension dynamics, it's probably because your pistons have too much “pack”, i.e. too small a hole surface or hole diameters.
On the opposite, if you need to use an oil higher than 800 cSt, it's probably because your pistons don't have enough pack (holes too large in diameter or number of holes too large).
Convinced? Would you like to replace your various oils with XTR oil?
Take direct advantage of our “starter” pack with the essentials of the most commonly used oils in one batch at a great price!
See you soon for a new episode!
The Shark
Reno Savoya
