Hi my fellow drivers,
On my last practice day i was doing data collection for my upcoming race next week. However, i struggled to get tire temp into the tires (it was chilly, but not super cold), and you can see from my log that even after 13 laps my outer edge of tires are still not firing up, especially on the right side.
I checked with my mechanic and found out he forgot to dial in the alignment for this track (lower speed twisty) from my last race (high speed corners), so i am suspecting i am running not enough caster and too much negative camber. (waiting for him to get back and confirm)
i am wondering, since my right side tire temps are so low, is it a good idea to run different camber setup for the fronts? for example, more positive camber on the right side compared to left side? forecast says it is very cold on race week so i am trying to stay ahead of the track conditions. (i always thought running more positive camber for qualifying would help get more heat into the tires quicker, but TJ’s video says otherwise)
also, what is a more ideal solution of getting the rear temps up? since we don’t get to do alignment on the rear. would changes that gets more side dig (ie, raise rear heigh) work? (i prefer not to raise the seat as its a fundamental change), or would i also be getting more rear temp generated from adding caster / positive camber?
tire pressure logic: at first i tried to lower the cold tire pressure, thinking it would help soften the tires side wall and let the tires dig into the gravel more to get more temp on the outer edge, but apparently i was wrong, it was harder to drive with less grip. should i bump them further up?
Thanks for the love! much appreciated!
If you’re looking to work the tire harder, raising pressures will accomplish that in most scenarios, especially when ambient/track temps are low.
I’ve been to certain circuits where the wear pattern across the front tires is vastly different. Similar to your case here, one tire was really “under-utilizing” the outside edge, but really this was the nature of the circuit, and that tire was always going to wear that way. Getting to my point here, even with the above example, I’m generally setting up the front end symmetrically.
From there I would step back and ask what are you trying to accomplish and solve for with this data? It sounds like the data may be able to help inform your setup changes, but I would first base your changes off of what the kart is doing (or not doing) on track and go from there. Data of this sort is something I would use to validate my results, and not necessarily inform my changes.
As a general rule, you raise pressure to increase grip. So you might want to try that as an option.
The higher pressure stiffens the sidewall, reduces the contact patch, and increase heat input into the tire contact patch. There is a point at which continuing to increase tire pressures can result in such a small contact patch that you overwork and overheat the smaller area and begin to lose grip.
As for the temperature balance across the tires, it looks like you were running on a track with more right turns, or a couple higher load rights?
Left Front → 4.5 PSI gain
Left Rear → 3.8 PSI gain
Right Front → 3.6 PSI gain
Right Rear → 3.5 PSI gain
Instead of running unbalanced chassis setup, start with unbalanced tires pressures with a goal of having all 4 corners close to the same temp and pressure at end of a run. So use the end of run pressure differences to figure out what the start of run splits need to be. From this data set you have, I would start with the LF 1 psi less than the RR and RF and the LR at 0.5 psi less than the RR.
Raise all 4 corners by 1-2 psi until you notice a change in overall grip, then start tuning in half and tenths PSI increments. After each run look at tire pressures and apply that split to your next run adjustments.
You need to make each run the same length and check hot tire temps and hot pressures at the same time or the data will be skewed. It is also good to try to keep breaks between sessions about the same.
Once you find a hot working pressure that gives you the grip you want, you can let everything cool and document the cold tire pressures. Now you have a cold tire pressure settings and warm tire pressure targets for that ambient condition.