I’m wondering how often I need new tires for club racing with a KA100 on MG Reds. How many heat cycles can you put them through before a serious drop in performance, and how long can you store them after the first heat cycle before they drop off?
Reds will fall off in performance long before they run out of tread, and basically every session there will be some degradation, but the fall off isn’t huge. For club racing, I would probably run them 3-5 weekends before changing to new tires, depending on wear and how competitive you want to be.
Sometimes a little drop off is not a bad thing. As the grip level drops you can make adjustments to the setup to account for it. Also, as they drop off, you may be a little less stuck off the corners. Not so great in the tight stuff, but very beneficial in fast corners.
If you are chasing tenths and in the hunt for wins new rubber might help. However, at our track in the same class, I don’t see huge gains or losses with new or old rubber. I have done a season (12 races) on one set but typically I plan on 2 sets a season. You likely would only see a noticeable drop off when the wear dots are gone or almost gone. When you say “store” that could be a separate concern. Tires sitting around I have found can be worse than heat cycles. So, tires that are seasons old are usually not good.
I have to swap out my Reds every 5 races or so in the summer, but I can get 6-7 races in the winter months. (Lo206)
For a KA-100 I’m sure you’d burn threw them alot faster. So I’d default to what TJ suggested.
Dean, aren’t you on Vega reds? If so, we’re talking 180 degrees difference in tires.
I think one reason for how often these threads pop up is the vagueness of the answers. Is a “race” a “race” or a “race weekend”. How many sessions - practice, qual, heat, race? Five weekends of three sessions is a lot fewer cycles than five weekends of six sessions.
My point is that, if the bottom line is how many heat cycles the tire can sustain, why not just directly use that number? If a race weekend is 4 heat cycles, say you change your tire after 20 cycles, and will remove a lot of the ambiguity.
Calab, this is a well intended idea, but even in the term heat cycle there are many variables. In my case a “race” is a 15 lap event, however, for practice, I will usually do about half as many laps. We also run a 5min qualifier which again is about 6 or 7 laps. Now true these are heat cycles but as far as wear, running 15 laps uses more rubber than a 6 lap qualifier. So I don’t think this would remove much ambiguity and might even add some.
With the MG Red, specifically, these discussions always have the senior members saying wear is far less important than cycles. So, in general, you are probably right, I’m limiting my statement to just the MG Red
Edit: more generally, you do address my biggest concern. It is much more helpful to describe what your weekend is like when you say the tire lasts five weekends. Without the description you provided, there’s next to nothing I can draw from it
Dang you right, disregard.
My experience: use as you wish.
The very first heat cycle on reds has a performance advantage like most tires. Typically worth about 0.1-0.2 sec/lap. From heat cycles 2-5/6 the performance is very consistent and then drops off progressively from there. By about HC10 you’re going to see a significant drop in time compared to new, but it can be hard to feel from the seat of the pants.
Lighter karts tend to be able to get more HC out of the tires before performance falls off. Also higher HC MGs will still perform outright decent times, but take many laps to get there in practice. I think that shows their performance deficit is worse in colder temps so if you’re in the summer months or just practicing you can try to stretch their life that way.
If you’re at the front of a competitive field and everyone brings new tires to each race, then you’ll be forced to do so in order to qualify well. If you’re willing to give up that advantage, then you could use 1-race old rubber and know that the performance evens out in the races.
In order to minimize HCs on your race tires, use a seperate set of wheels and tires for warmups. That way if you run qualifying, pre-final, final that’s only 3 HCs and you can better stretch that to 2 race weekends of 6 competitive HCs.
My typical use is to put 3 HC on new tires for a race, then those tires are used for testing and warmup for the next race, after that they’re used for practice until useless. Next race will start the cycle (pun intended) all over.
Once to temp a heat cycle is a heat cycle for most purposes. A heat cycle draws oils out of the rubber - as important if not more important than how much rubber crumbs off.
My experience with the MG Red is very similar to @Kutschca - heat cycle 1 is significantly better than the rest so if you are running for Pole in a competitive field new is a necessity. HC2 degrades and HC3 does as well just a bit more. From HC4-8 they are just a hair off of HC3 but just start to get dull to tuning. From HC9 until you are tired of trying to make gains with them they are just fine. You can throw every tuning trick at them and really not make any difference, good or bad. Just a good practice tire at that point to turn laps, but not to learn much in regard to tuning.
At somewhere like Trackhouse I’d move that competitive window to be a lot larger - not a terribly technical track so the falloff is less of an issue. At somewhere like MCCC or Badger with a lot of technical sections and less flat out, the falloff is probably more noticeable.
okay then…Would this also include storage? If tires are stored in a container or trailer that could get quite warm on a sunny summer day.
If they can get hot enough to operating temp, then absolutely. I have seen many tires “dry up” in storage with tons of useful rubber left on them.
I’ve never wrapped my tires in plastic wrap after races, but always advocate removing from the kart and keeping in a temperature controlled space and away from UV light. I would also avoid freezing temperatures at all costs when considering trailer storage.
I’ve seen more drop off from leaving tires unwrapped between races than from heat cycles, so I always wrap tires after events. I forgot to wrap tires between events once last year and the kart looked terrible, we were probably 4 tenths off where we should have been. As soon as I put on a set I had wrapped, the kart looked fine and the time came back.
This. I have some severely damaged Bridgestone somewhere I can post a pic of. That said, we took them straight from frozen to a burnout on the ice out front
So if I have a set of stickers for a race day, should I use another set of older tires for the opening practice session so that I use get those one or tenths in qualifying? Or do you find it’s more important to get some laps on them to get used to track conditions, the increased grip, and get them “scrubbed in”?