TXE36

I generally believed this as well until last weekend. Very busy with work and time was tight. NT-01s on the car were fairly worn in the front and mildly worn in the back. Fearing I'd cord the fronts, I threw a pair of unmounted sticker NT-01s in the back of the truck.

As luck would have it, I corded the fronts after lunch. Ran the corded tires and rims plus the stickers up to Discount Tire to have them mounted. Short on time and wanting to get the last run in, I just put the new ones on the front. Car was very sketchy for the first few laps - seemed like it had a lot of grip up front - too much. Wrote it off to warmed up tires in the back, cold tires in the front, and perhaps suboptimal pressures

The following morning, got to the track late and tried to run the first session with the same configuration - bad idea. I did have time to set the cold tire pressures properly. Within two turns of the green fist was out the window getting the car back to the garage. Ridiculous amount of oversteer. Swapped the tires front and back, and Bad Girl was herself again until I corded the fronts (formerly rears) late Sunday afternoon.

As a dryly humored friend commented, "Newer is always better".

-Mike

DTMiller

I had a very similar experience with RA1s today -- was hoping they'd be great as they are really getting worn but they were just rock hard. Switched to the much fresher backup set and having grip was pretty refreshing.

rlm328

Any tire company you query will always recommend that you put the new tires in back.

From Tirerack

When tires are replaced in pairs in situations like these, the new tires should always be installed on the rear axle and the partially worn tires moved to the front.

Alexandrius

probably more of a liability thing than a performance thing.

understeer for normal bro drivers isn't a big deal. Oversteer and they kill people.

Martin S.

When the rears are shot, I replace the entire set...Nittos are about $1,000 a set and are good for 20+ heat cycles. Sometimes it hurts to replace front tires that appear to be good for more, but I feel better. With the staggered sizes on the 993 car, and some others, we can't put the rears on the front...they won't fit.

Thundermoose

Same here. I run square set up. However when the first one cords I replace them all. They are all at end of life by that point for all intents and purposes.

Mike - I can't help but ask what would you say to one of your students if you saw a set of nearly dead tires on the rear and a set of stickers on the front of one of their cars.

Olemiss540

Don't you mean - what would you say to one of your fellow instructors if you saw a set of nearly dead tires and stickers on the front?

What an experienced and advanced instructor level driver does and what a beginner level INSTRUCTED level driver does are two very different scenarios. Mike should have the benifit of the doubt to be able to handle the variation in grip from having more worn tires on one axle. This isn't a Bugatti, and it's not like he ran unpinned coolant lines or something of blatant disregard to others safety!!

Thundermoose

What's with the double exclamation point?

I am sure Mike is able to manage oversteer and understeer. My question to him and now to you is what would you say to a student with same set-up? That's all.

surlynkid

No - I am pretty sure ThunderMoose said what he meant. I gave Mike the fuzzy eyeball when I saw the new ones on the rear and corded on the front, but he can do whatever he wants. He won't be chasing a PB like that.

Olemiss540

Great point. Maybe he should have stuck with a full set of brand new Hoosiers if seeking a PB was the goal. I bring two sets to every HPDE as lap times are all that are important in this hobby.

TXE36

I thought it was worth running the experiment. In my experience, even well worn NT-01s are decent tires and what better way to find out for sure that to put new ones up front with old ones at the back? Proved it very conclusively. If a beginner student tried doing this, I'd have him fix it. If an advanced student tried this, I'd ask them what they were trying to accomplish. If that explanation was similar to what I was trying, I'd say let's be cautious and go for it. No need for anybody to get their panties in a wad - I was careful and knew what I was doing.

What is still a curiosity for me is I've never set a PB on a full sticker set of NT-01s, it is almost always on a nearly fully worn set. This experiment tells me the reason isn't necessarily grip, but perhaps something else.

As I've stated on other threads, I have no interest in improving laptimes by going to better rubber. I know I'd be under two minutes on Z214s given that I've run a 2:01.00 on worn NT-01s (Z214s are generally good for a second and a half at TWS, same driver, same car), but that's not the point. VR, in this car, on NT-01s has run a 1:56 and change. Thus, there is no reason to upgrade the tires beyond NT-01s until I'm down around those times. I'm not made of money and I'm not racing and I'm only competing with myself.

And Surly, I never when out on corded tires and I came in early when they did cord during the long 50 minute session. Not sure how that deserves a fuzzy eyeball.

-Mike

Thundermoose

C'mon man. I think you are carrying this too far. Maybe I should've been more direct and just went ahead and made my point. Running mismatched tires is risky regardless of driving level experience and as an instructor you do set the example for your students.

Mike stated his intent was to experiment and I think that's fair.

Peace?

surlynkid

I never said you went out on corded tires. I was just trying to figure out what was going on while we talked as you were loading up. It deserved a fuzzy eyeball until you explained what you were doing. At near end of life, my Nittos are too cycled out. I seem to find the quickest times with them somewhere around mid-life.

TXE36

IMHO, that is a bit oversimplified. I would add

• Average lap times.
• Consistency.
• Level of drama.
• Ability to run different lines.
• Passing and being passed with minimal impact to both cars.
• Level of situation awareness.
• Ability to avoid mistakes with cars in mirror.
• If instructing, progressing as an instructor/coach.

and there are others. PBs are a nice simple way of measuring performance, but they are not the only metric. There is a whole lotta' stuff going on out there.



-Mike

Slakker

NT01s are great to the cords. Only getting 20 heat cylces is ridiculous. I had a set of rears that came free with some wheels I bought. The cross tread was gone but there was still a little of the two main grooves left. I was running a M030 suspension on that car for the first time so I put them on with another pair of front NT01s that were barely used to get used to the new setup. I brought along a fresh set of Hoosiers to swap to once I was comfortable pushing the limits.

I then proceeded to put 17 sessions on the NT01s and never bothered with the Hoosiers. The car felt awesome. You could trailbrake for days with it and just about the time the back end was about to whip around, I just squeezed down the accelerator and it would "catch" and rocket out. This was the same car that I took to the track on Pilot Super Sports (stock suspension) last time and spun 2 out of 3 sessions with almost no warning.

And I like Mike's list. I usually pick one car control skill and one driving skill I want to improve each session on focus on those two things.