Just wondering if I could get a rough comparison on the amount of time difference each tire makes.


So if you ran two (60 second on average) courses, 1 technical, the other fast with 3 sets of tires each, run flats, street tires(like a falken 615 or a kumho ecsta mx), and then r-compounds. Assuming the same driver and decent skill level, what kind of time differences would you expect to see between the tires?


I dont know if this question actually makes much sense as theres probably too many variables there, but just curious what kind of performance jump you might get with each tire?

 

I have run my Kumho V710's during timed runs and then my RT-215 Azenis during fun runs at a few events to see how much time difference there was between arguably the best autcross and street tires. Both are mounted on 16x6.5" wheels. The closest that I was able to get to my R compound time on the Azenis was about 1.5 seconds on a 45 second course.

I would guess that the Azenis are at least 1.5 seconds faster than a runflat on a 45 second course.

 

At the last autocross event i was at in South Bend Tire Rack, I was on my stock wheel configuration-S-Lites and Pirelli Euphoria Runflats. Other cars competing in GS were a Celica on Hoosiers, an SVT focus on Kumhos, and a VW GTI on a relatively high performance non-runflat tire. Others were a G6 and some volvo that really didnt matter what tires they were on. But the point is, i finished above all the cars except the celica, which had 2 drivers. The time gaps were as follows:

me from 1st place: 30.35 seconds-hes really good, and won the index times for the day

me from 2nd place: 1.108 seconds-not as good but he beat me

4th place guy from me: 1.345 seconds-decent gap-yay me

The tires make a huge difference, had i been on lighter wheels and hoosiers i would have been right up there with that first place guy. But overall i hear there is a big difference between runflats and the azenis.

 

on a pretty funny note that i just realized, i accidentally signed up for the novice class that day. i had done 2 events before that one so i figured that it may be good to do so. I was completely wrong. I totally demolished the novices that i feel bad. It was not good of me to do that, but it was kinda funny now that i look at it. To link this post with the topic, il lsay that maybe some of the newbs had performance tires, but all in all, driver makes the biggest difference.

 

Well, as you know, it depend on the course design. Lots of sweepers will accentuate the difference between R compounds and good street tires. On a course that is a mix, we've found about 1.5 seconds between the best Rs and the Falkens, over about 45 seconds. Cruddy street tires go down from there...3-4 seconds would be a rough estimate for the runflats.

Per

 

Hmm i dont know if the guys im running with now want to hear that. Currently running on Cruddy street tires. not as bad as runflats but damn close. I'm currently running about .5-1 second off the best R-compound guys. Im going to be switching (for now) from some Nexus Z rated tires with a treadwear rating of 320 to a set of the Hankook Ventus Rs2 Z212for the next run or 2. Then to a set of the Nitto NT01's for next year.

 

Well last year i ran 5 events here in Minnesota, on the stock run flats. Well by about the 3rd or 4th event i started running hard enough that the tires would not hold at all it seemed. Of course i am driving moms MCS so i it took awhile before i could talk her into buying new tires. This year i have been running good street tires not great but good. I feel i am running much faster and smoother. I would say between the two tires i am running easy 3 - 5 seconds faster. So runflats are not fun to run in at all, i hope next year i will be running Rs.

 

I'd say on your average 50 second course. Your all very close to what I've been seeing. A Celica that trophied last year at nationals was 1.5 seconds faster than me at the last event of the year. I was on Azenis and he was on V710's. Our lines we're pretty darn close. I did notice when I was on my S-Lites w/ run-flats (Summer Performance version, not the even crappier All-Seasons), he was consistantly 6-7 seconds (sometimes more) faster than me with his R-compounds at the same site with very similar course setup.

 

Times of runs vary with driver skill almost as much as which tire is used- especially if you don't have that much experience.

The more skillful the driver the greater the difference the tires can make.

As a new driver, one will make the most gains just driving better and smoother. If you are many seconds behind the leader in your class then tires are not your only concern.

If you are closing the gap to the leader then for a 60 second course-

Runflats- not so good traction but wears pretty good and doesn't cost any extra, good way to wear them out so you can replace them- index time 60 seconds.

Street tires- there are alot of tires that fall into this category and they are quite different. On the one hand are basic all season tires which are fine for the street but not so fine for autocross like Toyo Proxes 4. Then there are good performance street tires like Bridgestone Potenza S-03 or Goodyear Eagle F1 GS-D3 but these do cost more. Then there are autocross/street tires like Hankook Z212 or Falken 615s which are about as good as street tires can get but don't wear as long as other street tires.
Index time is about 1.5-2 seconds faster than runflats.

R-compounds- give the best performance and fastest times from 2 to 3 seconds faster than street tires. Comes in limited sizes compared to street tires. Wears fast and can't be run on the street much or even not at all if you care to save them for the track. High cost given they don't last much more than one full season if that much.

Something to keep in mind- you have to consider tire size and what rim size will work. For G-stock you have only two rim sizes. If you are working with an X-lyte 16x6.5" rim then you have lots of choices but if you have a 17x7" rim then that limits the R-compounds you can use.

Also worth considering- what are the potential weather conditions? Any rain? If so then R-compounds are not so good for the rain unless you have Kumho ecsta V700s with full tread. Most competition tires are not suitable for standing water- even a little. When wet the street tires are best. I have seen Kumho Victoracers nearly full tread do well in rain or dry.

As an example of driver skill being a big factor, I have driven in autocross using R-compounds and posted a reasonably fast time- say within 2 seconds of the leader in the class. Then later in the day I'd switch to street tires (Bridgestone S-03s) and complete the run just as faster or faster even with a passenger, just because I'd already done the course earlier.