What is the effect of wider wheels and tires on the S4s track handling and 1/4 times - e.g. 275/35/19. I would think that the extra unsprung weight would adversely affect bump and rebound, but the wider contact area would help in corning. Taller tire would mean that 1/4 times should go down due to final gearing change. I was curious to see if there was any correlation in the top posted 1/4 times and wheel/tire combos.
a shorter tire height will help you acclerate faster and should lower times. but since the top speed in each gear will decrease it may force you to make an additional shift negating that beit.
for tire width consider the weight of the tire and where that mass is positioned. changes in tire weight will be very impactful. Now that said, I recall the weight of similar tires not changing a ton with width, more so with diameter, so the effect may not be huge.
I never got a good 1/4 test between lw wheels and stock wheels, but my B6 S4 did show a 5-6% increase in acceleration in 3rd gear pulls when switching from a stock wheel with 245/40/18 tire to a lw wheel with 235/40/17 tire. Weight on the stock setup was about 55lbs per corner, lw setup was 37.5lbs per corner
You wouldn’t want 275.35…thats massive. It’s going to be 1.4 cm taller than stock
You would want 275.30.19 which is I believe 1/2" shorter than stock.
Should help you launch it if you’re spinning… But will provide resistance sown the track. I don’t think it’s huge but I am guessing
275.30.19 will only really work if you’re lowered. You’re adding 1/4" of wheel to fender gap. Could look monster truckish .
I think I am going to end up with one set of wheels/tires for daily aggressive street and freeway driving and another set for the strip. The stock setup I have now is 255/35/19 on 19x8.5. Michelin PSS 275/35s are 0.6 cm taller than the 255/35s. I am a little concerned about running 30s and damaging the rim, plus a harsher ride. The drag time table does not list tire size, so I was hoping to get some weigh in from those with top times.
This will not answer the OP’s specific question, but here is a relevant article from C&D a few years ago that tested different tire/wheel sizes on a 2.5L Golf slushbox.
http://www.caranddriver.com/features/effects-of-upsized-wheels-and-tires-tested
You can see the effect that weight has on acceleration, and the effect that width has on handling/braking. An interesting additional effect was the combined weight/rolling resistance effect on fuel economy.
Another interesting article. I’m still thinking about this one…
http://farm4.staticflickr.com/3763/9001791418_84580d3c19_c.jpg
http://farm4.staticflickr.com/3762/9001791984_0092a783e6_c.jpg
Alot of good stuff already covered… In regards to the S4, I think the car can be controlled via air pressure with pretty much any width tire… I run 245’s and don’t have trouble with spinning, I run 245’s for the weight savings… If this were RWD then it would be much different discussion… You want to run as much air pressure as possible w/o spinning and minimize the contact patch for less rolling resistance, however if you spin you can lower the pressure and create a wider contact patch and not spin… It takes practice, knowing the conditions and your car… I learn everytime I hit the strip… Most important thing is to remember what you did and it’s impact… That way you do or don’t do it again… Just my .02
In my personal experience, tire outside diameter does indeed affect my 1/4 mile time and trap speed. I ran 265/30 19s, and even though they were very cheap tires (heavier but yet softer sidewall), I was running consistent 12.08, 12.06 and my best 12.05@117mph. Most runs were 116mph and higher. Keep in mind I have a 2011, 6MT.
When I went back to the track, with similar weather conditions, but using my other wheel/tire combo (255/35 19) with a better tire, Bridgestone Potenza S-04s, a lighter, stiffer sidewall tire with much better grip, I lost about .3 time and 2mph average. I can’t speak for the weight of either combo, although to me they felt about the same.
I will repeat that these are my personal findings, yours may or may not differ…
Adrian
There’s also a torque multiplier effect of running a smaller circumference tire
Saki, could you expand on that please?
You can consider the wheel to just be another gear in the drivetrain. Smaller gears multiply the torque more.
I am weighing my options between 225 vs 235 for my b5. Have always ran 225 (8.5 wheel width). Thinking of switching to 235. More contact patch to hook up but adding a pound or 2 to each corner. Also remember discussion here about directional (v-pattern) vs block nonsym tread patterns (directional thought to be better for the strip). Of course the directional option I’m looking at are 2 pounds heavier than the other nonsym options I like. Which very likely rules them out.
So, stick with 225 (lighter) or bump up to 235? My hunch is 225? Or, will it help to have a bit wider contact patch?
Sorry, just read above to minimize contact patch as much as allowed without over spinning…combined with decreased rolling diam = best option.
From my research, S-04’s (and Bridgestone in general) are on the heavy side, ~3+ lbs more than like for like size compared to other manufacturers offerings. Assume mainly due to stiff sidewalls and the materials used to achieve. Great tires but better for twists n turns rather drag strip courage…
And to add one more variable to the mix…245/35/18 is slightly less overall rolling diam than even the 225/40. Would this be counteracted by the 245 being too wide a contact patch?
Either way I will be shedding about 10lbs at each corner vs current setup
Sorry to continue posting and asking this, but I would like to know what the general consensus here is of the following options;
225/40/18
235/40/18
245/35/18
Thanks in advance