Hoosier R6 16 or 17" - performance differences?
06-23-2010, 02:10 AM
#16
Rennlist Member
These are not really noticle changes when you find the right pressures for the tires to work as they should. the gearing changes are less than rounding errors in the entire picture of things.
"effective gearing ratios"?? pleeeeezzz!! anyway, the point was made to the general fact that most of these tire changes end up with the same rolling diameter or near the same rolling diameter. this makes the real differece in the amount of sidewall to play with. My point also referenced actual racing exerience of bouncing back and forth with same manufacturer of tires on 17s vs 18s. (which it doesnt seem like you have done much of, but maybe Im wrong ) the pressure setttings were the main dominant variable here, not rolling diameter.
You are such a knuckel head!
-M
"effective gearing ratios"?? pleeeeezzz!! anyway, the point was made to the general fact that most of these tire changes end up with the same rolling diameter or near the same rolling diameter. this makes the real differece in the amount of sidewall to play with. My point also referenced actual racing exerience of bouncing back and forth with same manufacturer of tires on 17s vs 18s. (which it doesnt seem like you have done much of, but maybe Im wrong ) the pressure setttings were the main dominant variable here, not rolling diameter.
You are such a knuckel head!
-M
LOL...think about it. Different wheel diameters may change your effective gear ratios, which may change much of the car's behavior arouund the track. For him to claim "there will be no noticeable lap time difference" is just plain ignorant. That is what I was parodying.
Professional Racing and Driving Coach
Professional Racing and Driving Coach
06-23-2010, 02:24 AM
#17
Rennlist Member
VR, learn to COMPREHEND! you CAN run a tire the same diameter on a 17" rim or 16" rim.
225/50/16, 24.7" OD,
245/45/16, 24.7" OD,
225/45/17, 24.7" OD,
245/40/17, 24.5" OD,
So, this goes back to my original point for which you mock (and you know what they say about mock'ers). all things being equal. (which they are), the main differences are the sidewall and subtle contact patch areas. rain tires like to have lower pressures and more sidewall flex thats why I suggested the rains be the 16s and the 17s be the dry.
__________________
thank you . VR (AKA cement head) calls himself a coach, but sure doesnt think or act like one.
06-23-2010, 02:27 AM
#18
Rennlist Member
And you are ? 
Maybe you should join VR and me at Highplains Raceway for the "Pop-off" shoot off.
-M
Maybe you should join VR and me at Highplains Raceway for the "Pop-off" shoot off.
-M
I agree. However not sure about the "no performance differece" thing. You may not be good enough to see a difference, but the 17's should be faster in the dry if you can use it. It won't be that much, but the difference does exist.
This assumes you can match the same overall diameter in both 16 and 17 sizes.
This assumes you can match the same overall diameter in both 16 and 17 sizes.
06-23-2010, 03:45 AM
#19
Three Wheelin'
Thread Starter
S2's here (NZ) either run 235/40/17 and 255/40/17 on 17x9's or a square setup on 16's, either 225/25/16 or 225/45/16's. Results don't identify a clear winner but the square setup is certainly more economical as tyres can be rotated around the car to even out wear - fwiw
06-23-2010, 08:19 AM
#20
Rennlist Member
How can you know SO little about SO much?
Professional Racing and Driving Coach
06-23-2010, 08:20 AM
#21
Rennlist Member
Eric, you can fit much wider wheels/tyres under your stock body. You don't have to spend a fortune either. Not that you need to go overly large...but it's always worth having a spare set or two of both.
06-23-2010, 11:03 AM
#22
Rennlist Member
It is true that many 16" and 17" tires have essentially the same rolling diameter, and therefore no difference in the "effective gearing ratio."
Now, the 225/45/15 and 275/35/15 Hoosiers are another story entirely. They do have a significantly smaller rolling diameter.
But the original post did not ask about 15"s.
And I don't know anyone who still uses 16"s (at least not on a 911, except for rains).
06-24-2010, 10:57 AM
#23
Three Wheelin'
Thread Starter
So I presume you are implying that 17's are the minimum and 18's are becoming more common?
06-24-2010, 11:30 AM
#24
Rennlist Member
The tire size selection for 16"s is limited and not that good. You can get anything you want in a 17". 18" tires have a shorter sidewall but the wheel is heavier.
06-24-2010, 02:50 PM
#25
Rennlist Member
Oh brother.
Im sure he would be equally as fast on the 16s as the 15s.
Dave, you really needs to look in the mirror. For example, you know if Buckley is running the exact same diameters? you know if those laps he ran would be effected by the 15 or 16" rims? you know his set up? you know the guys he has beaten had equal or better cars? why dont YOU enlighten us and me on what those factors might be. You know that those factors (if any) apply to all cars? Could it be if that car needed more side wall flex, it might be faster, where another that didnt , it wouldnt? For an instructor class individual, it amazes me of the idiotic things you come up with. Too many factors Dave! get over yourself. you have NO idea what you are talking about.
Yes, as I stated in the beginning. with equal diameters, but different sized rims, the tires will perform very closely if the pressures are optimized for the set up. you could have an advange either way , but in for most rain set ups, personally, I would go for the larger sidewall, as most would, due to the fact that you CAN get more tread action and compliance in the wet. So, back on track for the post here, for rains I would use the larger sidewalls and for drys I would use the smaller sidwalls. EVEN, if Buckley has had good luck with tall sidewalls in some "club" events..
better invite him to our race off too!
Im sure he would be equally as fast on the 16s as the 15s.
Dave, you really needs to look in the mirror. For example, you know if Buckley is running the exact same diameters? you know if those laps he ran would be effected by the 15 or 16" rims? you know his set up? you know the guys he has beaten had equal or better cars? why dont YOU enlighten us and me on what those factors might be. You know that those factors (if any) apply to all cars? Could it be if that car needed more side wall flex, it might be faster, where another that didnt , it wouldnt? For an instructor class individual, it amazes me of the idiotic things you come up with. Too many factors Dave! get over yourself. you have NO idea what you are talking about.
Yes, as I stated in the beginning. with equal diameters, but different sized rims, the tires will perform very closely if the pressures are optimized for the set up. you could have an advange either way , but in for most rain set ups, personally, I would go for the larger sidewall, as most would, due to the fact that you CAN get more tread action and compliance in the wet. So, back on track for the post here, for rains I would use the larger sidewalls and for drys I would use the smaller sidwalls. EVEN, if Buckley has had good luck with tall sidewalls in some "club" events..
better invite him to our race off too!
06-24-2010, 02:57 PM
#26
Rennlist Member
The wheel can be heavier, but then the tire, which is heavier to begin comparitively vs the wheel, is now lighter, and because it is on the outer most diameter, its effects are much more pronounced.
again, the original point was which tires would be better for rains vs dry's, given the same set of rims, but one 1" smaller in diameter vs the others. the logical answer is what I gave. the 17s are more common, also have less sidewall and seem to work better in most cases than 16s in the dry for most common set ups. (sure one guy might have proved this wong for his set up)
16s have more sidewall and can give more tuneability in the wet by varying pressures . again, from experience, i was alble to do this with my 17 vs 18" comparisons on a race by race basis. I think the 18s were slightly faster, but very hard to nail down why. certainly , they were more sensitive to higher pressures causing handling problems than the 17s, and that could have been do to my set up, or a myriad of other interative factors.
mk
again, the original point was which tires would be better for rains vs dry's, given the same set of rims, but one 1" smaller in diameter vs the others. the logical answer is what I gave. the 17s are more common, also have less sidewall and seem to work better in most cases than 16s in the dry for most common set ups. (sure one guy might have proved this wong for his set up)
16s have more sidewall and can give more tuneability in the wet by varying pressures . again, from experience, i was alble to do this with my 17 vs 18" comparisons on a race by race basis. I think the 18s were slightly faster, but very hard to nail down why. certainly , they were more sensitive to higher pressures causing handling problems than the 17s, and that could have been do to my set up, or a myriad of other interative factors.
mk
06-24-2010, 03:00 PM
#27
Drifting
Mark, you are pointing valid and perfectly standard comparison basis objections. But I can tell you that you are wrong in saying that "Im sure he would be equally as fast on the 16s as the 15s". 275/35/15s in the rear of a 78-89 911 are like bringing a Gatling gun to a spoon fight.
I know because I went from 25.5 inch rolling diameter to 23.5 inch rolling diameter rear tires this season (when going to 15s). The difference is simply staggering, and that holds true on two very different types of tracks (LRP and WG) so far.
I know because I went from 25.5 inch rolling diameter to 23.5 inch rolling diameter rear tires this season (when going to 15s). The difference is simply staggering, and that holds true on two very different types of tracks (LRP and WG) so far.
Oh brother.
Im sure he would be equally as fast on the 16s as the 15s.
Dave, you really needs to look in the mirror. For example, you know if Buckley is running the exact same diameters? you know if those laps he ran would be effected by the 15 or 16" rims? you know his set up? you know the guys he has beaten had equal or better cars? why dont YOU enlighten us and me on what those factors might be. You know that those factors (if any) apply to all cars? Could it be if that car needed more side wall flex, it might be faster, where another that didnt , it wouldnt? For an instructor class individual, it amazes me of the idiotic things you come up with. Too many factors Dave! get over yourself. you have NO idea what you are talking about.
Yes, as I stated in the beginning. with equal diameters, but different sized rims, the tires will perform very closely if the pressures are optimized for the set up. you could have an advange either way , but in for most rain set ups, personally, I would go for the larger sidewall, as most would, due to the fact that you CAN get more tread action and compliance in the wet. So, back on track for the post here, for rains I would use the larger sidewalls and for drys I would use the smaller sidwalls. EVEN, if Buckley has had good luck with tall sidewalls in some "club" events..
better invite him to our race off too!
Im sure he would be equally as fast on the 16s as the 15s.
Dave, you really needs to look in the mirror. For example, you know if Buckley is running the exact same diameters? you know if those laps he ran would be effected by the 15 or 16" rims? you know his set up? you know the guys he has beaten had equal or better cars? why dont YOU enlighten us and me on what those factors might be. You know that those factors (if any) apply to all cars? Could it be if that car needed more side wall flex, it might be faster, where another that didnt , it wouldnt? For an instructor class individual, it amazes me of the idiotic things you come up with. Too many factors Dave! get over yourself. you have NO idea what you are talking about.
Yes, as I stated in the beginning. with equal diameters, but different sized rims, the tires will perform very closely if the pressures are optimized for the set up. you could have an advange either way , but in for most rain set ups, personally, I would go for the larger sidewall, as most would, due to the fact that you CAN get more tread action and compliance in the wet. So, back on track for the post here, for rains I would use the larger sidewalls and for drys I would use the smaller sidwalls. EVEN, if Buckley has had good luck with tall sidewalls in some "club" events..
better invite him to our race off too!
06-24-2010, 03:23 PM
#28
Rennlist Member
Mark, you are pointing valid and perfectly standard comparison basis objections. But I can tell you that you are wrong in saying that "Im sure he would be equally as fast on the 16s as the 15s". 275/35/15s in the rear of a 78-89 911 are like bringing a Gatling gun to a spoon fight.
I know because I went from 25.5 inch rolling diameter to 23.5 inch rolling diameter rear tires this season (when going to 15s). The difference is simply staggering, and that holds true on two very different types of tracks (LRP and WG) so far.
I know because I went from 25.5 inch rolling diameter to 23.5 inch rolling diameter rear tires this season (when going to 15s). The difference is simply staggering, and that holds true on two very different types of tracks (LRP and WG) so far.
How's that big cup of You Don't Know Jack taste, Mark?
Professional Racing and Driving Coach
06-24-2010, 03:44 PM
#29
Mr. Excitement
Rennlist Member
Rennlist Member
VR, I know you and Mark are brothers from different mothers and love to chide each other in a brotherly way. In an attempt to defend the indefensible Mark was discussing the performance of tires with the same rolling distance. Fred C posted (as usual) a reply that had some good info. This is a good habit to have.
06-24-2010, 03:49 PM
#30
Rennlist Member
VR, I know you and Mark are brothers from different mothers and love to chide each other in a brotherly way. In an attempt to defend the indefensible Mark was discussing the performance of tires with the same rolling distance. Fred C posted (as usual) a reply that had some good info. This is a good habit to have.
Im sure he would be equally as fast on the 16s as the 15s.
Dave, you really needs to look in the mirror. For example, you know if Buckley is running the exact same diameters? you know if those laps he ran would be effected by the 15 or 16" rims? you know his set up? you know the guys he has beaten had equal or better cars? why dont YOU enlighten us and me on what those factors might be. You know that those factors (if any) apply to all cars? Could it be if that car needed more side wall flex, it might be faster, where another that didnt , it wouldnt? For an instructor class individual, it amazes me of the idiotic things you come up with. Too many factors Dave! get over yourself. you have NO idea what you are talking about.
I made a fundamentally true claim, which Fred reinforced. And yes I know Jim's set up.
Fundamentally untrue claims have no place here.
Case closed.
Professional Racing and Driving Coach