i know besides looks, upping the wheel size on your car can add performance to your car such as cornering speed, so in gt 3 you couldnt make a 17 inch rim up to an 18 or 19, can you do that in gt 4? because i have gt3 and lets say i get a new body style celica, i can change the rim but wouldnt it look great up make the wheel 1 or 2 inches bigger. plus are the ai cars in gt4 gonna be better and smarter or is it gonna be like pinball going through corners again to gain position?
Wheel Size And Ai Questions
- Thread starter smoove7
- 36 comments
- 1,371 views
- 7,889
- SolidFro
- RRoDzaaah!
By 'performance' you mean 'grip', that's what you meant, right? 
Increasing the wheel size does not improve performance. It improves grip (traction), because it has a larger contact patch. Even if you could increase wheel size in GT4, you'll have to be a pretty sensitive driver to notice any difference at all.
Hopefully, the AI will be greatly improved on. You'll have to ask PD themselves if you want a definite answer.
Increasing the wheel size does not improve performance. It improves grip (traction), because it has a larger contact patch. Even if you could increase wheel size in GT4, you'll have to be a pretty sensitive driver to notice any difference at all.
Hopefully, the AI will be greatly improved on. You'll have to ask PD themselves if you want a definite answer.
- 2,665
I think he's referring what we discussed in the rims thread about lighter wheels offering less resistance to acceleration, larger ones leading to a higher top speed, but I'm not sure.
See if this thread has any answeres: https://www.gtplanet.net/forum/t-43665.html
See if this thread has any answeres: https://www.gtplanet.net/forum/t-43665.html
Bigger alloys/tyres can provide more grip, as does fatter tyres. However, bigger wheels can affect steering and as they are heavier, they slow down acceleration. To minimise the acceleration slow-down, you can increase the size of the alloy, as long as the tyre is the same size as the factory spec.
Smaller tyres can offer better acceleration, due to smaller circumference and less weight. Only downside is that traction is reduced.
Whether you can change rims or not in GT4 - I've no idea.
Smaller tyres can offer better acceleration, due to smaller circumference and less weight. Only downside is that traction is reduced.
Whether you can change rims or not in GT4 - I've no idea.
Performance includes grip, not just acceleration. So his question was accurate, no need for the eye rolling.
I read somewhere last year, I can't remember but seemed like a good source, that GT4 will implement different wheel sizes and that it would affect the performance this time, unlike GT3.
I read somewhere last year, I can't remember but seemed like a good source, that GT4 will implement different wheel sizes and that it would affect the performance this time, unlike GT3.
Bigger wheels (larger diameter) don't actually provide more grip. You don't get a larger contact patch. The rolling diameter of the tyre is the same so given the same tyre pressure you will have the same contact patch. The lower profile tyre will however provide more control as there is less sidewall flex.
Even a wider tyre will in fact only provide the same contact patch if the tyre pressure is kept the same. You still have the same weight pushing down on the tyre. The shape of the contact patch will change however which can have complicated effects.
Even a wider tyre will in fact only provide the same contact patch if the tyre pressure is kept the same. You still have the same weight pushing down on the tyre. The shape of the contact patch will change however which can have complicated effects.
Think of a circle on a bit of paper. It would only touch a line it was sitting on at one point. If you put weight on it the bottom of the circle would squish and more of it would be touching the line.
Now imagine that circle was a cylinder. Assume a 1cm thick cylinder would need 1kg of weight to deform enough so it had a 1cm wide contact patch. A 1cmx1cm wide contact patch. Now if a 2cm thick cylinder had 1kg of weight it would only have a 0.5cm wide contact patch. A 2cm x 0.5cm contact patch. Think about it, or search the internet and I'm sure you'll find a much better explanation.
- 1,264
The diameter of a wheel and tire have very little, if anything, to do with the contact patch. Lower profile tires have a firmer sidewall, which improves feel and response, but not contact patch. Width of the tire, not aspect, determines contact.
205/55-16 and 205/35-19
Those are two totally different size of wheels and aspect of tire. But, because the overall diameter of the tire didn't change, nor did the width, the contact patch is the same.
205/55-16 and 245/35-18
Those are two tires that are the same overall diameter, but with a much wider width on the 245. That tire would have a greater contact patch. If that were not the case, having huge 315s or 335s on the back of a Viper or Vette would be pointless. But, it is the case. The wider the tire, the more tire is on the road, and thus the more power that can be effectively put down with it.
Hilg
205/55-16 and 205/35-19
Those are two totally different size of wheels and aspect of tire. But, because the overall diameter of the tire didn't change, nor did the width, the contact patch is the same.
205/55-16 and 245/35-18
Those are two tires that are the same overall diameter, but with a much wider width on the 245. That tire would have a greater contact patch. If that were not the case, having huge 315s or 335s on the back of a Viper or Vette would be pointless. But, it is the case. The wider the tire, the more tire is on the road, and thus the more power that can be effectively put down with it.
Hilg
Like I said, try doing some research on the internet using reputable sources.
"Increasing the width of the tyre will not necessarily increase the contact patch as the weight of the car is the same. "
http://www.whiteline.com.au/default.asp?page=/faqtyres01.htm
"Increasing the width of the tyre will not necessarily increase the contact patch as the weight of the car is the same. "
http://www.whiteline.com.au/default.asp?page=/faqtyres01.htm
- 3,165
- yeti_c
The "Contact Patch" also increases/decreases with speed and turning... I.e. the patch will get smaller as you get faster (Unless your car has some nice spoilers/splitters) as you brake the front tyres will increase their patch and the rears will decrease... as the weight/pressure goes forward.
As you turn the contact patches will go to the side on the outside of the turn as you load up those tyres...
Therefore I would have thought that having a wider tyre will handle better when in the turns (As the increase in pressure/weight will add to the contact patch) because they have the ability to have more of a contact patch than smaller tyres.
C.
As you turn the contact patches will go to the side on the outside of the turn as you load up those tyres...
Therefore I would have thought that having a wider tyre will handle better when in the turns (As the increase in pressure/weight will add to the contact patch) because they have the ability to have more of a contact patch than smaller tyres.
C.
- 2,665
...I have to admit to being baffled by the logic of a wider tyre not having a larger contact patch.
ASCII diagram time! Fill in the spaces.
[] - Tyre 1, 8" wide.
[ ] - Tyre 2, 12" wide.
The point of contact will be on the bottom of the tyre correct. Assuming everything else remains the same, the weight, instead of
[] 8 inches being in contact you would have
[ ] 12 inches in contact, width wise.
Now, whilst rambling that I may have stumbled across the logic - do you guys mean that increasing the width of the tyre will also change the weight distribution so the weight pressing down on the 12" tyre will be spread across a larger surface, leading to less contact longitudinally?
ASCII diagram time! Fill in the spaces.
[] - Tyre 1, 8" wide.
[ ] - Tyre 2, 12" wide.
The point of contact will be on the bottom of the tyre correct. Assuming everything else remains the same, the weight, instead of
[] 8 inches being in contact you would have
[ ] 12 inches in contact, width wise.
Now, whilst rambling that I may have stumbled across the logic - do you guys mean that increasing the width of the tyre will also change the weight distribution so the weight pressing down on the 12" tyre will be spread across a larger surface, leading to less contact longitudinally?
- 1,264
I think I understand the reasoning for what you guys are saying, but it just doesn't add up in my book. The link you provided didn't help either. In my example, I talked about a 205 and a 245 wide tire. You're saying that both will effectivly have the same contact patch once on the car???? That just doesn't make sense. Like I also suggested, if wider didn't equal more tire contact, why would almost every high performance car have wide tires??? I mean, if it doesn't matter, they could just use 225s and save some $$$$, right??? Again, maybe I'm just missing your point, but as of right now, I'm not buyin it. 
Hilg
Hilg
a 225 tire and a 275 tire have the same size contact patch, for a given car weight & tire pressure. Its the shape that changes.
Exagerated:
225 contact patch:
<--225->
######
######
######
######
275 contact patch
<---275---->
########
########
########
as it gets wider, the tire compresses less under the weight.
the shape of the contact patch detirmines how much grip it provides, (as well as the tire compound.) One reason for a wider tire is that the tire will deform less while its rolling.
Exagerated:
225 contact patch:
<--225->
######
######
######
######
275 contact patch
<---275---->
########
########
########
as it gets wider, the tire compresses less under the weight.
the shape of the contact patch detirmines how much grip it provides, (as well as the tire compound.) One reason for a wider tire is that the tire will deform less while its rolling.
- 1,264
Again, I see the reasoning, but it just doesn't add up. Using your diagrams, for the tire to have less front to rear contact, the outside diameter of the tire would have to change. If the outside diameter is the same, the front to back contact area doesn't change. If you look at the extremes of what you just showed, you'll see what I mean. I'll use your style to illustrate.....
125 contact patch
<-125->
##
##
##
##
##
##
##
##
375 contact patch
<-------375-------->
###########
###########
Now, those are obviously exagerated examples, but you see what I'm trying to say. For your theory to be true, a narrow 125 tire would end up with like 1/4 of the outter tread area touching. That just wouldn't happen, unless the tire was totally devoid of air, and even then I'm not sure you'd have that much. Again, those are extreme examples, but you see what I'm saying. If the outter diameter of the tire does not change, the front to rear contact area doesn't either. If you lay a round pencil on a table, it touches with X ammount of surface area. The more you use the pencil and the shorter it gets, the less surface area is left touching the table. Again, I see what your trying to say, but I just don't think its correct.
Hilg
it doesn't make sense at first, but thats the way it is... assuming the tires are at equal pressure.
If you took tires off your bike, inflated them to 35 PSI, and put them on your car, they would compress down to the wheel rim. Its the reason why space-saver spare tires have to be inflated to 60psi. If you took your tiny little 145mm wide space saver spare tire, inflated it to the same 35psi that your normal 245mm tires were at, the skinny little tire would compress to the point that it looked flat.
Your pencil analogy doesn't work because it is a solid object. Imagine, instead, a blob of wet clay.. If you flatten the blob of clay into a pancake, and put it on its side, the edge that is contacting the table will compress upward, until you have X surface area touching the table. Now, take a blob of clay that is the same shape, but 10" thick, and put it on its side, it will barely compress at all.
I guarantee you the way I drew it above is correct. It is explained in many resources from general physics, to racing-specific publications.
If you took tires off your bike, inflated them to 35 PSI, and put them on your car, they would compress down to the wheel rim. Its the reason why space-saver spare tires have to be inflated to 60psi. If you took your tiny little 145mm wide space saver spare tire, inflated it to the same 35psi that your normal 245mm tires were at, the skinny little tire would compress to the point that it looked flat.
Your pencil analogy doesn't work because it is a solid object. Imagine, instead, a blob of wet clay.. If you flatten the blob of clay into a pancake, and put it on its side, the edge that is contacting the table will compress upward, until you have X surface area touching the table. Now, take a blob of clay that is the same shape, but 10" thick, and put it on its side, it will barely compress at all.
I guarantee you the way I drew it above is correct. It is explained in many resources from general physics, to racing-specific publications.
- 1,264
I see what your saying, but it just doesn't add up for me. Why, then, do many sports cars have very wide tires in the rear for their drive wheels??? According to what your saying, they could have a much narrower tire, of the same compound, and have the same ammount of grip. If that were the case, I'm sure many cars would have that, because narrow tires are much better for aero reasons. I'm just trying to figure this out, I hope you don't think I'm being a dick 
Hilg
Hilg
- 29,915
- Cuddington, Cheshire
- JDA1982
I don't see the compression of a 225 tyre giving almost an extra 25% of area in the contact patch. It seems far too much, but the idea is there the tyre walls compress and add to the contact patch. As for wider tyre's they do allow a better heat dissipaion and because there is less flexing or the tyre wall's the tyre's durability is improved or something along thoes lines.
- 2,665
Greyout's diagram illustrated the point I eventually managed to find, though it took some doing on my behalf.
Often you'll find that the tyre sizes are regulated, don't forget that.
I'm just guessing here but I'd say that the lateral stability and resistance to centrifugal force would be better with a wider tyre too.
Often you'll find that the tyre sizes are regulated, don't forget that.
I'm just guessing here but I'd say that the lateral stability and resistance to centrifugal force would be better with a wider tyre too.
- 26,262
- Houston, Texas, USA
- JMarine25
I think you have to have wheels big enough to grip the road no matter what you drive, then light enough so that you won't sacrifice handling. Other than that, I have no other contributions to the subject because I am inexperienced.
But I'm baffled. You entitled this thread "Wheel Size and AI QUESTIONS." What questions do you have on AI? Do a search, there's been quite a lot of discussion from me and others on GTP. So if you have a seperate question, what would you want to know on what GT4's AI will be like?
But I'm baffled. You entitled this thread "Wheel Size and AI QUESTIONS." What questions do you have on AI? Do a search, there's been quite a lot of discussion from me and others on GTP. So if you have a seperate question, what would you want to know on what GT4's AI will be like?
Well I for one would like to know if GT4's AI is going to be as woeful as GTP's?
I mean I got the game, put it in, changed my settings to professional steering, all driving aids off and Pro AI, then raced my first ever race on each of the three tracks where you have opposition. Opposition, ha. I won them all by miles, without even knowing the tracks. That is just shameful. On Pro AI setting I'd hope to need near perfect laps on every lap in order to win, at LEAST Silver license level standards. I really was dissappointed
I mean I got the game, put it in, changed my settings to professional steering, all driving aids off and Pro AI, then raced my first ever race on each of the three tracks where you have opposition. Opposition, ha. I won them all by miles, without even knowing the tracks. That is just shameful. On Pro AI setting I'd hope to need near perfect laps on every lap in order to win, at LEAST Silver license level standards. I really was dissappointed
- 4
Originally posted by JNasty4G63
I see what your saying, but it just doesn't add up for me. Why, then, do many sports cars have very wide tires in the rear for their drive wheels??? According to what your saying, they could have a much narrower tire, of the same compound, and have the same ammount of grip. If that were the case, I'm sure many cars would have that, because narrow tires are much better for aero reasons. I'm just trying to figure this out, I hope you don't think I'm being a dick
Hilg
The wider tire won't deform as much as a narrower tire will during cornering.
True. This is why you see the tires expand so much on a top fuel dragster.
