GeeTeeFiveOh
Member
Love your build man I hope I'll be there someday
ReplicaR's Mustang build *finally on track again*
- Thread starter ReplicaR
- Start date
ditto... est 2006
I prefer not to think about money spent when there is so much left to spend 
So, fenders were pulled and rolled yesterday. Since there was a lot of space to make up, the guy who pulled them also had to unbolt them and slide them as far apart as possible. I've test mounted an old NT-01 on the Enkei wheel to make sure that we are at least close to where we need to be. No pictures yet, but I will post some tomorrow, because I want to tweak the right fender some more.
Another thing I found out is that my original R58 Cobra R wheel is 22 lbs. It's not as heavy as I though it was, my original estimate being 24.5 lbs, but it's still 5 lbs heavier than the 17 lbs Enkei. I also found out that one of the wheels is cracked at the main hoop, which is very strange because it was not losing pressure. I was planning on using them as street wheels, but I guess that plan is out of the window now. Anyway pictures and more info tomorrow.
Another thing I found out is that my original R58 Cobra R wheel is 22 lbs. It's not as heavy as I though it was, my original estimate being 24.5 lbs, but it's still 5 lbs heavier than the 17 lbs Enkei. I also found out that one of the wheels is cracked at the main hoop, which is very strange because it was not losing pressure. I was planning on using them as street wheels, but I guess that plan is out of the window now. Anyway pictures and more info tomorrow.
Cool man, glad to hear of the forward progress. My wheels (18x8.5) weigh 24.5 ea for comparison.
How much difference is the contact patch for 17x9 vs 17x10 on the 275 NT01? I'm limited to wheel option for my class but the GM nerds can run 17x9.5 which is a standard wheel for them. We run the Toyo RA1, but I'm curious what the extra 1" actualy does for you.
The RPFs are badass wheels, and the weight is unbeatable for the size. Very popular wheel for guys who turn. They are too light for my class, our popular wheels are the MB competition wheels, cheap/light/strong.
The RPFs are badass wheels, and the weight is unbeatable for the size. Very popular wheel for guys who turn. They are too light for my class, our popular wheels are the MB competition wheels, cheap/light/strong.
Rich, the answer to your question is below.
I have taken some pictures of the pulled fenders and mounted the wheel for another test fit. Fenders were pulled about an inch so it left me covering exactly the same amount as it did with the Cobra R wheels I had (smaller offset, 1 inch narrower) Here are some pictures of how the wheel fits on the car at ride height.
Now, onto the difference between the wheels themselves. Obvious difference is the weight. Original Japanese made Cobra R is tipping the scale at 22 lbs, while RPF1 being one inch wider is actually 5 lbs lighter at 17 lbs.
The way the tire sits on the wheel is different as well. Talking to a few of my friends who do time attack, and most tire experts, they are all convinced that your contact patch has be just a little bit smaller than the width of the actual wheel to get the most out of the tire, and make it more responsive under fast corners. You can really see that a 9 inch wheel is not an optimal choice for a 275 R comp from pictures below.
You can see in the picture that the sidewall on the 9 inch wheel is bulging quite a bit, while on a 10 inch wheel same tire sits perfectly flat. Note another thing from the picture below, how the contact patch looks like. The closer wheel is the 9 inch one. You can just tell by the contour of the surface, that it's bowing out, curves around the edges. The contact patch on the 10 inch wheel by contrast is a lot flatter, and might actually be able to put more tire on the ground. I know that some will say, oh but the tire is not under load. That is true that the tire will flatten out under the load and create the necessary contact patch, but it will not bring down the edges which are still rolling over due to sidewall being deflected.
I have taken some pictures of the pulled fenders and mounted the wheel for another test fit. Fenders were pulled about an inch so it left me covering exactly the same amount as it did with the Cobra R wheels I had (smaller offset, 1 inch narrower) Here are some pictures of how the wheel fits on the car at ride height.
Now, onto the difference between the wheels themselves. Obvious difference is the weight. Original Japanese made Cobra R is tipping the scale at 22 lbs, while RPF1 being one inch wider is actually 5 lbs lighter at 17 lbs.
The way the tire sits on the wheel is different as well. Talking to a few of my friends who do time attack, and most tire experts, they are all convinced that your contact patch has be just a little bit smaller than the width of the actual wheel to get the most out of the tire, and make it more responsive under fast corners. You can really see that a 9 inch wheel is not an optimal choice for a 275 R comp from pictures below.
You can see in the picture that the sidewall on the 9 inch wheel is bulging quite a bit, while on a 10 inch wheel same tire sits perfectly flat. Note another thing from the picture below, how the contact patch looks like. The closer wheel is the 9 inch one. You can just tell by the contour of the surface, that it's bowing out, curves around the edges. The contact patch on the 10 inch wheel by contrast is a lot flatter, and might actually be able to put more tire on the ground. I know that some will say, oh but the tire is not under load. That is true that the tire will flatten out under the load and create the necessary contact patch, but it will not bring down the edges which are still rolling over due to sidewall being deflected.
g36 monkey
Post Whore
Sweet! Love the tech in this thread!
+1 great answer Dmitry!!
JoshHooten
Well-Known Member
I love the fact that someone uses the car for both the Track and the street. so many people have just a track car.
Thanks Dmitry. It makes sense, and should be better when you stretch the tire and have less of a 'donut'. I read a while back that on the RA1 the 255 size tire on a 9" wheel is within .3" of a 275 on a 9" wheel. Which is almost nothing, but over .5" on the front and back. I think the weight is more important myself. Lighter wheel and tire is definitely an advantage, and if you can get more contact, it should be much less of a slip angle and should be advantageous.
Tough to do. But once a cage goes in, IMO street driving is out.
Tough to do. But once a cage goes in, IMO street driving is out.
Slykin
Well-Known Member
Legit.
This won't be a dual purpose car for much longer, if I have anything to do with it. Having a car that does both is not a win win, it's a lose lose. I can't optimize it for the track, because it has to be comfortable enough to drive daily, and I can't get good gas mileage and comfort either, because... well... it's a mustang. Gonna get a daily driver, and park this thing til weekends.
Brian95SVT
Legend
Badass ReplicaR. Do you only run 17s? I have some compound road racing tires with 1 pass on them that need a new home but they are 18s
greenscobie86
Well-Known Member
Looking REAL good. Would love a ride in this thing if I'm ever in Cali.
Well, street pads are almost done. Last time I got some, I was in a hurry and I bought Hawk Ceramics. I was not going to do the same mistake twice. This time I bought Hawk HPS. Will be installing this weekend, after I resurface a different set of rotors. Not really an update, more of a bump
