Bartman Posted February 29, 2008 Share Posted February 29, 2008 I GURANTEE that a 315 on a 10 will hook better than a 275 on a 10, plain and simple, Can you really guarantee this? I'm really curious, because I've read that you can get better traction by running tires recommended for your rim width then by running a wider tire that is recommended for a wider rim. Read post #8 in this thread regarding testing of different tire widths. http://forums.hybridz.org/showthread.php?t=112952 Quote Link to comment Share on other sites More sharing options...
Guest 280ZForce Posted February 29, 2008 Share Posted February 29, 2008 Can you really guarantee this? I'm really curious, because I've read that you can get better traction by running tires recommended for your rim width then by running a wider tire that is recommended for a wider rim. I agree, because say for example like w/ 1 fast z setup, you run a tire wider than recommended, that can and most likely will cause the tire to bubble or hump over the contact surface, so then your traction is mostly in the middle of the tire and only wearing down the middle, vs full tire contact patch and even wearing. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted February 29, 2008 Share Posted February 29, 2008 I am looking at the shot from the rear, is that an optical illusion or is there about an inch of tire not touching on the outside due to camber? I had redone my suspension and dialed the camber in, I saw a big increase in traction when using the entire tire width. I would especially think this would be the case in a z. Just trying to offer some constructive help. Evan Quote Link to comment Share on other sites More sharing options...
Bartman Posted February 29, 2008 Share Posted February 29, 2008 I am looking at the shot from the rear, is that an optical illusion or is there about an inch of tire not touching on the outside due to camber? Looking at this picture: It definitely looks like quite a bit of the outer part of the tire is not in contact with the pavement. Look at the shadow. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 29, 2008 Share Posted February 29, 2008 Looking at this picture: It definitely looks like quite a bit of the outer part of the tire is not in contact with the pavement. Look at the shadow. I don't know about the safety issue, and to be honest I kind of doubt there really is one. What shoving a big tire on a narrow rim does is give really sloppy handling, and as the picture above shows it pinches the tire in so tight that the edges sometimes don't touch the ground as Bartman says. I know I had that problem running a 250 on an 8, and the lower profile the tire is the worse contact patch you get when you put a wide tire on a narrow rim. I wanted to run that tire on a 10" rim, but could never afford the rims. For a 315, I'd use a 12, as 315/25.4= 12.4, assuming the width is what the tire manufacturer says it is. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted March 1, 2008 Administrators Share Posted March 1, 2008 For a 315, I'd use a 12, as 315/25.4= 12.4, assuming the width is what the tire manufacturer says it is. I have no opinion as to that tires performance on a 12, but I can say with some confidence that it was built for 11. The popular wheel width for BSP C4's was (and still largely is) 11. That specific tire was built for a specific market/application... Will it work better on 12? I couldn't even guess. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 1, 2008 Share Posted March 1, 2008 Coffey did some testing in this regard and found that he got the best lap times with a tire .5 inches narrower than the rim as I recall. He also quoted Hoosier as saying the same. So I'm guessing he'd say put it on a 13" rim. That's a road racing or autox recommendation, not drag racing, but I think the idea that the rim should be at least as wide as the tire tread is legitimate. A related thread: http://forums.hybridz.org/showthread.php?t=129535 I think that this car would really put the power down better with more sidewall, but the current style dictates that sidewalls are ugly. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted March 1, 2008 Administrators Share Posted March 1, 2008 I think that this car would really put the power down better with more sidewall, but the current style dictates that sidewalls are ugly. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 1, 2008 Author Share Posted March 1, 2008 Let me say it again. I BOUGHT 800.00 dollar tires for 260.00, they are good tires, they work good, and they were cheap and brand new, why go further for now? Sure I can run a 12" wheel, not a prob, maybe in the future. Actually that picture is deciving, I will take another pic to show that it is all the way on the ground, and I have my camber plates pushed all the way in. It is a 2.5 deg neg camber, and will be set at 1 neg for the street. Quote Link to comment Share on other sites More sharing options...
Clifton Posted March 1, 2008 Share Posted March 1, 2008 It's turned into another one of those threads. Grassroots Motorsport mag did a tire test with 285's on a 18x8. Look up what they recommend for that tire, it's far from an 8". They chose that size and wheel because it works in the solo class they run in even though they can run a narrower tire they don't because it works. They did test one 245 and that brands 285 wouldn't mount it was so wide. Quote Link to comment Share on other sites More sharing options...
BillZ260 Posted March 1, 2008 Share Posted March 1, 2008 They look cool, and kind of bring the 2 + 2 look together, Now, can you please post some video of you doing some doughnuts or something and then we can get back to the traction discussion... Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted March 1, 2008 Share Posted March 1, 2008 Many drag wheels are quite a bit narrower than the tread on the tire. This is most likely largly due to the low tire pressures the drag cars use, to get the tire to have more contact patch with the track surface than it would at higher pressure. As the tire spins into higher RPM (aka the car is traveling faster), the tire grows (well all tires do this to a point), and the contact patch becomes narrower and shorter. With the narrower rim, the tire to grow a bit more than it would on a wider rim, increasing the circumfrence to gain MPH and hopefully a lower ET. The smaller contact patch also reduces rolling resistance. Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted March 1, 2008 Share Posted March 1, 2008 With the torque/HP this puts out, It will never have the traction problem fixed no matter what, with only 2wd. The tires are almost flush with the side of the wheel, there not to wide for them. Hmm.. well Zgad seems to have no traction problems with 275 MT's I think around a 1.35 or so 60-ft.. I think if you actually heat these tires up you will be able to get some traction on a track.. on a crappy street might be another story.. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted March 1, 2008 Share Posted March 1, 2008 Wheels/ tires look great With a 17 inch rim, it will be hard to make anything hook well. There just isn't enough give in the sidewall (it's too short)... so we do what we can with what we have... Quote Link to comment Share on other sites More sharing options...
mannyvig Posted March 1, 2008 Share Posted March 1, 2008 Exactly for the price those rims and tires were there is no going wrong. They look great and I am pretty sure they will hook better than the previous combo. If I was given the opportunity to buy the tires that cheap I would be trying everything I could to get them on my 8.5" rim. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 1, 2008 Share Posted March 1, 2008 I think maybe there are two different subjects going on in this thread. One is talking about how to get the most from a given tire, and the other is trying to put as much tire under the car as is possible with a limited rim width. Again, I ran an 10" slick on an 8" rim and it worked. It didn't kind of work, it worked. The downside was that the tires were really floppy feeling in corners. I think that tire would have performed BETTER on a properly sized rim. I do think there is a limit to forcing a tire onto a narrow rim. 285's on an 8, unless its a narrow 285 or a wide 8 seems really retarded to me, unless its a cantilevered sidewall. But I'm sure the idea in that case was that the class rules limited that car to an 8, so they were trying to get the most tire they could under the car. As to whether a 285 or a 315 would perform better on this 10" rim, I'd guess that the 285 would, especially given the small aspect ratio of the tires in question. To counter the Grassroots Motorsports story, Tom Holt was running an 11" tire on his 10" rims, and then changed back to the narrower 9.5" tire because it handled transitions better (I searched and couldn't find the thread where he said so). I don't think there are any limitations on rim widths here, so I'd put the tire on the correct width rim. If you got the tires cheap and just wanted to stick them on that's fine, that's why I did what I did. When you go to buy a full price set of tires, you'll get the most from the tire if you get one that fits the rim correctly. If you want bigger tires, start saving for bigger rims (and flares). Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted March 4, 2008 Share Posted March 4, 2008 I feel that he's doing just fine for what he has. He got that set of wheels new for $550 shipped. Plus he got the tires cheap! The wheel company only makes a 10" wide rim in that model. He's just doing the best he can with what is affordable. I think he is doing a great job at that. Justin Quote Link to comment Share on other sites More sharing options...
evildky Posted March 5, 2008 Share Posted March 5, 2008 If you are breaking tires loose with 305 ft/lbs, it's the compound. Try something softer ( R compound). mine are r compounds, the issue becomes more power than the weight can keep on the ground, a 2105 lb car can only hold so much power to the ground, I'm going V6 to move the COG back and hope for a little more traction, also I run lots of camber which is great for turns but not for straight line traction Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 6, 2008 Share Posted March 6, 2008 Please correct me if I'm wrong.. but it seems that having a wider tire and a narrower rim will give you an excellent launch and straight line performance. while having narrower tires and wider rims reacts better in the turns for road racing.. soo from what i'm understanding.. Wide tires/Narrow rims = drag car Narrow tires/Wide rims = road race Is that about right?! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 6, 2008 Share Posted March 6, 2008 soo from what i'm understanding.. Wide tires/Narrow rims = drag car Narrow tires/Wide rims = road race Is that about right?! I don't think that is a safe assumption. I think the rim width needs to be correct so that the tread lays flat on the ground to get the best launch for drag racing. I think larger diameter tires (not wheels) will hook up better and more sidewall should also be better. I was informed today that I was doing my math wrong. I was using the number on the tire as though it were the tread width, but it isn't. It's the section width, which can vary pretty significantly from the tread width. So the best way to pick a tire is to measure it or find a website that has measured it for tread width and then go based on that. Here's more backup for bigger isn't always better: http://www.hoosiertire.com/faqrr.htm 4. What rim width should I use for my application? The answer depends on which type of tire you are using. For our radial tires a good rule of thumb is to take the tread width dimension (+-) 1/2 inch. This will put you in the optimum range for the tire. The tire will mount on a wheel outside of this range, however performance and wear may be negatively affected. If you find that your vehicle, or the rules, will not allow a wide enough wheel for the tire you think you would like, consider using a narrower tire. In most cases a properly sized wheel/tire combination will outperform a wider tire on a wheel that is too narrow. If you are looking at our DOT bias racing tires the tolerance is a bit broader. For our DOT bias line we publish a "measured rim" or "design rim" dimension. This dimension simply indicates the width of the wheel the tire was mounted on when the other listed dimensions are recorded. Bias ply tires are more tolerant of a range of wheel sizes. Typically, the listed rim dimension is a good starting point. The wider tires can range (+-) an inch without noticeable change in performance. A narrow (less than 6" wide) tire will tolerate (+-) 1/2 inch. This would also apply to the Historic product line in our tire specs. In the Road Racing section of our product line the racing slicks are typically designed for specific applications where the wheel width is controlled. The tire is designed to perform at its best on the wheel listed in the "design rim" or "recommended rim" column. Once again, there is a tolerance for this dimension. The tire will mount on a different sized rim but, may exhibit unusual wear or stability outside of the recommended rim. This is particularly important on "cantilevered" tires. This is a specific type of construction used in racing classes which have very narrow wheel restrictions. The design of the tire allows the usable tread to far exceed the width of the wheel. These tires should ONLY be mounted on the rim sizes indicated in the specs. I couldn't find anything in the drag racing section of their website that says anything about proper sizing. I did also find this page on the BFG website which recommends 11-12 inch rims for the 315s, so the tread width and section width must be pretty close: http://www.bfgoodrichtires.com/specs/g-force-r1/3824.html Quote Link to comment Share on other sites More sharing options...
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