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    1. #1
      Join Date
      Apr 2011
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      29
      Country Flag: United States

      Which tire size, 335 or 295?

      Trying to decide which tire size is better for the rear of my 71 Challenger, 335 30 18, or 295 35 18. Both will fit without a tub, and they are both around 26" tall. Is the extra weight of the 335 worth the extra width?

      The car will be used for 75% street/highway/road trips, and 25% road race course on open track days.
      Power is 600hp/603tq at the motor. Front tire will be 275 35 18.

      Also, I was thinking about using 275 40 17 on all four corners for the racing. Any thoughts?



    2. #2
      Join Date
      Sep 2006
      Location
      Henderson,NV
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      2,870
      Country Flag: United States
      I'd recommend the 335 or maybe a 315mm due to your power. Look at a ZR1, Z06, or Viper. You will need to tune your chassis to find the sweet spot with this set up.
      Todd

    3. #3
      Join Date
      Aug 2006
      Location
      austin
      Posts
      358
      I can't believe this is an issue. Bigger is ALWAYS better. And too much is just right

      Vipers have had 335s since 1992 with 400hp/400tq. They used 275s up front but now use 295s for the ACR.
      Greg
      1976 Trans Am SacrilEdge
      twin turbo 455
      Ttops and 4spd
      one of 110 made
      https://www.pro-touring.com/showthre...ect&highlight=
      https://www.pro-touring.com/showthre...ilEdge-is-free!

    4. #4
      Join Date
      Apr 2011
      Posts
      29
      Country Flag: United States
      Thanks guys,

      So when does the weight become a problem? Anybody running 335 35 18 on the road course? I'm just looking to find out if the extra unsprung weight of this wheel/tire combo affects acceleration, braking, control, and lap times, or if the extra footprint counters all those aspects.

    5. #5
      Join Date
      Jul 2006
      Location
      Orangevale, Ca
      Posts
      147
      Country Flag: United States

      Which tire size? 335 or 295?

      I think the 335 contact patch will be your friend with 600hp on tap.
      Bret Ervin

    6. #6
      Join Date
      Sep 2010
      Location
      Minneapolis, MN
      Posts
      19
      You are talking about over an inch and a half of extra contact patch. There is no question the 335 is the way to go. I have experience going from 8 to 10 inch rubber on stock cars and the performance difference was incredible. Wuih 600hp you want all the help you can get coming off the corners hard, The unsprung weight difference is not even noticeable. The braking consideration is a good thought, but I doubt you will see a significant difference. I assume you have disc brakes in the rear.

    7. #7
      Join Date
      Mar 2006
      Location
      Lowell, MI
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      397
      Country Flag: United States
      I went from a 295 to a 335 in the back of mine an noticed a huge increase in grip...and that's with only 450ft/lbs of torque.

      Turbo Charged LS1/T56

    8. #8
      Join Date
      Nov 2005
      Location
      Auburn, WA
      Posts
      1,360
      For your power level the larger tire would help forward grip, but the car will pretty much always understeer pretty bad due to the lack of front grip. You'll have to use the throttle quite a bit to feel neutral (which takes skill). I see lots of PT guys run a huge mismatch in tire sizes (due to the "bigger is better" mentality for the rear tires) and their cars always plow like a Deere. I have 275mm up front with 295mm in back and it's nicely balanced. To run a 335 in the back you really ought to use a 295 or 305 in the front...of course this all can depend on your suspension, roll rates, blah blah...
      Last edited by silver69camaro; 05-03-2012 at 08:49 AM.
      Matt Jones
      Mechanical Engineer
      Art Morrison Enterprises

    9. #9
      Join Date
      Nov 2005
      Posts
      827
      ^^^ The signature at the bottom of Matt's reply heavily backs up his advice and is something most guys trying to get 300+mm rubber rarely consider. Another thing to consider is that no supercars have come with that size tire in nearly 20 years so tire selection is limited. Pretty much 2 or 3 street tires and a few track day tires. And even with the straight line traction argument, it's going to be extremely difficult to hook that kind of hp in a straight line with that kind of tire unless you go drag radial.
      Jason

    10. #10
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      Sep 2006
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      Henderson,NV
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      I agree that the more front tire you can put on a muscle car the better. However, I don't agree with it having to push like a dump truck with a 275mm. Many modern sports cars have come with a similar stagger and I think you can find a reasonable chassis balance. You will ultimately need to make the rear of the car work less efficiently to loosen it up to find that neutral balance. With all this being said, I run a 295mm on the front of my car. ha ha In this case, bigger is better.
      Todd

    11. #11
      Join Date
      Nov 2005
      Location
      Auburn, WA
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      1,360
      Quote Originally Posted by Vegas69 View Post
      You will ultimately need to make the rear of the car work less efficiently to loosen it up to find that neutral balance.
      Exactly. So what's the point? To make the 335 tire work, you'll have to stiffen the roll and possibly ride rates which will make the car less street friendly. Sticking a larger rear bar in there will help the balance, but that's going to cause other problems too. And like Jason said, no street tire out there today will make good use out of 600HP without complex traction management systems. The front/rear size ratio used in the PT world would make sense on a supercar with 60% rear weight, but not for front engine cars with 55% on the nose.

      335s make a lot of road noise, too. Anyway, it can be made to work, but to use one just because it's the biggest you can get doesn't make it a smart choice.
      Last edited by silver69camaro; 05-03-2012 at 01:39 PM. Reason: Added Info
      Matt Jones
      Mechanical Engineer
      Art Morrison Enterprises

    12. #12
      Join Date
      Sep 2006
      Location
      Henderson,NV
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      Quote Originally Posted by silver69camaro View Post
      Exactly. So what's the point? To make the 335 tire work, you'll have to stiffen the roll and possibly ride rates which will make the car less street friendly. Sticking a larger rear bar in there will help the balance, but that's going to cause other problems too. And like Jason said, no street tire out there today will make good use out of 600HP without complex traction management systems. The front/rear size ratio used in the PT world would make sense on a supercar with 60% rear weight, but not for front engine cars with 55% on the nose.

      335s make a lot of road noise, too. Anyway, it can be made to work, but to use one just because it's the biggest you can get doesn't make it a smart choice.
      My car is 52/48 with a big block. Forward bite is the only real reason for the bigger tire. My car hooks pretty good from 2nd on up with 666/641 flywheel. You can certainly make a smaller tire handle just as well.(within reason) I don't think the increase in spring rate to loosen the car will effect ride that much. I went up 100 lbs in the back and it barely changed the ride. I agree, a more square car is going to be easier to tune for handling with more compliance.

      Steilow sure make a 325/275 combo work well!
      Todd

    13. #13
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      Nov 2005
      Location
      Auburn, WA
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      Quote Originally Posted by Vegas69 View Post
      Steilow sure make a 325/275 combo work well!
      Of course, it can be done. But did he go with a 275 because that was the optimum size for the front? No way. The front was dictated by packaging, and the rear was determined by power level. Then he adjusted roll rates to make them work, he can do that. Not everybody here can. Point being, way too many people here go with a 335 because they see everybody else do it and don't know any better. It will ride worse, make more noise, and be more difficult to tune and nobody here has mentioned that in this thread.

      Off topic, How did you manage a 52% up front with a BBC? Mine is 52% with an aluminum LS and a front sub that is 50lbs lighter than stock.
      Matt Jones
      Mechanical Engineer
      Art Morrison Enterprises

    14. #14
      Join Date
      Aug 2006
      Location
      austin
      Posts
      358
      JR,
      The 2002 Viper is only 10 years old, not 20. No traction management there. The 600hp 2010 Viper has no traction management either. The ACR is frequently one of the fastest "stock" cars on the track. Of course, these cars are only meant for real drivers that don't need no stinkin' traction control like the GT-R or Vette boys need. If you're not sliding then you're not going fast enough!
      The 2013 Viper only got traction control because of federal laws. Shame on you, US Gov't, for ruining such a pure sports car!

      Matt,
      Lamborghini makes a 335 work with a 245 on the front. I'm not saying its best, but you need rubber to stick to the road, and you put the rubber where you can! If this wasn't the real world, then nobody would make adjustable sway bars.

      A 335 ride worse? Matt, you are such a WUSS. I've got three vehicles with 335s on them, and the 275-295 fronts make the car ride worse than the 335s on the rear. Those large front tires follow every groove in the road! Remember that if you want to stuff a 305-30 under the front end.

      A 335 makes more road noise LOL! ROFL! I can't hear the road over my engines!

      RAW,
      put those darn 335s on the back and the 275s up front. Maybe even a 345-19 if you want a more modern size. The viper has used that same combo since 2003. Put a BIG adjustable bar on the back (NOT one designed for vehicles with equal footing) and a moderate bar up front, and go to the track and sort it out. That is what test and tune days are for.

      Do NOT change up your tire sizes when you go to the track. You don't want a balanced car on the track and an understeering dog on the street ( or how about a balanced street car and a drifting monster for the track?)

      For an all around tire check out Kumho XS, Toyo R888. Decent price but will wear out in 10K miles or so. If you don't put too many miles on your car then this may be a good way to go. The michelin pilot SS is a great street tire, but pricey and a little harder than I like. I run the michelin pilot sport cups myself, which I think is the ultimate. I put 3-4K miles a year on each car so my cups last a couple of years if I don't slide them on the track at 100+mph. This photo is me on PS2s though.








      I don't have a mechanical engineers degree (I got out after a couple years), but I speak from experience not book learning.
      Greg
      1976 Trans Am SacrilEdge
      twin turbo 455
      Ttops and 4spd
      one of 110 made
      https://www.pro-touring.com/showthre...ect&highlight=
      https://www.pro-touring.com/showthre...ilEdge-is-free!

    15. #15
      Join Date
      Nov 2005
      Location
      Auburn, WA
      Posts
      1,360
      Greg,
      Lambo's are rear engine. That's why they have huge rear tire bias, which is typical for the engine layout.

      Guys, here's where I come from:
      At Art Morrison, many of our customers drive high end European cars that ride like a dream yet handle superbly on the track. They come to us because they want their '55 Chev, '67 Camaro, or whatever else do the same thing. The PT industry focuses so much on handling, that people don't realize you can balance road manners and high grip at the same time, it doesn't have to be one or the other. We (and others) have the ability to blend the two, much like a M3 does. Lets face it, the majority of members here are not pro drivers, or rarely drive the on track at all. ALL of the novice drivers would be able to drive the pants off of a M3 but would be several seconds slower in their modified Camaro (or whatever) even though it has more tire and power. My job is to design a suspension system (which includes tires) that will allow anybody to hop in and turn some fast times, which is what makes BMWs so satisfying. Then, if you want, you could drive the car cross country in comfort. My own car turns over 1g on the skid pad on street tires with a 275/295 combo, which is more than most cars can do with a 335 - and the the best riding car I've been in so far.

      Let me say it again: You could make a car handle well with a 335, I never said it couldn't. Don't just slap the things on there and expect to have perfect handling dynamics, I can say with confidence that it wont. I just want people to look beyond the size before they make a choice. I know I'm in the minority here on this subject.

      Yes, I'm obsessed with the details. I look hard at bushing durometers, TLLTD figures, motion ratios, ride frequencies, NVH, etc. because my focus is to get these cars to be like the Euro sports cars. Not just in handling, but the whole package.
      Matt Jones
      Mechanical Engineer
      Art Morrison Enterprises

    16. #16
      Join Date
      Oct 2011
      Posts
      95
      Country Flag: United States
      Tire width is not the only factor, I would think the tire compound is where you find the grip, larger is not always better - but it sure looks good.

    17. #17
      Join Date
      Apr 2011
      Posts
      29
      Country Flag: United States
      Quote Originally Posted by silver69camaro View Post
      Greg,
      Lambo's are rear engine. That's why they have huge rear tire bias, which is typical for the engine layout.

      Guys, here's where I come from:
      At Art Morrison, many of our customers drive high end European cars that ride like a dream yet handle superbly on the track. They come to us because they want their '55 Chev, '67 Camaro, or whatever else do the same thing. The PT industry focuses so much on handling, that people don't realize you can balance road manners and high grip at the same time, it doesn't have to be one or the other. We (and others) have the ability to blend the two, much like a M3 does. Lets face it, the majority of members here are not pro drivers, or rarely drive the on track at all. ALL of the novice drivers would be able to drive the pants off of a M3 but would be several seconds slower in their modified Camaro (or whatever) even though it has more tire and power. My job is to design a suspension system (which includes tires) that will allow anybody to hop in and turn some fast times, which is what makes BMWs so satisfying. Then, if you want, you could drive the car cross country in comfort. My own car turns over 1g on the skid pad on street tires with a 275/295 combo, which is more than most cars can do with a 335 - and the the best riding car I've been in so far.

      Let me say it again: You could make a car handle well with a 335, I never said it couldn't. Don't just slap the things on there and expect to have perfect handling dynamics, I can say with confidence that it wont. I just want people to look beyond the size before they make a choice. I know I'm in the minority here on this subject.

      Yes, I'm obsessed with the details. I look hard at bushing durometers, TLLTD figures, motion ratios, ride frequencies, NVH, etc. because my focus is to get these cars to be like the Euro sports cars. Not just in handling, but the whole package.

      Matt,

      First off, what is roll rate? Can you explain more about this?
      Second, what are the things you did to your Camaro to get it to ride well, and have tons of grip? That's what I'm going for on my car, so even if you are the minority on here, I want to hear what you have to say. Give me details.

      275s on the front is probably the max I can go. And even that is pushing it. I'm probably going to have to notch the frame rail, possibly upper control arm, and roll the fender lip, but the handling and ride height is worth it to me.

      Say I did go with the 335 out back, are you saying I'd have to go with a lower spring rate to make it work, or what? How could it be better to go with less tire and greater spring rates? Wouldn't the ride suffer more like that? Please be specific as I'm trying to learn as much as possible.

    18. #18
      Join Date
      Aug 2006
      Location
      austin
      Posts
      358
      Springs are there to support your car. You want them to be stiff enough to prevent your car from bottoming out on the track at the ride height that you track the car. If your car is bottoming out and hitting the bump stops, then you have effectively tripled or quadrupled your spring rate, which is not good. You want to stay off the bumpstops.
      Generally speaking, the less suspension travel and the heavier the load, the more spring rate you need. This has nothing to do with the size of tire on your vehicle. Other issues may effect spring rate. For instance, when Dodge put the LeMans wing on the viper, they increased the rate of the rear springs from 800lbin to 1100lbin to prevent the rear from hitting the bumpstops at high speeds. The wing added 300 lbs of downforce at 100-150mph (not sure exactly where) so they compensated with stiffer spring.

      Roll bars are used for tuning oversteer/understeer. You can tune with tire sizes also, but generally the more tire you put under your vehicle the better.
      Greg
      1976 Trans Am SacrilEdge
      twin turbo 455
      Ttops and 4spd
      one of 110 made
      https://www.pro-touring.com/showthre...ect&highlight=
      https://www.pro-touring.com/showthre...ilEdge-is-free!

    19. #19
      Join Date
      Jun 2001
      Location
      Orlando, FL
      Posts
      10,603
      Country Flag: United States
      I'd go with the 295s or maybe a 315, but the 335 is too big with a 275 front tire. 30mm as a max difference is a good rule of thumb -- more tire is better only when you're talking about all 4. As a couple others have said, a big mismatch in tire size with too much tire in the back will cause the car to push -- and that's no fun on the track.

      Suspension and the ability to tune matters a lot. If you can't resist the urge for the bigger rear tires, you'll be needing to tune the suspension. What are your plans for the rear suspension?

      Listen to Mr. Jones. He knows what he's talking about (and agrees with me, which is even better).
      John Parsons

      UnRivaled Rides -- Modern upgrades for your ride.

      UnRivaled Rides recent project -- LS9-powered 69 Camaro

    20. #20
      Join Date
      Nov 2004
      Posts
      6
      I just went from 275s in the rear and 245's in the back to 315's in the rear and 275's up front on my 2010 Camaro. I can tell you that it's made a huge difference tracking wise, the car feels much more stable staying where you point it and in a straight line especially on the freeway. This has been my (and my girlfriends) biggest peeve with the car. It always has felt like you had to do a lot of correction just to keep it straight on the freeway, so bad in fact that my girlfriend doesn't even really like driving it. I'm gonna do some other things to help with the handling but I'm definitely glad I did that so far. Oh and I was able to fit these sizes by taking the front wheel which was an 8 inch wheel and getting it widened to 10.8 inches wide, and putting the rear wheel which is 9 inches up front.

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