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#1
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Should I Go With 15 or 17 Inch Rims & Tires
Before I buy a ready-built rear (probably from Moser) and a 5 or 6 speed Tremec tranny; I think rims and tires should first be fitted to replace my original 14-inch rims and tires. From the threads I've read, I see mixed results of what size rim and tire to go with. My fear with a 17-inch rim and tire is that it may look goofy or just not right. So thus far, I'm inclined to go with a 15-inch tire/rim combo. Also, with a standard 5 or 6-speed tranny and a 3.73 rear (which I plan to buy), I can cruise on the interstate at a relatively low RPM and still have decent acceleration when the light changes to green. Lastly, my intention for this car is to be a cruiser, no track, no racing.
I would like to hear thoughts and opinions on your preference for tires and rims on your ride. Also, please elaborate on your rear and tranny.
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1967 GTO, hard top, 400 Block, Butler Performance Build, EFI Holley Sniper, Tremec 5-Speed, Moser 373 Rear, 4 Wheel Disc Brakes |
#2
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I will show you the exact same car with both 15's and 17's. '64 GTO Convertible with the original Muncie 4spd and I've had 3.23, 3.36 (both 10 bolts), 342 and now 3.08 gears (12 bolt).
The first two photos are with 15's - 235/60/15 front and 255/60/15 rear (driven this way from 1995 - 2017. The second two photos are with 17's - 215/55/17 front and 245/50/17 rear. I decided to go with 17's because I thought they looked fine and gave me much better tire options. I'm very happy with the 17's |
The Following User Says Thank You to The Champ For This Useful Post: | ||
#3
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1967 GTO, hard top, 400 Block, Butler Performance Build, EFI Holley Sniper, Tremec 5-Speed, Moser 373 Rear, 4 Wheel Disc Brakes |
#4
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Here are pics of my 67 with 255/45/17 on 17x8 wheels with 5.5 backspace on all 4 corners.
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#5
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Your car is a 67 like mine. Your car is gorgeous and I like the slight rake. Your car is the look I want. The 17-inch rims/wheels look just fine just like our friend above showed us on his vehicle. My 67 sags in the rear; I've got to fix this so it looks like yours. In another thread I started regarding "sag", I received a lot of great advice but I think the best idea is to install station wagon springs or there's a company that makes them custom. "Backspacing" This is a subject I have to study up on. Currently; I have 14 inch wheels, so moving up to a 17 inch and whatever width I decide, I think I need to know about back spacing.
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1967 GTO, hard top, 400 Block, Butler Performance Build, EFI Holley Sniper, Tremec 5-Speed, Moser 373 Rear, 4 Wheel Disc Brakes |
#6
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Back in the 80's I had '68 GTO convertible and I took rear springs out of a 65 full size Pontiac wagon and they made my stance perfect like gtospieg's, in the 90's I had an '86 Monte Carlo SS with a big block and once again I used the rear springs out of a full size wagon, and again had the same results and I would do that again, but you won't find much support on this forum for that.
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1978 Black & Gold T/A [complete 70 Ram Air III (carb to pan) PQ and 12 bolt], fully loaded, deluxe, WS6, T-Top car - 1972 Formula 455HO Ram Air numbers matching Julep Green - 1971 T/A 455, 320 CFM Eheads, RP cam, Doug's headers, Fuel injection, TKX 5 Spd. 12 Bolt 3.73, 4 wheel disc. All A/C cars |
#7
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Thank you jimib....not inexpensive
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#8
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gtospieg: Your car looks fantastic with the 17's and I like the slight rake.
__________________
1967 GTO, hard top, 400 Block, Butler Performance Build, EFI Holley Sniper, Tremec 5-Speed, Moser 373 Rear, 4 Wheel Disc Brakes |
#9
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Backspacing isn't that hard to figure out when upsizing rims.
Let's say your current rims are 6" wide with 4" BS. It doesn't matter what diameter the rim is, a 6" wide rim should have the same BS as your existing rim assuming the tire width remains the same. If you go to a 7" wide rim, you need to go to 4.5" BS to put the wheel and tire in the same position. If you go to an 8" wide rim, you need to go to 5" BS to put the wheel and tire in the same position. Now, if you're planning to go to a wider tire, you may want to go with more BS. I prefer to keep the rear tire size as close to 27" (original tire height) as possible. My 255/60/15's were 27.1" tall, my 245/50/17's are 26.6" tall. If you add disc brakes, they normally increase the need for BS by about .25". I added disc brakes up front - my 15x7" rims had 4.25" BS and my 235/60/15's (26.1" tall) had a tendency to rub slightly under certain conditions after the switch. My 17x7" rims have 4.625" BS and I now have zero rubbing on my front 215/55/17's (26.3" tall). When I made my switch to 17's, my grandson worked for Continental and I was able to use his employee discount to purchase my tires. This limited my tire size options and I had to order my tires through Tire Rack. The largest rear tire I could get through Continental was the 245/50/17 although I would have preferred a 255/50/17 (27" tall). But I only paid about $400 delivered for my 4 Continental Extreme Contact DWS 06's - normally over $650 at Tire Rack. |
#10
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On my 69, I've found that it drives and rides much better with 70 series tires on the front.
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frittering and wasting the hours in an off hand way.... 1969 GTO, 455ci, 230/236 Pontiac Dude's "Butcher Special" Comp hyd roller cam with Crower HIPPO solid roller lifters, Q-jet, Edelbrock P4B-QJ, Doug's headers, ported 6X-8 (97cc) heads, TKO600, 3.73 geared Eaton Tru-Trac 8.5", hydroboost, rear disc brakes......and my greatest mechanical feat....a new heater core. |
#11
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If you are going to buy a new rear-end for the car, get that BEFORE you buy new wheels. Pontiac track widths vary from their chevy counterparts for which those new axles are going to be based around. Adding things like disc brakes further change total hub to hub distances.
Do those items before you buy wheels so that you can measure properly and not find yourself in a situation where you may have just put tires on a set of wheels that cost you a couple grand, only to find out that they don't fit.
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-Jason 1969 Pontiac Firebird |
The Following User Says Thank You to JLMounce For This Useful Post: | ||
#12
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I’m a big fan of 17’s- we are so used to seeing 20 and 22’s that 17’s have just enough tire on them. I kept the original Rallye wheels on my 66 because I like the look on a 66-67. Still, if you are going with aftermarket wheels I would go with 17s.
Here is a pic of my 66 - I used the rear springs that Ames sells for the stance. |
#13
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Even the Firebirds are wider from the factory than their Camaro counterparts. Luckily for me, when I swapped rearends I went from drums to discs at the same time and that basically made it a wash. Which is another point. If you plan to change brakes, do both the rear and brakes before you fit new wheels.
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"The Mustang's front end is problematic... get yourself a Firebird." - Red Forman |
#14
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Stay with the 15" wheels, the 18 wheels look goofy. The body wasn't made for those big wheels like the new cars. The handling and braking is in the suspension parts and brake lining material. Use Porterfield brake pads and matching shoes and it will stop on the dime..
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#15
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The most important performance part on a car is the tires connecting it to the road. Suspension matters and so does brake linings, but it's meaningless if you can't transfer that to the road. The tires you can put on a 17" or 18" wheel are superior in just about every way to the tires currently available on a 14" or 15" wheel. In those sizes you are stuck with the likes of BFG Radials, Cooper Cobras or drag radials. For the purposes of handling and braking, these cars are horribly undersprung and under-damped. Those large, soft tires like a Cooper Cobra also act as the suspension, further softening it. They allow the contact patch to distort and because the section width is carried in the sidewall and not at the contact patch, you lose further grip through a smaller actual contact patch. Even on a completely stock suspension and factory brakes, a car with a 17" wheel with a modern performance all season tire will outhandle and outbrake that same car on old style tires. This will continue to be the case until somebody decides to provide 15" wheel size tires with modern construction and compounds.
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-Jason 1969 Pontiac Firebird |
The Following User Says Thank You to JLMounce For This Useful Post: | ||
#16
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#17
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Yeah these cars are real soft when compared to modern cars. Not too many people in the market for cars these days desire a floaty disconnected feel from their vehicle.
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-Jason 1969 Pontiac Firebird |
#18
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#19
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Secondly, these cars came with bias ply tires, but most of us use radial tires today for improved ride and handling. Thirdly, these cars were built with 14's, so even a 15" wheel is larger. I've driven my GTO since 1994. Originally drove it with 14" 75 series radials, then 15" 65 series radials and then 60 series radials and now with 17" 55 and 50 series radials. I've posted photos of my car with both the 15's and the 17's. The original poster stated that he likes the looks of my car with the 17's. Most people don't even notice I've got 17's until I point it out. Must not look too goofy.... If he likes the looks of a 60's GTO with 17's - then he should go that way with his car. |
#20
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