I have an 88 GT 5 spd with 4.10 gears and 285/40/17 rear tires with overall diameter of about 25.8 inches. I am thinking of going with 295/45/17 with overall diameter of 27.2 inches. My main reasons are to lower rpm at 70-75 mph and the wider and stickier tire for more traction. Also with the soon to be installed cobra intake and 75hp shot of N20 I am worried about keeping it in 4th gear at the end of the 1/4 mile. I know I will be effectively lowering my gear ratio but I don't remember the formula to figure out exactly what it will be. As long as it is 3.55 or higher I would be ok with it. Can anyone help me? Thanks!
Tire Size Question
- Thread starter Bob F
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The extra 10mm of width is not going to make a damn bit of difference at the track. If you want to actually get some grip, buy a pair of 15" wheels and a dedicated track tire setup.
Also, depending on your weight and actual final HP... you're probably still going to trap lower than 110mph. So your current "26" inch tire should be plenty for you to trap below 6000rpm.
Also, depending on your weight and actual final HP... you're probably still going to trap lower than 110mph. So your current "26" inch tire should be plenty for you to trap below 6000rpm.
I do have the origanal 15x7 turbine wheels that I could put track tires on. I have thought about getting those rears widened to 8 or 9 inches and putting some slicks on or just putting on the widest tire that will fit on the stock 7 inch.
It's not going to make a noticeable difference on highway either. You can run a drag radial at the track. Nitto 555's are an ok compromise but are mediocre at the starting line/60ft times. They will be fine at speed though. I ran a 125 shot with mine without any problems. Getting them to work in first 60ft is difficult though with a manual trans. I have a difficult time getting them to 60ft and the nitrous. The best way was to launch off idle and roll into wot. Still the best I ever did was a 1.85-1.90 and 12.47@117mph.
I would use your 15's with a 26x8.5" slick/soft dot bias ply tire like M&H,Hoosiers or Mickey Thompsons.
Yup I have been looking at those. My problem like most people is money. I have a long list of mods I want to do and it gets expensive. I only go to the track 2 or 3 times per year so my thought was the 295/45/17 mickey thompson et street radial will be a good choice. My concern is 27.2 inches with my 4.10 gear going to slow me down a lot?
It shouldn't slow you down? I can't remember do you have an auto or a manual trans? You might even run quicker with that tire depending on your powerband and trans type.
It is a stock T-5 and stock clutch with firewall adjuster. Also I think I should do torque box reinforcements before i put on sticky tires.
Do you know anyone in the northern il area that is good for installing the torque box kit?
Shhh...don't tell anyone "I haven't installed mine yet!" Lol. I was going to do it myself(like I was going to do my h/c/i but didn't
). If you just do the bolt in kit reinforcement, it's not very complicated. One of your techs can do it easily enough. If they can't or don't want to do it just pm me. I've got a guy in town that will (probably can talk him into welding it too
)
mikestang63
SN Certified Technician
I assume you BFH the inner fenders and lip to get those to fit? I'm going 275/40/17 for the rear tires on mine
Mike, I didn't have to roll the fenders and I have full Dynomax exhaust.
Thanks I will let you know. I'm just paranoid about it but you are running drag radials and have not seen any cracking or damage?Shhh...don't tell anyone "I haven't installed mine yet!" Lol. I was going to do it myself(like I was going to do my h/c/i but didn't
Well there's spinning and then there's spinning. Regular radials will keep you from having a ton of strain on boxes,transmission,axles etc. They will not hook up on the track or the street with a nitrous shot. Also bouncing off the revlimiter due to tire slippage is a problem. A bias ply won't tear your car up. Unless you've got a great suspension etc it's not going to dead hook and break stuff.
I do like the Nitto's on the street. They stick better than regular radials. You can still drive them at speed,when it's wet,etc like any radial tire. They are a softer compound and will wear faster. If you are just using them for cruising and a few passes a year they will last probably 10k miles or better. I've had mine on for 3 years but only a few thousand miles and they've held up well. Should last a couple more years(or more with how little I've driven the car).
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