Who switched from 305/45r17's to 315/50r17's??

[Markp]

Would the 315s be too much for a stock Redeye with 2.62s? My best 60 on the 305s so far is 1.474. I am hoping I can get into the low 1.4s

 

[motorhead]

Would the 315s be too much for a stock Redeye with 2.62s? My best 60 on the 305s so far is 1.474. I am hoping I can get into the low 1.4s

The additional rotational mass is a greater concern than the gearing since first gear is so low already. I'd also look at what engine speed you are trapping at with the current tires - are you going to benefit from the increased diameter of the tires throughout the entire run or will it potentially slow you down by using them? You can easily log your acceleration rate in HP Tuners to see if there is/was a trade off.

 

[WhipCat]

I swapped over. Helped a little bit. Still can’t get my 60’ to drop under 1.45

I keep blowing the tires on the hit. I got to try taking power out of it on launch.

 

[DRAGRCR]

Would the 315s be too much for a stock Redeye with 2.62s? My best 60 on the 305s so far is 1.474. I am hoping I can get into the low 1.4s

If you can get the car to hook it will be faster on the lighter and shorter tire. On a stock car the next thing I would do is the 3.09's and/or weight reduction. At that point I might pair the 315's with the 3.09's but the car would still be faster with the shorter/lighter tire if you have really good prep and it will hook. Almost always the smaller/shorter tire is lighter. Only exception that I can think of is some Drag Slicks are made in a light weight version. In that case they might be faster even though they are taller. If you are going to modify with big power I would stay with the 2.62 gear.

 

[TNREDEYE]

Would the 315s be too much for a stock Redeye with 2.62s? My best 60 on the 305s so far is 1.474. I am hoping I can get into the low 1.4s

I have never run the 305 tire but I have run the 315 w a 2.62 as well as a 3.09 gear.
I had a best of 1.48 w the 2.62 gear and so far I've been 1.46 w the 3.09.
Different tracks but similar DA of 600'.

This doesn't directly answer your question but it's at least some real world info for you.

Also, it appears that their is a difference of around 7 lbs ea between the 305 vs 315 tire. Obviously 14 lbs of rotational mass is theoretically worth some et.

 

[Hpindy]

Would the 315s be too much for a stock Redeye with 2.62s? My best 60 on the 305s so far is 1.474. I am hoping I can get into the low 1.4s

For what it's worth here is my opinion.

On a stock power 2.62 car I would stay with the 305's .

Plus on a regular body you will need to "massage" the rib in the inner fender .

Sent from my BBF100-2 using Tapatalk

 

[hellno]

I have the 315 with the 2.62 and I cut a 1.39 best and a1.40 before it

 

[Hpindy]

I have the 315 with the 2.62 and I cut a 1.39 best and a1.40 before it

With the added power you new need more tire to hook up . But it would be curious to see what a 3.09 gear would do VS the 2.62 in your car . You will have to test that next summer .

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[hellno]

With the added power you new need more tire to hook up . But it would be curious to see what a 3.09 gear would do VS the 2.62 in your car . You will have to test that next summer .

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I have the 3.09 but it’s noises my next project will be taking it apart and seeing if I can find the pinion bearings for it my gears look good in it and I’m hoping I can find a source on parts other then the gears which I believe aren’t available

 

[Marc W]

I swapped over. Helped a little bit. Still can’t get my 60’ to drop under 1.45

I keep blowing the tires on the hit. I got to try taking power out of it on launch.

View attachment 7750

I can actually see the negative camber you've got in the rear in that picture. Go positive and you'll do better.
Nice picture btw.... Looking forward to GB!

 

[WhipCat]

I can actually see the negative camber you've got in the rear in that picture. Go positive and you'll do better.
Nice picture btw.... Looking forward to GB!

Yep. We will be getting an alignment done for the this wheel and tire combo next week.
Appreciate the heads up.

 

[Hpmaniac]

I swapped over. Helped a little bit. Still can’t get my 60’ to drop under 1.45

I keep blowing the tires on the hit. I got to try taking power out of it on launch.

View attachment 7750

Bad ass looking car. What wheels are those?

 

[WhipCat]

Bad ass looking car. What wheels are those?

bogarts

 

[16GoManGoHC2]

I’m currently fitting the 315/50-17’s with a 2.98 first M6 which is around 11.5 final drive ratio. Going from a 315/35-20 Nitto NT05r should improve my 60’ immensely, Can’t wait to try them!!

 

[zhc]

The additional rotational mass is a greater concern than the gearing since first gear is so low already. I'd also look at what engine speed you are trapping at with the current tires - are you going to benefit from the increased diameter of the tires throughout the entire run or will it potentially slow you down by using them? You can easily log your acceleration rate in HP Tuners to see if there is/was a trade off.

Changing tire diameter on these cars affect the speedometer reading. For example, a taller tire will register a slower speed than actual. A gps based speedometer reading can confirm this before and after.

When logging in HPTuners, if acceleration rate is based on change in speed over time, the calculation will be affected by the diameter change so it won’t be an apples to apples comparison using this method. A larger diameter tire will appear to accelerate slower with that method even though in reality it may be the same. Not saying that acceleration won’t be affected here, just pointing out a minor flaw in the method of measurement for this particular case. As you stated, the extra tire mass is certainly a factor to consider.

 

[Hpindy]

But after a certain point you will need the extra contact patch for traction . Spinning will get you no where .

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[Indigo Joe]

Is there any chance of a damaged fender on a NB Challenger/Redeye with the 315's when the rear squats, or hits a large bump ? What wheel width, offset and/or back space is recommended for those tires? And as a side question while I am here with you gurus would the 1320 springs be adequate for a redeye or forget those and go with the Demon knock offs ? Thanks

 

[motorhead]

Changing tire diameter on these cars affect the speedometer reading. For example, a taller tire will register a slower speed than actual. A gps based speedometer reading can confirm this before and after.

When logging in HPTuners, if acceleration rate is based on change in speed over time, the calculation will be affected by the diameter change so it won’t be an apples to apples comparison using this method. A larger diameter tire will appear to accelerate slower with that method even though in reality it may be the same. Not saying that acceleration won’t be affected here, just pointing out a minor flaw in the method of measurement for this particular case. As you stated, the extra tire mass is certainly a factor to consider.

I get your point here. But, I didn't realize that I had to teach people how to recalibrate their car/speedo with a tire swap. I guess it is just painfully obvious to me at this stage in life. That's experience for ya.

 

[zhc]

I get your point here. But, I didn't realize that I had to teach people how to recalibrate their car/speedo with a tire swap. I guess it is just painfully obvious to me at this stage in life. That's experience for ya.

True. Honestly I never bother recalibrating given how often I swap out to different sized tires of varying stagings of wear for different uses.

 

[DRAGRCR]

True. Honestly I never bother recalibrating given how often I swap out to different sized tires of varying stagings of wear for different uses.

When I was data logging with T1000 I am pretty sure the car was using the Front tires for the speed most of the time. I think it will use the back if the front data is unavailable for any reason. I came to this conclusion by comparing my time slips to the data logs and so on. This was also done with 26" rear tires and should have been real easy to confirm with this large variance in tire diameter (front were 28.7"). Something to think about, not trying to start an argument.