Relocation brackets and/or an adjustable upper CA mount also help traction immensely. I have no doubt I could pull a 1.5-7 with my LCA's set to the relocation brackets lower holes on street tires. The upper CA adjustable mount also doesn't negatively affect roll-steer like the lower brackets do.

That's my next project....

 

As are many cars on this forum mine is in transition. The end goal will some day be an centri + IC and near 450whp.

The M&H 275/50/R17 has more sidewall than the 275/45/R18 or a 285/40/R18. At some point that might be required. I really don't know. Would a 285/40/R18 nitto 555R be enough to hold 450whp?

Perhaps I should just say screw this, keep my 18x10 boat anchors, and worry about wheels and drag radials when I really need it instead of making a choice now.

 

In NO way do I think you should keep your current boat anchor wheels. I'm planning to look into those RPF1's myself very soon. I think you should find some 15's/drag radials/skinnies for the track and mount up some street tires to the RPF1's, even if you had 450whp now. You can get substantial street traction with a combination of pinion angle adjustment and relocation brackets on street tires. With your current 285/40's on those much lighter RPF1's along with some relocation brackets your traction/speed will improve significantly.

Those guys running around on drag radials are posers lol. Get your rear suspension setup right and smoke them on street tires.

 

Regardless about what people might think of me around these parts for saying this. I have no desire to run 15s and skinnies. Pretty much ever.

My desire is to keep the car at or near 450whp and get a wheel/tire combo that can hold that power while still keeping stock diameter and running a 17/18" rim. I realize once you reach a certain point you'll need to run a small wheel with a huge tire. I don't ever want to be there.

I am not lowering the car so pinion angle adjustments shouldn't be a problem and from what I've read relocation brackets aren't needed unless the car is lowered.

 

contrary to what you hear, relocation brackets have less to do with lowering the car. while they do bring the control arms back inline (relocating instant center) after lowering their main objective is to adjust instant center of the rear axle which increases traction and weight transfer.

 

The question to me kinda boils down to whether or not a 285/40/18 drag radial like the 555R is going to hold 450whp or not. Assume 4.10 gearing, manual transmission, and a centri type blower.

If the answer is no then there is the M&H in 275/45/18. But it doesn't have that much more sidewall than a 285/40/18 and has less width. Might do the trick, might not.

In the end the 17x9 with a 275/50/R17 M&H, which has 1/2" more sidewall than the 275/45/18, might be required.

These are unknowns. Opinions vary. That's why I'm tempted at this point to keep the boat anchors and address this problem once the power is actually there.

EDIT: There is also a 305/40/18 555R. Should be better than a 285/40. There are more options in 18" vs. 17". But they all have less sidewall than a 275/50/17. And more weight.

 

If you're not concerned with the OVERALL performance of your car, then it's wise to keep what you have.

 

the M&H will hook better as the compound of the tire is better, the Nitto has the least sticky compound of the three DRs

 

When the blower goes on I might find myself wanting more sidewall. Therefore, I will wait. When the time comes I'll try a 305/40/18 555R or 275/45/18 M&H.

If that won't hold then I guess I'll get the 17s and try the 275/50/17 M&H.

 

Do you want it to dead hook? The harder you hook, the more stress you put on the trans and rear. My opinion still stands with the Nittos. They are a good balance between the street and the track. They'll hold plenty of power and are more than capable of a 1.5 60'. 450 rwhp won't be a problem on them if you do your part. The get bad reports because a lot of people don't know how to heat them and/or try to over launch them.