Quote:
Originally Posted by rhyary
Quote:
Originally Posted by slicer
Quote:
Originally Posted by rhyary
Quote:
Originally Posted by slicer
Quote:
Originally Posted by rhyary
Quote:
Originally Posted by slicer
A spacer will not help fender liner clearance. It will make it worse. Think about the wheel position when the wheel is turned. Adding a spacer will push it closer to the fender liner.
That being said there are a couple of options. There is metal that can be cut to increase room on the back side of wheel well. In addition the windshield washer tank is located behind the liner on passenger side. That can be removed (saves 10 lbs with fluid). Lastly you can install steering rack limiters to prevent turning the wheel far enough to cause clearance issues.
Another thing to point out is that you can improve inner clearance with your JRZ by going to a shorter spring and or helper. Do you know if you are using a no-load helper? If not there may be some available stack height reduction by switching to a no-load helper. I was able to completely delete my helper but Ohlins uses an inverted design which allows me to pre-load the spring without a helper.
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Here is my 275/30/19 and JRZ
Perhaps it will give you some insights into coming up with a solution. |
That's a rated tender spring. Going to a no- load helper will push the perch up about 12mm because it has a 12mm shorter stack height.
You can possibly gain more by going to a shorter main spring if a shorter spring has enough travel for your suspension setup |
I am not sure 12mm will solve the problem.
I am concerned that a shorter spring may not results in better laptime.
Also, both the 265/35 and 295/30 are taller.
A 295 perhaps would have too much hard issues to solve. Will 265/35 be easier to solve?
I hate engineering. There is always something in the way. |
265 is definitely easier to solve. There's zero reason to make any adjustment to the suspension for a 265/35/19. It will fit easily - other than the diameter causing some rubbing on the fender liner (which would not likely be solved by a more conservative offset afforded by more inner clearance). The need for increased inner space is for fitting a wide 295 which needs all the room it can get (width-wise).
A shorter spring in the same spring rate would have zero impact on your lap time. The change will not be detectable As long as the spring has enough travel (you simply want to avoid a spring that will bottom out before the suspension does). The gain would come from the added grip of a wider 295 tire (afforded by the extra space provided by the shorter spring)
I will point out that all of this is easier with 18" wheels because of available tire sizes. For example 265/35/18 and 295/30/18 are far easier to fit due to their 1" smaller diameter (when compared to 19" tires of the same width and aspect ratio). I know you are committed to your current brake kit and would not consider changing it. However this point will benefit others considering what brake kit and wheel size to build around. For those of you who don't know - @rhyary has a Brembo 380 kit which is very limiting when it comes to wheel fitment. There are only a select few 18" wheels that can clear that kit, therefore @rhyary is focused on 19" wheel and tire fitments.
Here's a picture to illustrate the reduced stack height of a no -load helper. Note how thin the helper spring coils are.
 Wheel fit by slicerM, on Flickr |
"265 is definitely easier to solve. There's zero reason to make any adjustment to the suspension for a 265/35/19. It will fit easily"
@Slicer, thank you.
2 x 1 hour session and
2 x 30 minutes at LRP and no issues with the Hoosier 265/35/19 up front |
What did you think of Hoosiers?