Front tire poke at zero toe and zero camber

Joel,

I did some very rough preliminary checks of my front tire fitment last night. I am running Nitto NT05s and my fronts are 275-30ZR19. These overhang the rims slightly just like your first set did and protrude past the body at zero camber. (sorry no pictures, left my phone in the house last night). I cranked the top control arm all the way in (which achieved an obscene -3 degree camber) and the tops pulled in well inside the fender well. This also creates a major amount of toe in that I cannot adjust out without modifying something (the rack tie rod ends are adjusted all the way in on both sides). I do not plan on running anywhere near this amount of camber though. I think your 255 front wheel choice is spot on. I am hoping that I will not need to replace my 275s. Once I do an initial alignment and suspension setup I'll have a better idea. Right now everything is very rough setup as the factory put it together. I also need to get my body fitting better. The factory did not cutout the floors in my tub and it is currently sitting about 1" off of the chassis, this is messing the spider location up badly. Need to get the Camaro and GTO out of my shop and up to the house so I have some more room to work in order to fix that. Will do that once it stays warm here in NW Ohio. Still getting cold at night.
 

Joel K

Supporter
Joel,

I did some very rough preliminary checks of my front tire fitment last night. I am running Nitto NT05s and my fronts are 275-30ZR19. These overhang the rims slightly just like your first set did and protrude past the body at zero camber. (sorry no pictures, left my phone in the house last night). I cranked the top control arm all the way in (which achieved an obscene -3 degree camber) and the tops pulled in well inside the fender well. This also creates a major amount of toe in that I cannot adjust out without modifying something (the rack tie rod ends are adjusted all the way in on both sides). I do not plan on running anywhere near this amount of camber though. I think your 255 front wheel choice is spot on. I am hoping that I will not need to replace my 275s. Once I do an initial alignment and suspension setup I'll have a better idea. Right now everything is very rough setup as the factory put it together. I also need to get my body fitting better. The factory did not cutout the floors in my tub and it is currently sitting about 1" off of the chassis, this is messing the spider location up badly. Need to get the Camaro and GTO out of my shop and up to the house so I have some more room to work in order to fix that. Will do that once it stays warm here in NW Ohio. Still getting cold at night.

I think you will be good with the 275’s since Cam and Johan are using those on the 19” rims and they look really good with camber set and a little trimming of the inside fender well. I selected Michelin Super Sport Run flats and did to want to mix/match run flats on the back which fit really nice with non run flats on the front etc. The two Sizes I could have went with were 245/35/19, 25.8” tall and 9.8” wide, or the 255/30/19, 25.1” tall and 10.2” wide. I chose the wider tire, but probably will need to settle on 4.25” ride height, with the taller tire you could get 4.5” front ride height with the wheels nicely centered vertically in the body.
 
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Joel K

Supporter
Joel,

I did some very rough preliminary checks of my front tire fitment last night. I am running Nitto NT05s and my fronts are 275-30ZR19. These overhang the rims slightly just like your first set did and protrude past the body at zero camber. (sorry no pictures, left my phone in the house last night). I cranked the top control arm all the way in (which achieved an obscene -3 degree camber) and the tops pulled in well inside the fender well. This also creates a major amount of toe in that I cannot adjust out without modifying something (the rack tie rod ends are adjusted all the way in on both sides). I do not plan on running anywhere near this amount of camber though. I think your 255 front wheel choice is spot on. I am hoping that I will not need to replace my 275s. Once I do an initial alignment and suspension setup I'll have a better idea. Right now everything is very rough setup as the factory put it together. I also need to get my body fitting better. The factory did not cutout the floors in my tub and it is currently sitting about 1" off of the chassis, this is messing the spider location up badly. Need to get the Camaro and GTO out of my shop and up to the house so I have some more room to work in order to fix that. Will do that once it stays warm here in NW Ohio. Still getting cold at night.

One other note, the 285/30/19s stuck out .8” wider than the rim. When I added 1.5 degree of camber the tires appeared to be .25”-.33” too wide on top. So if your tires are sticking out .5” or less from the rim I think they will fit good with camber dialed in.
 
One other note, the 285/30/19s stuck out .8” wider than the rim. When I added 1.5 degree of camber the tires appeared to be .25”-.33” too wide on top. So if your tires are sticking out .5” or less from the rim I think they will fit good with camber dialed in.

Joel,

Thank you for those dimensions. Went out to the shop "after work" today and measured. My tires only stick out 1/4" from my rims (front and rear are the same) so I should be good. That is good to know!

2020-04-01 16.44.07.jpg


This is with the -3 degrees of camber. I'll probably settle on around -1 degrees.

2020-04-01 16.44.19.jpg
 
I need to order tires and I noticed that the recommended tires for 19x9.5/10" rims have not changed from 285/30/19. Was there a final determination as to why the recommended tire size would not fit? I'd like to run the Pilot Sport 4S, but they don't come in 285/30/19, so I was considering the 275/35/19.
 

Joel K

Supporter
I need to order tires and I noticed that the recommended tires for 19x9.5/10" rims have not changed from 285/30/19. Was there a final determination as to why the recommended tire size would not fit? I'd like to run the Pilot Sport 4S, but they don't come in 285/30/19, so I was considering the 275/35/19.

Troy, my recommendation is do not buy 285/30/19. You run the risk of the tires not being mountable on the rims and have your rims finish ruined as well as having too much tire poke. Others have had the same issue. The 275/35/19 IMO is too tall.

If you are sticking with the 19” rims, try to find 275/30 or 265/30, they would fit well. I went with 255/30 for the front although I think 265/30 or 275/30 is a better choice.
 
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Troy, my recommendation is do not buy 285/30/19. You run the risk of the tires not being mountable on the rims and have your rims finish ruined as well as having too much tire poke. Others have had the same issue. The 275/35/19 IMO is too tall.

If you are sticking with the 19” rims, try to find 275/30 or 265/30, they would fit well. I went with 255/30 for the front although I think 265/30 or 275/30 is a better choice.

100% agree. Definitely do not order 285s, a ruined finish of the front wheels is all you'll end up with. Plus tires TireRack won't take back. True story.
 
I got the email yesterday from Bill to purchase my tires for RCR which sounds promising. However, after reading this thread 4-5 times now, I wanted to stay out of what Joel called the “Wrong Tire Choice Club” :)

I am debating between the MICHELIN PILOT SPORT 4S which have great ratings but are pricy and Pirelli P Zero's or the NITTO INVO's which both have strong and very similar ratings to each other but not as great as the Pilot Sport 4Ss. However, they are also less expensive.

In the end...it came down to Availability. I called around and it was EXTREMELY difficult to find these sizes in these tires OR ANY TIRES for that matter.

Tire Rack came through. I called them vs looking on line and the guy at Tire Rack was able to find me :
  • Front – 265/30ZR-19 Michelin Pilot Sport 4S XL - Had only 2 left in inventory in Nevada
  • Rears – 325/25ZR-20 Michelin Pilot Sport 4S XL - Had many in inventory at the HQ in Indiana
Note - the 275's for the front are out of stock and not going to be replenished (at least that is what the Tire Rack guy said his system says) so I went with the 265s that they had to source as their last 2 out of Nevada. Although he said they do show a few single 265s around the country right now but going fast. The Rear 325s were in stock at the HQ in Indiana.

The good news is that both sets shipped today from their locations to be onsite at RCR tomorrow.

Based on what I read in the various threads, it sounded like the 275s may be a bit wide for the front so I'm hoping the 265's will fit perfectly. We shall see...







They had to be placed on sperate orders so the The Fronts will ship from Nevada with expedited shipping to arrive tomorrow afternoon while the Rears are coming from the headquarters in Indiana and arriving in the AM
 

Joel K

Supporter
Here are some pics to compare. Turns out the 285s work on 10” wide rims but not on the 9.5 rims. so 265s will be right between mine(blue) and Johan’s car(Red).

275 on what I think are 9.5” rims…
E5545EFF-BEAE-48ED-949F-B0571C1E131A.jpeg


255 on 9.5” rims…
6D1BDE77-C221-402C-833B-30411D833543.jpeg


Stephan’s car with 285s on 10” Rims…
7C7DBEB3-9D55-4AF8-96EF-CCF23F22FD0B.jpeg
 
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Here are some pics to compare. Turns out the 285s work on 10” wide rims but not on the 9.5 rims. so 265s will be right between mine(blue) and Johan’s car(Red).

275 on what I think are 9.5” rims…
View attachment 121710

255 on 9.5” rims…
View attachment 121712

Stephan’s car with 285s on 10” Rims…
View attachment 121711
This is a great post Joel. When mine get mounted and put on the car with the body on I will get a picture to add to the above for other folks to see
 
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Joel K

Supporter
Ok, I’m revisiting this thread. I’m doing the final alignment of the body and wheels before I mount the body on the chassis and still dealing with what I think is an excess amount of tire poke. I have the rear lower forks all the way in and the front lower forks have two turns out to help pivot the front wheels back to center the wheels in the body wheel wells. It doesn’t effect the poke much and is not the cause of what I’m seeing.

Here are pics of my tires with the body centered and the wheels stick out more than any other pics I have of other SLCs. Ken Roberts mentioned the backspacing may be off on my wheels and now I’m starting to think that. Originally I had Bill measure a set at RCR and they were the same as mine, but something still seems off.

I have -1 degree camber on the fronts and really don’t want to run more than that on a street car. Also, there is a good 5/16” gap between the caliper and the wheel spoke which makes me think the backspacing could be off.

If someone has 9.5” Forgestar F14 wheels could measure the distance between the spoke and caliper that would be helpful. Also, if you have a set off the car and can provide the backspace measurements of the front wheels I’d appreciate it.

Front right, you can see the tire poke on top…
IMG_2349.jpeg


Front left…
IMG_2350.jpeg


From behind
IMG_2351.jpeg


IMG_2352.jpeg


At least a 5/16” gap between the spoke and the caliper…
IMG_2356.jpeg


Good pic of the gap…
IMG_2353.jpeg


For reference…


IMG_2354.jpeg
 
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Johan

Supporter
Joel,
I sold my car a year ago so I can’t take any measurements, sorry. That said, don’t do any body fitment without having the windshield installed (not final but taped in place). I remember when I was doing my final fitment, took me a month fore sure and when I was satisfied with it all and laid the windshield on I had a 3/4” gap at the lower corners. So I had to rethink it with priority on the windshield fitment.
I ended up fabbing a long adjustable rod with balljoint on each end and bonded brackets just below the lower windshild corners to adjust the widht of front part of the spider then bolted it in place. It worked perfect.
When it comes to your wheel poke I woldn’t be suprised if it’s your body that’s deformed sligtly (fiberglass is a living material). My rear hood on the GT-R got about 20mm wider in just 6-7 months when sitting vertically. I had to strap it together and put it through a heatcycle to get it right again. Maybe better to request measurements of the width between the wheel arces from other builders.
Good luck Joel.
 

Joel K

Supporter
Joel,
I sold my car a year ago so I can’t take any measurements, sorry. That said, don’t do any body fitment without having the windshield installed (not final but taped in place). I remember when I was doing my final fitment, took me a month fore sure and when I was satisfied with it all and laid the windshield on I had a 3/4” gap at the lower corners. So I had to rethink it with priority on the windshield fitment.
I ended up fabbing a long adjustable rod with balljoint on each end and bonded brackets just below the lower windshild corners to adjust the widht of front part of the spider then bolted it in place. It worked perfect.
When it comes to your wheel poke I woldn’t be suprised if it’s your body that’s deformed sligtly (fiberglass is a living material). My rear hood on the GT-R got about 20mm wider in just 6-7 months when sitting vertically. I had to strap it together and put it through a heatcycle to get it right again. Maybe better to request measurements of the width between the wheel arces from other builders.
Good luck Joel.
Good advice, thanks Johan
 

Joel K

Supporter
After thinking about this request some more, if anyone with a 9.5” front Foregestar Wheel(doesn’t matter the model) can measure the backspace that would be a big help. Even measuring from the back of the highest point on the flange to the outside of the tire instead of the rim would work.

My bet is my backspace is a good 1/2” off.
 
After thinking about this request some more, if anyone with a 9.5” front Foregestar Wheel(doesn’t matter the model) can measure the backspace that would be a big help. Even measuring from the back of the highest point on the flange to the outside of the tire instead of the rim would work.

My bet is my backspace is a good 1/2” off.
Joel, Just checked my front Forgestar 9.5" wheel - Exactly 175mm ( 6.9" ) back space - and 275/35 Michelin Pilot sport tyre side wall only extends about 2 - 3 mm beyond edge of rim. Rims have been powder coated.
 
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