Tire talk; Skinny tires, Medium tires, Fat tires

Suspension, including wheel, tire and brake.
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JordanTr
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by JordanTr » 26 Sep 2013 17:25

I don't have much to offer but I have also joined the 205/50/15 crowd for most of the reasons above. I have a set of 15x6.5 that are cheap, readily available and very light so for me its win win win.

I love my 16s but I am not willing to put R comps on them because I drive my car too much on the street to warrant the expense. Having 2 sets of rims means 1 set with HP summer tires and 1 set of DOT approved R comps for autoX (maybe track).

To have money in the budget for real tires..... priceless.. :lol:
Jordan | '72 2 door KA project | '94 240sx RB26DETT | '97 Silvia RB25DET | '90 Audi 90 Quattro 20V (DD)

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duke
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by duke » 27 Sep 2013 10:02

Sleepys-14 wrote:Im still unsure why you want to use r-comps. Z2's/rivals will do the same lap times as r888 or similar tire with much less wear. A hoosier r6 will be faster, but that gets horrible life. Considering that your car is not strictly a race car that gets trailered to the track, it would be nice to use a tire that is good at lower temps(ripping around on the country roads/auto-x). Also wet traction is something to consider...
While I do agree that Z2's/Rivals/R1R's are all excellent tires, there is time to be had by switching to R-comps. I would bet in a 60 second auto-x the lower end, longer wearing, R-comps like the Nitto NT01 or Toyo R888 would be worth about 1 to 1.5 seconds. The higher end R-comps (Hoosier A6/R6, Kumho V710) would be worth a whole 2 seconds. The new UHP tires are good, but not that good.
Duke Schimmer

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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by Sleepys-14 » 27 Sep 2013 10:47

duke wrote:
Sleepys-14 wrote:Im still unsure why you want to use r-comps. Z2's/rivals will do the same lap times as r888 or similar tire with much less wear. A hoosier r6 will be faster, but that gets horrible life. Considering that your car is not strictly a race car that gets trailered to the track, it would be nice to use a tire that is good at lower temps(ripping around on the country roads/auto-x). Also wet traction is something to consider...
While I do agree that Z2's/Rivals/R1R's are all excellent tires, there is time to be had by switching to R-comps. I would bet in a 60 second auto-x the lower end, longer wearing, R-comps like the Nitto NT01 or Toyo R888 would be worth about 1 to 1.5 seconds. The higher end R-comps (Hoosier A6/R6, Kumho V710) would be worth a whole 2 seconds. The new UHP tires are good, but not that good.

You are 100% correct that r-comp tires are going to be faster. My point was just to add the pros and cons to using a UPH tire vs. r-comp tires.

UPH tire pros:
-long wearing
-good grip at lower temps
-good in the wet
-makes a bit of noise at the limit, which help the driver hear the grip
-Heat cycles dont matter
-cost less

UPH cons:
-sacrifice grip for tire wear
-some types overheat when abused

R-comp pros:
-Extreme grip
-Most can be abused at high heat levels

R-comp cons:
-Need to pay attention to heat cycles (6-10 usually) (r888/nt01 can do about 15-20 with out loosing to much adhesion)
-Can be used in the rain (only light sprinkle), but most will be less than stellar in the wet
-more sensitive to alignment settings
-cost more

Maybe R-comps are the right tire for him, but if you drive your car on the street, you are just wasting the compound and using up the heat cycles.
Beer... The cause of, and solution to, all of lives problems- Homer Simpson

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S15DET
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by S15DET » 27 Sep 2013 12:27

I certainly can't afford R-cpd. for street tires, I drive my car a lot. In my case, they will be on a 2nd set of wheels that I'll swap at the track. A not-so-obvious benefit that that I may be able to use a day-to-day tire that will give more life, instead of a do everything tire. I have a set of steelies and a roof rack, and with my 11 and 8-year-old crew, we'll get wheel changes down to a few minutes.

Hey, now I need to install air jacks!!

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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by Sleepys-14 » 27 Sep 2013 14:14

Good call on the 2nd set of tires!

MMMmmmmm... air jacks... I've been looking for a used set off of a ALMS car for some time now. From time to time they come up for sale.
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by bertvorgon » 28 Sep 2013 07:12

two sets is what I USED to do.

Believe it or not, 4 x 13" Panasports, with Goodyear Cantilever race tires 9.5", would fit across the back seat area. That way I got a season out of a set of tires.

Just an FYI too, my last set of Yokohama 048's had 5,000 miles on them, 3 slaloms, a couple of VERY HOT scenic tours, and still had some tread life left in them. They had hardened up towards the end.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by DADZSUN » 04 Oct 2013 05:35

Interesting topic - I've spent a LOT of time thinking about what I can get away with for Solo2 next year.

I'm currently running 14x7 0ET Watanabes with 195/60/14 Azeniz 615K. Once a great UHP tire, now considered an average tire (still amazing grip compared to 10 years ago). The best part of the Azenis is the price, < $400 for new tires. The 195s on a 14x7 0ET *just* tuck in the rear with moderate camber ~-1.5 range. The front clear on the 280zx coil-over struts w/o a spacer but I've added a 5mm spacer (with corresponding longer studs) to allow for tire flex.

The car has been clawing it's way up the ranks and is now a few seconds from FTD. It's time for R compounds (amongst a whole slew of other changes). Because I'm a cheap bastard I've shopped the whole R compound thing to death and have come up with what I think is a good cost effective solution. My plan is to run the early 80's 14x7 8ET Supra wheel ($100 on Kijiji :lol: ) with Hankook's Ventus 214 C71 in 205/55 R14 for $151 each (very decent price). Basically $700 for a solid R compound package.

The Supra's 8ET should offer 8mm additional tuck in the rear compared to the 0ET Watanabes, but the 7.7" wide 205mm Ventus tires is a full inch wider than the 6.6" 195mm Azenis. Unfortunately this means I'll have to run a bit more rear camber and/or 'massage' the rear fenders a bit to account for the remaining 4-5mm width (25.4mm/2 - 8mm). The front will likely need a few more mm spacer.

I really wanted to try a 15x7.5 rim with 225/45 R15. I tested a buddy's 15x8 ET15 in the rear and it cleared nicely but it obviously didn't have a chance in the front. Honestly, I really don't know how well a 225 tire / 7.5" rim will clear the front w/o flares. I'm also not that convinced the ~1/2" extra width compared to the 205s will result in substantial gains on such a light car.
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by Sleepys-14 » 04 Oct 2013 06:35

I think you have the right idea. I would stick with the 205/55r14 r-comps if you have a stock body. Plus the added sidewall is going to give you a bit more compliance over rough corners. That is something I wish had a bit more of. With the added grip of r-comps, you might need to add a bit more roll stiffness.
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by Byron510 » 04 Oct 2013 21:19

I did my first track day in the Bronze a few weeks ago, and learned a lot, including some interesting wear on the A048's that I ran.

Admittedly, these tires were new to the car and to the road, but we're 5 years old and going off quickly.

The three size is 205/60-13 rims are 13X7 0 offset American Racing Libre wheels.

At the end of the day I felt I had perfect wear across the rear tires, with no notable change in depth of tread across the tire, which meant that the 28 psi pressure must have been correct, and that the -0.5 degrees of camber is spot on.

The front was a different story; I the first two sessions on a wet track, the car under steered horribly when pushed at all. Later in the third session the track started to dry and the steering be amenities more neutral, and in the fourth session under a mostly dry track I was pulling the inside front tire right off the ground as the R compounds finally got some heat in them and started to work.

For the car, it’s simple ' I need stiffer rear springs, the exact opposite of what Brad was dealing with on his track days earlier this year.

For tire wear, we'll the outside edges of the front tires took a beating and the tread blocks are nearly pealed off due to the abuse. Solution? Well, get the rear sorted so that both front tires steer the car, and. Other just the overloaded outside tire. And second, maybe more that 0.5 degrees negative vam may be necessary.

I look forward to the next track day with a few additions.

Byron
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by rnorrish » 05 Oct 2013 00:52

The front lift on the ice racer, when at the road course, was fixed just by upgrading the rear shocks.
The handling is pretty neutral, and we didn't want to (nor really could) up the rear rate from the Specialty RR springs.

We went with adjustable Koni's for a later model Camaro.
richard norrish
'68 'goon resto / '71 ice racer / '72 'goon project / '70 4-door rust pile / '67 520 project
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by bertvorgon » 05 Oct 2013 07:55

Byron, I found 28 psi cold was the perfect pressure for the 048's, and, I run a bit more camber up front.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

Keith Law
1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by DADZSUN » 11 Oct 2013 06:33

duke wrote:While I do agree that Z2's/Rivals/R1R's are all excellent tires, there is time to be had by switching to R-comps. I would bet in a 60 second auto-x the lower end, longer wearing, R-comps like the Nitto NT01 or Toyo R888 would be worth about 1 to 1.5 seconds. The higher end R-comps (Hoosier A6/R6, Kumho V710) would be worth a whole 2 seconds. The new UHP tires are good, but not that good.
I would estimate that the gap is even closer than that.

There's talk that the Rival is about 1 second off the NT01 on a road course (approx 90 seconds).

A few years ago, good R compound tires were approx. 3 seconds faster than Azenis/Kumho MX. With the Rival getting a good second quicker than its competitors, I'll bet the difference to R compounds is down to only 2 seconds - especially after the first dozen runs on the Rs.

The fact is that street tires continue to evolve almost yearly while the ubiquitous V710/A6 have not changed in the last ~5 years.
Last edited by DADZSUN on 11 Oct 2013 06:43, edited 1 time in total.
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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by DADZSUN » 11 Oct 2013 06:41

DADZSUN wrote:... My plan is to run the early 80's 14x7 8ET Supra wheel ($100 on Kijiji :lol: )...
It turns out my plan may have a fault. I had considered the Celica's bolts pattern, width and offset... but not the required wheel nuts.

I had assumed that the Celica wheel uses a tapered nut, but apparently it uses a shanked nut which was more prominent during that era.

My research indicates that the Toyota uses a shanked nut with .725" diameter and M12x1.5" pitch. The Datsun uses a M12x1.25" pitch and .687" a shanked nut (as near as I can tell). So I can't use the Toyota nut on the Datsun hub (wrong thread), nor will the Datsun nuts fit tight-enough on the Supra rims.

I'm all ears to suggestions, apart from swapping wheel bolts or ordering potentially expensive custom shanked nuts.
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'72 Datsun 510 - Orange w/Watanabes & KA24E
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www.datsunrestomods.com

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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by HudsonMC » 11 Oct 2013 07:03

http://www.prestigewheel.com/Imagewi510.asp

This is the common solution, although I've never had to use them. Someone recently posted that they kept on snapping these things. Hopefully someone can chime in with a suggested brand. I just pulled those from a google search.

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Re: Tire talk; Skinny tires, Medium tires, Fat tires

Post by StrutlessWonder » 13 Oct 2013 13:46

DADZSUN wrote:
DADZSUN wrote:... My plan is to run the early 80's 14x7 8ET Supra wheel ($100 on Kijiji :lol: )...
It turns out my plan may have a fault. I had considered the Celica's bolts pattern, width and offset... but not the required wheel nuts.

I had assumed that the Celica wheel uses a tapered nut, but apparently it uses a shanked nut which was more prominent during that era.

My research indicates that the Toyota uses a shanked nut with .725" diameter and M12x1.5" pitch. The Datsun uses a M12x1.25" pitch and .687" a shanked nut (as near as I can tell). So I can't use the Toyota nut on the Datsun hub (wrong thread), nor will the Datsun nuts fit tight-enough on the Supra rims.

I'm all ears to suggestions, apart from swapping wheel bolts or ordering potentially expensive custom shanked nuts.
You can swap all 16 wheel studs to M12x1.5. No big deal, just cost and time.
Then you can use the OEM Toyata lug nuts.

BTW: Did you test fit to see if the center hole clears the 510 frt hub/dustcap? Make sure the wheel fits the rears as well.
I'd bet it may need to be machined larger to clear--at least, that was my experience.
And the supply of 14" performance tires is dropping all the time.
Sometimes cheap is not really as cheap as it seems in the end.
Kurt Hafer
'70 2dr VG30et "Strutless Wonder"

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