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MikeJinCO · Posted: Tue May 15, 2018 2:10 pm Post subject: Beginner Tire Recommendations

The car is finally beginning to come together. I need to get some tires for a beginner driver. I have both the 6" spiderwebs and 7" cookie cutters for wheels. I have fender flares rear and front and the coil overs have about 2-1/2" springs so fender and clearance shouldn't be an issue. I figure I need a pretty forgiving tire that lasts well and a couple or reports recommended a BFG Rival over the Toyo R888R or Kumho RS4. They will be used track only for vintage use. I will probably have about 140HP(10-1, mild port, 264 deg cam,MSDS) and weight of 2100b(guess). I figured on a tire size of 205/50 but could go to 225. I cannot legally go below the 50 section. I'm not even considering Hoosiers at this time.

Among the local vintage group Hoosiers are recognized fastest, the RS-4 good for longevity and some use Toyo's.

Which tires would be recommended?
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Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

Cedric · Joined: 27 Aug 2004 Posts: 2721 Location: Sweden

Is it for racing or just track days? For a track day NA i would stay on 205s on 7" wheels, i really like that setup, but all tyres are not the same width, even though they are sold as the same size.

All tyres i have been running have been very progressive on my cars, even aggressive compunds, though its a bit heavier than yours which of course affects the car response. My NA was very nice aswell, even with aggressive Rcomps. But of course, when stuff happens it happens at a higher speed level, which can get you into troubble. I didnt like the old R888s, way to sloppy sidewalls, couldnt handle heat that good aswell, but the R888r seemt to be much better at those points. What was nice with them though was the short warm up time, more aggressive tyres could be very sketchy until they reached a good heat level, the toyos were almost good from the start, not completely unimportant factor.

A more street oriented tyre will most likely be a bit more slippery at a lower limit, and thus making it easier to learn how to manage the traction in the best way. With that weight i think you will have quite some margin for tyre overheating and thus could chose tyre more freely, otherwise that is mostly the drive to have more tyre width.
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1980 924 Turbo
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924RACR · Posted: Tue May 15, 2018 10:51 pm Post subject:

Can't speak to those tire choices, since I'm only running on Ho-ho's, but size-wise I'd be inclined to use the 205's on the 6's, not 7's - save the weight/rotational inertia...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Cedric · Joined: 27 Aug 2004 Posts: 2721 Location: Sweden

I don't know if there is any weight differences between those wheels, the spider webs are no lightweights. The 7'' cookies are 6.9kg if i remember correctly, a really good track wheel.
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1980 924 Turbo
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924RACR · Posted: Wed May 16, 2018 5:29 am Post subject:

Even if they weighed the same, a 6" wide rim should have a little less rotational inertia due to less wheel flange.

But I'm pretty sure once upon a time I weighed them and confirmed they were lighter.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Cedric · Joined: 27 Aug 2004 Posts: 2721 Location: Sweden

MikeJinCO · Posted: Wed May 16, 2018 8:34 am Post subject:

The car is track only although it might get a couple of illegal test drives if it can clear the driveway rocks. I weighed both wheels on bathroom balance scale and the cookie is about 3/4 lb lighter than the spiderweb. I think Ill probably go with the 205 Toyos on the 7" cookies as the increase in track should help a bit.
_________________
Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

winddude · Joined: 15 Jan 2020 Posts: 61 Location: Vancouver Island

are those on 15" or 16"s? I'm trying to figure out tire sizes for myself as well.

MikeJinCO · Posted: Wed Jul 22, 2020 11:29 pm Post subject:

I have 15"x7" cookie cutters. Tires I'm using are Nitto 01's 205/50/15. I'm still experimenting with tire pressure. I do not have a temperature gauge so shooting for about 34psi hot at this point. Last time out started at 26 cold and were 32 when hot so next time I start at 27psi. Maybe not the best way to do it, but best I can do for now. Our group is restricted to max of 50 section tires, I believe 924RACR is or was using 225/45's.
_________________
Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

924RACR · Posted: Wed Jul 22, 2020 11:40 pm Post subject:

We were using 225/45/15 Hoosier R6s.

We, in ITB, are restricted not by tire size but by rim size, and so run 15x6s.

Yes, with 225 rubber - it can be done.

But we've since dropped back to 205/50/15 SM6 tires - used Spec Miata tires are a lot cheaper, and may be a touch faster on the larger tracks!

(less rolling resistance)
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Fifty50Plus · Posted: Thu Jul 23, 2020 2:23 am Post subject:

IT-B is allowed 7 inch rims now. I'm running 7 inch cookie cutters with the Miata Hoosiers (they are designed for a 7 inch rim). A very slight improvement over the 6 inch cookies. Also based on tire wear and temps, I run more camber on the left side of the car since most turns are right handers.
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1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car

924RACR · Posted: Thu Jul 23, 2020 3:27 am Post subject:

Oh wow, that's weird, didn't notice that. I see that those are also switched up so you can run 225s with 6.0" rims, or 205s with 7.0" rims... goofy...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype