Please let me know what you all think is the best 15” tire to run on a 5.5” wide rim? I have 195/65 on my speedster and the rear end feels loose and comes around a little (it’s not breaking loose and might be best described as yaw). It reminds me of driving my '65 Chevy on bias-ply tires.
Also, what tire pressure are you running?
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Tires are like oil. Opinions vary. And you know what they say about opinions. You can do a search here for the different opinions among the posters. It depends on what you want. Several manufacturers make reproduction vintage tires, but they’re pricey. Finding a modern tire to fit your needs can be harder as tire sizes seems to be getting larger every year.
As for pressures, most guys run 18-24. An old motorcycle racer taught me a formula for determining the proper pressure for a tire on a specific vehicle: Your hot TP should be your cold TP+10%. The tire pressure I found for my Spyder is 18F-22R. Speedster guys like a little more rear TP because of the rear vs mid engine.
@dlearl476 - Thanks for input.
I searched and the newest posting was over ten years old. I couldn't believe there wasn't something newer. I'm not ruling out that it could be my lame forum skills 
There are more recent discussions about tires but some might be embedded in thread drift. If you didn't, use the advanced search.
On my Speedster I run Vredestein Sprint Classic, 175/70 at 18f/28r. I can't use wider tires on the IRS rear.
The ideal tire width for a 5.5" rim is less than your 195.
There have been multiple tire threads, or threads that became tire threads. If you want, search "Vredestein". Somebody will bring them up every time there's a discussion, and it should take you to what you need. We've talked tires at least 4 or 5 times in the last couple of years.
If you feel your back end squirming, then raise the pressure, but be careful. Harder tires make oversteer easier to initiate. If you have a swing-axle car, you're already prone to snap-oversteer. I run 30 psi in my rear tires, but I'm on IRS and the car is really low.
I have 5.5" rims on a VMC build with IRS. The tire-to-rim convention I'm familiar with (on a much wider rims) is the tread width should be 1/2" less than rim width. On these Speedster rims, that math means the tread-width (and tire) will be too narrow.
TireRack.com lists manufacturer specs which suggest a range of rim widths that work with various tire sizes and consistently states a 5-1/2" rim is the narrowest rim for a 195/60 application. The Vredestein Sprint + in this size has a 7.7" section width and 6.2" tread width. On the other hand, the Goodyear Eagle RSA has a 6.0" tread width...that's getter closer to a "balanced" sizing. Two different looking tires, but same nominal size.
I bring this up because this defies my understanding of tire sizing, so I want to ask you what you're running, if you're happy or what would you do differently? I've come to drink from the well of wisdom.
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Stan's advice will find you tire discussions here. But note, when you select the search function, there's also an option for 'Advanced Search'. With that, you can limit a search by a date range and if you set that to 'after May 1, 2021', you'll find dozens of recent threads.
When it comes to tires, I'm something of a contrarian. I think, with a swing axle rear end, grip is more limited by the meager suspension geometry than by the quality of the tire. So, practically any decent tire from a major company should deliver reasonable grip. I've driven IRS Speedies, and the grip in the rear feels a lot closer to how a modern car responds in corners (compared to swing axle), so I can see how a good, performance tire could make a big difference there.
The problem is availability. A lot of folks (I think mostly IRS drivers) say the Vredestein Sportrac is the best tire for our cars, but it was never easy to find in appropriate sizes, and is now virtually unobtainium (as are most other summer performance tires).
A lot of engineering goes into getting the best grip from a modern suspension. It's a delicate balance of grippy compound, enough stiffness in the tread, and enough compliance in the sidewall, so that the tread stays flat on the road without rolling under when side loads are applied .The problem with swing axles is that the suspension itself allows the tire to roll under, no matter what the tire engineer has done.
Oddly enough, I have exactly the same tires on my Speedy and my 2009 MINI — Continental ContiPremiumContacts in 175/65. These are summer compound tires and were OEM on the MINI. Driving the two cars, you'd never guess they have the same tires. The MINI grips like grim death in the corners. The Speedy does too, in a manner of speaking.
You just need to interpret the phrase 'grim death' very differently for the Speedy.
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That Goodyear Eagle RS-A is an A/S tire. Everything in a 195/60R15 besides the Vredestein Sprint + is an A/S tire. The Vred is a summer tire. I ran the precursor to this tire (the Sportrak 4) in a 195/60R15 on a 5.5" rim, and the handling and ride were transformative. My Sportraks weren't $188/tire, but if you buy before June 8, there's an $80 card for buying 4 of any Vredestein tires.
TireRack doesn't sell them in a 15" size, but Vredestein also makes a summer tire a lot of guys have used and loved called the Sprint Classic. Their website lists them as making both a 175/70R15 and a 185/70R15 Sprint Classic. Coker Tire has Sprint Classics in 175/70R15 in an H speed rating (130 mph) for $153/tire. That's a deal.
I'm moving to 16" rubber, and will be looking for a 205/55R16, and I find that Vredestein also lists a Sprint + in that size (it's the only 16" size they make). It's unfortunately in a W speed rating (168 mph), which means it has a stiffer sidewall than I'd like - but I loved my Sportraks enough to try to find a set and summer tires are not hard to find in 16".
Did I mention how much I loved the Sportraks? I think I did. I loved the Sportraks. I was Spyder-fast in the twisties (ask any of the Tour-de-Smo boyz), and the ride on the interstate was sublime. They stick like glue, and ride like a carpet. They're definitely worth what I paid, and I paid around $150/tire.
More broadly, I'm not sure if it was the Vredestein brand that was so wonderful, or the fact that it was a summer tire. Regardless - you have two good choices for a Vredestein summer tire available (the Sprint Classic and the Sprint +). As for me, I'm 100% convinced that I'll not put another A/S tire on my car as long as I own it. The fact that there aren't any other 15" summer tires that cost less than $250/tire narrows the field down a bit, at least for a working class schlub like this guy. For the proletariat, in 15" summer tires it's Vredestein or bust.
Perhaps your situation is different. If you're a Rockefeller heir, you might enjoy a $300+/each tire. If so, @chines1 or @Marty Grzynkowicz have both explored the netherland of a $1500 set of tires on a replica, and would have better information to offer than I do.
@Sacto Mitch - I had no idea those Continental ContiPremiumContacts even existed, let alone that they were available in a 175/65R15. I looked them up - they are indeed a summer tire, rated for cars (no SUVs, etc.). That seems like a solid find for guys with 5-1/2" x 15" rims. Your testimonial means a lot to me.
Well done.
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Stan, those Contis were available for years on Tire Rack (in that size, at least), but alas, no more. So, I'm not sure if Conti is still making them.
The only thing similar in that size on Tire Rack now is a ' ContiProContact', an all-season tire with a harder compound.
So, the Vred Sprint Classic may be the best option now.
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@Sacto Mitch posted:.Stan, those Contis were available for years on Tire Rack (in that size, at least), but alas, no more. So, I'm not sure if Conti is still making them.
The only thing similar in that size on Tire Rack now is a ' ContiProContact', an all-season tire with a harder compound.
So, the Vred Sprint Classic may be the best option now.
I think they’re still made, Mitch. I found them on the Continental website. It’s probably a TireRack thing. They seem to only want to carry tires that sell briskly, and a 15” summer tire probably doesn’t fly off the shelves.
I found a place that still has them in a 195/55R16 (perfect for 5.5x16) for something like $85/ each. That’s a closeout price, which means an older date of manufacture code - but I can’t resist. I’m buying a set. It’s hard to sneeze at $340 for 4 tires.
If I hate ‘em, it’s not like they ever last 50,000 miles. I’ll let you know.
I'm not in agreement with Mitch on the swing axle suspension. The swing axle handles totally great IF TRAVEL IS CONTROLLED. Keep the car low, and the camber near zero positive toward the negative range, and handling is good. There are various ways to do this.
1. A camber compensator bolted under the trans(usually need longer studs for this). This is a great option for Speedsters.
2. A Z-bar keeps the positive camber controlled by allowing roll in the rear suspension but NOT positive camber. This is custom fabrication and the most effort, especially tuning it, as it adds rear spring rate.
3. Limiting straps can be installed to prevent positive camber. This is the method I used on my Spyder. Camber is limited to a couple degrees positive, which doesn't allow the tire to ride on its outside edge.
4. The last option is zero-roll. This is used on Formula Vee cars(I have one) and uses one shock and a droop limiter rod to control rear camber. Not really practical for a street car, but excellent on the track in a Formula car.
A lot of people don't run a front anti-sway bar on the Speedster or Spyder. A front bar does shift the handling to neutral/understeer but the car is much more predictable. It corners much flatter. The cornering limits are higher before snap oversteer shows up.
The stock 1/2" VW bar does a little. The aftermarket 3/4" EMPI does too much. Years ago there was a 5/8" bar available(which was the sweet spot). Since they weren't available, I built my own, with conventional attachments: sway bar bushings and end links.
Do not, under any circumstances, install a rear ant-roll bar on a Speedster with swing axle rear end. Just don't.
Now, onto tire sizing.
A 185 section width should be on a minimum 5.0" rim. I run 185/65R15 on a 4.5" front rim on my Spyder. Yes, it's not recommended, but with the backspacing requirements, tires available, and wheel well space it is what it is. I run 22F pressure, no less. It works.
So a 175 on a 4.5" rim is about perfect.
On to the 5.5" rims. In my experience, you can run up to a 205mm tread width. 195 appears to be a sweet spot, with 195/60R15 on the rear of my Spyder at 25-26 psi.
I was lucky enough to get a set of Vred Sportrac5 a couple years ago for about $300. Yup, for the whole SET.
The treadwear number on those is 300. Anything higher than that is too hard. If you're looking for GOOD and sticky street tires, look for 200-300 on treadwear. That is the sweet spot. There used to be some Yokohama Direzzas with a 300 rating that Henry would put on his IMs. Similar to the Vreds, sticky, but not too sticky.
The Sprint Classic is a good choice. I think Pirelli, Conti, and maybe a couple others make vintage-specific sizes with sticky or semi-sticky offerings.
There are Avons available with a 100 rating(I think Marty had these on his IM turbo) but IMHO too sticky(and high treadwear) for street usage.
But that smoking deal on the Sportracs is a gone thing...
And for the record, I absolutely LOVE mine. Transformative, indeed, as Stan states.
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Ah, I just knew I'd catch some heat from Danny for ragging on swing axles.
He can be a bit touchy about that.
I don't drive on the ragged edge like he does. I don't have the patience or inclination to set up my suspension, wheels, and tires to their theoretical best. And I'd guess that more Speedy drivers fall into my camp than into Danny's. So I'd still wager that most real world IRS Speedies will have more useable grip than most swing axle Speedies.
In my case, I got tired of straightening out low hanging tail pipes and replacing sump plate nuts, so I had the car's rear end raised to what is a more practical ride height for me, thus ending any chance of entering the Valhalla of running slightly negative camber. (There's still a manhole cover somewhere in Amador County that's having a good laugh at my expense.)
I also wanted cheap, easily obtained or replaced tires, so I'm not running the optimum size for max grip, either. I am thus content with, shall we say 'middle of the road' adhesion. I know my place in the firmament and drive accordingly.
No matter, though. The wine at the winery, when I finally arrive, tastes just as sweet.
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We have those grape fermenting places out here as well. It does taste just as good, whether you putt over in the daily or tear up the roads in your sports car!
@Sacto Mitch You are probably right about the suspension/tires and the 90% or maybe 95% of owners.
There are a few of us that enjoy wheeling and hooning though. I kind of got the impression that NorCal Dave was one of us...
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I'm sure there are others who have fallen, Danny.
But this is a nurturing group. Surely, we can all try to understand and to find it in our hearts to forgive.
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@Sacto Mitch posted:.I'm sure there are others who have fallen, Danny.
But this is a nurturing group. Surely, we can all try to understand and to find it in our hearts to forgive.
"Whether 'tis nobler in the mind to suffer the hoots and catcalls of outrageous fortune, or to take arms against a sea of Mustangs and by downshifting pass them when the way is clear ahead.
It may be better to have hooned and lost than never to have hooned at all, but I'd rather live to hoon another day."
- Mitch Toll, SOC Poet Laureate
There's no "may" about it. "It's truly better to have hooned and lost than never to have hooned at all," and you said it, Senior Toll.
I'd like this on my tombstone, please.
I've been running the VREDs Sprint Classic 165/15's on my swing axle speedster for the past three years. I ran those on two 750-mile rallies. I do run a kafer bar in the back, and haven't had any issues......yet. I will say, the car handles remarkably different when driving solo than with a 185 lb passenger.
I replaced the Pirelli p5's that came with my car. The p5's were quite a bit wider and shorter than the VREDs. I did notice a difference in the curves, but not enough to hate on them. I do love the added comfort the VREDs provide. It is night and day. And the car travels at a higher speed and lower rpm with those tires, making 85+mph easier on the highway without passing 4k rpms.
From what I understand though, if you are feeling speedy, the AVONs are worth every penny. But I'm not at that level.
Hey Dave, my VS has a swing-axle and not an IRS as your Speedster does. Subsequently, the info I'm adding here falls into an apples to oranges comparison. However, I just wanted to provide another bit of info your visual and mechanical reference regarding your tire selection/tire pressure conundrum.
My VS is a 2015 Kirk Duncan build.
* Used as a daily driver in SoCal mostly in 'cruiser mode' with occacional hooning (as solo driver) on local mountain and twisty roads.
* Front lowered via Select-A-Drop and 2" Drop spindles
* Rear lowered via adjustable swing-plate for a slightly negative camber.
* Wheels Empi replica Fuchs 5.5x15" with Khumo 185/60R 84H. Rated to 130mph (40mph over my live-another-day-top-speed). Warranty for 65,000 miles. I currently have 49,000 miles on these.
* Tire pressure F = 18 R = 24 gives this suspension and tire combo pretty good handling characteristics (within my performance expectations and driving skills).
I hope you find this info helpful! 
@MusbJim - Yes, super helpful. Thank you!
Nice set up and great stance!
@MusbJim posted:* Front lowered via Select-A-Drop and 2" Drop Spindles
Hmmm, this makes me wonder. My Spyder already sits pretty low.
I wonder what it would do to my suspension geometry to raise it up a couple of inches via the torsion bars then use drop spindles to fit a set of 40lb< disk brakes. Plenty of zero offset disc options minus the adapters with drop spindle kits.
I also have an adjustable front beam, but not adjustable spring plates.
@DaveNorCal posted:
Yeah. That 760 tread wear rating on the Pirelli won't be sticky. At all!
@dlearl476 Don't do it, Dave. If you raise your car, you will forfeit your membership here, and be blacklisted and shunned for life.
He he he.
Seriously, you don't want to raise or use drop spindles on a Spyder. There is no need.
@DannyP posted:Yeah. That 760 tread wear rating on the Pirelli won't be sticky. At all!
He's presently running the concrete tires. He wants to run the Vreds. They've got a 300 tread wear rating.
Great call. Let us know how you like them, @DaveNorCal!
@Stan Galat and @DannyP…yeah, the Pirellis don’t feel right, so I’ll definitely report back on how the Vreds feel. Thanks for all the feedback!!!
@P.S., @dlearl476, your Spyder looks great.
But wait there’s more…The Vreds are super close in section and tread width to the Pirellis, but slightly smaller diameter (65 series to 60). Here’s a pic of the current set up…
The 195/60R15 is about 3/4" in diameter shorter than the 195/65R15.
That means the car will physically sit 3/8" lower(1/2 diameter is the radius).
IMHO you won't really notice it. You will get very slightly better acceleration, as there will be more revolutions turned per mile travelled(25.6 or so).
Here is a tire size comparo calculator:
@dannyp - Yes, I totally agree with you. It'll look better IMHO.
That picture makes the Pirellis look wider and lower profile than real life. I'm hoping the Vreds look as good as this picture.
The universe figured I needed some inspiration to replace the front tires that I’ve been procrastinating ever since I got it out earlier this year. Picked up a drywall screw at the car show yesterday.
So I ordered some new Hankooks for it and it got me thinking about this thread. 50 series might be too low for most, but I can’t speak highly enough of the Ventus V12s I run on the 968. They’re really economical and for the driving I do, they’re every bit as sporty as the Pilot sports they replaced.
These are one of the few tires they make in 15”, but they’re in the “Extreme Summer Performance” category. Seems like they’d go great with a lowered car on 6” Fuchs.
https://www.tirerack.com/tires...Z232XL&tab=Sizes
These are listed as “High Performance summer” and come in 175/65-15 and I’d bet they compare favorably to the NLA Vredestein Sportracs that everyone raves about. https://www.tirerack.com/tires/hankook-kinergy-eco
At a 400 treadwear rating I'm gonna respectfully disagree. They won't be as sticky as the Vredesteins.
I had some Pirelli with a 400 rating, I believe the old Bridgestone Pole Positions 960AS were the same. So yes, I've compared 400 to 300 rating in the real world.
Under braking, the Vreds have it, I can brake WAY harder and later than I ever could before.
I might throw the Spyder around the cones sometime this year. I'll let you know how they feel. It's been a couple years since I've autocrossed the Spyder.
I'm late to the Vred praise game but after having had a set of the Vred Sprint Classics on my Speedster and driving a lot of mountain twisty roads I can also say how well they grip the roads. Even not so smooth roads. The roads in our mountains see their fair share of rain, frost, ice, snow, and refreeze so they're a little beat up. Not as bad as areas where they just hang a sign that warns you of "road heaves" but not smooth. And they still maintain their grip in the corner very well.
All this sticky tire talk made me go out and look at what came on my Boxster when it was delivered. Well, I knew what tires came on it I just didn't know what the UTQG rating was and it turns out for the Yokohama ADVAN Sport V105s that are on there it is 240AA/A. I should probably just order another set of tires now.
@dlearl476 posted:LOL. The Hankooks I just ordered are 320 AA. They had about 25K on them in 10 years. Just as well. If the tread lasted any longer I’d have to replace them anyway because they’d start cracking.
That's standard for a weekender car. I put 25K on my Speedster in less time than that and I plan on driving the Boxster more than that, I hope. We'll see how long they last. A lot of guys on the 718 Forum are saying they're only getting 20K or less out of them and that is w/o any track time on them. Tire Rack calls them a "high-performance street/occasional light track use tire". For me they will be a mountain road twisties, wine country touring, coastal cruiser tire.
@Robert M posted:That's standard for a weekender car.
At one time I had a Riviera as a DD as well as my SC, Sprint Veloce, and 968. Even taking them out and using them daily for a month or two, none of them got a lot of miles.
Even after I sold the Riv and gave the Alfa to my son, I mostly rode my Ducati to work and alternated the SC and 968. I never had to worry about the 2500 mile limitation on my NV classic registration. In fact, when I sold my SC, I had 8,000 miles “banked.”
i’d planned on doing a road trip after I got it painted, but work got in the way. (I started touring again and there just wasn’t time)
ps: I got the 968 and cleaned up ostensibly to sell it, but I’ve been using it as a DD for a little over a month and I’m having a hard time letting go. It’s so sweet. I really want to sell it and get a 986 and a new motor for my Spyder, though.
The Box that started it all. Great car if you can find one that hasn’t been flogged too hard.
I had an appt Friday but 60% rain was in the forecast, so I called to verify they came in today. I figure I used all my good rain god karma yesterday. I pulled under the carport just as the big drops started coming down. The storm made the 10:00 news: .41” in 10 minutes.
They did come in, so I went out and had them installed. That “soft sidewall oversteer” is sweet. Seems like my power steering is “turned up to 11.”
Quite possibly the freshest tires I’ve ever bought.
I couldn’t find the date stamp on the other tire. I’m guessing they only stamp one side. But while looking I did find this, which surprised me.
@dlearl476…what did you find…that the tire is made in the good ol’ USA?
@DaveNorCal posted:@dlearl476…what did you find…that the tire is made in the good ol’ USA?
Yes.
