Tire sizes....again.

I know this topic has been beat to death but I can't seem to find the old posts. Anyway what tire tire size is everyone using? I ask because I just fit a set of 195/65/15 on the car and feel the car is super mushy not from lack of pressure but the tire seems too wide for the rim. I'm running a 5.5 wide standard VW rim. Even thought the manufacturer says the tire will work with a 5.5" tire I think the handling got worse than with the old 175/70/15 I had on there.

What's everyone running? 185/65 or 185/60's?

J-P

I have 195's on 5 1/2" rims and they work very well.

Mine are 185 65 15 on 5.5 wheels.
Eddie

195s will work great on 5 1/5 or 6 inch rims. What did you have on before? If you had 165s and then switched to 195s the extra 'stick' will be very noticeable. That 'mushy' feeling may be your stock suspension telling you to upgrade. Do you have good shocks (especially in the back) and are you running sway bars, front and back? Also, what brand of tire do you have?
Ron

So the 175's 70 15's actually handled better than the 195's not in grip but feel to the road....the tires I bought were a touring T4 Yokohama in a 195/65/15 to replace the smaller Dunlops. The car became scary to drive....you could turn the wheel back and fourth several times at highway speed then center the wheel and the car would still be moving side to side....didn't do that with the 175's. I could also push the car side to side when parked and see the sidewall flex even with 35psi in the tire. The manufacturer recomends a 6.0" rim for that size tire.....I think there right. I've got the car at the tire shop now...the shop was nice enough to exchange these tires for something like a 185/65/15. The 185's by manufacture spec are .5" smaller in dia and .5" smaller in width. Don't know what the added cost will be for the exchange...don't care got to get these off the car.

As for suspension....I'm using a 5/8th sway bar in the front, camber compensator in the rear and KYB shocks all around. Any advice would be great...tempted to put a rear swaybar on the car after all this is done...we'll see.

J-P

Make sure the tires are inflated properly. I think 35 psi is too much. Something like 18-22 psi front and 25-29 psi rear. Won't hurt to experiment and see what works best for you. Good Luck, have fun.

Ok...got the car back from the tire shop...big differance! 195/65/15 are too big for a 5.5" rim. The car feels much more stable with the 185/65/15. I can definatly feel the suspension could use a little more tuning but now I can at least tell that there is a road under me. The 195's feel like marshmellos left in a microwave for a minute, puffy. I've yet to get the car up to say 60-70 mph but just by driving around the block I can tell they'll be OK. Again this was a back to back comparision, same inflation, same tire, same day testing just different size. Bigger is not always better. If I was running a six inch wide rim I'd go with the 195's. Anyway...just my results, others may find something different.
Time to adjust inflation (lower) and get everything dialed in.

J-P

JP you're right, sometimes if you put a wider tire on a narrow wheel and the side wall is not stiff enough, the side wall will flex and the steering will be less positive. Also the contact patch will have a tendency squirm. This will not happen with a racing tire, as the side walls are much stiffer. Before side walls were made stiffer, it was best to run a slightly narrower tire than wheel so the side wall flex would be used up getting to the wheel rim, and would give very positive steering response. Of course with modern tires this is much less common. Also, the stiffer the side wall, the stiffer the ride will be. Try high and low tire pressures and you will feel it in the seat of your pants.

Eddie

Bingo....Eddie you read my mind. I think that's the case here...too much side wall flex with the 195's. I'll adjust the pressure next....what pressure do you run on your tires?

J-P

Jean-Paul, I'm sure that others know much more on this subject, but here's my thoughts on shocks.

On a pan based car with the short wheel base, swing axle, and light Replicar weight a stiffer, or more performance oriented shock, "may" be counter-productive in what you are trying to achieve. I replaced mine this year in just a PM effort. After reading through old posts on the matter I decided to go with stockers and break them in by hand per John Steele's (JPS) excellent instructions (available in the archives search).

Now, I would welcome other's thoughts regarding this subject. And your suggestions based on your experiences too. I am not an expert on the subject, and just went with a conservative approach that was proven and what JPS does with their cars.

I will say that adding the larger gas tank has had a nice side effect of improving the ride with the increased weight. I hardly ever get below needing to pump 6 or 7 gallons now except on that OKC-LA-OKC run where I hit some 300 mile runs between pumps. The extra 7 gallons over what I normally ran on the low side has made the car more stable at higher speeds and with side wind/drafts. (another 2 pesos)

As far as PSI's? My two pesos is that I run 28 back and 26 front for daily driving on Dunlop's A2 185/65s. 2 1/2 years of 32K miles driving and they were still in great shape, I finally replaced them just because I was going over the car. I also discovered someone recently ripped off a set of valve caps that were chrome with the logo on top. It was a little gift from my daughter. Pissed me off.

Good luck on all your improvements! That's 50% of the joy of these cars.

Three tires that I like in the 185/65 x 15 size are:
Potenza RE 950
Dunlop SP Sport A2
Falken ZIEX ZE 512

The optimum rim size for all three is 5.5 inches. I had the Potenzas and the Dunlops on my IM and I liked both. The Falkens recently placed very high on the last Consumers Report tire test.

Ron

Let me jump in on this since I'm about to change tires,

Now I have Pirelli 165 on a 5.5 rim. I'm going to replace and 165 seem to be hard to find. Cooper has a Sportmaster which I can get from my local dealer. Do I move to a 185 - As to clearance my finger drags a little on the top part of the passenger rear well, the other side is fine.

What do I gain with the 185 vs. staying with the 165? It drives OK now with the 165.

I'm pretty much on the same page as Jimbo, the front of these cars is lighter than most other cars on the road so most shocks are designed for more weight than a speedster weighs. That's why it's real easy to over shock a VS or a JPS. The IM's have a slightly different weight bais, and have more weight on the front wheels. That's why Kirk and John use the inexpensive shocks on the front, because most performance shocks are designed for more force than stock shocks, and produce a harsher ride.
Regarding tire pressures, Kirk recommened 22/26 for best ride, John says 28/35 I think, and I use 25/30 most of the time

Eddie

185s should improve the handling in a big way. This will be especially true if you go with a fairly high performance 185 tire. The big problem with 165s, as you mentioned, is that you can't find any 'performance' tires in that size.
If you go with a 185, any fender clearance problems will be in the rear. Also, most speedster have a bit more clearance on one side than the other. I had my tire shop mount one 195/60 on my rim and I mounted it on the front and back to see if it would clear...it did. So, I bought 4 tires, had them mounted, balanced and then put them on my car. Turns out the tire rubbed the fender on the back passenger side...the side I didn't do a trial fit on. I ended up trading the new tires in on 185s, which fit just fine.
Ron

Ron,

Thanks for the input. I'll look into the 185s, although I'm not a speed demon. As I always say, "Another fine mess I've gotten myself into, Ollie." Let's see where I wind up.

Thanks again.

The 185's are a really good improvement over the stock 165's...The car feels more secure on the road and if need be I can get on the brakes alot harder than before without locking anything up. The 195's don't handle too well on 5.5" rims, at least this is my experiance....had no rubbing when I put those on.
Anyway...tire rack has a really good selection of tires...but go to a tire dealer for your first set so you can do a little trial fitting first.
If you've got at leat 10+ mm between the tire and fender with the 165's then you stand a good chance that 185's will fit.

J-P

i'm running 190/60/15 michelin hydro edge;an amazing tire after the general 2000'S that were put on in 96.the only problem i have is they rub on the lower arms when i try a very tight turn into a parking space.

Angus,

Adjust the steering stops on the axle beam quarter to half a turn

Hey Dick Robinson...

I got to crawlin' around on the garage floor (Dale F. shamed me into washing my car Sat. night after the show) and I'm running 195s on my car, not 165s like we talked about.

195-60-15s on 6 inch wheels. I just replaced the originals tires, same size, washed and shined everything up and was going to check the tire pressure. Well something came up and after torqueing the wheels on the car.

Driving down to the Northern Cal Kit Car Club show I thought the car was awfully twitchy. Driving home felt the same way and some of the freeway curves felt real freaky. I checked the pressure in the morning (cold) and found I had 35-38psig in the tires. Doooooh!

Much better now.