best tires

[woobie1966]

ok, here goes... my 1970 corvette is a toy/weekend driver, so since its time for new tires all the way around i figured what the hell let me get the widest,stickiest i can fit/find.
i have been to several websites (tireack etc), several local tire stores, and of course everyone has a different opinion of the best tire. so i put my case before my brethren to see what others are using. i still have the original 15x8 rims, and currently have 225x70 all the way around. i have been told i can go as wide as 235 up front and 255 in back, does this sound right? i would also like lower profile (60, 50...40?) but im afraid too low profile might leave a big gap between the tire and the fenderwell
any comments or experiences would be appreciated
thanks
mike

 

[Bob Chadwick]

I don't know the answer but have been debating the question in my mind as well. I would like to stay with the stock width but am considering a 16 or 17 inch rim with a 50 or 60 series tire and then having the speedo recalibrated.

I don't want to have to deal with offsets and spacers. Just a direct bolt on.

Bob

 

[woobie1966]

i thought about some billet wheels (16" or 17") just to give me more tire options, but i have now heard that aftermarket wheels will not allow the parking brake to work. with the stock 15" wheels im stuck with few choices in tires in the widest size i can fit (235x60 in front and 255x60 in back) .

 

[Hijinx]

All,
I am working on a Wheel/Tire size article for next months Shark Bites column. I hope to have a good overview of everything from stock 15x8 - 225/70R15's up through 20 inch monsters. If you can (and I know how hard that can be), you may want to wait till I post that article. I plan on going into tire sizes, wheel off-set, speed ratings, and needed modifications for these changes.

Just thought I would drop this in here to let you know its coming.

 

[GWHITE75]

Seven years ago I bought a set of Centerline Billet wheels (Scorpions) because I liked the look, weight and did not want to put spacers on my car. I went with the 16" x 8", at a time when 17" wheels were coming into popularity. Now, I wished I would have gone larger.

My wheels have a 4 1/2 back spacing. I put on a set of 4 - BF Goodrich ZR1 255 x 50 x 16" tires and run them with no problem, however I am not sure if your front fenders will allow that size to turn properly. Also, I moved my emergency brake mounts to the top of the trailing arms.

 

[woobie1966]

well, things recently have taken a turn, the other night during some spirited driving the fan shaft broke off the water pump sending the fan into the radiator.....sad, very sad results.
well i still plan to change the tires, but now im also considering another choice.... aluminum or copper/brass radiator? either way i think im going with an electric fan and high volume water pump
any one have experience with any of the aluminum radiator
manufacturers , electric fans, water pumps?

 

[Hijinx]

Woobie, bad news. Do a search on the main C3 tech forum. There has been a lot of past discussion on radiators and electric fan setups.

 

[GWHITE75]

well, things recently have taken a turn, the other night during some spirited driving the fan shaft broke off the water pump sending the fan into the radiator.....sad, very sad results.

The same thing happened to me with a Weiand aluminum water pump. Ruined my fan shroud, fan and farily new OEM radiator. I installed a universal aluminum Griffin radiator after fabricating brackets and hose routes. I had the water pump rebuilt at a local shop. They installed a bigger impeller and bearing set. I suspect belt tension and the mechanical fan spacer caused the malfunction. I don't believe the pump was defective.

Initially, I bought and installed the Spal dual 11" fans, but they proved ineffective, therfore, I re-installed a fan clutch, 18" fan and repaired my shroud. I now run at 190 with my A/C on during 90+ degree days and only get up to 210* in traffic. I could not maintain those temperatures with the Spal fans. I now have over 5000 miles on my vehicle and the pump, fan and belts are still secure with no signs of problems.

 

[woobie1966]

im glad to hear some one else had a similar theory, about the belt tension. i had never had any problems with overheating before this, no odd sounds eminating from the pump. i believe on the night in question, i lost traction at around 45 mph when i hit a wet spot of pavement, the rpms went up quickly and.....
also i remember when putting the belt on thinking " geez, this is tight" i contacted griffin, theyhave an alum direct replacement
for $731. its too bad about the electric fan, i kind of had my heart set on it. maybe it was just that brand/setup?
one other question, the a/c on your vette, is it factory or aftermarket? i have been looking at an aftermarket setup (the car i believe originally had air, has "a/c "on vent dials but someone took it off . also,i know the a/c will tax the cooling system i was thinking of installing an oil cooler to assist, any comments?

 

[GWHITE75]

It never ends. Hey, if money is not a problem, you might investigate the BeCool radiator instead of the Griffin. I was told that the BeCool is totally welded, where mine is not. The tanks are bonded to the tubes. I am not totally sure if this is a bad thing longevity wise, but I would probably have bought the BeCool if I had it to do over. I did not know this Griffin was bonded.

As for the fans. I installed them properly, with a total seal between them and the radiator. All the time I was thinking that these units would not pull enough air thru my radiator during the summer to keep the motor cool at speeds in the 10 - 40 MPH range. (Stop and Go traffic) They didn't.

Before I ruined my first radiator, cooling was adequate with the shroud and mechanical 17" fan. With the Spals, the temps got up past 220 degrees in traffic and would not drop until I was driving 60-75 MPH. Putting on an 18" fan, with clutch and shroud, has got me up past OEM specs and the aluminum radiator/water pump keep my motor at 210 degrees in traffic and at 185 at speed during 195+ degree days.

I sold the fans to someone up in Illinois. I know that a lot of people use them with success, but I am not sure how many run their A/C's in the summer with 95 - 100 degree days in traffic. I would like to hear how they were able to get these fans to work for them. There have to be a few who have.

As for the A/C, it's a Vintage Air CompacII system. I understand that Vintage Air now makes a unit for the C-3. This was not available to me when I bought mine. It's great, uses R134, smaller compressor, smaller condensor coil and there is no longer a box hanging out in the firewall. It will not allow you to bring in outside air or vent though. If that is a requirement, then you might not want this system. It recirculates the inside air and drops the temperature easily.

Oil coolers and even a remote transmission cooler would not be a bad idea. Locating available space for them is the biggest issue. You could always do away with your spare tire and put them there.

 

[Last Ride]

I see lots of concern here about problems with the tires interfering with the e-brake. Does that thing even work? I know mine never has. I run 255/60 R15 at all four corners with no problems. I know where I can get a custom set of rims built (in the near future, I hope) in 17x8 on the front and 18x9 on the rear all under the stock flare and trailing arms. Do some digging, choices are out there!

 

[woobie1966]

i had the emergency brakes re-done, my driveway is on an incline
and i need it with my 4 spd. if i had known that the brakes would interfere with larger rims i might have looked at other options.
for now im going to get the widest to fit and in the future ill look into rotating the e-brake, and putting bigger wheels on

 

[LT4hitsthespot]

tires

I am running 265-50-15 on my 78 with the stock wheels. They are big and meaty. It is my understanding though that 78's have wider wheel wells. They are in need of being replaced (atleast the rear tires......can't figure out why. LOL). I am thinking of going to a 17" wheel and then maybe going to more of a low profile tire. I want anything I can get to give me more tractioin in autocrossing. I am just not sure of what I need to watch out for as far as problems on changing wheel sizes. Any info on what to be aware of?

 

[Bill Meyer]

Sorry to hear about your radiator. I have a 1977 Corvete w/ 15x8" rims and I use a 255x60 on all 4 corners- no problem.

 

[a69vette]

On the '69 I used to have 225/70's all the way around. I just changed tires a couple of months ago. I got the BF Goodridge TA Radial. I choose the 235/60's because it does NOT hit anywhere on the front's. It's my understanding that somewhere around '74 or so, GM enlarged the wheel well area to accept a wider tire. You can put a 245/60 on the front but it will rub. The rears should be able to take a 255/60. I've seen several cars with 2 different sizes on them. If you don't care about a rotation, then mix. If you don't mind not being able to turn the car the full amount go to the 245.
Good luck.
Rick

 

[woobie1966]

thats exactly what i've been getting (info) as far as the tire sizes
that sometime in the mid 70's they widened the wells.
i think im going with the 235 up front and the 255 in the back.
im going to put the car in the shop for the radiator work, re-upholster the seats, install a/c and the tires all at once (present to self!). the car is red/red. a bit too much red for me. im going to re-do the interior in either lt. or dark saddle. im going to do the seats early because the originals are worn and not the most comfortable.
i believe this car was originally an a/c car( it has "ac" on the vent dial) and down here it is necessary, especially in summer traffic , between the sun glaring and the engine heat....any how barring any more disasters, ive had dreams of the clutch going south
i should be up and running in march i hope