Hello,

I'm brand new to the forum, so go easy on me:-). I know there are endless tire threads for the C3 Corvettes, but I just have a very specific question. I just bought a 1968 427 (L36) and it has 20 year old Coker Classic P205/75R15 tires. Needless to say, they need to be replaced ASAP. I would like to install BF Goodrich Radial T/As, but wanted confirmation on the largest size I can install without any issues. The wheels are stock 15 x 7. From what I have gathered from other threads, I should be able to go with a P235/60R15 without any problems. Can anyone confirm this? Also, if it is possible to go a bit larger, that would be helpful to know as well. I really don't want any rubbing and I'm not interested in relocating the emergency brake cable. Please let me know if you need any additional information.

Thanks in advance for your help on this!

Scott

 

beautiful 68 I like to run BF radial T/A ‘s 225 60R15 sits nice in the wheel well and will not rub

 

Thanks so much Grady for confirming that the 225s will fit with no issue. I will wait to see if anyone has had good luck with the 235s, otherwise I will order up a set of the 225s. I feel very fortunate to have come across such a beautiful 1968 and I'm looking forward to getting advice from the many experts on this forum regarding other issues I have yet to tackle.

 

The modern equivalent to your 68's original F70x15 tires is a P215/70R15. I'd either go with the 215/70 or maybe a P225/70R15, which will visually fill the wheel opening better (compared to the original F70's). If you want a wider tire, I'd go with a P245/60R15, which like the 225/70, will fill the wheel opening better and still fit with no issues. Even 255/60R15's should fit, as they were an OEM option from 78-82.

To be honest, I really like the look of the red lines, which were an option in 68, unlike white lettered tires. If it were mine, I think I'd be looking at either the 215/70R15 or 225/70R15 repro red line BFG radial tires from someone like Universal Vintage Tires. I know they're not cheap, but then neither is a beautiful 68 big block coupe like yours.

225/60's are going to be way to short visually, and will throw your speedo off, since they're much shorter than the original tires.

https://www.universaltire.com/215-70r15-bf-goodrich-3-8-redline-tire.html

https://www.universaltire.com/225-70r15-bf-goodrich-3-8-redline-tire.html

 

I just replaced tires on one of my trucks this spring which were 20 years old! LOL. Different compounds age differently. Lot of the so-called 'good' brands, Michelin, Bridgestone, and probably some others seem to use a high-silicone which start cracking real bad in 5-7 years. Other tires I've seen look great after 15 or more. Ever look at tractor tires that are 30 years old? Many still look great! I bet tire companies like it when Consumer Reports say to replace tires after 8 years, or whatever they're down to these days. I know tire shops do. Coopers I've had (and I've got a few pr of truck tires out there on some vehicles) seem to last a long time before they get brittle and weather. Just sayin ...not suggesting you still drive on yours.

Someone put on Destination LE3's (another post) and they look good. I'm an OWL guy myself (can't get out of the 80's!!! he he).

Some guys report that some brands W/W's turn yellow ..so you might want to avoid those (unless you like yellow, or dirty-white).

Show us what you get when you've had them installed.

 

Thanks for the wonderful information gbvette62. I must admit that I do like the red line tires that are on the car now, so you have certainly made my decision a bit harder:-). The car was restored pretty much 100% stock, so the factory option red line tires are quite compelling.

So given that I am looking for a wider tire, it looks like my choices are the BF Goodrich Radial T/As in a P245/60R15, or the BF Goodrich radial red lines in a 225/70R15. While the red lines are quite a bit more expensive, they just might be the best choice.

I also can't thank you enough for explaining the importance of filling the wheel well out properly - something I wasn't focused on enough.

I must admit the car stops traffic with the existing red line tires, so as they say "if it isn't broken, don't fix it":-).

Thanks again!!

 

FWIW, if you want to get a real good balance on them, get them Road Force balanced.

GM service departments are required (according to my GM service dept buddy) to each have a Hunter Road Force Balancer. They're the best. And my local small town Chevy shop will charge me $75 to road force balance (and rim-match) a set of tires ...if I bring in my own. What does that do compared to other tire balancers? Well, the R/F balancer has a spinning drum which puts about 1,200#'s of pressure on the tire as it's spinning, and the balancer can determine tire out-of-roundness and also rim warpage. The balancer can advise which part of the tire can be rotated to a specific part of the rim to achieve the best balance with the least weights. That's called 'rim matching'.

A lot of places have Hunter Road Force Balancers, primarily for tough warranty purposes, but very few places will ACTUALLY perform the Road Force balancing proceedure, and even fewer places will perform the rim-matching. The reason is simple: it takes a LOT more time to rim-match ...because after the balancer determines the proper tire/rim indexing, you gotta put the tire back on the changer and break the tire bead, then rotate the tire to the mark on the rim, then re-inflate the tire. It takes time. Secondly, a lot of tire techs don't understand how to use the features of the R/F balancer because they don't use it often enough.

But the local GM garage, that's ALL they do ..every set of tires they install. For referrence I had Walmart balance some 10 ply truck tires. The weights they had on them were insane. I had them re-balanced at the Chevy garage ($75/set -- I had them off and in my truck) ...and they cut the weighs down significantly. There is 1/3 of the weight Walmart had on them. Plus the Hunter machine gives an actual read-out (an actual number) when yer done what the actual quality of the balance is. That gives you a standard you can compare to. If you had an out-of-round tire, another shop would just pile weights on and they'd bop and bobble on the road and you wouldn't know what was up. Something like that wouldn't slip past a R/F balancer with a competent operator. Plus the RF balancer can line the weights to fit behind the rim spokes (for spoked wheels). I don't work for them ..just letting you know.

Anyway, if you want a real smooth ride, consider paying a few bucks more for a great balance job. There's lots of Y/T videos on them...

 

Thanks Mark. Great information!

Surprisingly, the side walls on my existing 20 year old tires do not look cracked at all. They're probably good for another 20 years - LOL.

Sure sounds like I need to select my tire installer carefully - very helpful insight into how a proper balancing job is done.

I will definitely post a pic of whatever tires get installed:-).

 

I had BFG 235/60 R 15's once, but I have had 245/60 R 15's ever since. They looked too small and did not corner like the 245's that I had previously on the car.
And that is a beautiful 68! Lou.

 

Many thanks for the kind comments Lou! With your confirmation, as well as the recommendation from gbvette62, I now feel quite confident that the P245/60 R15s are the way to go with the BFG Radial T/As. But, I just can't decide between red line and white lettered tires. The red line tires will certainly adhere to the 100% stock restoration that was done to the car and give it an understated classy look. With that said, I also love the look of the Radial T/As, especially in contrast to the red paint. Decisions, decisions...

Thanks again!

Scott

 

Just to warn you, BFG has had their white lettering turn brown after a while. Many posts on here. I left the blue protector coat on mine and will deal with it later. Scott, I am a fifty year coupe owner and my company made C-3 parts. Lou.

 

Thanks for the heads up Lou. I did decide to go with the Radial T/As, so hopefully I have better luck with them staying white for awhile. I will also look forward to getting advice from you on future upgrades, given your extensive background on these beauties:-). Next project is to swap the stock radiator with a DeWitts (black to keep the stock look )and change out the aging hoses & thermostat. The 427 is currently running quite hot on warm days. It has the correct seals and shroud installed, fresh coolant and a new radiator cap, so it appears that it's just a case of the passages narrowing from corrosion over time and a slight loss of pressure from a small leak on one of the seams.

Thanks again!

Scott

 

X2 on road for e balancing…had to replace 2 bfta not that old.
ask for the number for each.

 

The 68 Corvette was the first GM car that only got cooling air from the front spoiler area, called a bottom breather. 68 Owners "tested" them for GM. The 68 radiator supports ,that my company made, were identical to the 63-67's. There is only one problem with that. Look at the huge open grille that the C-2's had. C-3's headlights and rubber stone guards blocked the air going into the two front side grilles and a license plate blocks the center grille incoming air. The radiator supports and the radiators were made larger in 1969 because of their cooling inability. Lou.

 

don't by coker red lines. buy them from diamond back if you want red lines

 

Thanks Lou regarding the cooling issues. That explains why I'm running so hot. I'm contemplating moving to Anchorage to resolve this issue:-). California weather is not real accommodating to a 68' 427 (at least not a bone stock one).

Thanks Nowhere Man on where to buy the red lines. I actually made the decision over the weekend to go with Radial T/As. It was a hard decision since both look great.

 

A lot of guys really like the Radial T/A's.... I think you'll be happy with them. Let's see a pic of your nice new car when you get the new shoes installed!!

 

Thanks Mark. I'm sure I will love them, assuming the left rear tire doesn't rub against the emergency brake cable. It's going to be close tolerances with these 245/60 R15s on the original 15 x 7 rims, but others here on the forum (with vast experience)have had good luck with this size tire on the 68', so fingers crossed. If it doesn't fit as planned (since all 68's are not the same after 54 years), I will default back to the 235s. But, if all goes well with the mounting this Thursday, pics will be posted later that day.

 

Not to confuse you some more, but my opinion
15x7 AG rims using 245x15 will round the tire a little and I feel will not sit flat. If you use a 15x8 AZ rim then it will sit flatter but you will probably have tire rub
I personally would not go with 245 tires as it will rub. I have a 68 and I plan on using 235x60 all the way around for driving.
I have 15x8 with 245x60 on my 71 454 and no issues. The design fits better. I also have a 71 LT1 and it has 255x60 and looks great and again no rubbing issues

For your 68 using the 15x7 AG rims I would go with 235x 60's for the front and rears. But if you like put 245x60 in the back.
or borrow a set of 15x7 AG with 235 and then try 245 to see if there is any issues.
g

 

When I got mine it had the 225/60 and it always looked weird and like it should be lowered (stock suspension). Went with the 225/70 and could not be more happy, looks great now.

Edit: And now the speedo shows correct

gbvette62's post was spot on.