jusplainwacky

Frank...I'm not being **** or obsessive....just trying to figure out why people would opt for the 70R15 when it's smaller in diameter than the original. Considering that I'm not a tire expert...maybe there is something I'm not considering. In fact, while researching if I should even go with the 205 or the 215R75...I never thought about the tire fitting in the spare tire compartment. It's all about doing homework and knowing I'm making the right decision.

jusplainwacky

BTW....Frank...you don't mention what you bought.

61 Roadster

I chose the 205/75R15 diamond back MX and couldn't be happier with them! Yes, the spare tire board sits slightly above the well, but it doesn't bother me.

SW Vette

What you seemingly fail to comprehend, despite receiving several explanations and all the conversion info in clear graphic form, is that 215/70 is roughly equivalent in diameter to 205/75. The difference between them is mainly in width, not diameter.

I know, I know... nevermind

woodsdesign

I originally put the 215/75R 15 Diamond Backs on my 65 coupe. They barely rubbed the lower front valance on an extreme left turn. No problem, I just filed a little bit off and touched it up. They were good for quite a while. Then one day I made a hard left turn while pulling into my drive. When I hit the apron bump the tire came up and hit the lip cracking the front fender slightly. I think that is why most guys don't go with the 75's. They are just too close for comfort. I Have 215/70's now. All is well.

jusplainwacky

Why some people feel the need to insult and talk down to people on this forum to make their point is beyond me.

Why do you think I'm asking the question!?! I haven't a clue if this negligible difference makes a BIG difference in the ride, performance, speedometer accuracy, ability to steer, hitting the body, etc...unless I ask. And it goes back to the original question...if they were so similar...why would a person opt for one over the other...simple question.

It would be one thing to be so "****" and 'obsessive" about buying a 20 dollar part and it's another spending over 1,000 dollars on tires....why not get all the information you can?

Thanks Lawrence for sharing your experience...it's info like this that to me is important.

SW Vette

He told you exactly what I said in post #3.

jusplainwacky

This is what you said in post #3....Sorry...but that doesn't tell me squat...or perhaps anyone else having the same question. Maybe if you said, it's the best overall tire BECAUSE (and gave a reason base on your experience and knowledge).....but you don't.

AND if it was the obvious choice then I guess everyone that has put on 215/75R15 or 205/70R15 or 205/75R15 doesn't know what the heck they are doing or maybe just got a hell of a deal that it didn't matter to them. To me it does matter.

Geesh...this is just a real simple thread on why people opted for the tires they did, and nothing more. No need to get into a "who's tire is bigger" discussion. If my posts are driving anyone crazy...they don't freaking read them much less respond.

SW Vette

So now you've got a guy who says that 205/75 works for him, and another who says 215/70 is the right setup. Whatcha gonna do? Dude, it's not that complicated.

Frankie definitely has a point

jusplainwacky

The jury is still out.
There was some great information on tires presented here, including the difference in speedometer reading verses tire diameter. Before I started this thread, I read about every thread out there, but this thread has information that others didn't....especially the website where you can put in the tire size and get information.
Although many may have opted for the 70R15....I'm leaning towards the 75R15's because they are closer in diameter to the original. Now as far as tread width (205 or 215)....I don't know. I understand that people say that 205 will handle better at low speeds)...but the 215 rides better. And from what I have read, putting on 215's isn't a problem with them hitting.

59BlueSilver

jusplainwacky

I'm not making this complicated...but some of you are. This thread was just to understand WHY (repeat WHY) people bought what they did...that's it! Not "what works", or "I got a deal"...etc. People bought what they did for a reason...I'm just curious as what that reason was.

Let me give an example of what I was looking for. (Just making this up)..

I bought the 75R15 because they have bigger sidewalls, which results in a smoother ride, but I find doesn't corner as well.
I bought the 70R15 because the turning radius is better.
I bought the 215's because they track better in the rain and it rains a lot where we live.

As pointed out...not that complicated.

jimh_1962

I have two different sizes. The ones on the back were oddball size (larger and slightly wider). I decided to run smaller set in front. I had a tire get cut so I needed another front set. The size was not in stock so I went with a thinner tires on the front. The ones on the rear do slightly rub on the inner well when I get on it. All of the rims are 15x6.

jusplainwacky

What sizes are you running?

jimh_1962

No reason why to understand what everyone is doing. Tires are like women. All kind of shapes and sizes.

In my cases, I bought a set of American Racing Torq Thrust plus tires from a guy who owned a 62 honduras maroon just like mine.
He recently purchased the restored car from a dealer. He did not like the look so he went with steel wheels with hubcaps plus diamond backs with thin white walls. I bought his set of four tires/rims for 1000.00. Heck of deal for a set set of new American Racing wheels plus tires. The tires still had the stickers. I ran with the size tires around until I cut one down during a drive. Now, I have set of smaller and thinner tires on the front. Its fine for me until I get enough rubber worn down on the rear.

You have to keep in mind what type of roads you are driving on. I am sure you are going to driving on some crappy roads in the bay area. I know I have driven them.

jimh_1962

I do not know on the top of my head. I will get you the size. I remember the one set were very tough to find. I called around to find two more tires and settled on something more available.

jusplainwacky

Ok...let me throw in a twist in here...

As I'm sure most of you know, Diamondback doesn't manufacture tires...they just buy tires then modify them with their "special secret glue" (what ever that is).

What about avoiding all this and just buying a tire where the whitewall is engineered into the tire manufacturing process...like "American Classic" from Lucas Tires in Long Beach, CA?
To me it seems like it would be less prone to coming apart buying a tire where the whitewall is part of the manufacturing process...but I'm sure from all the reviews that the Diamonbacks are excellent tires.

I'm leaning to the Diamondback...but don't know anything about "American Classic" tires...are they any good?

Thoughts anyone?

Viet Nam Vett

Also ..keep in mind that that the 65 Corvette Speedo..(Others may fall into this category).. are not dead nuts on speed. According to youtube speedo rebuilds posted by rebuilders ...they even state that back in the day the speed's were 5 to 7 % differential in speed.

They are were not meant to be rebuilt but replaced per the factory at that time. Since today you can have them rebuilt..and calibrated by a speedo calibration machine that they use, this does not guarantee they will be accurate at different speeds.

You are probably better of with your Apple speed app. I use "Speed Box". But don't have to any more.

Since I no longer have the old tech and dash I don't worry about it. I did the Dakota Digital Direct fit dash which is dead nuts on. In fact you set the speed when you program it.

No more whiling cables for me...

ohiovet

Dennis,
It is plain and simple;
The replacement tire for a bias 670-15 is a radial 205 75 R15.
I have used that size on all my C1 Corvettes for years and have had no speeding tickets.
I actually check my speed with a GPS and it was very close.
Bruce B

jusplainwacky

Hey Bruce...thanks for the input. That's the size I'm planning to go with and what Diamondback recommends.

I was on the verge of just ordering them from Diamondback, but then I decided to look on the forum and see what others were using and I was surprised to see many people going with the 70R15...and that just perplexed me. The natural question was...why? Is there something I'm missing? Ergo I created the thread.

By the time I'm done, it will cost me close $1,400...for 5 tires and that includes putting them on the rim's....so yea, I'm going to do my research and ask questions. I read so many threads from people laying down some serious money only to complain what they bought....I don't think I'll be one of them.