Help me with tire selection

[MrFreeze]

Turbinator has supplied me with some restored wheels for my '64 (15 x 6 #895).  Now I need to select tires.  I was considering 225/75R15, but I have heard they may rub, and that 225/70R15 is a better choice.  Anyone out there running either of these sizes that can provide real-world input?  I am also planning on running blackwalls, as I think they would look better given this car's paint scheme.  Anybody want to recommend a particular tire for a fair-weather cruiser?  Either way I'm sure it will be a challenge finding good tires in 15" diameter these days.

 

Some pics for inspiration:

 

 

Appreciate any input you folks may have.

 

MrFreeze

[RivNut]

Did the 895s, with their 1/2” deeper back spacing clear the fins on the drums without a spacer?  Are they clearing all of the upper and lower suspension pieces?  Tires depend on what you’re after. With the 1/2” deeper back spacing you liable to experience tire/frame rub with anything over 215 or 70 series tires.  I had 225/70R15 Goodyear Eagles on my 63 with stock 6” steel rims and got tire rub on the inside of the left front tire at left lock or when pulling into the driveway. Totally stock suspension.

[MrFreeze]

The car has 1-1/2" spacers on the rear wheel compliments of the previous owner.  On the front, excess fins have been not-so-gently removed from the aluminum drums.  Wheels appear to seat properly and clear the suspension with no issues.

 

Interesting to hear you had rub with stock rims at 225/70R15.  Any chance you had tired/saggy front springs contributing to the issue?  What was the original tire size on these cars?

 

Appreciate the input.  Unfortunately, it looks like Goodyear no longer offers any tires in either of my 2 preferred sizes, unless you count trailer tires.

 

Best regards,

MrFreeze

[RivNut]

Stock suspension and wheels. Everything measured to specs.  As I said it only occurred during full lock to the left. There were no issues during normal driving.  The only evidence was a shiny rivet head on the frame, the tire would keep paint and dirt off the rivet head.  

[RivNut]

There are lots of 15” tires out there, maybe not all season radials by the old standards Firestone, Goodyear, or BF Goodrich, buts lots of good tires.  Why did you put the 895 series wheels on the car knowing that they wouldn’t fit without some problems,

Edited April 15 by RivNut (see edit history)

[atencioee]

I like my 205/75R15s...Gives it a little lower look. Currently have 895s on my 64 with spacers.

[Seafoam65]

I've had two different sets of 225-75-15 tires on my car with no rubbing

[Barney Eaton]

Attached is a chart (powerdog.com) that compares different sizes mentioned above.  

In a reference book, it said 1963 & 64 Rivieras came with 7.10 x 15 and 1965, 66, 67 came with 8.45 x 15 

consulting another chart .. found one that said 7.10 x 15 converted to a 225/75r15   and a different chart did not show 

the 7.10 size but had 8.45 X 15 converted to 225/75 r 15 so there may have been a tire industry change in designations. 

Gene above said he liked the 205 because of the shorter sidewall, note the 225/70 sidewall is only 1/10 inch taller and the 235 is 1/10 shorter.

When you use powerdog,  the first tire you enter should be your base as all the other are compared to the first entry. 

 

Specification	Sidewall	Radius	Diameter	Circumference	Revolutions	Speedometer	Odometer	Difference
225/75-15	6.6"	14.1"	28.3"	88.9"	713/mi	60MPH	10000mi	N/A
205/75-15	6.1"	13.6"	27.1"	85.2"	744/mi	63MPH	10436mi	-4.2%
225/70-15	6.2"	13.7"	27.4"	86.1"	736/mi	62MPH	10323mi	-3.1%
235/65-15	6.0"	13.5"	27.0"	84.9"	746/mi	63MPH	10466mi	-4.5%

h

[Barney Eaton]

I might add that the first number of the tire size is allegedly the fattest (widest) part of the tire in mm. 

If a 225 (8.86 inches) does not rub,  a 235 (9.25 inches) is only .39 wider.   That is spread equally to each side

so the 235 would only be .195 wider on each side.    All this does not take into consideration what rim you are using. 

[1965rivgs]

  Barney, there was an industry size designation change between `64 and `65. You are correct that the standard size tire in `63-`64 was the 7.10 but the oversize tire option was a 7.60. The `64 7.60 is the equivalent of the `65 8.45. The charts seem to often contradict each other but my guesstimate would be a 7.10 is comparable to a 215 and the 8.45 is somewhere between a 215 and 225; probably closer to a 225

Tom Mooney

[RivNut]

Buick also took rim width into consideration with tire size.  In 63 and 64, the standard size tire for the Riviera was the 7.10 x 15. It came from the factory mounted on 5.5” wide rims.  If you ordered the optional “Oversized” 7.60 x 15 tire, it came from the factory on a 6” wide rim.  There’s a 1/4” difference in offset on each side for the 6” rim.  This doesn’t come into play much except if you’re running the 63/64 cast aluminum wheel covers.  The wheel covers are fastened to the wheel from the rear with a two ended shoulder bolt.  The wider rim takes a bolt with a 1/4” wider shoulder. The cover itself is drawn tight against the shoulder, not the rim of the wheel. The “For Service Only” chart below tells you which shoulder bolt to use based on the original tire size. The part numbers in the upper right Corner are for complete assemblies, different assemblies based on wheel width.  When measuring a rim, be sure to measure inside the bead, not across the outside lip to lip.  I know a lot of this is rehash, but there are newbies coming our way often who have probably not run across this.

 

 

As long as we’re discussing cast aluminum covers, be advised that when the car was delivered new, there were five cast covers but only four spinners.  Your spare should have a cast cover bolted to it.  When rotating tires, you did not R & R the cast cover.

 

 

 

 

Edited April 15 by RivNut (see edit history)

[RivNut]

2 hours ago, Barney Eaton said:

Attached is a chart (powerdog.com) that compares different sizes mentioned above.  

In a reference book, it said 1963 & 64 Rivieras came with 7.10 x 15 and 1965, 66, 67 came with 8.45 x 15 

consulting another chart .. found one that said 7.10 x 15 converted to a 225/75r15   and a different chart did not show 

the 7.10 size but had 8.45 X 15 converted to 225/75 r 15 so there may have been a tire industry change in designations. 

Gene above said he liked the 205 because of the shorter sidewall, note the 225/70 sidewall is only 1/10 inch taller and the 235 is 1/10 shorter.

When you use powerdog,  the first tire you enter should be your base as all the other are compared to the first entry. 

 

Specification	Sidewall	Radius	Diameter	Circumference	Revolutions	Speedometer	Odometer	Difference
225/75-15	6.6"	14.1"	28.3"	88.9"	713/mi	60MPH	10000mi	N/A
205/75-15	6.1"	13.6"	27.1"	85.2"	744/mi	63MPH	10436mi	-4.2%
225/70-15	6.2"	13.7"	27.4"	86.1"	736/mi	62MPH	10323mi	-3.1%
235/65-15	6.0"	13.5"	27.0"	84.9"	746/mi	63MPH	10466mi	-4.5%

h

Here’s a list from the ROA’s website that shows equivalent tire sizes. The chart is incomplete because it only shows one tire size for 1963.  Refer to the 1964 line for the same info for 1963. It also show an 8.85 tire for 1965 which is incorrect.  The larger tires in 63, 64, and 65 were for the heavier Electras.

 

https://rivowners.org/features/Ev_Stats/dimensions.html

 

 

Edited April 15 by RivNut (see edit history)

[Craig Balzer]

These photos are from my 65 Riviera Gran Sport (made in December 64) -- may help.

 

Sorry for the dirty tires/rims - I live on a dirt road.

[MrFreeze]

16 hours ago, atencioee said:

I like my 205/75R15s...Gives it a little lower look. Currently have 895s on my 64 with spacers.

That's what I have on the car now, but they are just a little small for my taste.

 

What size spacer do you have on the front?

 

MrFreeze

[MrFreeze]

7 hours ago, Seafoam65 said:

I've had two different sets of 225-75-15 tires on my car with no rubbing

I take it this is on a '65 Riv?  I "assume" the '64 and '65 have the same amount of room inside the fenders.  Would you happen to know what wheels you are running, or what the backspace is?

 

Thanks,

MrFreeze

[MrFreeze]

6 hours ago, Barney Eaton said:

Attached is a chart (powerdog.com) that compares different sizes mentioned above.  

In a reference book, it said 1963 & 64 Rivieras came with 7.10 x 15 and 1965, 66, 67 came with 8.45 x 15 

consulting another chart .. found one that said 7.10 x 15 converted to a 225/75r15   and a different chart did not show 

the 7.10 size but had 8.45 X 15 converted to 225/75 r 15 so there may have been a tire industry change in designations. 

Gene above said he liked the 205 because of the shorter sidewall, note the 225/70 sidewall is only 1/10 inch taller and the 235 is 1/10 shorter.

When you use powerdog,  the first tire you enter should be your base as all the other are compared to the first entry. 

 

Specification	Sidewall	Radius	Diameter	Circumference	Revolutions	Speedometer	Odometer	Difference
225/75-15	6.6"	14.1"	28.3"	88.9"	713/mi	60MPH	10000mi	N/A
205/75-15	6.1"	13.6"	27.1"	85.2"	744/mi	63MPH	10436mi	-4.2%
225/70-15	6.2"	13.7"	27.4"	86.1"	736/mi	62MPH	10323mi	-3.1%
235/65-15	6.0"	13.5"	27.0"	84.9"	746/mi	63MPH	10466mi	-4.5%

h

 

Very helpful, thank you.

 

MrFreeze

[MrFreeze]

4 hours ago, RivNut said:

Here’s a list from the ROA’s website that shows equivalent tire sizes. The chart is incomplete because it only shows one tire size for 1963.  Refer to the 1964 line for the same info for 1963. It also show an 8.85 tire for 1965 which is incorrect.  The larger tires in 63, 64, and 65 were for the heavier Electras.

 

https://rivowners.org/features/Ev_Stats/dimensions.html

 

 

Good info, thanks.  I always forget to check the ROA for info, but when I do, they nearly always have something helpful.

 

MrFreeze

[MrFreeze]

@Craig Balzer, do you have any rubbing issues with those tires?

 

Love the color on that car.

 

MrFreeze

[XframeFX]

3 hours ago, Craig Balzer said:

Sorry for the dirty tires/rims - I live on a dirt road.

 

But you have a nice Garage/Man Cave - IMPORTANT!

[1965rivgs]

4 hours ago, Craig Balzer said:

These photos are from my 65 Riviera Gran Sport (made in December 64) -- may help.

 

Sorry for the dirty tires/rims - I live on a dirt road.

Craig, your chrome wheel is a '71 and up wheel.

Tom Mooney

[Craig Balzer]

3 hours ago, 1965rivgs said:

Craig, your chrome wheel is a '71 and up wheel.

Now -- how the h3ll can you tell that!! - 🤔 -- calibrated eyeballs??!!??

 

BTW - that rim needed to be replaced when a garage neglected to torque the 5x lug nuts. The old (original?) rim was held on with 2 lug nuts and the holes were well and truly auger-ed out. I was lucky to find it and didn't know it was "off" by 6 years

[Craig Balzer]

5 hours ago, MrFreeze said:

do you have any rubbing issues with those tires?

None what so ever.

I have no idea if the dimensions of a 64 and 65 wheel wells are the same.

 

I agree - Verde Green is a nice color

[1965rivgs]

11 hours ago, Craig Balzer said:

Now -- how the h3ll can you tell that!! - 🤔 -- calibrated eyeballs??!!??

 

BTW - that rim needed to be replaced when a garage neglected to torque the 5x lug nuts. The old (original?) rim was held on with 2 lug nuts and the holes were well and truly auger-ed out. I was lucky to find it and didn't know it was "off" by 6 years

Trust me, it's the wrong wheel and most importantly the wrong offset.

If I understand your statement correctly, the lug nuts may have, in reality, been "tightened" but when offset is incorrect the inside edge of the rim contacts the fins of the brake drum before the center of the wheel contacts the axle. That gives the illusion the lugs are tightening when in fact the lug nuts are bending the rim. It's easy to stop tightening because as the rim distorts tightening the lug nuts requires increased effort but the rim is not properly seated against the axle. End result is the wheel may loosen up.

  Beware of using 895 rims on a pre '70 application and beware of anyone who us recommending same; besides, it's the most unattractive version of the Buick chrome wheel because in overall appearance it lacks depth.

Tom Mooney

[Craig Balzer]

Tom

 

The lug nuts that were improperly tightened were on a rim I no longer have - that is the one that sustained damage to the lug nut holes. The rim in my photo is a replacement rim procured by the garage (from a seller in Denver) and is currently in place on my car. Now I am worried this rim may be the wrong type/style/size/offset (a disaster waiting to happen).

 

I have noticed several threads mentioning 3 or more styles / types of rims each what I assume is differing off-sets. I never really understood the difference between them.

 

1) Which style / type of rim (the three digit number) ought I have on my 65 Riviera Gran Sport (I assume the one I photo'ed is a 895?) ? Where is this number found?

 

2) What is the proper offset I ought to have? (this may sound similar to question 1 above but inquiring minds want to know)

[Turbinator]

5 hours ago, 1965rivgs said:

Beware of using 895 rims on a pre '70 application and beware of anyone who us recommending same; besides, it's the most unattractive version of the Buick chrome wheel because in overall appearance it lacks depth.

Opinion only. What one likes another may not. Because you say it does not look good does not make it Gospel. You are entitled to your opinion. 

Give us an example of what does look good. Does anything to you look good?

Later Gator

The Turbinator

[RivNut]

The first part of Tom’s post is a fact. In fact it may save someone’s life.  The second part is an opinion. Everyone should be entitled to express his/hers without any repercussions.  

Like my opinion “If wire wheels were meant to be on a Riviera, the designers would have built it that way. That’s what they did with the 53 and 54 Skylarks. Best looking wheel treatment for the 63/64 is the cast aluminum cover.”  Thanks for letting me express my opinion. 
Ed 😎

[EmTee]

Using "895" wheels on a pre-1970 drum brake application will require a minimum spacer width of 1/4".  That's what was on my '67 when i bought it.  Even then, the back of the wheel 'kissed' the aluminum front brake fins and the lug nuts lose 1/4" of thread engagement.  They also do look somewhat different with that offset, but you probably wouldn't really notice unless you saw them side-by-side.

 

In the end, I wound-up buying a set of original 1967 "802" wheels and I sold the "895" wheels.  Everything fits as designed - no spacers.

 

Edited April 16 by EmTee (see edit history)

[1965rivgs]

7 hours ago, Turbinator said:

Opinion only. What one likes another may not. Because you say it does not look good does not make it Gospel. You are entitled to your opinion. 

Give us an example of what does look good. Does anything to you look good?

Later Gator

The Turbinator

  Bob, my last comment was offered as an opinion and I intended that it would be regarded as one. As you know, opinions are like axxholes, everyone has one.

  I think your wires wheels look good, but again, what`s one man`s opinion worth?

Tom Mooney 

  

[Turbinator]

Tom, i was referring to your comment regarding the 895’s in a 64. Of course, I could  very well be mistaken I thought you made the comment that the 895’s were not at all appealing on the 64. It could have been some else making the comment and you were responding to the comment. No problems or worries we can agree to disagree ( on other topics) without being disagreeable.

Later Gator

Turbinator

[65VerdeGS]

I'm running 225/75R15 sized tires on my '65 GS.  As RivNut reported, they do rub ever so slightly under certain circumstances (e.g. full lock to the left, on a sloping driveway). This rubbing is so slight that I only noticed it when I removed the front tires to restore the undercarriage and saw the faint rub marks on the frame. The rubbing does no damage to the tire or the frame, so I would suggest this size of tire as it fills the wheel wells very nicely!

[Shootey]

Several years ago I took the train from London to the countryside in Lincolnshire. I was going to visit a firm named Kelvedon which specialized in racing parts for Lotuses. Pat Thomas, the proprietor, was famous in the Lotus world. I had and still have a 1966 Elan. I was met at the train station by Pat’s assistant, an older gentlemen with a nearly indecipherable brogue and several missing teeth. He arrived in some small English sedan and we flew away over hill and dale toward Pat’s house and shop.  Apparently he had oversized wheels and tires on his normal seeming sedan. The country road had many turns and dips. Almost every time the car hit a dip or turn the tires would seriously rub on the wheel wells emitting a sizzling noise. It didn’t bother my driver one bit.
 

My visit with Pat Thomas was very pleasant and included lunch with him and his wife. I ended up buying quite a lot of suspension parts and some Yokohama tires that were unavailable in the states and that required me to do some tasteful flares on the lips. Lotus owners are not very pure. The trip to Pat’s was memorable but the sizzling tire rubs were the best part. 
 

[1965rivgs]

On 4/16/2024 at 12:46 PM, Craig Balzer said:

Tom

 

The lug nuts that were improperly tightened were on a rim I no longer have - that is the one that sustained damage to the lug nut holes. The rim in my photo is a replacement rim procured by the garage (from a seller in Denver) and is currently in place on my car. Now I am worried this rim may be the wrong type/style/size/offset (a disaster waiting to happen).

 

I have noticed several threads mentioning 3 or more styles / types of rims each what I assume is differing off-sets. I never really understood the difference between them.

 

1) Which style / type of rim (the three digit number) ought I have on my 65 Riviera Gran Sport (I assume the one I photo'ed is a 895?) ? Where is this number found?

 

2) What is the proper offset I ought to have? (this may sound similar to question 1 above but inquiring minds want to know)

Hi Craig,

  I could type all day about the chrome wheels; best to call me with your questions. You have my number.

Thanks,

Tom

 

[65VerdeGS]

On 4/17/2024 at 9:02 PM, 65VerdeGS said:

I'm running 225/75R15 sized tires on my '65 GS.  As RivNut reported, they do rub ever so slightly under certain circumstances (e.g. full lock to the left, on a sloping driveway). This rubbing is so slight that I only noticed it when I removed the front tires to restore the undercarriage and saw the faint rub marks on the frame. The rubbing does no damage to the tire or the frame, so I would suggest this size of tire as it fills the wheel wells very nicely!

I need to correct my earlier statement about tire size because I verified the tire size on my Riv tonight.  I'm actually running 215/75R15's, not 225's!  As mentioned, these tires do rub on the frame at full lock but this is so slight that I never noticed it until I took the tires off to work on the undercarriage. 

 

[MrFreeze]

Alex, thanks for double-checking that.  Would you happen to know if the occasional rub is due to tire HEIGHT, or tire WIDTH?

 

MrFreeze

[RivNut]

Tire width is the first three digits in the size.  225 mm is 225 mm whether it is 75 or 35.  The two digit number following the / in the tire size is the height expressed as a % of the width.  A 225/75 tire means that the height is 75% of 225mm.  A 225/60 tire means the height is 60% of 225mm.  Both are the same width.  One thing that could dictate whether a tire rubs or doesn’t rub might be the rim width or back spacing.

 

What we tend to forget is that in 63, 64, and 65, bias ply tires were closer to 83% height to width ratios.  Modern tires the same height as the originals will be wider than the originals so unless run a much smaller tire, you’re liable to experience some tire rub.  To get away from any rubbing possibilities, you’d probably have to drop down to a 205 width on a 5.5” rim.  That would create an unusual appearance and the rolling diameter of the tire would cause you to run the engine at higher than normal RPMs which will have a negative affect your gas mileage.  If you’re thinking that you want to run that small of a tire, be sure to check the load range of the tire which determines how much weight the tires will carry safely.  My 1990 Riviera uses 205/70R15 tires but it weights 600 lbs less than the 63 or 64.