FC/Van 14" Tire Size Question

[TimeMachineParadox]

Hi guys,

I'm working on getting tires for my van and I'm a little conflicted with the available options. I haven't been able to find any threads with the size combination I'm looking for.

Who has successfully run 215/70 R14 tires with a 3.5" backspace on their FC? Or does this conflict with the rear fender?

I know I could use a 205/75 R14 tire without issue, but the available options don't have me convinced yet. I know some people use the Hankook Kinergy ST tires, but opinion about these doesn't seem too great - particularily in the wet or in mild snow.

A 215/70/14 would allow me to use the General Altimax RT45 tires. I have these on my daily driver and I'm familiar with them, they're fine for 95% of the Kentucky weather and seasons. Since I would like my van to be more than a "fair weather driver" I want to have confidence that the tires will be fine in wet and cold.

Any help, or other model recommendations would be appreciated

[joelsplace]

With tall skinny tires I wouldn't run anything but LT truck tires for the stiffer sidewalls. FCs drive terrible with tall car tires, especially in crosswinds. If you run short sidewalls car tires are fine. 245/50R16s will fit with the proper offset but I'm not sure what that is. I have 16x8 IROC Z-28 wheels on one of mine. I think they are all rears. The IROC had different front/rear offsets.

[caraholic4life]

I have a set of Western Bullet 15 X 7 Wheels on my 1964 Greenbrier with 205/65R-15 Tires and they work well.
I seem to recall that the back Spacing on these wheels is about 4 Inches.
This van has been driven well over 3,000 miles with these wheels and tires, many at highway speeds and there had been no indication of rubbing or interference at any time.
The 205/65R-15 tires are 25.4 inches in diameter and the Speedometer is very close to being the actual speed according to my GPS.

I had a set of these wheels on my 1962 95 Van with 235/60R-15 Tires but never drove the van with them. The clearance was very tight but when pushing it around the yard, I never saw any indication of interference.
When the Western Wheels were removed from the 95 Van, I stuck a set of Camaro/Chevelle Steel five spoke wheels on it that also have 235/60R-15 tires on them and the clearance is about the same as the it was with the Western Wheels.

Attached are photo's of two of the three variations mentioned.
You did not mention the wheel width you have but I suspect the tire choice you have won't rub unless the Back Spacing on your wheels puts the wheels to far outboard.

[vairchet]

'63 Rampside with 205/75-14 tires mounted on Chevy S10 wheels. Fit perfectly. Any wider, tires will rub on rear quarter panels (fenders):

[TimeMachineParadox]

I knew I should have included my wheel size. They are just 14x6 chevy rally(e) wheels, I double checked the backspacing - they actually have a 4" backspace (1" / 25mm offset).
The stock wheels are 14x5 with a 3.5" backspace (1" / 25mm offset)

Joel's wheels and tires are the largest so far, the 16x8 rear Iroc-Z wheels have a 5.125" backspace (28mm offset)
Here are the 215/70R14 tires compared to the 245/50R16 tires, with respective wheels. They fit inside the volume taken up by the 16" tires.

Caraholic's tires and wheels aren't quite as wide, but the outer wall is in a comparable position.
15x7 wheels with a 4" backspace gives a 12.7mm offset. Interestingly, this places the tire about 0.5" farther out from center compared to the stock tires, increasing the scrub radius a bit and causing a bit more steering effort.
Here are the 215/70R14 tires compared to the 205/65R15 tires, with respective wheels.

This does answer my question though, it appears that a 215/70R14 tire would fit.


Now I just have to decide on a tire model, I like to consider all possibilities anyway.
I looked around for LT tires, but they don't seem to be available in 14". I would like to stay with the wheel size I have, and I'm not sure if I would like the negative ride comfort effect that an LT tire would have anyway.

I did find out that the 205/70R14 General Altimax RT45 tire has an XL Load range with a 98 load index, as compared to other passenger tire options, and Altimax models, that have an SL range with a slightly lower index.
By my admittedly limited understanding of tires, I would think this means it has a slightly stiffer sidewall.

Anyone have any other model recommendations?

[joelsplace]

Here are some LT tires:
https://www.tirerack.com/tires/TireSear ... iameter=14 I have these on a Rampside and they drive fairly well at maximum pressure.
More on my IROC wheels - I did have to grind on the shock tower and lower control arm for clearance. At the fender the tire looks like it would have to rub but it never did. Seems the swing axle pulls the tire away on compression and the tire drops out of the fender quick enough to clear on droop.
The front I had to grind on the outer tie rod ends.

[TimeMachineParadox]

Update on this topic,
Warning: long read, I'm somewhat infodumping what I found in case it's useful to someone else

I'll split this into two post, one on tire discussion, and one smaller one on my solution

PART 1a: TIRES, GENERALLY

Joel's comment about the LT tires and sidewall stiffness sent me down a rabbit hole where I learned a bit more about tires. Frustratingly, it seems that in the Corvair world there is relatively little specific discussion about tire types and models other than "choose what size fits, and what looks good" or statements of brand loyalty that don't seem to evaluate the actual tire .

While looking, I stumbled on this very in-depth thread on TheSamba discussing tire options for the T3 (maybe also T4) VW busses. Also check out the PDF they have with a chart of tire options for each size. That thread is quite handy since the VW busses have a similar tire size, and body size/shape to the FCs.
You can search the threads to get some opinions about specific tire models. The guys there do seem to take their vans out more, and in harsher environments, than the average FC owner. So it can be hard to find opinions on more "regular" tires, but it can be helpful information nonetheless.

https://www.thesamba.com/vw/forum/viewt ... 6557756f23


If anybody reading this goes to look for tires, I would encourage you to read into what load range and load index is. In very short, load range denotes more how the tire is constructed (how strong, so to say), and load index denotes what the maximum load carrying capacity of a tire is.
Load range is often expressed with an equivalency to the old bias-ply ply rating (but does not reflect the actual plies)

Here's a table I stole from Discount Tire's page on load range and index

Light Truck (LT) tires and Euro Metric van tires refer to tires with a C1 load range
Passenger (P) tires refer to SL and XL load ranges
________________________________________________________________________________________________________
So what load range do you want?

This is one of the things I also couldn't find much FC discussion on. I felt like I virtually only found Joel mentioning that you want the increased sidewall stiffness of LT tires to help with crosswind, or other, stability. This was on both forums over the years
Also very few people mentioned anything about load range. I suppose maybe many people don't care to determine it. There was no real tire discussion in the Corvanatics newsletter except an article from the mid 70s on the then new radial tires. I'm sure tire tech has progressed a bit since then.

On a couple TheSamba threads I did see mention that stiffer, higher load range (C or greater), tires did help with general stability and wandering in cross-winds. Sidenote - the lack of this discussion in regard to FCs did make me wonder how much some of the FC stability complaints are impacted by SL range passenger tires.

Usually you choose a load range in relation to the load your vehicle can carry, not on the tire stiffness that you want. I couldn't really find any information on how, specifically, tire sidewall stiffness is impacted by load range other than "higher range, stronger tire". Some posts in various internet threads mentioned that you want a sidewall that is at least 2 plies (of what?) for greater sidewall stiffness. Cool, but how do you know if your tire has that?
Usually it's stamped into your tire sidewall, but for the tires I looked at, this information was not published by the manufacturer in their catalogs. So you can't know what construction your tire has until you've bought it - useless.

Let's back up a bit, what did GM originally specify for the FCs?
Per the 64 FC engineering specs, it seems like the vans could either have a standard 4 ply tire, or a 6 ply tire option.
It seems to imply that trucks either had a 6 ply or 8 ply tire. Remember, bias ply.

Theoretically, a 4 ply equivalent passenger tire should be adequate based on this. But we also know that at least some FC people and some VW people don't think highly of passenger tires. I'm not old enough to have ever experienced bias-ply tires (feel old yet? ) but I haven't heard great things about them in retrospect, I do wonder how poorly 4 ply tires would even compare to passenger tires.

Since we want better, we want more than a 4 ply equivalent SL tire. There are also XL range passenger tires available for some sizes, these should theoretically be slightly stiffer as a result of a bit more load capacity. Actual confirmation of this was impossible to find. There is also no published construction information to compare an SL to an XL tire.
Since the General AltiMAX RT45 is available in SL and XL for some of the same sizes I emailed General about this in regard to sidewall stiffness and wandering.

General tire didn't answer my question about construction (maybe they didn't want to answer the insane person asking insane questions), but they did say this:

In terms of lateral stiffness specifically, the XL tire will generally have a stiffer sidewall than an SL tire because it is built to carry more weight without significantly increasing the overall tire size. However, it may not fully address the issues of wandering and crosswind stability you're concerned about. Based on this we recommend going with a Euro Metric Van Tire.

As for using a 205/65R15C tire; C-load range tire (often referred to as a commercial load range) is a type of tire designed for light trucks, vans, and other vehicles that may carry heavier loads. These tires are similar to LT (Light Truck) tires in construction, as they typically have reinforced sidewalls and more plies compared to regular passenger tires.


I wound up using a Metric van C tire, so I didn't try to find more about XL tires. I believe that it could be acceptable to use an XL tire to improve stability, but I didn't want to test this :P.

Overall, the use of a C load range tire to improve stability still stands

________________________________________________________________________________________________________
So what load index do you need?

If you look through the Samba thread, you'll see that the VW busses need a higher load index of around 100 to be acceptable for use. This has the adverse affect of tires that fall below this being unmentioned and untested in the threads.
Our FCs are lighter and get by with a lower load index. Per the 64 engineering specs the FC weight tops out at around 4600 lbs with curb weight and a full load. If I assume a 50-50 weight distribution that puts around 1150 lbs on each tire at full load.

This would equate to a minimum load index of 87, or 90 for a Passenger tire with load derating considered. Since it would be difficult to find a tire with an index this low, the load index on most tires is acceptable. This is also why I didn't calculate the numbers more accurately.

Generally, a load index of 90, or greater, is acceptable

________________________________________________________________________________________________________


PART 1b: TIRES, SPECIFICALLY

Tire choices aren't great and aren't getting better.

As far as I've been able to determine, these are the usable, available, tire sizes that are close to the original 26.3" diameter and would fit 5-6" wide wheels without having too large of a section width. Further updates would be appreciated. I did not look into larger wheel sizes.

14":
195/75R14 = 25.5x7.7R14 (SL, C, D)
205/70R14 = 25.3x8.1R14 (SL, XL)
215/70R14 = 25.9x8.5R14 (SL)
205/75R14 = 26.1x8.1R14 (SL, C) (Do not get ST trailer tires)

15":
205/65R15 = 25.5x8.1R15 (SL, XL, C, D)
215/60R15 = 25.2x8.5R15 (SL, XL, C)
205/70R15 = 26.3x8.1R15 (SL, XL, C, D)

Of those tire sizes with a C or D load range the options are starting to dwindle. Many models in these sizes are getting discontinued
As of March 2025 you really only have the option of the C or D tires you can find under the 205/65R15 or 195/75R14 sizes
You can see the Samba PDF with the collection of tire models, some are only winter tires, of the decent all seasons there's really only these:

Continental Vanco Fourseason (205/65R15, Discontinued, some stock still available)
Nokian One HT (205/65R15)
Michelin Agilis Crossclimate DT (205/65R15) (Not well reviewed)
Yokohama BluEarth RY61 (To be discontinued in 205/65R15, some stock still available)
Yokohama Y356 (Supposedly discontinued in 195/75R14)

I didn't look much into other cheaper models because I wanted tires I could trust. Also, I got a very good deal on the Yoko BluEarth RY61s


I'm running out of time for today, so I'll reflect some more on the tire models in my second post. I wound up buying 15" GM rally wheels to fit the BluEarth RY61s. I'll also post some information I found on refinishing those.

[Lane66Monza]

For my Greenbrier van (sold) , I did a search and found the factory 7.00-14 tire had a 26.8 diameter. 225/60R15 tire has a 25.6 diameter, but with a tire search for Corvair tires it seemed to be the prevalent tire of choice. The 215/70R15 seems closer to diameter at 26.9". I will get with local Goodyear store and see what they have in this size and reasonable cost.

I wound up with Goodyear Endurance 215/70R15 on a set of American Racing Torque Thrust 15 x 7" (wheels came on the van). I wanted my speedometer close to actual driven speed, not reading fast like the factory tires.

Here is 8 ply tire that fits the range and size. Thunderer Ranger R402 Per per tire with 4 being purchased = $81.97

Based in Thailand, Thunderer Tire is a member of the Deestone family that designs and engineers tires with North American drivers in mind. They manufacture tires for a wide range of vehicles, such as passenger cars, light trucks, SUVs, or specialty, commercial, or trailer tires, at various price points for different budgets.

The Thunderer Ranger R402 is perfect for service trucks and route vans. It is a commercial-grade light truck tire that features an enhanced load capacity and upgraded ply rating.

Features and Benefits
The Ranger R402 is Thunderer's extreme performance tire engineered with top-level traction.
Longer tread life: The tire displays a twin steel belt construction that enhances strength and durability for a higher load-carrying capacity and a longer tread life.
Solid handling: The Ranger R402 has an all-season tread pattern for year-round traction and handling performance.
Reduced hydroplaning: Chevron-shaped tread design channels water away to resist hydroplaning for superior performance, while a unique tread design delivers better control in wet conditions.
Great traction: The Ranger R402 has a reinforced sidewall protecting the tire against scuffs, chips, and abrasions.
The wheel size ranges from 15 to 16 inches, making it ideal for a wide range of commercial-grade light trucks on the road today.

https://www.tires-easy.com/215-70-15/th ... ifications

Google search

https://www.google.com/search?q=Thunder ... nt=gws-wiz

[Alex58]

Hey!I used 215/70 R14 on my van and had no issues with fenders.General Altimax RT45 are great on wet and cold surfaces.Maybe check if someone used them with a 3.5-inch gap.Check if anyone has experience with these tires on the forum. :)

[joelsplace]

The Y356 Yokohamas I'm running are load range D.
The first Greenbrier I bought many years ago had stock wheels and passenger car tires. It was super scary in crosswinds. All I did was change to 15x7 aluminum rear wheels with 215/65r15 tires. (Still passenger) It made a huge difference. The aluminum wheels took out a lot of flex and combined with less sidewall and wider rim took all the scary out of it.
I ran max recommended pressure from the sidewall in both.

[Kamila59]

I haven't seen the 215/70 R14 set on an FC, but I do know General Altimax RT45 tires work well in the rain. Maybe see if anyone has put them on in other sizes? Try to find opinions on other forums; someone may have had the same experience. :)