Originally Posted By: NMBurb02
Originally Posted By: surfstar
Then how does Discount Tire Direct get off by offering these (2000 Civic) as my tire choices?:
185/65-14
Original Tire Size
The tire size listed is the most common original fitment for your vehicle, however some vehicles have different original equipment tire options. Please check your current tires for the appropriate size.
Optional Tire Sizes
Plus Zero
175/70-14
195/60-14
195/65-14
205/60-14
215/60-14
Plus One
175/65-15
185/60-15
195/55-15
205/55-15
Plus Two
175/55-16
185/55-16
195/50-16
205/45-16
205/50-16
215/45-16
Plus Three
195/40-17
195/45-17
205/40-17
215/40-17
Plus Four
215/35-18
DT did a plus zero for me on the Burb so the two tires I was buying would match the two that the PO had put on shortly before I bought it.
Do the tire shops you all have had problems with also sell wheels? If so, I would think they would be fine with doing non-OEM tire sizes, as not doing so would seriously limit their aftermarket wheel offerings.
From what I've learned at work, load range is the most important factor in plus or minus sizing tires. Second I'd say is what RMA/Tire and Rim Association guidelines are for a given tire width, tire aspect ratio and the wheel width. So that is [the simple] part of why there are more than one tire listed for plus zero fitment. It gets more technical than that, but I'd say that load range and approved rim width are the two most basic things when plus/minus sizing.
For example, a 255/40R18 Michelin Pilot Sport A/S 3 has a manufacturer approved rim width of 8.5-10 which I believe is in line with the charts the RMA/Tire and Rim association publishes. Not only does it become more difficult to mount and dismount tires on non-approved widths, the overall performance, safety and integrity of the tire can be compromised. An example of this is we have a customer that comes in with their new '13 Audi A4 model, they have aftermarket 20x8 wheels. The OEM 19" wheels [not sure on their width but at 255 tire I'd assume at least 8.5"] use a 255/35R19, so a plus to 20" would (generally) require a 255/30R20 (I would think even a 245/35R20 might work on a 20x8 but I haven't looked that up), but the customer insists that we mount a 275/30R20 on a 8" wide wheel because he wants a wider looking tire. A 275 at that low of an aspect ratio requires at least a 9.5" wide wheel. Since I'm just a service tech, I follow what my service coordinator/ASM says, but if I were in their position I would refuse. Either buy an approved width tire for your wheel or buy a wider wheel. I had to mount and dismount these, it was not easy, and the worst part was getting the bead to seat since it was difficult to get it to seal so it could inflate. Ok rant over.
