Isuzu KB tire upsize & plus-size guide
Every safe upsize, plus-size, wider, and winter-narrower option for the Isuzu KB; covering all 3 of its factory tire sizes, each inside the ETRTO ±3% overall-diameter tolerance, with speedometer impact and catalog availability per size.
This guide takes the factory tire sizes of the Isuzu KB and shows every geometrically valid alternative; the plus-sizes that fill the wheel arch, the wider sizes that add grip, and the narrower winter sizes that bite through snow. All math is derived from the ±3% ETRTO safe-fit rule, not scraped listings.
195/75R14; factory fitment (1972–1986)
Overall diameter 648.1 mm (25.52 in). Alternatives below are grouped by upgrade intent; every one is inside the ±3% safe-fit envelope for this size.
Plus-1 (next rim size up)
Plus-1 keeps overall diameter constant while bumping rim diameter by one inch and dropping aspect ratio by ten points. The standard daily-driver upgrade; sharper steering response, mild ride penalty, modest tire-cost premium.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
205/65R15 |
648 | -0.09% | 59.94 mph | Safe | - |
225/60R15 |
651 | 0.45% | 60.27 mph | Safe | - |
165/80R15 |
645 | -0.48% | 59.71 mph | Safe | - |
175/75R15 |
644 | -0.71% | 59.57 mph | Safe | - |
195/70R15 |
654 | 0.91% | 60.55 mph | Safe | - |
185/70R15 |
640 | -1.25% | 59.25 mph | Within tolerance | - |
215/60R15 |
639 | -1.40% | 59.16 mph | Within tolerance | - |
185/75R15 |
659 | 1.60% | 60.96 mph | Within tolerance | - |
215/65R15 |
661 | 1.91% | 61.15 mph | Within tolerance | - |
175/80R15 |
661 | 1.99% | 61.19 mph | Within tolerance | - |
165/85R15 |
662 | 2.07% | 61.24 mph | Within tolerance | - |
195/65R15 |
635 | -2.10% | 58.74 mph | Within tolerance | Yes |
Plus-2 (two rim sizes up)
Plus-2 lifts rim diameter by two inches with a twenty-point aspect drop. Noticeable ride penalty, higher pothole risk, and a meaningful tire-cost premium. Suitable for performance trims and aesthetic upgrades.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
185/65R16 |
647 | -0.19% | 59.89 mph | Safe | - |
175/70R16 |
651 | 0.51% | 60.31 mph | Safe | - |
205/60R16 |
652 | 0.66% | 60.40 mph | Safe | Yes |
215/55R16 |
643 | -0.80% | 59.52 mph | Safe | Yes |
165/75R16 |
654 | 0.89% | 60.54 mph | Safe | - |
225/55R16 |
654 | 0.89% | 60.54 mph | Safe | - |
195/60R16 |
640 | -1.19% | 59.29 mph | Within tolerance | - |
165/70R16 |
637 | -1.65% | 59.01 mph | Within tolerance | - |
195/65R16 |
660 | 1.82% | 61.09 mph | Within tolerance | - |
175/65R16 |
634 | -2.19% | 58.69 mph | Within tolerance | - |
205/55R16 |
632 | -2.50% | 58.50 mph | Within tolerance | Yes |
215/60R16 |
664 | 2.52% | 61.51 mph | Within tolerance | Yes |
185/70R16 |
665 | 2.67% | 61.60 mph | Within tolerance | - |
Same rim, wider footprint
Same rim diameter as your OEM, just a wider footprint. Increases grip and footprint contact at the cost of fuel economy and steering effort. Confirm fender clearance at full lock before purchase.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
225/65R14 |
648 | 0.00% | 60.00 mph | Safe | - |
205/70R14 |
643 | -0.85% | 59.49 mph | Safe | - |
215/70R14 |
657 | 1.31% | 60.79 mph | Within tolerance | - |
215/65R14 |
635 | -2.01% | 58.80 mph | Within tolerance | - |
205/75R14 |
663 | 2.31% | 61.39 mph | Within tolerance | - |
Winter / narrower contact
Narrower than OEM, aspect ratio raised to preserve overall diameter. Higher contact pressure improves snow and slush bite; the Nokian-style rule of one width step down for winter on the same overall diameter.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
185/85R13 |
645 | -0.52% | 59.69 mph | Safe | - |
185/80R14 |
652 | 0.54% | 60.32 mph | Safe | - |
175/85R14 |
653 | 0.77% | 60.46 mph | Safe | - |
165/85R14 |
636 | -1.85% | 58.89 mph | Within tolerance | - |
175/80R14 |
636 | -1.93% | 58.84 mph | Within tolerance | - |
185/75R14 |
633 | -2.31% | 58.61 mph | Within tolerance | - |
Other geometric alternatives
Geometrically valid alternatives that don't fit a named category. Often combinations of rim and aspect change that happen to land in tolerance.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
225/70R13 |
645 | -0.45% | 59.73 mph | Safe | - |
215/75R13 |
653 | 0.71% | 60.43 mph | Safe | - |
195/80R13 |
642 | -0.91% | 59.45 mph | Safe | - |
205/80R13 |
658 | 1.56% | 60.94 mph | Within tolerance | - |
205/75R13 |
638 | -1.60% | 59.04 mph | Within tolerance | - |
195/85R13 |
662 | 2.10% | 61.26 mph | Within tolerance | - |
215/70R13 |
631 | -2.61% | 58.44 mph | Within tolerance | - |
215/70R16; factory fitment (2015–2018)
Overall diameter 707.4 mm (27.85 in). Alternatives below are grouped by upgrade intent; every one is inside the ±3% safe-fit envelope for this size.
Plus-1 (next rim size up)
Plus-1 keeps overall diameter constant while bumping rim diameter by one inch and dropping aspect ratio by ten points. The standard daily-driver upgrade; sharper steering response, mild ride penalty, modest tire-cost premium.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
185/75R17 |
709 | 0.27% | 60.16 mph | Safe | - |
195/70R17 |
705 | -0.37% | 59.78 mph | Safe | - |
215/65R17 |
711 | 0.55% | 60.33 mph | Safe | - |
225/60R17 |
702 | -0.79% | 59.53 mph | Safe | Yes |
245/55R17 |
701 | -0.86% | 59.48 mph | Safe | - |
235/60R17 |
714 | 0.90% | 60.54 mph | Safe | - |
205/65R17 |
698 | -1.29% | 59.23 mph | Within tolerance | - |
205/70R17 |
719 | 1.61% | 60.97 mph | Within tolerance | - |
185/70R17 |
691 | -2.35% | 58.59 mph | Within tolerance | - |
195/75R17 |
724 | 2.39% | 61.43 mph | Within tolerance | - |
225/65R17 |
724 | 2.39% | 61.43 mph | Within tolerance | Yes |
235/55R17 |
690 | -2.42% | 58.55 mph | Within tolerance | Yes |
215/60R17 |
690 | -2.49% | 58.51 mph | Within tolerance | Yes |
245/60R17 |
726 | 2.60% | 61.56 mph | Within tolerance | - |
185/80R17 |
728 | 2.88% | 61.73 mph | Within tolerance | - |
Plus-2 (two rim sizes up)
Plus-2 lifts rim diameter by two inches with a twenty-point aspect drop. Noticeable ride penalty, higher pothole risk, and a meaningful tire-cost premium. Suitable for performance trims and aesthetic upgrades.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
225/55R18 |
705 | -0.38% | 59.77 mph | Safe | - |
195/65R18 |
711 | 0.47% | 60.28 mph | Safe | - |
205/60R18 |
703 | -0.59% | 59.64 mph | Safe | - |
245/50R18 |
702 | -0.74% | 59.56 mph | Safe | - |
215/60R18 |
715 | 1.10% | 60.66 mph | Within tolerance | - |
235/55R18 |
716 | 1.17% | 60.70 mph | Within tolerance | Yes |
185/70R18 |
716 | 1.24% | 60.75 mph | Within tolerance | - |
185/65R18 |
698 | -1.37% | 59.18 mph | Within tolerance | - |
215/55R18 |
694 | -1.94% | 58.84 mph | Within tolerance | - |
235/50R18 |
692 | -2.15% | 58.71 mph | Within tolerance | - |
195/60R18 |
691 | -2.29% | 58.63 mph | Within tolerance | - |
205/65R18 |
724 | 2.30% | 61.38 mph | Within tolerance | - |
245/55R18 |
727 | 2.73% | 61.64 mph | Within tolerance | - |
225/60R18 |
727 | 2.80% | 61.68 mph | Within tolerance | - |
Same rim, wider footprint
Same rim diameter as your OEM, just a wider footprint. Increases grip and footprint contact at the cost of fuel economy and steering effort. Confirm fender clearance at full lock before purchase.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
235/65R16 |
712 | 0.64% | 60.38 mph | Safe | - |
245/60R16 |
700 | -0.99% | 59.41 mph | Safe | - |
225/65R16 |
699 | -1.20% | 59.28 mph | Within tolerance | Yes |
225/70R16 |
721 | 1.98% | 61.19 mph | Within tolerance | - |
245/65R16 |
725 | 2.47% | 61.48 mph | Within tolerance | - |
235/60R16 |
688 | -2.69% | 58.39 mph | Within tolerance | - |
Winter / narrower contact
Narrower than OEM, aspect ratio raised to preserve overall diameter. Higher contact pressure improves snow and slush bite; the Nokian-style rule of one width step down for winter on the same overall diameter.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
205/80R15 |
709 | 0.23% | 60.14 mph | Safe | - |
185/80R16 |
702 | -0.71% | 59.58 mph | Safe | - |
195/85R15 |
713 | 0.72% | 60.43 mph | Safe | - |
205/75R16 |
714 | 0.92% | 60.55 mph | Safe | - |
195/75R16 |
699 | -1.20% | 59.28 mph | Within tolerance | - |
195/80R16 |
718 | 1.55% | 60.93 mph | Within tolerance | - |
185/85R15 |
696 | -1.68% | 58.99 mph | Within tolerance | - |
185/85R16 |
721 | 1.91% | 61.15 mph | Within tolerance | - |
205/70R16 |
693 | -1.98% | 58.81 mph | Within tolerance | - |
195/80R15 |
693 | -2.04% | 58.78 mph | Within tolerance | - |
205/75R15 |
689 | -2.67% | 58.40 mph | Within tolerance | - |
Other geometric alternatives
Geometrically valid alternatives that don't fit a named category. Often combinations of rim and aspect change that happen to land in tolerance.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
235/75R14 |
708 | 0.10% | 60.06 mph | Safe | - |
235/70R15 |
710 | 0.37% | 60.22 mph | Safe | - |
205/85R14 |
704 | -0.47% | 59.72 mph | Safe | - |
215/75R15 |
704 | -0.55% | 59.67 mph | Safe | - |
215/80R14 |
700 | -1.10% | 59.34 mph | Within tolerance | - |
245/65R15 |
700 | -1.12% | 59.33 mph | Within tolerance | - |
225/80R14 |
716 | 1.16% | 60.70 mph | Within tolerance | - |
245/70R14 |
699 | -1.24% | 59.25 mph | Within tolerance | - |
225/75R15 |
719 | 1.57% | 60.94 mph | Within tolerance | - |
225/70R15 |
696 | -1.61% | 59.03 mph | Within tolerance | - |
215/85R14 |
721 | 1.94% | 61.16 mph | Within tolerance | - |
225/75R14 |
693 | -2.02% | 58.79 mph | Within tolerance | - |
245/75R14 |
723 | 2.22% | 61.33 mph | Within tolerance | - |
245/70R15 |
724 | 2.35% | 61.41 mph | Within tolerance | - |
215/80R15 |
725 | 2.49% | 61.49 mph | Within tolerance | - |
195/85R14 |
687 | -2.87% | 58.28 mph | Within tolerance | - |
235/65R15 |
687 | -2.95% | 58.23 mph | Within tolerance | - |
255/65R17; factory fitment (2005–2009)
Overall diameter 763.3 mm (30.05 in). Alternatives below are grouped by upgrade intent; every one is inside the ±3% safe-fit envelope for this size.
Plus-1 (next rim size up)
Plus-1 keeps overall diameter constant while bumping rim diameter by one inch and dropping aspect ratio by ten points. The standard daily-driver upgrade; sharper steering response, mild ride penalty, modest tire-cost premium.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
255/60R18 |
763 | -0.01% | 59.99 mph | Safe | - |
235/65R18 |
763 | -0.08% | 59.95 mph | Safe | - |
275/55R18 |
760 | -0.47% | 59.72 mph | Safe | - |
285/55R18 |
771 | 0.97% | 60.58 mph | Safe | - |
225/70R18 |
772 | 1.17% | 60.70 mph | Within tolerance | - |
265/60R18 |
775 | 1.56% | 60.94 mph | Within tolerance | - |
245/60R18 |
751 | -1.59% | 59.05 mph | Within tolerance | - |
245/65R18 |
776 | 1.62% | 60.97 mph | Within tolerance | - |
225/65R18 |
750 | -1.78% | 58.93 mph | Within tolerance | - |
265/55R18 |
749 | -1.91% | 58.85 mph | Within tolerance | - |
285/50R18 |
742 | -2.76% | 58.34 mph | Within tolerance | - |
Plus-2 (two rim sizes up)
Plus-2 lifts rim diameter by two inches with a twenty-point aspect drop. Noticeable ride penalty, higher pothole risk, and a meaningful tire-cost premium. Suitable for performance trims and aesthetic upgrades.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
255/55R19 |
763 | -0.03% | 59.98 mph | Safe | - |
235/60R19 |
765 | 0.17% | 60.10 mph | Safe | - |
285/50R19 |
768 | 0.56% | 60.34 mph | Safe | - |
275/50R19 |
758 | -0.75% | 59.55 mph | Safe | - |
225/60R19 |
753 | -1.40% | 59.16 mph | Within tolerance | - |
265/55R19 |
774 | 1.41% | 60.85 mph | Within tolerance | - |
245/55R19 |
752 | -1.47% | 59.12 mph | Within tolerance | - |
225/65R19 |
775 | 1.55% | 60.93 mph | Within tolerance | - |
245/60R19 |
777 | 1.74% | 61.05 mph | Within tolerance | - |
265/50R19 |
748 | -2.06% | 58.77 mph | Within tolerance | - |
275/55R19 |
785 | 2.86% | 61.71 mph | Within tolerance | - |
235/55R19 |
741 | -2.91% | 58.25 mph | Within tolerance | - |
Same rim, wider footprint
Same rim diameter as your OEM, just a wider footprint. Increases grip and footprint contact at the cost of fuel economy and steering effort. Confirm fender clearance at full lock before purchase.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
275/60R17 |
762 | -0.20% | 59.88 mph | Safe | - |
285/60R17 |
774 | 1.38% | 60.83 mph | Within tolerance | - |
265/65R17 |
776 | 1.70% | 61.02 mph | Within tolerance | Yes |
265/60R17 |
750 | -1.77% | 58.94 mph | Within tolerance | - |
285/55R17 |
745 | -2.36% | 58.59 mph | Within tolerance | - |
Winter / narrower contact
Narrower than OEM, aspect ratio raised to preserve overall diameter. Higher contact pressure improves snow and slush bite; the Nokian-style rule of one width step down for winter on the same overall diameter.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
235/70R17 |
761 | -0.33% | 59.80 mph | Safe | - |
225/80R16 |
766 | 0.41% | 60.24 mph | Safe | - |
235/75R16 |
759 | -0.58% | 59.65 mph | Safe | - |
225/75R17 |
769 | 0.79% | 60.47 mph | Safe | - |
245/75R16 |
774 | 1.39% | 60.83 mph | Within tolerance | - |
245/70R17 |
775 | 1.51% | 60.90 mph | Within tolerance | - |
245/65R17 |
750 | -1.70% | 58.98 mph | Within tolerance | - |
245/70R16 |
749 | -1.82% | 58.91 mph | Within tolerance | - |
225/70R17 |
747 | -2.16% | 58.70 mph | Within tolerance | - |
235/80R16 |
782 | 2.50% | 61.50 mph | Within tolerance | - |
225/75R16 |
744 | -2.54% | 58.48 mph | Within tolerance | - |
235/75R17 |
784 | 2.75% | 61.65 mph | Within tolerance | - |
Other geometric alternatives
Geometrically valid alternatives that don't fit a named category. Often combinations of rim and aspect change that happen to land in tolerance.
| Size | OD (mm) | %Δ | True @ 60 mph | Verdict | In catalog |
|---|---|---|---|---|---|
255/70R16 |
763 | 0.01% | 60.01 mph | Safe | - |
225/85R15 |
764 | 0.03% | 60.02 mph | Safe | - |
255/75R15 |
764 | 0.03% | 60.02 mph | Safe | - |
275/65R16 |
764 | 0.08% | 60.05 mph | Safe | - |
275/70R15 |
766 | 0.35% | 60.21 mph | Safe | - |
235/80R15 |
757 | -0.83% | 59.50 mph | Safe | - |
245/80R15 |
773 | 1.27% | 60.76 mph | Within tolerance | - |
265/70R15 |
752 | -1.48% | 59.11 mph | Within tolerance | - |
285/65R15 |
752 | -1.55% | 59.07 mph | Within tolerance | - |
265/65R16 |
751 | -1.62% | 59.03 mph | Within tolerance | - |
285/65R16 |
777 | 1.78% | 61.07 mph | Within tolerance | - |
265/70R16 |
777 | 1.85% | 61.11 mph | Within tolerance | - |
245/75R15 |
749 | -1.94% | 58.84 mph | Within tolerance | - |
285/60R16 |
748 | -1.95% | 58.83 mph | Within tolerance | - |
265/75R15 |
779 | 1.99% | 61.19 mph | Within tolerance | - |
285/70R15 |
780 | 2.19% | 61.31 mph | Within tolerance | - |
235/85R15 |
781 | 2.25% | 61.35 mph | Within tolerance | - |
225/80R15 |
741 | -2.92% | 58.25 mph | Within tolerance | - |
Which upsize path fits your priorities?
Every option on this page is inside the ETRTO ±3% overall-diameter tolerance, so any of them is mechanically safe on the factory rim geometry. The difference is what each trades. Use this to pick the category, then read the verdict table above for the exact sizes.
| Category | Ride comfort | Handling | Fuel economy | Road noise | Tire cost |
|---|---|---|---|---|---|
| Plus-1 | Slightly firmer | Sharper | ≈ neutral | ≈ neutral | Modest premium |
| Plus-2 | Firmer | Sharpest | Slightly worse | Slightly higher | Higher premium |
| Wider (same rim) | ≈ neutral | More grip | Slightly worse | Slightly higher | Modest premium |
| Winter narrower | Softer | Softer dry | ≈ neutral | Lower | ≈ neutral |
| Narrower (same rim) | Softer | Less grip | Better | Lower | Often cheaper |
| OEM-equivalent | ≈ OEM | ≈ OEM | ≈ OEM | ≈ OEM | ≈ OEM |
"≈" means no meaningful change versus the factory size. Comfort and noise assume the same tire model and load rating; switching brand or category (touring → performance) usually moves these more than the size change does.
Winter setup for the Isuzu KB
For winter, the European engineering rule is to step down one width while raising aspect ratio to hold the same overall diameter; the "Winter / narrower contact" rows in the table above. A narrower footprint concentrates the vehicle's weight over less rubber, raising contact pressure so the tread bites through snow and slush instead of floating on it. Keep the overall diameter within ±3% of 195/75R14 so ABS, TPMS, and (on AWD trims) the center coupling stay inside their factory calibration. Fit four matching winter tires, never two.
Related pages
- Isuzu KB fitment specs; OE sizes, load/speed ratings, and recommended tires by year
- Best tires for the Isuzu KB; data-backed rankings
- Every vehicle running 195/75R14 and its full alternative-size table
- Every vehicle running 215/70R16 and its full alternative-size table
- Every vehicle running 255/65R17 and its full alternative-size table
FAQ
Can I put bigger tires on my Isuzu KB?
What is the OEM tire size for the Isuzu KB?
Will bigger tires hurt my Isuzu KB's fuel economy or ride?
Do I need new wheels to change tire size on my Isuzu KB?
Sources & methodology
Last verified 2026-05-17 against the standards below.
- ETRTO 2024 Standards Manual §2.3 (section width, aspect ratio, overall diameter formula). European Tyre and Rim Technical Organisation, Brussels.
- SAE J1349 (speedometer accuracy reference envelope).
- NHTSA FMVSS 138 Tire Pressure Monitoring Systems; rev/mile calibration requirements.
- Tire Industry Association Technical Bulletin TB-2019-04 (plus-sizing guidance).
- Nokian Tyres "Why winter tyres should be narrower" technical bulletin, 2019.