Chain Conversion Calculator: 630 to 530, 530 to 520 & 428 to 520
Pick your current and target chain and get the new sprocket tooth counts, chain length, front sprocket clearance and chain mass change.
Stock vs. Target Chain
Pitch ×1.2- Pitch
- 19.05 → 15.875 mm
- Inner width
- 9.525 → 9.525 mm
- Mass / 100L
- 2520 → 2080 g
Converted front tooth bias
Converted 530 Kit
18T / 47T
New chain:110 links
Final Drive Ratio
2.611:1+0.43%
Stock 630:2.6:1
Chain Mass Change
+20 g
From spec data:avg. mass / 100 links
Front sprocket clearance check
Front OD -1.50 mm (101.1 → 99.6 mm)
- Solid: stock
- Dashed (blue or red): new
- Dashed (amber): your limit
- Rear OD change
- 247.4 → 246.7 mm
- Axle shift
- +15.13 mm (110L)
630 → 530 candidates
| Choose | Sprockets | Ratio (Δ%) | Front OD Δ | 530 links | Wear (GCD) |
|---|---|---|---|---|---|
| 18T / 46T | 2.556:1 (-1.71%) | -1.50 mm | 108L (+3.44 mm) | GCD 2 | |
| 18T / 47T | 2.611:1 (+0.43%) | -1.50 mm | 110L (+15.13 mm) | GCD 1 | |
| 18T / 48T | 2.667:1 (+2.56%) | -1.50 mm | 110L (+10.82 mm) | GCD 6 |
Pitch-Scaling vs. Width-Only Chain Conversions
Whether tooth counts must change depends on whether the pitch changes. Check the new sprockets against your gearing with the motorcycle gearing calculator once you know the kit.
Pitch-scaling: 630 → 530, 428 → 520
A 15T front sprocket on 630 chain has an outside diameter of about 101.1 mm. The same 15T on 530 would shrink to 84.2 mm and change your gearing. Multiplying by 6/5 gives 18T, at 99.6 mm, which keeps the pitch diameter and the ratio.
Width-only: 530 or 525 → 520
The pitch is the same 5/8 inch (15.875 mm), so teeth and links stay the same. Only the roller width narrows:
- 5206.35 mm inner width
- 5257.94 mm inner width
- 5309.525 mm inner width
Common Chain Conversions Worked Out
Each row runs a preset through the calculator's engine, using the closest-ratio candidate. Confirm sprocket sizes with the sprocket diameter calculator or recalculate how many links the new chain needs with the chain length calculator. If you are unsure which chain you have now, the chain size calculator identifies it from a caliper reading.
| Conversion | Stock | Pitch multiplier | Converted | New ratio (Δ%) | Front OD Δ | Chain mass |
|---|---|---|---|---|---|---|
| 630 → 530 | 15T / 39T · 90L | ×1.2 | 18T / 47T · 110L | 2.611:1 (+0.43%) | -1.50 mm | +20 g |
| 530 → 520 | 16T / 43T · 114L | ×1 | 16T / 43T · 114L | 2.688:1 (0%) | 0 mm | -604 g |
| 525 → 520 | 16T / 45T · 114L | ×1 | 16T / 45T · 114L | 2.813:1 (0%) | 0 mm | -547 g |
| 428 → 520 | 17T / 54T · 132L | ×0.8 | 14T / 43T · 106L | 3.071:1 (-3.31%) | +3.52 mm | +363 g |
| #35 → #219 | 12T / 62T · 106L | ×1.225 | 15T / 76T · 132L | 5.067:1 (-1.94%) | -0.02 mm | +3 g |
Chain mass uses the average mass per 100 links in the chain database, so treat it as an estimate. Sprocket mass is not modeled.