diff --git a/packages/rpc-provider/src/mock/subscribe.spec.ts b/packages/rpc-provider/src/mock/subscribe.spec.ts
index 85a9426648..64fd1cb49b 100644
--- a/packages/rpc-provider/src/mock/subscribe.spec.ts
+++ b/packages/rpc-provider/src/mock/subscribe.spec.ts
@@ -39,7 +39,7 @@ describe('subscribe', () => {
 
   it('calls back with new headers', (done) => {
     return mock.subscribe('chain_newHead', 'chain_subscribeNewHead', (_: any, header: any) => {
-      if (header.number === '0x0000000000000004') {
+      if (header.number === 4) {
         done();
       }
     });
@@ -55,7 +55,7 @@ describe('subscribe', () => {
         throw new Error('testing');
       }
 
-      if (header.number === '0x0000000000000003') {
+      if (header.number === 3) {
         done();
       }
     });
diff --git a/packages/types/src/Digest.spec.ts b/packages/types/src/Digest.spec.ts
index 772eeab701..4ca58911c0 100644
--- a/packages/types/src/Digest.spec.ts
+++ b/packages/types/src/Digest.spec.ts
@@ -15,7 +15,7 @@ describe('Digest', () => {
 
     expect(log.type).toBe('Seal');
     expect(log.value.toJSON()).toEqual([
-      '0x000000000f4e8607',
+      256804359,
       '0x2c0e0ee8a5d1a073da3f8db002b8eaebcd7b1a7eb25662e09f9ef0ac58d96bf17896256cd5f0bc672f96aab49fe5163ca5cb4c1a0f047dc39e89cd4a9eb2ea05'
     ]);
   });
diff --git a/packages/types/src/I128.ts b/packages/types/src/I128.ts
index 7e1308045d..4c95eccbbb 100644
--- a/packages/types/src/I128.ts
+++ b/packages/types/src/I128.ts
@@ -13,6 +13,6 @@ import Int from './codec/Int';
  */
 export default class I128 extends Int {
   constructor (value?: AnyNumber) {
-    super(value, 128, true);
+    super(value, 128);
   }
 }
diff --git a/packages/types/src/I16.ts b/packages/types/src/I16.ts
index be220865c8..bad7c36c95 100644
--- a/packages/types/src/I16.ts
+++ b/packages/types/src/I16.ts
@@ -13,6 +13,6 @@ import Int from './codec/Int';
  */
 export default class I16 extends Int {
   constructor (value?: AnyNumber) {
-    super(value, 16, false);
+    super(value, 16);
   }
 }
diff --git a/packages/types/src/I256.ts b/packages/types/src/I256.ts
index 3ae4d99861..bd873605ab 100644
--- a/packages/types/src/I256.ts
+++ b/packages/types/src/I256.ts
@@ -13,6 +13,6 @@ import Int from './codec/Int';
  */
 export default class I256 extends Int {
   constructor (value?: AnyNumber) {
-    super(value, 256, true);
+    super(value, 256);
   }
 }
diff --git a/packages/types/src/I32.ts b/packages/types/src/I32.ts
index 364ed56634..6b6691ac8c 100644
--- a/packages/types/src/I32.ts
+++ b/packages/types/src/I32.ts
@@ -13,6 +13,6 @@ import Int from './codec/Int';
  */
 export default class I32 extends Int {
   constructor (value?: AnyNumber) {
-    super(value, 32, false);
+    super(value, 32);
   }
 }
diff --git a/packages/types/src/I64.ts b/packages/types/src/I64.ts
index 71a56069d5..daf68e045e 100644
--- a/packages/types/src/I64.ts
+++ b/packages/types/src/I64.ts
@@ -13,6 +13,6 @@ import Int from './codec/Int';
  */
 export default class I64 extends Int {
   constructor (value?: AnyNumber) {
-    super(value, 64, true);
+    super(value, 64);
   }
 }
diff --git a/packages/types/src/I8.ts b/packages/types/src/I8.ts
index 65e27daa9a..b10aece88a 100644
--- a/packages/types/src/I8.ts
+++ b/packages/types/src/I8.ts
@@ -13,6 +13,6 @@ import Int from './codec/Int';
  */
 export default class I8 extends Int {
   constructor (value?: AnyNumber) {
-    super(value, 8, false);
+    super(value, 8);
   }
 }
diff --git a/packages/types/src/U128.ts b/packages/types/src/U128.ts
index 385f67b969..461636e785 100644
--- a/packages/types/src/U128.ts
+++ b/packages/types/src/U128.ts
@@ -13,6 +13,6 @@ import UInt from './codec/UInt';
  */
 export default class U128 extends UInt {
   constructor (value?: AnyNumber) {
-    super(value, 128, true);
+    super(value, 128);
   }
 }
diff --git a/packages/types/src/U16.ts b/packages/types/src/U16.ts
index bdda09535d..e38b1753cf 100644
--- a/packages/types/src/U16.ts
+++ b/packages/types/src/U16.ts
@@ -13,6 +13,6 @@ import UInt from './codec/UInt';
  */
 export default class U16 extends UInt {
   constructor (value?: AnyNumber) {
-    super(value, 16, false);
+    super(value, 16);
   }
 }
diff --git a/packages/types/src/U256.ts b/packages/types/src/U256.ts
index 35f276fd18..6731fe6195 100644
--- a/packages/types/src/U256.ts
+++ b/packages/types/src/U256.ts
@@ -13,6 +13,6 @@ import UInt from './codec/UInt';
  */
 export default class U256 extends UInt {
   constructor (value?: AnyNumber) {
-    super(value, 256, true);
+    super(value, 256);
   }
 }
diff --git a/packages/types/src/U32.ts b/packages/types/src/U32.ts
index 9045119301..3abe5f5046 100644
--- a/packages/types/src/U32.ts
+++ b/packages/types/src/U32.ts
@@ -13,6 +13,6 @@ import UInt from './codec/UInt';
  */
 export default class U32 extends UInt {
   constructor (value?: AnyNumber) {
-    super(value, 32, false);
+    super(value, 32);
   }
 }
diff --git a/packages/types/src/U64.ts b/packages/types/src/U64.ts
index 9379a31c97..8f14a57482 100644
--- a/packages/types/src/U64.ts
+++ b/packages/types/src/U64.ts
@@ -13,6 +13,6 @@ import UInt from './codec/UInt';
  */
 export default class U64 extends UInt {
   constructor (value?: AnyNumber) {
-    super(value, 64, true);
+    super(value, 64);
   }
 }
diff --git a/packages/types/src/U8.ts b/packages/types/src/U8.ts
index cbf0414af3..1172886ffb 100644
--- a/packages/types/src/U8.ts
+++ b/packages/types/src/U8.ts
@@ -13,6 +13,6 @@ import UInt from './codec/UInt';
  */
 export default class U8 extends UInt {
   constructor (value?: AnyNumber) {
-    super(value, 8, false);
+    super(value, 8);
   }
 }
diff --git a/packages/types/src/codec/AbstractInt.ts b/packages/types/src/codec/AbstractInt.ts
index d71866d2e7..a947c92f5e 100644
--- a/packages/types/src/codec/AbstractInt.ts
+++ b/packages/types/src/codec/AbstractInt.ts
@@ -101,7 +101,8 @@ export default abstract class AbstractInt extends BN implements Codec {
    * @description Converts the Object to JSON, typically used for RPC transfers
    */
   toJSON (): any {
-    return this._isHexJson
+    // Maximum allowed integer for JS is 2^53 - 1, set limit at 52
+    return this._isHexJson || (super.bitLength() > 52)
       ? this.toHex()
       : this.toNumber();
   }
diff --git a/packages/types/src/codec/UInt.spec.ts b/packages/types/src/codec/UInt.spec.ts
index 869eb3138a..cc167d693b 100644
--- a/packages/types/src/codec/UInt.spec.ts
+++ b/packages/types/src/codec/UInt.spec.ts
@@ -46,9 +46,10 @@ describe('UInt', () => {
     ).toEqual(123);
   });
 
-  it('converts to JSON depending on flags', () => {
-    expect(new UInt(0x12, 16).toJSON()).toEqual('0x0012');
-    expect(new UInt(0x12, 16, false).toJSON()).toEqual(0x12);
+  it('converts to JSON representation based on flags/size', () => {
+    expect(new UInt('0x12345678', 64, true).toJSON()).toEqual('0x0000000012345678');
+    expect(new UInt('0x1234567890', 64, false).toJSON()).toEqual(0x1234567890);
+    expect(new UInt('0x1234567890abcdef', 64, false).toJSON()).toEqual('0x1234567890abcdef');
   });
 
   describe('eq', () => {
diff --git a/packages/types/src/codec/UInt.ts b/packages/types/src/codec/UInt.ts
index d4dd3c9f71..abf2da7ac1 100644
--- a/packages/types/src/codec/UInt.ts
+++ b/packages/types/src/codec/UInt.ts
@@ -21,7 +21,7 @@ import AbstractInt, { DEFAULT_UINT_BITS, UIntBitLength } from './AbstractInt';
 export default class UInt extends AbstractInt {
   constructor (
     value: AnyNumber = 0,
-    bitLength: UIntBitLength = DEFAULT_UINT_BITS, isHexJson: boolean = true) {
+    bitLength: UIntBitLength = DEFAULT_UINT_BITS, isHexJson: boolean = false) {
     super(
       false,
       value,
diff --git a/packages/types/src/codec/createType.spec.ts b/packages/types/src/codec/createType.spec.ts
index 79f5e24509..967b854756 100644
--- a/packages/types/src/codec/createType.spec.ts
+++ b/packages/types/src/codec/createType.spec.ts
@@ -208,7 +208,7 @@ describe('createType', () => {
         index: '0x10'
       }).toJSON()
     ).toEqual({
-      balance: '0x000000000000000000000000000004d2',
+      balance: 1234,
       index: 16
     });
   });