Tire Size Conversion Chart

This chart will help you find the right size tires to replace those dried up originals.   The K5 had 3.25-19 on the front and 3.50-18 on the rear.  I replaced my Bridgestone/Dunlop combo with a Continental SuperTwin 3.25 X 19 and an IRC GS-11 3.50S18.  I chose these tires based solely on tread pattern likeness to the original tires.   These were available in the traditional sizes, and they fit & look perfect.  You will have many more options if you use the metric measurements below.
 

Tube Size

Will Fit Tire Size:  

2.50/2.75 - 8 2.50 - 8 2.75 - 8                  
3.00/3.25 - 8 3.00 - 8 3.25 - 8                  
3.50/4.00 - 8 3.50 - 8 4.00 - 8                  
2.50/2.75 - 10 2.50 - 10 2.75 - 10                  
3.00/3.25 - 10 3.00 - 10 3.25 - 10 80/90 - 10                
3.50/4.00 - 10 3.50 - 10 4.00 - 10 100/90 - 10                
2.75/3.00 - 12 2.75 - 12 3.00 - 12 80/100 - 12 100/80 - 12              
3.00/3.25 - 12 3.00 - 12 3.25 - 12 80/100 - 12 100/80 - 12              
2.75/3.00 - 14 2.75 - 14 3.00 - 14 3.60 - 14 80/80 - 14              
3.50/3.75 - 14 3.50 - 14 3.75 - 14 4.10 - 14 110/80 - 14              
2.75/3.00 - 16 2.75 - 16 3.00 - 16 80/100 - 16 80/90 - 16              
3.00/3.25 - 16 3.00 - 16 3.25 - 16 90/90 - 16 100/80 - 16              
3.25/3.50 - 16 3.25 - 16 3.50 - 16 100/90 - 16 90/100 - 16 90/90 - 16 100/80 - 16          
4.00/4.60 - 16 4.00 - 16 4.60 - 16 120/80 - 16 110/90 - 16 120/90 - 16            
5.00/5.10 - 16 5.00 - 16 5.10 - 16 130/90 - 16 140/80 - 16 140/90 - 16 150/80 - 16          
2.25/2.50 - 17 2.25 - 17 2.50 - 17 3.10 - 17 70/100 - 17              
2.75/3.00 - 17 2.75 - 17 3.00 - 17 3.10 - 17 80/90 - 17 100/80 - 17            
3.00/3.25 - 17 3.00 - 17 3.25 - 17 100/80 - 17                
3.25/3.50 - 17 3.25 - 17 3.50 - 17 110/80 - 17                
3.75/4.00 - 17 3.75 - 17 4.00 - 17 120/80 - 17                
4.00/4.50 - 17 4.00 - 17 4.50 - 17 4.25 - 17 4.60 - 17 110/90 - 17 110/100 - 17 120/80 - 17 120/90 - 17 130/80 - 17 130/70 - 17  
5.00/5.10 - 17 5.00 - 17 5.10 - 17 130/90 - 17 140/80 - 17 140/90 - 17 5.30 - 17          
2.25/2.50 - 18 2.25 - 18 2.50 - 18 3.10 - 18                
2.50/2.75 - 18 2.50 - 18 2.75 - 18 3.10 - 18 80/90 - 18              
2.75/3.00 - 18 2.75 - 18 3.00 - 18 3.60 - 18 80/90 - 18 90/90 - 18 80/100 - 18          
3.00/3.25 - 18 3.00 - 18 3.25 - 18 3.60 - 18 90/90 - 18              
3.25/3.50 - 18 3.25 - 18 3.50 - 18 3.60 - 18 4.10 - 18 90/90 - 18 90/100 - 18 100/90 - 18 110/80 - 18      
3.50/4.00 - 18 3.50 - 18 4.00 - 18 4.10 - 18 4.25 - 18 4.60 - 18 100/90 - 18 100/100 - 18 110/80 - 18 110/90 - 18 120/80 - 18  
3.75/4.00 - 18 3.75 - 18 4.00 - 18 4.25 - 18 4.60 - 18 100/100 - 18 110/90 - 18 120/80 - 18        
4.00/4.50 - 18 4.00 - 18 4.50 - 18 4.25 - 18 4.60 - 18 4.70 - 18 110/90 - 18 110/100 - 18 120/80 - 18 120/90 - 18 130/70 - 18 130/80 - 18
5.00/5.10 - 18 5.00 - 18 5.10 - 18 130/90 - 18 140/80 - 18 140/90 - 18 120/100 - 18 140/70 - 18        
2.50/2.75 - 19 2.50 - 19 2.75 - 19 70/100 - 19                
2.75/3.00 - 19 2.75 - 19 3.00 - 19 3.60 - 19 90/90 - 19              
3.00/3.25 - 19 3.00 - 19 3.25 - 19 3.60 - 19 90/90 - 19              
3.25/3.50 - 19 3.25 - 19 3.50 - 19 3.60 - 19 4.10 - 19 90/90 - 19 100/90 - 19 110/80 - 19        
3.50/4.00 - 19 3.50 - 19 4.00 - 19 4.10 - 19 4.25 - 19 4.60 - 19 100/90 - 19 110/80 - 19 110/90 - 19 120/80 - 19    
4.00/4.25 - 19 4.00 - 19 4.25 - 19 110/90 - 19 120/80 - 19 120/90 - 19            
2.50/2.75 - 21 2.50 - 21 2.75 - 21 70/100 - 21 80/80 - 21 80/90 - 21 90/80 - 21          
2.75/3.00 - 21 2.75 - 21 3.00 - 21 80/90 - 21 80/100 - 21 90/80 - 21 90/90 - 21 100/80 - 21        
2.75/3.00 - 22 2.75 - 22 3.00 - 22                  
2.75 - 23 2.75 - 23                    

FRONT:    Original Dunlop Gold Seal F6                            New Continental SuperTwin

                       

 

REAR:    Original Bridgestone Super Speed 21R2                New IRC GS-11

                       


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