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20 inch tire question

Discussion in 'Gear and Equipment' started by Gary B, Aug 17, 2012.  |  Print Topic

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  1. Gary B

    Gary B

    Region:
    SouthEast
    State/Country:
    NJ
    City:
    Jackson
    Ride:
    burley hepcat
    Name:
    Gary
    What is the difference between a 20 inch (451) mm tire and a 20 inch (409) mm tire. Is the difference in height of the tire? Is there any difference in performance?

    Thanks


    Gary
     
    Gary B, Aug 17, 2012
    #1
  2. A.D.

    A.D. #1 Custodian

    Region:
    SouthEast
    State/Country:
    TN
    City:
    Athens
    Ride:
    Reynolds T-Bone
    Name:
    AD
    The 406mm decimal size was commonly used on bikes from France, Holland and the US. Typically BMX, juvenile, folding, recumbent bicycles, and some trailers use a 406. They're well suited for smaller riders, their lower cost is compatible with inexpensive bicycles, and the size makes them stronger to withstand the additional loads generated by BMX stunts.

    The 451mm fractional size was used on bikes from Italy and Britain. With lightweight 406mm tires and rims available today, the 451mm option isn’t as much of an advantage anymore.

    Lastly, the 406mm (fractional decimal) standard is more common and it's easy to get spares in that size. The 451mm (decimal fractional) size is relatively rare, in comparison.

    And this, from the Hostel Shoppe's Help Guide:
    20" Tires:
    Twenty-inch recumbent wheels use either 406mm or 451mm tires...

    The 406mm wheels are the most common and can be fit with tires ranging from skinny to fat. Common tire sizes for 406mm wheels are 20x1.35", 20x1.5", 20x1.75", 20x2.0" and 20x2.15".

    451mm wheels, on the other hand, are limited to using either a 20x1-1/8" or 20x1-3/8" tire.
    ​
    Also, there's an older thread entitled "20" wheels 406mm X 451mm big diference?" over on BROL you may want to peruse as well. :wink9:
     
    A.D., Aug 20, 2012
    #2
  3. DTresenriter

    DTresenriter

    Region:
    Middle
    State/Country:
    IL
    City:
    East Peoria
    Ride:
    WC Di2 VTX
    Name:
    Denny
    Just to add, 451 is closer to a True 20". A 451 with a 28mm tire has a diameter of 507mm, or just 1 mm shy of 20".

    A 406, on the other hand, is roughly 2" less in diameter.

    I own bikes with both 451 and 406 front wheels. It feels to me that the 451 rolls better but it may be more in my head. :laugh9:
     
    DTresenriter, Aug 21, 2012
    #3
  4. BlazingPedals

    BlazingPedals

    Region:
    North
    State/Country:
    MI
    City:
    Haslett
    Ride:
    M5CHR
    Name:
    John
    AD mixed his message. The 406 size is usually designated by decimal sizing, i.e. "20x1.5" whereas the 451 size is designated with fractional sizes such as "20x1 1/8." The exception is Conti which uses fractional sizes for 406. As for the difference, the rim diameter of a 451 is almost 2 inches larger. A wheel/tire combination has almost the same diameter if you compare a 20x1 1/8 with a 20x2.00, about 507mm. Which coincidentally is the *rim* size of a 24" wheel. Of course, the fat 406 tire will have a lot more heavy rubber, and will weigh several hundred grams more than the 451 tire.

    When I first got into recumbents, EasyRacers and RANS were the big names, and they used 451 for their front tires. Then the Rocket came out with 406 and within a year all the RANS lineup used 406 front wheels. ER continued using 451 exclusively for several years more, before offering 406 as part of their "EX" package. At the time the only skinny tire available in 406 was the Conti GP, which was horribly fragile. But, the theory of the time was that recumbents worked best with fat tires. Eventually the industry standardized on 406; and as demand for skinny tires in that size has grown, we've gotten more choices. But things could have just as easily gone in the other direction, and IMNSHO they should have. If they'd standardized on 451, there would now be all the skinny and fat options that 406 currently has. I think it's ludicrous that we now have bikes which never get ridden off-road, which have a BMX wheel in front and a mountain bike wheel in back. SAY WHAT??? :confused9:
     
    BlazingPedals, Aug 21, 2012
    #4
  5. DTresenriter

    DTresenriter

    Region:
    Middle
    State/Country:
    IL
    City:
    East Peoria
    Ride:
    WC Di2 VTX
    Name:
    Denny
    I don't understand the 'mtb' wheel on the back of many recumbents at all. The only advantage is that tubes and tires are easier to find but the 650C (571) is a far superior tire for road use, IMHO.
     
    DTresenriter, Aug 21, 2012
    #5
  6. A.D.

    A.D. #1 Custodian

    Region:
    SouthEast
    State/Country:
    TN
    City:
    Athens
    Ride:
    Reynolds T-Bone
    Name:
    AD
    :goodpoint: I didn't notice what I'd actually typed, right after the tire sizes! :laugh9:

    Anyway, I've done my best to revise it in my original reply above now. :thanks:
     
    A.D., Aug 21, 2012
    #6
  7. Geyatautsilvsgi

    Geyatautsilvsgi Supporter

    Region:
    SouthEast
    State/Country:
    TN
    City:
    Seymour
    Ride:
    ?
    Name:
    Geyatautsilvsgi
    I used a 451/700c wheel combo on my first bent. What a ride! Man I loved it. I had a fast and COMFY bike. However, it was a pain in the toosh when it come to touring 'cause we always had to carry extra front tubes for me rather than a tube that could have been used for either one of us.
     
    Geyatautsilvsgi, Aug 22, 2012
    #7
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