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BMX General => BMX Chat => Topic started by: Devilock on June 03, 2012, 10:35 AM

Title: Stupid question
Post by: Devilock on June 03, 2012, 10:35 AM
Can a 1 3/8 tyre be installed on a 1.75 rim for a low profile...? :-[
Title: Re: Stupid question
Post by: Jon The Bassist on June 03, 2012, 10:40 AM
No, fractional tyre sizes (eg 1&3/8 inch) fit a different diameter rim than decimal tyres (eg 1.5).
Title: Re: Stupid question
Post by: hunterdubber on June 03, 2012, 10:44 AM
Just saying Rich IF,,, it could stretch to the rim edge using a thin inner tube , aren't the internal radius larger on a 1 3/8 tyre/wheel  ???

so it would be baggy trying it over the rim anyway ,,I could be wrong  :-\


Edit  :D as Jon said too   :)
Title: Re: Stupid question
Post by: Jon The Bassist on June 03, 2012, 10:55 AM
A 1.5 would work nicely though :daumenhoch:
Title: Re: Stupid question
Post by: Devilock on June 03, 2012, 12:13 PM
Ok thank you Jon & thank you Chris...! :daumenhoch:

So 20 x 1 1/38 is bigger than 20inch...?? ???
Title: Re: Stupid question
Post by: Jon The Bassist on June 03, 2012, 12:25 PM
Ok thank you Jon & thank you Chris...! :daumenhoch:

So 20 x 1 1/38 is bigger than 20inch...?? ???


Yes, but it's the 20 x 1 3/8 that i actually nearer to being 20 inches.  Generally the metric sizes are only near their stated diameter when measured including a fairly fat tyre (eg 2.125 tyre).
Title: Re: Stupid question
Post by: bobbbbsy on June 03, 2012, 12:31 PM
20x1.75 wont go on a 1 3/8 rim at all ever so i would imagine the other way round is terminally wrong to !
Title: Re: Stupid question
Post by: xGoose on June 03, 2012, 12:37 PM
Here my 2p's worth Rich, but not sure if it applies to ALL 20" rims & tires,

20X1-1/8 & 20X1-3/8 = 451mm diameter
20X1.50 & 20X1.75 = 406mm diameter (also 1.95, 2.20 etc. tires)

So only 451mm (fractional) tires will fit on 451mm rims and only 406mm (decimal) tires will fit on 406mm rims.

Be careful about what the frame is actually supposed to take as well as the brake positioning will also vary. For new school with lugs, some brakes like LDC have loads of adjustment so can be used on a mini / junior frame with 406mm  rims. For old school if you want to put a 451mm rim onto a pro frame you might need to find a smaller roadie style brake.

Hope that helps a bit ;)


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