gfxgfx
 
logo
 
gfx gfx
gfx
975804 Posts in 138943 Topics by 6363 Members - Latest Member: V6 DOW November 23, 2024, 02:38 AM
*
gfx* Home | Portal | Forum | Merchandise | Help | Login | Register | gfx
gfx
RADBMX.CO.UK  |  Technical & Reference Section  |  Tech and Restoration  |  What tyres do I need ?
gfx
gfxgfx
 

Author Topic: What tyres do I need ?  (Read 2375 times)

0 Members and 1 Guest are viewing this topic.

Offline Michael bmx

  • Curb Endo
  • **
  • Posts: 141
  • Rated:
What tyres do I need ?
« on: January 11, 2019, 02:10 PM »
I have a set of alex rim dr13 they measure 18" in diameter and 1 " wide, I brought some 20" tyres thinking they were considerdd as 20" then found that 20" only measure 16" across, so do I need to try and find a 22" tyre?

Offline Michael bmx

  • Curb Endo
  • **
  • Posts: 141
  • Rated:
Re: What tyres do I need ?
« Reply #1 on: January 11, 2019, 02:11 PM »
Also forgot to say that the original tyres say 20x 1 1/8 and the new ones say 20 x 1, the wide isnt the issue so could someone explain why the 20 is?

Offline CustardLips

  • Site Supporter
  • Berm Worm
  • *
  • Posts: 7314
  • Rated:
Re: What tyres do I need ?
« Reply #2 on: January 11, 2019, 03:09 PM »
What's the actual size of rhe rim... 20 x 1 3/8 ?
"Every year is getting shorter, never seem to find the time"

"WWG1WGA"

Offline Michael bmx

  • Curb Endo
  • **
  • Posts: 141
  • Rated:
Re: What tyres do I need ?
« Reply #3 on: January 11, 2019, 07:01 PM »
The wheel itself measures 18" in diameter and 1 1/8 in diameter, I just found out that this is a 451mm tyre where a standard 20" wheel uses a 406 I made a mistake

Offline BMX1973

  • Site Supporter
  • Berm Worm
  • *
  • Posts: 8414
  • Rated:
Re: What tyres do I need ?
« Reply #4 on: January 12, 2019, 12:22 PM »
I remember selling some 20"  Weinmann rims on here and the irate buyer (newbie) said I sold them 18" child's wheels . They will not fit my repop Comp3s which Im getting :shocked:

 I said when tyres arrive see if they fit, which they did. 

The wheel will be 20" when the tyres are put on  :daumenhoch:


Offline Michael bmx

  • Curb Endo
  • **
  • Posts: 141
  • Rated:
Re: What tyres do I need ?
« Reply #5 on: January 12, 2019, 09:06 PM »
Thanks again for the reply, yes they are 20" with tyres, there where I made the mistake, I thought all 20" wheels where the same size, but they are not lol, a standard 20" wheel seems to be 16" in diameter but my alex rims are 18" but both are 20" with tyres on, so when I brought 20" wheel tyres I was sent a set for the standard instead of the 451 mm type I needed guess im stuck in the 80s/90s lol before mm was used ha ha. All sorted now 👍

Offline brettypeeps

  • Team Admin / Mechanic
  • My life is Radbmx
  • *
  • Posts: I am a geek!!
    • Bretts Bikes
  • Rated:
Re: What tyres do I need ?
« Reply #6 on: January 12, 2019, 11:11 PM »
The tyre size is 20 x 1 3/8.


Offline Spen69

  • Site Supporter
  • Tail Whip
  • *
  • Posts: 5646
  • It was less than TWELVE parsecs.... .
  • Rated:
Re: What tyres do I need ?
« Reply #7 on: January 13, 2019, 07:36 AM »
20" is the maximum OUTSIDE diameter of the tyre once fitted  :coolsmiley:

Narrow 1-1/8"  & 1-3/8" rims use different tyres but are still only 20" max when inflated.

I could be wrong but I think it has something to do with very early racing rules but either way there are two sizes, one is denoted with a fraction in the notation and the other uses a decimal. A standard rim is termed 20x1.75" or 20x1.5" and will fit any tyre from 20x1.5" upwards, seen newschool running 20x2.4" fairly often. The other rim is noted 20x1-1/8" and will run 20x1-1/8" or 20-3/8" tyres :coolsmiley:

Hope that helps - can probably post a few pictures if it's still not clear but for example my kids race bikes have a 1-1/8" narrow rear tyre and slightly wider 1-3/8" front for better grip :daumenhoch:

Oh, and don't forget you will need different size brake caliper - probably 610 size not standard 890/900/1000/1020's - if you're not sure what I mean the measure the centre of the brake spindle hole to the middle of the rim brake surface in mm then add a zero which will give you a number to aim for in the serial size of the caliper :daumenhoch:
« Last Edit: January 13, 2019, 08:04 AM by Spen69 »
Still limping......

Offline Michael bmx

  • Curb Endo
  • **
  • Posts: 141
  • Rated:
Re: What tyres do I need ?
« Reply #8 on: January 13, 2019, 09:13 PM »
Thank you so much for the info it is a great help, I have converted to disc breaks but that info will help in the future. Thank you guys

Offline Michael bmx

  • Curb Endo
  • **
  • Posts: 141
  • Rated:
Re: What tyres do I need ?
« Reply #9 on: January 13, 2019, 10:00 PM »
I have alex rims and these ankie ones

RADBMX.CO.UK  |  Technical & Reference Section  |  Tech and Restoration  |  What tyres do I need ?
 

gfxgfx
gfx gfx
Powered by MySQL Powered by PHP Valid XHTML 1.0! Valid CSS!
SimplePortal 2.3.5 © 2008-2012, SimplePortal