***Ping Bonj***

[Andy in Sig]

What is ERTRO?

What is 4120?

What is T6?

What is 68mm or 73mm?

What is OLND?

What is BCD?

Why is 1.75 inches not the same as 1 3/4 inches?

Eh? Eh? Eh? Eh? Eh? Huh?

You'll never get a job as a bike mechanic at this rate.

You're going to have to enlighten us on that one as I suspect a lot of people would swear they are the same.

 

[bonj2]

the answer is something along the lines of "a tyre described as 1.75 inches will not fit a rim described as needing 1 3/4 inch tyres."
http://www.sheldonbrown.com/tire_sizing.html

 

[mickle]

26x1.75 is American Imperial standard using the same rim bead seat diameter as the 1930s 26x2.125 'baloon' tyre equipped cruisers. Its the standard still used by mountain bikes.

26x1 3/4 is British Imperial standard, one of a range of 26inch tyres which includes 26x1 1/4, 26x1 3/8, 26x1 1/8. none of which were compatible. Although they shared the same tyre outside diameter the bead seat diameters were different.

Interesting huh? Well I find it interesting.................

 

[bonj2]

26x1.75 is American Imperial standard using the same rim bead seat diameter as the 1930s 26x2.125 'baloon' tyre equipped cruisers. Its the standard still used by mountain bikes.

26x1 3/4 is British Imperial standard, one of a range of 26inch tyres which includes 26x1 1/4, 26x1 3/8, 26x1 1/8. none of which were compatible. Although they shared the same tyre outside diameter the bead seat diameters were different.

Interesting huh? Well I find it interesting.................

mind bogglingly...

 

[mickle]

What is ERTRO? The international tyre standards body.

What is 4120? Chromoly or Chrome/molebdinum alloyed steel.

What is T6? The heat treatment process for 6061 aloonyman.

What is 68mm or 73mm? The two bottom bracket width standards.

What is OLND? Over Lock Nut Dimension, or the face to face inside surface distance of frame drop-outs.

What is BCD? Chainring Bolt Circle Diameter.

Why is 1.75 inches not the same as 1 3/4 inches?

.

 

[Noodley]

Dunno if they are all the same length straight from the box but thats irrelevant. Ten spd chains, like 9,8,7,6,5 and single speed chains should be a length which is appropriate for the transmission. The relevant factors are chainstay length, largest sprocket and chainring diameters and rear deraillieur capacity.

Perhaps I should take this question over to Technical section as I am interested in this as there never appears to be any indication of what length a chain is when purchasing it, and I am unsure about how to work out what length my chain should be. I knew 8, 9, 10 speed chains were different widths but had never given too much thought to length until now as I had always just gone with what I was given by LBS.

I'll go and take it over to the appropraite section. See you there. Maybe.