Is 5 & 6 speed Shimano indexing compatible?

[SkipdiverJohn]

I might want to swap a 6 speed MTB rear wheel into a frame which currently has a 5 speed freewheel and 5 speed SIS handlebar shifter. Apart from me not being able to use all six rear gears, will the 5 speed indexing still work ok on the 6 speed freewheel or are the sprocket spacings different?

 

[Smokin Joe]

They are different. You might get the five gears to engage, but they will be noisy in operation and it won't do chain and sprockets any favours.

 

[raleighnut]

Can you not switch the indexing off at the lever.

 

[SkipdiverJohn]

They are different. You might get the five gears to engage, but they will be noisy in operation and it won't do chain and sprockets any favours.

Thanks, glad I asked the question, because visually they didn't really look any different. I had assumed the extra sprocket on a 6 speed was an add-on in width rather than being squeezed into the same space.

@raleighnut the shifters appear to be dedicated to 5 or 6 speeds and are marked as such. They are not downtube-style friction shifters. It just means a bit more messing around as I'll need to move the shifters with the wheel. I'll probably end up swapping another 5-speed rear wheel, but it will be a steel one!

 

[simon.r]

Thanks, glad I asked the question, because visually they didn't really look any different. I had assumed the extra sprocket on a 6 speed was an add-on in width rather than being squeezed into the same space.

@raleighnut the shifters appear to be dedicated to 5 or 6 speeds and are marked as such. They are not downtube-style friction shifters. It just means a bit more messing around as I'll need to move the shifters with the wheel. I'll probably end up swapping another 5-speed rear wheel, but it will be a steel one!

Not something I have a lot of experience of, but my 6 speed handlebar mounted SIS shifter (from about 1993) has a little ‘switch’ that changes it from an indexed to a friction shifter.

 

[raleighnut]

Not something I have a lot of experience of, but my 6 speed handlebar mounted SIS shifter (from about 1993) has a little ‘switch’ that changes it from an indexed to a friction shifter.

That's what I mean, a little oblong 'flat topped' knob on the top. I've had a couple of bikes with that 'feature'.

 

[Ajax Bay]

I might want to swap a 6 speed MTB rear wheel into a frame which currently has a 5 speed freewheel and 5 speed SIS handlebar shifter. Apart from me not being able to use all six rear gears, will the 5 speed indexing still work ok on the 6 speed freewheel or are the sprocket spacings different?

John - I suggest you have a look at Sheldon on Cassette /Freewheel Spacing (scroll down about 1/4 page).
My understanding was/is that the spacings on 5 and 6 speed freewheel blocks are identical, and the table suggests just that.

They are different.

In what way are the sprocket spacings different, Joe? [5.5mm]

 

[raleighnut]

Why not just swap the freewheels over ?

 

[mickle]

Line the two blocks up sprocket to sprocket (turn one of them upside down) and look. It'll be obvious if they're different.

I seem to remember 5 & 6 being the same spacing.

 

[Smokin Joe]

John - I suggest you have a look at Sheldon on Cassette /Freewheel Spacing (scroll down about 1/4 page).
My understanding was/is that the spacings on 5 and 6 speed freewheel blocks are identical, and the table suggests just that.

In what way are the sprocket spacings different, Joe? [5.5mm]

If so, I stand corrected.