msdumo

I have a Raleigh Portage with a broken 5 speed SIS shifter. Can't seem to find one.
There are 6 speed shifters.
The question is, are the gears on my 5 speed freewheel distanced the same as a 6 speed freewheel.
If they are then a 6 speed shifter is likely to work.
I know that this distance is less on a 7 speed freewheel making the indexing probably not workable.
I am pretty sure that a 7 speed freewheel probably would not fit on my hub.
I need help or specs to confirm whether this option will work for me.

sch

5 spd FW spacing is same as 6 spd FW, but is ~5-6mm wider, hence need for longer axle and a spread of
rear fork spacing (120mm -> 126 mm ). 6 spd shifter should work ok with friction shifting or indexed on a 5spd FW. If you
continue with 5sp FW than axle length is immaterial (but will be 120mm).

msdumo

Can I adjust cable on rear derailer to skip first or last index on a Shimano sl-tx30-6r 6 speed shifter?
Thanks for reply. My first post!

fietsbob

I have used friction shifters , the derailleur has 2 stroke limit screws H & L they stop the motion over the 1st & last cog.

its the synchronization of the clicks in the lever on the handle bars to land under the 2,3 & 4 cogs that's the tricky part,

That friction shifting eliminates,,

msdumo

I don't think the Shimano Tourney shifters have a friction setting. Can you suggest a shifter that does or should I just use a friction shifter with no indexing?

fietsbob

Old stuff .. thumb shifters, downtube shifters , bar end shifters , Rivendale 'Silver' Shifters (Reproduced Sun tour Sprint)

Gevenalle Brake levers with a friction shift lever on the front of it.

70sSanO

If you are going to use the same rear derailleur and same freewheel you are currently using, you don't need to adjust the derailleur; other than normal index adjustments (if it high-low stops are set up correctly now).

To run 5 cogs with a 6 speed shifter you merely set up the shifter in the first position and when the derailleur stops at the 5th cog the shifter can't move because the 6th position is already blocked out by the derailleur.

John

msdumo

Thanks John.
My Shimano 6 spd Tourney shifter should arrive soon and you confirmed my plan of attack.
I will provide feedback for others when done.

msdumo

I installed the Shimano Tourney 6 spd shifter as John suggested and all is well.
Thanks

Miele Man

An old steel wheel MTB with a 5-speed index shifter was left at my BinL's place. I'll check and see if the bike is still there. If it is I'll pul the 5-speed index shifter off it and send it to you.

Cheers

msdumo

Thanks for the offer. Pretty generous and kind of you. My 6 spd Tourney shifter works very well.

70sSanO

Starting around 1986 (non-Dura Ace), and for the next 25 years Shimano SIS rear derailleurs all moved the same ratio based on how much cable the Shimano index shifter would pull.

Every cassette has a spacing that consists of cog thickness and a spacer between each cog.

For 5 speed the center to center distance is 5.5mm for each click. For 6 speed the distance is also 5.5mm for each click.

When setting up the rear derailleur you adjust the limit screws to stop after 4 clicks (5 cogs).

All of this is driven by the shifter and how much cable is pulled between clicks.

This is why people use 6 speed to 10 speed (9 for mountain bike) marketed rear derailleurs for whatever setup they have. They all have the same shift ratio and the shifter controls the amount of cable.

John

70sSanO

Additional:

That shift ratio was 1.7.

For example:
If the shifter pulled 1mm of cable, the derailleur would move over 1.7mm.

2mm of cable would move the derailleur over 3.4mm.

3mm of cable would move the derailleur over 5.1mm.

Obviously, cable pull is not limited to whole mm amounts.

John

db143

Hi all, hope this is an ok place to ask this question, John I am particularly interested in your response.

I'm toying with the idea of converting a 70s beater I have to index shifting. At the back is a Sunrace 5 speed freewheel and currently installed is a simplex derailleur which is completely knackered and needs replacing. My question is...

Would a set of Sunrace M20 MTB 5-speed indexed thumb shifters work with the spacing of the freewheel? Or, do I need to first select my replacement derailleur, if this impacts the shift ratio that you describe John? (I'm looking at a Sunrace M2 5-speed, but their website provides no information on ratios.)

PS I am aware that my simplex-style hanger won't take other derailleurs - a workaround is planned if I go this route.