Rear Derailleur Compatibilty for 5speed

hias9

1 kW
Joined
Jul 11, 2018
Messages
422
When using a 5speed freewheel cassette on a big rear hub motor, with which rear derailleurs can it be combined?
Is a 7/8 speed or even 9speed derailleur fine, or does it have to be a 5speed derailleur from the 70s?
 
Sheldon Brown has good info on his website.

https://www.sheldonbrown.com/drivetrain-mixing.shtml

https://sheldonbrown.com/speeds.html
 
7 speed will work, its just the chain width that would make a 9 speed work less well. I mean use 7 speed chain on 7 or less gear freewheels.

Shifter is another story, but I think a 7 speed shifter will still work fine. indexes the same. Just set the stops on the derailleur to limit movement to the gears that are not there.

Also a possibility, get a friction shifter that does not index.
 
Standard 7 speed is 5.0mm spacing.
Standard 5 speed is 5.3mm spacing.
They aren't comparable, but it's close enough to "work". However, you will only be seated on 1 gear correctly, and all the others will grind. That will eventually lead to sprocket and chain failure, and isn't so healthy for the derailleur either.
Nothing else used 5.3mm spacing. for 5, 6, and 7 speeds, the derailleur is often the same, as the chain width is the same. the difference is in the shifter. A 5 speed uses different spacing between it's index points, moving the cable a bit more.

If you have no other options, you could try setting up the 5 speed sprocket and 7 speed shifter doing all your tuning and spacing adjustments using 3rd gear. With 3rd gear being perfectly centered, that would mean 2nd and 4th were only .3mm off, and might not make much noise. 1st and 5th would be .6mm off and would make more noise but maybe not much if you keep the chain well greased. This would be functional for a short time, maybe long enough if you never shift out of 3rd. But it will eventuality fail, And this is the kind of failure that only breaks when stressed, like when you are pedaling hard to get away from some angry dog, angry swarm of bees, or angry husband who just caught you with his lovely wife.


Here's the chart of spacings:
https://www.sheldonbrown.com/gloss_sp-ss.html#spacingk7

And now the sauce, this is the first google hit I found for a 5 speed shifter: https://www.ebay.com/p/691209372?iid=302916374297
 
Twist grip shifters are the ones working best with 5 spd. Then if you want perfect alignment, use a vintage derailer that has no indexed shifting. Those have a continuous displacement without any step points. So you can twist the grip shifter to the precise, smooth position for each cog. 5 spd twist grip shifters do exist, but if you can’t find one and have to use a 7spd, it is easy to cut the speed dent tab to make it twist continuously without steps.
 
hias9 said:
When using a 5speed freewheel cassette on a big rear hub motor, with which rear derailleurs can it be combined?
Is a 7/8 speed or even 9speed derailleur fine, or does it have to be a 5speed derailleur from the 70s?

There are index 5 and 6 speed shifters on “modern” (but very cheap) bikes. They interact with the same derailleurs that work on Shimano pattern 7, 8, and 9 speed freewheels and cassettes. For about $15 retail, you can get a SRAM twist grip shifter that does the job. Shimano and Sunrace make thumbshifters for 5 and 6 speed.

What you do not want, if you want index shifting, is an old pre-index derailleur. Those won’t have a correct ratio between shift cable pull and derailleur travel.

One advantage of a friction shifter, like MadRhino suggested, is that you can use the same shifter and derailleur with any number of freewheel sprockets.
 
On another bike I use a Shimano 5speed vintage derailleur (I think from the 70s) and a non-index thumb shifter.
Probably I will try a friction shifter this time, but I would need one for the left side because on the right I have a Domino throttle and a thumb throttle for variable regen.

Can a 3speed friction shifter for the left side also be modified to work with 5speed?
 
Grip shifters can be installed both sides. You push up speeds when on the left grip, and pull up speeds when installed on the right side. :idea:
 
hias9 said:
Can a 3speed friction shifter for the left side also be modified to work with 5speed?

Friction shifters don't know how many speeds they're shifting. No modification is necessary. There is no such thing as a "3-speed" or "5-speed" friction shifter-- only left and right. Some old shifters from 5 or 6-speed days will run out of cable travel when used to shift say 8 gears, but that's not your situation.
 
www.modernbike.com has lots of that stuff for a cheap price, but some maybe most items maybe sold out because of whats going on.
 
Sorry, I confused friction shifter with grip shifter.
What I have already on one bike is a non-index friction (thumb) shifter.
What I would like to try is a twist grip shifter. Do you think a 5speed indexed would work fine with a vintage 5speed Shimano derailleur? Would a non-index 3speed grip shift (for front derailleur) also work with the rear 5speed derailleur?
 
Older twist grip shifters were simple friction shifters. The more modern type have a small plastic ring and tab system added to match indexed derailers increments, easy to break or remove, making a friction shifter out of them.
 
Thanks, I think that’s the best option.
Did anybody already try if 3speed (non-index or converted to non-index :D ) twist grip shifters for front derailleurs would work with a 5speed rear derailleur?
 
hias9 said:
Thanks, I think that’s the best option.
Did anybody already try if 3speed (non-index or converted to non-index :D ) twist grip shifters for front derailleurs would work with a 5speed rear derailleur?

I doubt it will as the cable throw won't likely be enough for the 5 speed rear. But you can try it. If it's not indexed, there's no harm in trying.
 
hias9 said:
Thanks, I think that’s the best option.
Did anybody already try if 3speed (non-index or converted to non-index :D ) twist grip shifters for front derailleurs would work with a 5speed rear derailleur?

Unfortunately, all front twist grip shifters are indexed. Some have just the three clicks on them, and others try to emulate a friction shifter by having a lot of smaller detents. The problem with the latter kind is that if the clicks don't correspond to your gears, there are no "in between" positions available to use.

If you break out the tabs as MadRhino prescribed, there will be nothing to hold the shifter in position, and it will return to its fully extended cable setting as soon as you let go of it.

If you have a friction thumbshifter, use it. Thumbshifters are much more satisfactory than twist grip shifters, and uniformly preferred among the two by experienced cyclists. (Though trigger shifters are more popular by far.) Grip shifters primarily appeal to, and get sold to, noobs and once-in-a-while riders.

If your thumbshifter is for the right side, you can mount it underneath the bar on the left.

If you want indexing, new 5-speed stuff is as cheap as it gets. Full retail at my shop for a Sunrace 5-speed index thumbshifter (SL-M2T) is $5. The corresponding RD-M2T rear derailleur is $7. There things are both out of stock because of the chaos in the bike business right now, but somebody has them.
 
hias9 said:
Sorry, I confused friction shifter with grip shifter.
What I have already on one bike is a non-index friction (thumb) shifter.
What I would like to try is a twist grip shifter. Do you think a 5speed indexed would work fine with a vintage 5speed Shimano derailleur? Would a non-index 3speed grip shift (for front derailleur) also work with the rear 5speed derailleur?

Twist shifters aren't good IMO
Use the thumb shifter

I ran into a problem with the Twist shifter, how do you install a RH thumb throttle, well you can its just very awkward because the palm of my hand would be on the bulk of shifter. Sure you can install the throttle on the left side, I am not used to that. Though I would like to try a 2 throttle setup as sometimes my right hand gets tired, sure I could try to find the cruise wires suuuuuuuure
 
Domino throttle and thumb throttle for regen are on the right and I dont want to change that, so the shifter has to be on the left.
There are non-index grip shifters for the left (at least they say that on the ebay description) but I dont know if cable length would be okay. I will probably try that. Alternative would be 5speed (I think better non-index because the 5speed derailleurs are not meant for indexed shifting) upside down or using a thumb friction shifter again.
 
hias9 said:
There are non-index grip shifters for the left (at least they say that on the ebay description)

They aren't friction shifters, though. They're "micro" click shifters. That's fine as long as some of the micro clicks correspond to your gears. If not, it's very bothersome.

Alternative would be 5speed (I think better non-index because the 5speed derailleurs are not meant for indexed shifting)

Index shifting 5, 6, 7, 8, and 9-speed derailleurs are usually interchangeable. It's the shifters that differ. 10, 11, 12 speed are usually specific to a single gear count.
 
Interesting about the spacing for 5 and 7. I thought it was the same for both, then changed for 8 speed. I often run a 7 speed motor wheel with 8 speed shifter, but then it runs smooth enough in only 3 of the gears. If I really need the lower gears, I can tweak the barrel nut on the shifter, or derailleur.

But it seems there is some agreement, non indexed shifter of any kind is what you need.

There is of course, the leave it in the highest gear all the time method. I tend to shift only if the battery dies, then I need the lowest gear. So on my cruiser, friction shifter is the way to go for me.

On my dirt bike, I get three gears that work well for me, and I tweak the barrel nut to get smooth running in the middle three gears I use most.
 
dogman dan said:
Interesting about the spacing for 5 and 7. I thought it was the same for both, then changed for 8 speed. I often run a 7 speed motor wheel with 8 speed shifter, but then it runs smooth enough in only 3 of the gears. If I really need the lower gears, I can tweak the barrel nut on the shifter, or derailleur.

Spacing between gears differs among all those gear counts. What doesn’t change, among Shimano derailleurs and their many clones, is the ratio of cable travel to derailleur travel. Until you get to 10-speed, that is. I think Shimano eventually decided adding a gear was such an easy sell, that they’d rather sell a new derailleur instead of only a shifter and cassette.

Now they’re making a different kind of freehub spline, so you’ll have to get a new wheel too, to keep up with the latest.
 
Back
Top