RFC

OK, here is where I am:

Nashbar Aero Sprint with a single 49t chainring.

Suntour 5000 rear derailleur

6 speed Suntour indexed levers

I just switched out the 5-speed freewheel for a 7-speed

Index shifting it is a little funky and I obviously lose one gear.

Fine in friction.

Here is the question: I have an extra set of Ultegra 7-speed shift levers. Would these get me back to index shifting with this combination?

Thanks as always,

RFC

rmfnla

I never understand questions like this.

You have the parts; stick 'em on and see if they work!

Then you can tell us rather than ask us.

RFC

Let me tell you why I ask.

I enjoy working on bikes, but I have a busy life. I try to think these bike questions through as well as possible. However, before I am going to use my precious time, I like to inquire whether anyone else has experience with this. This is how knowledge grows. We don't start from scratch each time.

cs1

I'll give you the best advice anyone can. 99% of the time mixing and matching doesn't work well or at all. Mfg's spend millions of dollars trying to get their groups to work well together. That doesn't include working well with other mfg's groups. That keeps you the consumer buying parts from that mfg, not the competition.

With that said, there are work arounds in certain situations. It's best to stay with one mfg than mixing if you want to keep your busy life simple. Good luck on your project it sounds like a lot of fun.

TIm

BikeManDan

Check out the freewheel/cassette spacing table
https://www.sheldonbrown.com/gloss_sp-ss.html#spacingk7

Looks like it may not work out so well as Suntour 7 speeds seem to have a variable spacer dimension

Point

I'd give it a try.......it may work well enough for your use. You could also try a 7-speed Shimano compatible freewheel, since there'e lots out there, without much $$ out of pocket.

When all else fails, check Sheldon's (RIP) site.

roccobike

+1, According to specs it will not work, or at least, not work well. If you don't have the time to experiment, then you should buy the matching shifter/freewheel combination. If you've got the time, try it.

That said, I'm running 7 speed Suntour downtube shifter with a 6 speed Suntour freewheel. According to the Specs it should not work at all. However, in actual practice it works. I have no idea why. One shift, (second to third) is sloppy, but other than that it works. I do have to keep on top of the derailer adjustment as it easily goes out of tune. AND the chain, derailer and freewheel have many miles together prior to my changing the bike to index.

RFC

Thanks all.

I recently replaced the entire drivetrains on a TT bike and a Tri bike. This one I am trying to keep simple. Interestingly, the more I work with the Suntour the levers, the better it works.

mrmw

Caveat: Suntour 3000 series 6 speed shifters only work with Suntour 3000 series derailleurs.

And, Suntour regular six speed (not 3000) will index Shimano SIS 6 speed freewheels (several reports here of bikes having come factory equipped this way).

Confused yet?

As far as anecdotal reports of what mix and match setup works, here's my experience. None of them worked. I say that because when I tried them, none were as precise as a simple cheap xmart Shimano sis setup.

Here is what I found that does work:
Always use the same brand shifters mated to the same brand rear derailleur.

For a Suntour setup use Accushift Plus rear derailleurs 1989 and later, so they have dual pivots.

Then space your rear cogs to be compatible with Suntour Accushift spacings. An added advantage of this is that you get modern shifting ramps.

Note: Sheldon Brown's Suntour seven speed spacing chart is off. Spacing on the smallest two spacings center to center is 5.3mm, then for the remaining four spacings its 4.8 mm c to c. I've posted previously here in more detail, you could google it. Its the only error I have ever found at sheldonbrown.com.

So, for seven speed, secure a Shimano eight speed cassette. Use the top five largest cogs and spacers (all 4.8mm c to center). Then a 2.56mm 9 speed spacer plus a 1 mm spacer. Then the sixth (i.e. second smallest) eight speed cog. Then a 1mm spacer.

Then a nine speed first position cog (the smallest cog--with built in spacer).

Then a lockring sized for the nine speed first position cog.

I guaran-damn-tee you that Suntour Accushift shifters mated to a Suntour Accushift rear derailleur will index this setup precisely. Like a swiss watch. And on a seven speed Shimano freehub, the stack height will fit exactly.

And if it doesn't index precisely--why in the world even bother? Ratcheting friction is pretty fine too.

hhabca

In friction mode anything works...

RFC; Thanks for the tips!