MrCjolsen

Shimano SY20-A

Sunrace 7 speed clamp on downtube shifters

The bike is a 1986 Miyata One-Ten that has been extensively upgraded with Campy rims, Dura Ace and Ultegra 7-Speed drivetrain, a Brooks Saddle, etc. (I had a neighbor who was changing hobbies from cycling to woodworking and needed to clear space in his garage and gave me a big box of really nice old parts. If I was buying all that stuff, I sure would have put it on a nicer frame)

Anyway, the bike presently has Shimano clamp on downtube friction shifters. They work OK, but I'd like the rear to be indexed. I tried taking them apart, and putting Dura Ace indexed shifters on but it was off when using the big ring.

Now, it says the Sunrace shifters don't work with Dura Ace. Why is that? I held a non-DA freewheel up the DA freewheel, and laterally, the cogs lined up perfectly.

And if the Sunrace shifters don't work, will the Shimano one's work OK? Or should I just stay with the non-indexed shifters?

Bianchigirll 

dura ace RDs had a different travel or 'pull' than other shimano RDs. the FW/Cassette spacing was the same they just made the dura ace RD a bit different so you could not spec a bike with all 600 but use a dura ace RD or replace a broken/worn dura ace with a lower quality one.

so a 600 or any other should work great with your shifters. there was clamp on Index shifters back in the early index days. the shifter itself was the same but it had a different backing plate to interface witht he supplied clamp

hope this helps

OH a nice index Sprint or Cyclone may work too

Zaphod Beeblebrox 

I'd love to see a pic of this tricked out Miyata.

First question, how far off was the indexing when you were on the big ring? If its off by just a little it might just need to be trimmed using the barrel adjuster on the RD.

Secondly, the Amazon item description that says those 7 speed shifters aren't compatible with Dura-Ace are likely talking about Dura-Ace freehubs, not Freewheels. Since you're using a 7 speed SunRace freewheel, there's no reason why 7 speed sun race Index shifters shouldn't work. The indexing works because of the right combination of Shifter & Freewheel....the RD (at least in this case) is just along for the ride so to speak....it will go wherever the cable pulls it to.

MrCjolsen

So you're both kind of saying different things. If it's a matter of Derailleur pull, then no problem since I have no shortage of fairly nice non-DA derailleurs (thanks to the box of parts). But I want to keep using the Dura Ace (not Sunrace) Freewheel because its 13-24 gearing is perfect for my uses.

I'll try to get some more pics up of the bike soon. It's the "Souped Up Miyata One-Ten" in my sig, but I've made many changes to it since. Back then, it had a 9 speed double which I found to be really tricky to use on the road. So I made it a fixed gear. But then I hardly ever rode it since I already had a fixed gear.

So now I've put gears back on it, replaced the moustache bars with drop bars, and made a few other changes.

MrCjolsen

Here's a picture

EjustE

Need some more information

esp. What part is Dura Ace and what model Dura Ace it is (the 7xxx number). If you got DA cranks you are home free, but DA derailleurs index only with DA shifters (in the 74xx generation). Best way around it, is to replace the DA part (if a derailleur) and get a set of 7sp DT 600 Ultegra/Sante/105/RX100 shifters. They will work. And you can replace it with any of the forementioned groups of the same era (RD does not look DA from here, so that's good)

Bianchigirll 

OK from what I could glean from your posting I assumed that you had:

a dura ace RD of some 7spd vintage.

a dura ace freewheel 7spd

a generic shimano spaced 7spd freewheel

a pair of SunRace 7spd shifters.

I assumption was that the SunRace shifters dura ace RD and the dura ace FW where installed on the bike at first.

since early dura ace RDs were designed to only work with dura ace shifters I thought that was your problem.

MrCjolsen

The shifters are the only drivetrain part that came with the bike. According to the 1986 Miyata catalog they are Shimano L-523 or L-422. They are not indexed, but sort of ratchet. They clamp to the frame. I previously had them working with a 9 speed Ultegra setup. But it was tricky to accurately shift without indexing.

My solution to that problem was to convert the bike to a fixed gear.

Two years later (last Saturday) I decided to set the bike up geared again. The only issue is the bike has no downtube shifter bosses and no cable stops either (if it did, I would have used barcons). I had a wheel with a 7 speed freewheel on it. So I put that on. The 7 speed had the same gears as my 9 speed setups, minus two gears I never use.

I went ahead and ordered the Sunrace shifters. If they don't work with the DA, I'll try the Ultegra. If that doesn't work, I have a few other derailleurs that could work. The thing with the SunRace shifters is that it says on the websites that they don't work with "Dura Ace." It didn't specify whether it meant gearing or derailleurs.

The funny thing is I rode the bike 28 miles today and didn't have any real problems with the friction shifters and the 7 speed. But I ride in traffic a lot and it would be nice to not have to fiddle with shifting any more than I need to.

Zaphod Beeblebrox 

Just to clear up any misinformation, I was completely wrong and Bianchigirl is correct regarding the DuraAce RD and Shifter Compatability.

There is a cam-like mechanism in the RD that varies the way it pulls through its range