Help with SunTour and 7-speed freewheel questions
 

Folks;

This edit comes 24 hours later. Please page down to my new details about the SunTour.

I've appreciated all the help available on this forum.

Let me start by saying I've tried to do my homework before asking for help. My question is about putting a 7-speed freewheel on my old (1987) Cannondale. The bike came with a SunTour 6-speed freewheel and according to the catalog, an indexed shifter for the SunTour Sprint rear derailleur.

See http://www.vintagecannondale.com/year/1987/1987.pdf

Page down to the SR800, and you're looking at my bike 22 years ago.

According to the SunTour dealer catalog for 1987, the Sprint 9000 rear der could take a 7-speed freewheel, but there is no notation for the Sprint being 7-speed compatible. I'd like to have a tighter cluster of ratios near cruising speed, and have ordered the SunRace 7-speed freewheel from AEBike (very reasonably priced!), with a 13-14-15-17-19-21-24 set of cogs.

See http://www.wooljersey.com/gallery/v/...s/SunTour/1987

Sheldon Brown (RIP, and a wonderful source of arcane details) says that one can mix various manufacturer's equipment, with the proviso that the SunTour rear der may not work on Shimano-spaced 7-speed freewheels.

So here are the questions:

1. Will my old SunTour Sprint rear der shift over the full range of cogs on the SunRace 7-speed freewheel?

2. Are the SunRace cogs spaced so differently on the freewheel body that the SunTour derailleur and shifter can't move chain on and off them reliably?

3. Is there a way to adjust the SunTour rear shifter to convert from its current index setting to friction? It does have a wire bail handle at the base of the shift handle, but no apparent markings to show whether the shifter is set on friction or index.

4. If I need to go to a Shimano rear der as Sheldon notes may be required (grrr, hope not, love the black and gold colors), what model Shimano have others used successfully?

This has gotten lengthy and complex. Thanks in advance for any help.

Joe F

1. Yes
2. No. SunRace is probably Shimano-compatible 7-speed spacing (6 x 5.0mm spacings) while Suntour 7-speed is 3 x 4.8mm spacings between the larger cogs and 3 x 5.0mm between the smaller cogs. I have a bike with Sprint shifting and have used my Shimano 7-speed touring wheel in it. The shifting works fine but it also works a little better if I swap the 3 spacers between the largest cogs to 8-speed (which makes the Shimano cassette an exact match of Suntour spacing).
3. Probably. My Sprint shifter (from 1989 I think) has 6-speed index, 7-speed index, and friction settings. They are clearly marked on the housing. I forget how to change as I never do but I think you loosen the D-ring a little, rotate the housing, and tighten the D-ring back up.
4. If you go to Shimano rear der, you will also need Shimano rear shifter to match. Shimano and Suntour indexing isn't the same.

Page down to the SR800, and you're looking at my bike 22 years ago.

EDIT: The rear derailleur is a Sprint 9000. There are markings on the shifter (small notches, apparently representing positions, with two, three, and four notches per position).

New question: Anyone know what the various positions represent? Anyone have an old manual for this shifter and derailleur combination. I've looked at Technical Bulletin on Accushift problems, but need documentation on basic product configuration.

Thanks again in advance.

JF


"According to the SunTour dealer catalog for 1987, the Sprint 9000 rear der could take a 7-speed freewheel, but there is no notation for the Sprint being 7-speed compatible. I'd like to have a tighter cluster of ratios near cruising speed, and have ordered the SunRace 7-speed freewheel from AEBike (very reasonably priced!), with a 13-14-15-17-19-21-24 set of cogs."

This is kind of jumping to the "can't it just be simple" point of view, and not to belittle the issues you are encountering, I've been there!

BUT, I use that Sunrayce cluster in friction-shift setups and get very good shifting, with a Shimano or SRAM chain. The shifting is good enough that I don't feel the need for indexing. I use Shimano 600 6207 series downtube friction shifters on this bike. Maybe you could go that way?

Road Fan

I bought my stuff new but I doubt that I still have the manuals that came with. I will take a look, though.

I bet the three positions are the settings for 6-index, 7-index, or friction. I found an old Bicycling article on Sheldon Brown's site...

http://www.sheldonbrown.com/bridgest...oneRB11989.pdf

"The AccuShift lever features 3 settings:
UL, for index shifting with Sun-
Tour's narrow-spaced Ultra-7 freewheel;
F, for friction shifting ; and RE (regular),
for index shifting with most standardspaced
5- or 6-speed freewheels."

Wow! Right on target!
 

Folks;

Went to the garage where my steed awaits, and sure enough, the little marks on the shifter bezel say, respectively, UL, F, and RE.

Wonders never cease on this forum.

Many thanks to all!

Joe F

Folks;

Latest on this issue: The SunRace 7-speed freewheel from AE Bike looks pretty good! The teeth are ramped and angled, no doubt to help chain climb up onto a larger cog.

What's interesting so far is that the 13-24 freewheel is not, as advertized, a 13-14-15-17-19-21-24, but a 13-15-16-18-20-22-24. Not much different, but different still. I'm not going to take it up with AE Bike, who were quick shippers, and at $11.99, the freewheel was priced right!

In fact, I like the freewheel's appearance, since it has a "straight-block" look, less dished and more nearly evenly graduated between cogs.

--JF

How to change spacing on the SunRace freewheel?
 

Gonzo Bob;

First, many thanks for the very helpful reply. Now that I've got the SunRace freewheel in hand, how does one change the spacing between cogs?

Or is this one of those questions that requires an answer far too complex for the Bike Forums.

In any event, happy holidays and thanks again!

--JF

In my post, I said I customized the spacing of a cassette, not a freewheel. It's not possible on a freewheel. To match Suntour spacing you'd want to put slightly thinner spacers between the 4 largest cogs. The problem is that most (all?) freehwheels have multiple spline sizes (usually two but sometimes three) as opposed to a cassette where there is just one spline size. What that means is that even if you put the thinner spacers on, the large spline on the freewheel body will still result in you getting the original spacing - except now there will be play between your largest cogs. I probably didn't explain this very well but one way to look at it is that a freehub of a cassette has nothing in it which restricts the spacing, i.e. you can put a 7-speed cassette on a "6-speed" freehub and you can put 9- and 10-speed cassettes on an "8-speed" freehub. But a freewheel body is "hard-coded" to a specific speed and spacer thickness, i.e. you can't convert a 6-speed freewheel to 7-speed and you can't use thinner spacers in a freewheel.

The Sunrace 7-speed will work fine with the Sprint shifters. You will just have to fiddle with the barrel adjuster to get the best compromise.

http://aebike.com/product/falcon-hg-...w5007-qc30.htm

Interesting reading this thread. Makes me wonder.. if you access this link you find the listing of SIX gears... for a 7 speed. Found this everywhere on the net.

?? anyone have any experience with these freewheels?

I'm not sure what you're talking about. That's a 7 speed shimano compatible freewheel you've linked. And this thread is one year old with no relevance to the original topic. Unless your post got cut off.

Item SpecificationsColorBlackSpeeds7Freewheel Teeth14-28 teethFreewheel Cogs14,16,18,21,24,28Chain Compatibility3/32"Weight406 ghttp://aebike.com/images/library/cat...50m/FW5007.jpg



I was referencing this item that appeared on that page.. lists only 6 gears in the cog set. Am wondering what number is missing.... a 15 I presume?

Email inquiry sez the missing one is a 22... does that make any sense? When I set in the details with my 2nd post the gear set pic showed.. now it doesnt on that post.

Doesnt a 15 look right per the pic?

Edit: the Shimano shows 14 - 16 - 18 - 20 - 22 - 24 - 28 Teeth.. this freewheel ad copy data is just wrong.. a 20 and 22 vs the 21 listed.

Needs a 15er >>>>>.

This is what I believe near ideal for me....


For 27 X 1 1/4 / 32-630 tire with 170 mm cranks
With Custom Sizes Cassette
52t 40t
14t 18.0 13.8 << mph @ 60 rpm
7.1 %
15 16.8 12.9
6.7 %
16 1 5.7 12.1
12.5 %
18 14.0 10.7
16.7 %
21 12.0 9.2
14.3 %
24 10.5 8.1
16.7 %
28 9.0 6.9

Count this:

http://www.jensonusa.com/store/produ...Freewheel.aspx