phtomita

I got the 13-24 6sp freewheel MF-6208 with 52-42T front for the Centurion Ironman Master and after trying some climbing my legs say I need a lower gear.

1. What is the proper removal tool for this? Park Tool FR-1.3 looks like the right one from web.
2. I have a 14-32 Suntour Maeda 6sp freewheel on my bin - Would it fit on here? The RD drive pulley is already very close with the current 13-24 so....

Thanks!

ThermionicScott 

FR-1.x should work. Velobase gives a max cog size of 26T for that RD. You can probably push it to 28ish, but I'm doubtful of 32T: VeloBase.com - Component: Shimano RD-6208, 600EX (SIS)

SurferRosa

Doubt you can use a short cage 600 SIS with a 32t cog. A 28t would probably work, even if velobase rates your derailleur at 26t max. Sunrace freewheels on ebay are a good deal. You can go 6- or 7-speed. Those with a silver finish are a little nicer than the black ones, I think.

edit: oops, shoulda read scott's post above. "Great minds ..."

pastorbobnlnh 

Just a guess, but a 14-32, 6 speed Suntour is most likely a ProCompe or Perfect model. They came in two different 6 speed spacing configurations, Suntour standard or Suntour Ultra (narrow) spacing. Neither are truly compatible with Shimano SIS 6 speed index shifting. If your shifters have a friction setting, you will need to switch to that for a Suntour. I have the spare sprockets needed to convert to a 14-28T. Can you check the Suntour model and post a picture?

phtomita

Ah, thanks for the info.
The Suntour I have is a Maeda Perfect 8.8.8 if I am not wrong 14-17-21(or 20?)-24-28-32 that I cleaned up and greased last winter.
Also, I have another one that is 13-28 (??), but I noticed that when screwing into the hub has resistance and the threading seems different (well I paid an exorbitant $1 for it .... so no complain).

Other option I have in mind is to go from 42T to something 36, 34 on the small chain ring

SurferRosa

The wide gap between that and the 52t would cause headaches with chain wrap, leaving you only a cog or two for the big ring.

With short cage derailleurs, even a 52/39 often causes chain wrap issues where you have to make "sophie's choice" type decisions on gear selection.

ThermionicScott 

If you swap parts at both ends, you *might* get away with a 48/34 crank and 14-28T freewheel. That would put you right at the RD's capacity.

But if you're willing to go that far, swapping to a long-cage RD would be a wise move and open up more possibilities.

phtomita

Thank you for the heads up.
I did some weird things on my Sekai - don't really recall if it is a 52/40 front or something close to it.
I got a 34T 110BCD and replaced the 40T and I think it was switching fine (I just went for a short 20 miles ride or so)
Then, I got this super deal on CL for a full Ultegra 6700 groupo and it got rebuilt with that. Now the 6700 bits have moved to my Tri-A

The Sekai RD is a Suntour Cyclone - does it have a longer cage than the Shimano 600?
Currently, the Sekai is being rebuilt back to the original specs (chain rings back to 52/40) since it is a bit larger for me.

phtomita

Today morning I just picked up the 14-32 freewheel (Suntour Perfect) and put in parallel with the MF-6208 on the bike to roughly compare the total width.
The Suntour one looks narrower from a quick visual inspection by half of spacing between two cogs.
So for now, it seems a no deal because index shifting will be gone. (I prefer IS than friction....)

Is modern Shimano freewheel (6 speed or 7 speed) spacing same as the MF-6208? From some threads/web it seems they have same spacing.

texaspandj

Yes, same spacing.
I've only been able to put a 26 largest cog freewheel on a Ironman experts 105 rear derailleur which is similar to the Ironman masters 600 rear derailleur. However others have reportedly been able to put a 28. But anything beyond will not work unless you use a long cage rear derailleur. The deore LX rear derailleur looks very similar to the masters 600.
As far as changing drivetrain and compatibility one of these guys can help @rccardr @RobbieTunes @seypat

phtomita

Thank you for info texaspandj!
I have a rear derailleur in my bin (I think it was a long cage - it came with the Centurion ProTour I have rebuilt).
Since spacing is good, I am thinking now on the megadrive and have a 34T rear.

rccardr 

Hmmmm.
Any 1050/105, 6208/600 or 640X/tricolor RD will shift up to a 28 rear cog when paired with either the standard 52/42 (or 53/39) chainset or a compact 50/34 or 52/36-34 on an Ironman frame. Just measure the chain big/big plus 2 links, pay attention to the B screw setting, and pull the wheel farther back into the dropouts if necessary. Not doing all three of those will likely ensure interference between the cog and upper pully wheel. Any problem will always be with the small/big combination, so concentrate on that first and the rest will kinda fall into place.

I've had great success using a 13-28 or 14-28 freewheel paired with a vintage Shimano Deore or 6206 crankset (110 bcd on the larger rings) using modern 50/34 rings, FSA rings in particular. The 50-13 combo doesn't spin out until 26-28mph, and the 34-28 combo is good for riding up almost anything including Skyline Drive, Thunder Ridge and the Dare.

I can include pics if you'd like, as my personal CIM uses a 50/34 paired with a 13-28.

phtomita

I was looking my bin and the RD that came with Centurion PT15 was a Deore DX long cage.
It has a bit rusty in some parts but looks very promising and was working great on PT15.
I was looking the web and it seems Deore DX is the equivalent of Ultegra/600 for mountain bike and works fine with SIS.
And, going to pick up a 38T (130 BCD) chainring this weekend.

seypat

rccardr's info is spot on. You could also find a 110/74 crank if a smaller inner ring is needed.

phtomita

phtomita

I tried the Deore DX rear derailleur with 14-17-21-24-28-34 freewheel I had in my parts bin.
No good.

From 28 to 34, the pulley and sprocket almost touch each other.
Didn't change the front inner chainring to the 38T yet.

phtomita

Question out there.
So I have the 600 SIS dt shifters on the Ironman.
Can I pair with a modern Shimano rear derailleur? Will it work fine?

delbiker1 

I have a Park 1.3 and also another brand, I cannot remember what, that works with the shimano freewheel. You are welcome to the off brand for cost of shipping.

verktyg 

Huh?

Shimano Deore DX derailleurs were made with a very long pulley cage to eat up a lot of chain on MTBs with triples. There were a few DX made with a short cage and they were listed at 28T maximum size FW.

Info on the DX derailleurs:

Archival Review of Shimano DX Rear Derailleur - the Buyer's Guide, 2015

Here's an earlier Deore LX that has the same pulley cage design. I'm only running a 28T FW but a 28T small chain ring on a triple crank. These can easily handle a 34T and even larger FWs.



Here's a later Deore LX medium arm RD with a 11T-32T 8speed cassette. It's a bit overkill because I'm only running 48T-38T chainrings but it indexes flawlessly.



Later Shimano Tri Color 600 derailleurs running 30T and 32T sprockets. I cheat a little and only use 50T, 49T or 48T large chainrings on most of my bikes.





@texaspandj "I've only been able to put a 26 largest cog freewheel on a Ironman experts 105 rear derailleur which is similar to the Ironman masters 600 rear derailleur. However others have reportedly been able to put a 28. But anything beyond will not work unless you use a long cage rear derailleur." Huh???

Shimano 105 RD on my Ironman running a 30T cassette with 48T-38T chainrings. I really like the 105 derailleurs. They have a little longer pulley cage than the 600 series plus they're steel which is rigid on hard upshifts. They can easily handle up to 32T.



The point I want to make is published derailleur capacities are very conservative. If you stay within those parameters the particular derailleur should work on an average bike with very few adjustments or trial and error.

There are a whole bunch of fixes to make derailleurs function beyond the published limits.

My first suggestion, if you don't already have one, buy a good chain breaker tool.

If you don't have have one of these, quick change chain links buy one. It makes experimenting with chain length much easier. SRAM, KMC and other chain brands sell them. Get 2 of the links for 6-7-8 speed chains; they're cheap and if you drop one of the plates you'll have a backup.


Here's a how to website:

Connect A Chain With A SRAM Powerlink - MadeGood

When changing freewheels, it's always a good idea to replace the chain. Modern chains for your bike are listed as 6-7-8 speed.

Next check the upper pulley. It should have about 1.5mm to 2mm of side to side play. If there is more than a few millimeters of angular play then it's worn out and needs to be replaced.

After trial and error with chain length, you will probably need to adjust the chain gap. That adjustment controls how much the chain wraps around the FW.

BTW, there were 3 versions of the early Suntour Cyclone derailleurs. Two of them had a 24T maximum size sprocket and one could handle 26T. Suntour's 26T Max spec was the MAX!



Most Shimano and Suntour RDs had what's called a "B" screw. In this photo it's labeled "A".



Tightening the screw drops the angle of the derailleur downward creating less wrap and a larger chain gap. Loosening the screw allows the top derailleur to move up towards the sprocket. Trial and error.

Hint, the screws are soft and hard to turn. Use a good screwdriver or Phillips and pull the derailleur back by hand to relieve the tension on the screw.

One other thing, derailleur hangers are frequently misaligned. They can be out of alignment with the plane of the rear wheel, top to bottom and/or front to rear. Get the system working then if you have problems you can fine tune it with this and other tricks.



verktyg

texaspandj

The one thing I Didn't do and only recently realized and @rccardr post reminded me, is to push rear wheel back all the way. The good Doc was puzzled as well as to why I couldn't get a 28 to work without all the grinding noise. As he had succeeded with the same 105 setup I had. Mystery solved. As usual thanks Doc.

phtomita

Thank you for the write ups.
One thing I noticed is that the rear wheel is all way forward.
Then, when trying to go from 28T to 34T there is only a tiny gap between the sprocket and the pulley on Deore DX.

Will try the suggestion here and post some pics on how it goes.

ThermionicScott 

Before pulling the wheel all the way back in the dropouts, try it so that the axle is at the midpoint, roughly in line with the seat stays. I feel like this is the position Shimano derailleurs of the time were designed around, and some bikes meant for indexed shifting came with little crescent-shaped spacers in the backs of the dropouts to ensure that the wheel would end up in this sweet spot.

Having the wheel all the way back -- without making any other adjustments -- increases the chain gap, which may allow for larger cogs but can also degrade shifting a little.

canklecat

Ditto the above:

• Adjust the rear wheel position in the horizontal dropouts to see if it'll solve some shifting issues with short cage RDs and cogs larger than 25 teeth.
• Try a Vuelta 38 or 39 small ring for 130 BCD. Works great on my Ironman. Good value too.
• The long cage Deore should work with dinner plate sized freewheels and cassettes. That sucker has massive reach.

phtomita

Back to this - I think I updated some info in other thread too.
I got the Shimano 7 speed mega range freewheel, the one that jumps from 24T to 34T,
moved the rear wheel closer to the back of the dropout, and have the Deore DX rear derailleur.
Since the Shimano 600 SIS shifter only supports 6 speeds, I have adjusted to go from the second small cog to the big 34T.

I've adjusted the B screw all the way to give some more space between the guide pulley and the 34T cog,
but it seems not right - the chain is touching the side of the big cog when trying to go from 24 to 34T.
On stand I can shift it somehow, but seems calling for trouble when riding.
Will place a pick tomorrow.

canklecat

Those Shimano MegaRange freewheels are awful, especially the one with the 24-34 jump. You'll get tired of that abrupt, awkward shift pretty quickly. They're made for comfort hybrids and city cruisers for casual riders who occasionally need a granny or bailout gear.

And they're picky about chains -- only chains labeled "narrow" on every link plate will work reliably with MegaRange freewheels. Anything wider will skip in the smaller cogs under pressure, even with new freewheel and chain. Been there, cussed that, put the MegaRange in the parts bin.

Try a SunRace freewheel, or Shimano Tourney freewheel. The Tourney 14-28 seems good -- there's one on my Trekenstein 5900 at the moment, no problems. But it'll be replaced soon by a 13-28 SunRace because I need the 13T cog for some fast downhills where I'm spun out at 130 rpm.

At the moment the comfort hybrid that had that MegaRange freewheel now wears a SunRace 14-28. Seems good.

The '89 Ironman with Suntour GPX group now wears a 13-25 SunRace freewheel. It shifts better and runs more smoothly than the original Suntour Alpha 13-24. However the Ironman didn't like 14 cog smallest freewheels. Those would cause chain rub against the chainstay/dropout unless I was very careful about wheel placement in the horizontal dropout. So I switched back to the 13-25. Soon it'll be replaced by a 13-26 Suntour Alpha freewheel.