speedyspaghetti

So this happened yesterday - I was riding my Bridgestone MB-6 on one of my local trails to take an easy day after a brutal road bike day the day before. Everything was going smooth - I'm less than a 1/4 mile from the top of the climb and I give a little hard push to get over a little steep section and I start feeling as if my rear wheel were slipping/rubbing, so I get off the bike to inspect but everything seems normal. I pull the wheel off and spin it to see if it somehow bent the rim, but its perfectly true. I put the wheel back on and try to keep going but the rims keeps wobbling all the way over to the left once a revolution as if the wheel is completely out of true. I inspect the freewheel and it looks a little off-kilter (see below)



It looks a bit "off," but nothing seemed to be loose or broken. Unfortunately I had to hike down the 3 miles I had ridden up before I could do any further inspection. I got the bike home, pulled the wheel, and loosened the axle out of the hub only to find that the freewheel body had completely sheared off of the hub itself (!!)





I still have no idea how or why this happened, but regardless, I'm going to at least need a new rear wheel for the MB-6. So I guess I'd like to run some ideas by you guys and see what you think I should do.

The MB-6 has full Suntour XCM components on it - including Accushift 7s shifters - which I believe is incompatible with Shimano freewheels. The freewheel is still in great condition, but I have no earthly idea how I would ever get it off of the remnants of the freewheel body without damaging the freewheel itself. If anyone as an idea, I'd love to hear it.

So, as I see it, here are my options:

1. Swap the wheels from my MB-3 onto the MB-6 since they have a freewheel hub. Question for this option is whether the SunRun freewheel I have on those wheels would work with the Accushift shifters. If not, are the freewheel threads universal? Would it just be a matter of putting a Suntour freewheel on the MB-3 wheelseet?
2. Buy another 7s wheelset off of Craigslist - seems like I can find a set with a freewheel and tires for between $50 and $100.
3. Go with option 1 but then do an 8, 9, or 10s conversion on the MB-3 OR if the Suntour components are too hard to work with/find a replacement freewheel, I could potentially do the the 8/9/10 upgrade on the MB-6 instead.

What would you guys go with / why do you think the freewheel/hub failed so spectacularly?

Thanks, as always!

sch

Aluminum metal fatigue, which aluminum is somewhat more prone to than other frame materials. Wheel is 25-35 yrs old. It seems odd that Shimano
FW are incompatible with Accushift 7, I would expect any incompatibility to be in the RD because of cable pull variances between brands of shifter and
the RD. RD/shifters are relatively cheap as are wheels but adding up these components and cassette and soon you are into real money, ie north of
$200, so upto you if you want to go the 8spd + route versus new wheel and cassette. You might be able to salvage the FW with some careful
hacksaw work and thread cleanup afterward, not sure it is worth it considering FW is $20-30. You would remove the innards that rotate first.

andrewclaus

Considering the torque needed to remove some freewheels, thread failure is not too much of a surprise. Never seen that though. Usually spokes fail first. Broken axles are common (from different forces).

I also wouldn't think of trying to salvaging the freewheel. Assume those threads are locked in there.

I recently upgraded an old six speed to an eight speed with parts salvaged from a co-op bin and nice wheels from Craigslist. It took a few months to gather the parts, less than $100 total. I had to reset the rear dropout spacing, realign them and the derailleur hanger, all with co-op tools.

dedhed

I dunno, I'd try a small drill in many places on the aluminium and pick it out in pieces - If it was in good enough shape to justify.

onsay99

Looking at the broken freewheel threads that are stuck in the freewheel, I would try
a light tapping with hammer and punch on the broken off aluminum threads. When it was
installed on the freewheel, this is a very tight mounting. Now that it is sheared
off, it may be less loaded and may actually turn when hammer and punched in the loosening
direction, ccw. Worth a try, and may save the cost of drive train changeouts. Hub will
obviously need replacement, also axle if needed.

onsay99

Also forgot to mention, punch the old hub cup out of the way.

EddyR

When I was flipping bikes and going through hundreds of bikes I only remember seeing this two times. Both times it was on a bikes I had sold and the person brought the bike back to me. I had lots of wheels and just replaced the entire wheel for them. Later I Was able to repair both by tapping out the broken pieces.
Ed

grizzly59

If you need the freewheel-

Find some 1/4" screwdriver type bits small enough to work with the dimensions of the broken piece. Maybe T10 - T15 torx bits.

Drill 2 holes 180 degrees apart into the broken part of the hub stuck in the freewheel, drill bit diameter to work with the bits. Make a spanner, clamp the bits to a piece of angle iron, etc with a vise grip for each. I would soak some penetrating oil into the broken piece / freewheel for a while.

With some luck and the proper freewheel tool you can remove the broken piece.

Iride01 

New freewheels are inexpensive. Steel is very recyclable. When you get 10 old FW's you might get 40¢ <grin>

Bill Kapaun

It's probably not "time efficient", but some of us have lots of time....
Can you slit it with a hacksaw blade in 3-4 places and then try driving the pieces in toward the center.Kind of "peeling" it away from the threads...
Maybe a cut off wheel would work for the initial slitting. A worn down one (smaller dia.) may work better.

dedhed

Compatible with 7s indexed Suntour accushift - not so much. While many have gotten it to work satisfactorily with Shimano spec FW others have not. It's really a try it and see.

https://www.ebay.com/c/570857406

Iride01 

Center to center spacing between the cogs on most 7 speed SunTours and Shimano FW's were 5.0 mm. But I don't have the info on exactly what all the SunTours were. On page 17 of this tech doc https://www.yellowjersey.org/Suntour21.pdf , it says that
Ultra 7's were 5 mm center to center per Sheldon.

It is also interesting that there is a suggestion of a selector on the shift lever for the type of FW. Not sure if that is for number of cogs on the FW or something else.

3alarmer 

...
...I think, but am not certain, that the axle was busted and you did not notice it for a while. The QR keeps the pieces in place well enough that the wheel works (sort of). From there it's not a big jump to the forces now visited upon the hub body to fatigue the aluminum and break off the freewheel. Just a guess.

When faced with similar conundrums, I usually just go with replacing what I need to meet the current most available parts supply. When I worked at the co-op, I probably would have just scrounged up another used freewheel with the same spacing standards, and put it on a different wheel.

Today, with no access to that source of parts, I'd probably swap out what I needed to swap out to get it working with Shimano 8 speed indexing (if I still wanted indexing). That would be probably a new wheel built around an 8 speed width Shimano freehub, and an 8 speed Shimano cog cluster, with some of their still available online (new) 8 speed indexing shifters. IME, trying to continue maintenance on a mechanical system, that has been outdated long enough to make parts sourcing a problem, never ends well for me. I end up kicking myself for not just biting the bullet in the first instance, and updating everything....assuming you plan to keep this bike for a long while. You might need to respace the rear by cold setting, but that's not a big deal and there are instructions for doing that all over the internet (some of them work well, some less well)

SurferRosa

Gnarly fail. Never seen that happen.



For japanese stuff, yes. The only real issue is with french stuff.

Quote:

Would it just be a matter of putting a Suntour freewheel on the MB-3 wheelset

Yes, probably. Then tune everything, like the rear derailleur limit screws.

If the rims are good of the failed wheelset, I'd rebuild the rear. (I prefer matching wheels on my bikes.) If not, then that opens up the possibility of a new wheelset, etc.

veganbikes

It is wholly possible that ride was pretty filthy but it looks like things weren't super well maintained. Granted yes it was probably fatigue over the years and a freewheel for MTB probably not my choice. However regular cleaning and proper greasing would benefit that bike a lot.

In terms of freewheel the IRD freewheel is my favorite though I cannot speak to indexing well with Suntour Accushift but I cannot imagine it will go so poorly. However I might consider rebuilding the wheel with a properly spaced new cassette hub and use a Shimano cassette (again not sure of good shifting with Suntour) and that should help with longevity and less likelihood of breaking on a climb.

If worse comes to worse just set it in Friction mode which I believe they had (I could be wrong not the Suntour expert) and then you can shift just about anything.

70sSanO

Since the last Suntour freewheel I had was in the mid-80’s and was a 6 speed, I will refer to Sheldon Brown.

A 7 speed Suntour Ultra is spaced the same as a Shimano freewheel. 5.0mm center to center. So if the OP’s Accushift works with a 7 speed Ultra, then it “should” work with a Shimano compatible aka, IRD.

If it is a Micro drive the 3 lowest cogs are spaced at 4.8mm center to center and the 3 highest cogs are at 5.0mm. The middle cog is Switzerland.

Also I have read that some Suntour shifters let you choose have an index setting and an Ultra; as well as friction.

If there is not an Ultra selection then A Shimano freewheel might work okay as the 4.8mm spacing is close enough to Shimano’s 5.0mm and some people just run a Shimano freewheel.

If the OP wants to run a 7 speed cassette, new wheel, with a Suntour drivetrain, it is pretty simple to break the cassette open, sand the spacers for Suntour and re-assemble. It might be necessary to get a .5mm or 1.0mm spacer to put between the lockring and the first cog if the lockring bottoms out.

John

Edit added: of course since the OP has the Suntour freewheel, he can measure it to see how it is spaced.

SJX426 

@speedyspaghetti - this is not unlike a stuck seat post only it treads. Since the freewheel is easily replaced and it is all steel, I would stick in a solution of Lye. It works for dissolving seat posts and stems, why not the remnants of a hub?

Just do it outside and away from all flames as Hydrogen is a byproduct!

sch

Lye is a good degreaser as well, but it also nicely dissolves human skin so considerable care needs to be taken
using it, particularly eye protection where a splash of lye solution could result in blindness.

sovende

Everybody's thinking it but I'm going to say it, a little bit of (OK any!) TLC early on and throughout the life of this bike just may have prevented the disaster that's been presented. I'm pretty sure such an occurrence is relatively uncommon! Just sayin'!

speedyspaghetti

Yeah I know, it had literally bought it the week before though.

Unca_Sam

What's the plan, man?

Accushift 7 speed and up used 5 mm spacing on the smallest two cogs, and 4.8 mm spacing for the rest. The shifter bodies are eccentric to account for the extra pull needed to move up from the smallest two. From what I can tell, as long as the RD has the range, the shifter controls the cable pull, and therefore the shift. There have been posts for years where members have achieved acceptable indexing with a mix of Shimano/Suntour Accushift, but IIRC the key has been Shimano's floating guide pulley, requiring at least a Shimano RD.

I'm sorry that your components failed in such a spectacular fashion. You won't need a Suntour hub to build into a new wheel, but a 1:1 replacement will simplify rebuilding in that you could potentially reuse spokes, or if not, you know what lengths you need without computation or guessing. If you want to keep the rest of the drivetrain, you'll need to use the freewheel you have to preserve indexing, or find an Accushift Plus replacement. 7 speed XCM was upper entry-level stuff, but finding 7 speed AP freewheels that aren't corncobs gets expensive. There's currently a 13-28 freewheel sitting on the 'bay for 39.95 and shipping. Does your FW have a larger big cog?

I'd follow the advice for trying to remove the remainder of the hub from the freewheel body, including the lye dip. My greatest concern there is the destruction of the lubricant inside the freewheel (only because I've never learned to refurbish one).