Shimano Dura Ace Freewheel body repair or replacement.

[Mr.Gib]

I have a set of handbuilts on Dura Ace 7900 hubs. The freewheel is feeling and sounding a bit dry and catchy. I took the hub apart only to realize that the ratchet mechanism is enclosed within the freehub body and not easily serviceable. I watched a how to video and came to the conclusion that it is wiser to just replace the part (special tools required and no guarantee that it is even salvageable). Problem - the replacement part costs $175 - $200 It seems senseless to invest this amount of money into 10 speed technology on a wheelset with rims that are half worn out and will need to be rebuilt soon.

I am starting to think that Shimano Dura Ace 10 speed hubs are a disposable part given that I can buy a set of Campy Zonda's C17's for below $500.

Has anybody pulled one of these enclosed freewheel bodies apart? Is servicing somehow easier than it appears?

[steelbikerider]

They normally last for 1000's of a shot of oil or grease(I know but t works for me) every few months. Considering a new set of wheels is $500+, I would say it is cheaper to replace the freehub. I have had to replace one out of 6 sets of DA hubs and 30 years of riding. If I remember, all it takes is an 8 or 10mm allen head wrench besides the normal cone wrench and 5mm allen to service the hub.

[Mr.Gib]

@steelbikerider,

I think you're referring to older models. IIRC starting with 7900 the freewheel bodies have an enclosed ratchet system that is not customer serviceable. It is easy take off the freewheel body (takes a 14 mm hex) but no way to get at the pawls or ratchet teeth to clean or lube - they are internal to the part. They certainly are as durable as any bike part on the market but they are not immortal. It would be nice to keep them perfectly maintained but that is not possible. It comes down to a game of how much deterioration one is willing to tolerate before replacement.

Even if you could get them apart I don't think you could get parts. There are something like 50 tiny little bearings inside the freewheel body, and some seals that I doubt you could replace if you happened to damage them during disassembly.

[TonyM]

How many km did you ride your wheels ?
And in which weather conditions? winter with grid on the roads?

[Mr.Gib]

Not sure of the total km but not huge because they shared duty with at least 4 other sets over 8 years. They only saw good weather except for a good portion of one winter on typical wet, grimy, PNW roads. Of course that is likely what has hurt them.

The wheels are currently on my wife's number 3 bike - her travel bike, so they need to be decent for next summer as they will see action in the Alps. I did everything I could maintenancewise and they are acceptable. It would be nice to make them perfect though. I was able to eliminate some of the grittiness by cleaning and greasing the area where the freewheel body butts up against the hub shell.

[TonyM]

Not sure of the total km but not huge because they shared duty with at least 4 other sets over 8 years. They only saw good weather except for a good portion of one winter on typical wet, grimy, PNW roads. Of course that is likely what has hurt them.

The wheels are currently on my wife's number 3 bike - her travel bike, so they need to be decent for next summer as they will see action in the Alps. I did everything I could maintenancewise and they are acceptable. It would be nice to make them perfect though. I was able to eliminate some of the grittiness by cleaning and greasing the area where the freewheel body butts up against the hub shell.

I also live in PNW, in Canada British Columbia in the greater Vancouver area, and I am surprised that with so few kilometres in the winter your wheels are already damaged. Especially because DA is usually known to be quite robust.

For this winter I have bought a nice wheelset for my winter/ rain bike and I suppose I should have a look soon to see how it looks before it is too late....

If you go for a nice vacation in the Alps with biking I would most probably go for a new wheelset and use the adapter for using it with 10 speed.
Many shops have Sales now.

[jekyll man]

AFAIK shimano freehubs (going back to 7spd) have never been a serviceable item, however you can get in them and service them quite easily.

Remove the freehub body from the hub, and using a slightly modified 17mm hex headed bolt (need to grind a corner down), mount the bolt in a vice with the freehub on top. Then with a piece of plate that will fit in the slots on the bearing cone but also clear the inside of the body, undo it.

There is a lot of little bearings in there, 50 sounds about right, but provided you are careful you should be okay. Clean / grease / replace.
Reassembly is a little more difficult as you have to make sure the balls don't ride up on each other.

Alternatively what ive done for others is buy a low end wheel (rs10 etc) and bastardize it for parts if the cones are ropey, and utilize the whole axle assembly.

[mattr]

@steelbikerider,

I think you're referring to older models. IIRC starting with 7900 the freewheel bodies have an enclosed ratchet system that is not customer serviceable. It is easy take off the freewheel body (takes a 14 mm hex) but no way to get at the pawls or ratchet teeth to clean or lube - they are internal to the part. They certainly are as durable as any bike part on the market but they are not immortal. It would be nice to keep them perfectly maintained but that is not possible. It comes down to a game of how much deterioration one is willing to tolerate before replacement.

The shimano freehub body has been a sealed one shot unit for as long as i can remember. At least the days of 7 and 8 speed. Just need an allen key to remove.
There is/was a tool to inject grease/oil into the free hub once it's off the wheel, but thats more preventative maintenance. Once it's gone, it's just a matter of how long until it gives up completely.

If its a handbuilt, you *could* simply buy another hub and build it up, IIRC the latest 9000 are close enough in flange dimensions to use same the spokes. Or alternatively, a complete 7900 hub can be stripped for the freehub/new axle. Probably for not much more than a free hub. If you can find one of course!
Might also be worth checking compatibility (i've recovered older mtb hubs using newer freehubs from lower in the range, but it might be a ballache finding a compatible but cheaper one to fit D-A).

TBH, depending on the rim and spokes, new 9000 hub would be my choice. (Or even 8000!)
Then the hub can be pressed into service on your new 11 speed groupset..... ;O)

[BdaGhisallo]

The 7800 cassette body was similar to Campy's design in that you could access the pawls and relubricate them. Shimano tried that design (including the oversized body splines if you remember) but quickly abandoned that and reverted to their tried and true design of bolt on cassette bodies with the axle supported at the ends with the FH-7850. Its design was the same as Shimano used in 7700 and older hubs and they have returned to that with the 7900 and beyond freehubs.

[mattr]

That's weird. I made my post before jekyll mans post appeared.
I also made it about 10 seconds before i went for lunch, at about 11:15......

Hmmmm

[Mr.Gib]

Thanks for all the info.

From my perspective I think tearing this thing apart isn't worth the trouble. I watched a video and no- thanks - I might make it worse. As noted I have it operating well at this point. It just sounds a little dry. The injecting lube idea would probably deal with the issue but I've never heard of this before or the equipment needed.

In the end it comes down to economics. Even if the freewheel body was un-fixable, spending $200 to replace it is questionable on a wheel that will need to be rebuilt soon because the rim is half worn out (so add another $200). That's $400 assuming the spokes can be re-used and that is just one wheel. With Campy Zonda's available at about $450, I end up with a full wheelset that is about the same weight and quality. These hubs are great but just not as service friendly as I would like.

[TonyM]

(...) With Campy Zonda's available at about $450, I end up with a full wheelset that is about the same weight and quality. These hubs are great but just not as service friendly as I would like.

Price/ cost wise the good choice IMHO
Quality wise you may want to go for a better Campy/ Fulcrum wheelset but then the pricing is going up

[bobones]

There must be plenty of DA 7900 with worn rims but perfectly decent hubs, sitting unused and gathering dust in garages around the globe. (Mine are on my turbo bike). Perhaps it's worth posting wanted enquiry on one of the cycle parts Facebook groups near you?

[mattr]

FWIW, i have done a "seal off, dribble thick oil into the back of the free hub for a few days" that got me about a year out of an old XT freehub.

[TheKaiser]

This is the tool for flushing and lubing freehub bodies that a few others have mentioned:

http://morningstartools.com/Pages/FreehubBuddy.aspx
http://www.cheapbikeparts360.com/produc ... ustshield/

Depending on the hub, removing the dust shield may bend or otherwise damage it, so you may want to have a spare handy. It looks like the second link above comes with a spare although I am not sure how universal the fit is. I used one of those tools in the shop years ago in the 8spd era, and it worked quite well. Just dribbling lube in the outside edge can restore a dry hub, but if you see a lot of nasty crap coming out the bottom while doing so then the Freehub Buddy can allow more of a power flushing with a large volume of liquid to really clean it out thoroughly.