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-   -   Is my DA 7700 rear hub cooked? (https://www.bikeforums.net/bicycle-mechanics/1172696-my-da-7700-rear-hub-cooked.html)

Carbonated 05-10-19 08:33 PM

Is my DA 7700 rear hub cooked?
 
My Mavic Open Pro rear wheel with DA 7700 started to make some grinding noise.
I took axle off and the cones and ball bearings look fine.
I spun the wheel with my finger in the bearing cup and feel some pit marks or protrusions.
I hate to give up on the hubs as I have had them for many years and they have served me well.
Is there anything I can do to repair them for a reasonable price or should I toss them?

thanks in advance.

Bill Kapaun 05-10-19 09:04 PM

You need to also inspect the bearing races.

Dave Mayer 05-10-19 09:56 PM


Originally Posted by Carbonated (Post 20924160)
My Mavic Open Pro rear wheel with DA 7700 started to make some grinding noise.

I spun the wheel with my finger in the bearing cup and feel some pit marks or protrusions.

Is there anything I can do to repair them for a reasonable price or should I toss them?

These hubs get my vote as the best road hubs ever. It is unusual that the cups went before the cones or balls. The cups can be replaced; it takes the same tools and technique as replacing a cartridge bearing. Trick is finding the cup from another donor 7700 hub. Or an XTR From about the same era. IIRC, a Campagnolo Record freewheel hub cup should also fit. I think the critical dimension is a cup O.D. Of 28.0mm.

I've also replaced the cup with a 6001 cart bearing, supported with the appropriate 10-12mm sleeve of course.

davidad 05-11-19 11:35 AM

Both cups?

Dave Mayer 05-11-19 12:57 PM


Originally Posted by davidad (Post 20924790)
Both cups?

Good point: if the cup in the freehub is pooched, then you should replace the freehub - whole. You may not be able to source the sweet titanium freehubs that came stock with 7700, but almost any Shimano 8/9/10 speed unit should fit - if you use your old outer dust cap.

Carbonated 05-12-19 10:14 AM

Yes, it's both cups.

I damaged the freehub cup. I tried to remove it from the backside of the hub by tapping it with a screwdriver.
I saw a video on youtube which claimed it worked but evidently I was too forceful - it's a delicate process!
Anyway, either I will try to locate a replacement cup or buy a Shimano freehub.
Since I also have the non drive side to be replaced, I will try to find an economical method of removing the cup and hope I can find a good cup.

Mad Honk 05-12-19 04:17 PM

If you can see the damage and it is not too deep, brinneled cups can be cleaned. It requires a Dremel tool and a rubber diamond grit infused bit shaped to 1/4". I have done at least ten outer bearing races and they work fine after the treatment. The inner races are easy to replace so replace them. If you need help PM me and I can walk you through it. HTH, MH

davidad 05-12-19 04:23 PM


Originally Posted by Dave Mayer (Post 20924898)
Good point: if the cup in the freehub is pooched, then you should replace the freehub - whole. You may not be able to source the sweet titanium freehubs that came stock with 7700, but almost any Shimano 8/9/10 speed unit should fit - if you use your old outer dust cap.

The standard freehub is a better choice and only cost a few insignificant grams. I swapped mine out years ago. I Just weighed them and the difference is 10 grams.

Koyote 05-13-19 06:26 AM

Even if the cups or cones are a bit knackered (but not too much), you can pack 'em full of good grease and they will run smoothly. At least, that's true of the cheapie hubs that came on my commuter bike.

Carbonated 05-13-19 04:14 PM

I'll replace the hub
 

Originally Posted by Koyote (Post 20927211)
Even if the cups or cones are a bit knackered (but not too much), you can pack 'em full of good grease and they will run smoothly. At least, that's true of the cheapie hubs that came on my commuter bike.

I think I will buy a new free hub as suggested and that will take care of the drive side.
I will try regreasing the cup on the non drive side and hopefully it will be OK. If not, I would like to replace the cup rather than trashing the hub.
Now to order the hub.
Thanks!

Nessism 05-13-19 04:16 PM

I'd love to see a tutorial on replacing the cups. Something tells me it's not for the faint of heart.

Mad Honk 05-13-19 06:21 PM

Search the forums. I just read a series about replacing Campy NR races last week. A specialty tool was involved but may likely be purchased from the poster. Smiles, MH


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