Run or replace. Shimano un51 73x113
 

This Shimano UN51 73x113 resides in my 96 Karakorum. Bike was lightly used before multi year storage.

I read they are non servicable. I cannot regrease. Is this right? Can i run this with factory supplied grease after 16 years?
The bearing is tight. No play. No noises. Spins nicely. What would you do?

If I were to replace it, and for future reference. What canI replace it with? I dont think the Un51 is around anymore.

Thanks in advance.

You are right you can not service the bottom bracket . If it spin smoothly and there no play in it , I would just use it until it die . To replace it , use UN-54 in the size you need .

Ride it till it dies. from your other posts, you hardly used the bike, for 1 year, then put in storage, would be more concerned with the elastomers in the Quadra 21R's than anything else on the bike for being worn out.

Ok then. Ill run it. I plan on going through the forks as well. Even saw a youtube video on the exact kind I have. What do I need to look for? Would they be stiff or loose? Parts available? I also read I can upgrade to a shock with more travel....but too much would be bad on headset tube? (right name or fork tube?) Waiting on some specialty tools I ordered.

Thanks again guys.

Your bike has a 1 1/8th head tube, so most current fork will fit (just not tapered), the biggest issue will be getting ones with rim brake mounts, although some are still around, your frame will run upto 100mm forks with no issue (I was running a 1996 GT Bravado with 100mm Rock Shox Judys till earlier this year)

There is still some aftermarket support for Quadras, and the 21R's were the best Quadras, but they aren't that good compared to modern forks.

Well...after reading a little. And doing some thinking. I think I'll put some tubes in this bike. Plop a new seat on it. And ride it after Im healed up. May not be until next spring. Ill concentrate on setting it up correctly (just a little readin and I saw how out of whack my bike is) I'll get my legs and endurance back. By then I'll have read enough to become immersed in the sport again. I already know a full suspension bike and a hardtail 29 are in the future. Maybe even a road bike too. Niether one of those bikes are going to rehab me any better, or do anthing the GT cant do at least my first ride season back. Sound reasonable? I always loved riding bikes. Strange how I let myself forget.