SpandexSpeeder

Hi all, I have one of those el cheapo orange GMC Denali road bikes (22.5" model). I put about 3000 miles on it last year and totally wore out the bottom bracket and the headset. I do not know much about bikes and my LBS recently went out of business. Does anyone know what replacement parts would fit?

After reading the forum for a bit, it seems the common consensus is to to just buy a higher end bike instead of repairing the Denali. However, I want to repair this bike because I plan to use it to commute to college where bike theft is pretty rampant. I got hooked on road biking with this cheap bike last year so I plan to buy a better bike in a few weeks but I do not want a $1500+ bike to get jacked.

mynewnchome

From the video description:

BiggFred

Jadesfire 

I get it. I did this to my Denali. But I will say, even if you do the work yourself, you still need at minimum a crank puller and bottom bracket tool. The head set tool you can make yourself from some nuts, washers, and threaded rod. Just be aware that you won't be saving any money, in fact you'll most likely lose money doing it. From experience, if money is tight, I second just getting another cheapo- even another Denali since they actually do just fine for campus commuting- until you're in a better position to upgrade.
That being said, yes, it takes a 68mm English threaded UN54 bottom bracket and I think it's a 1 inch threaded head set if you're not boing to upgrade the stem and bars.

thehammerdog

JohnJ80

My kids went through 4 years each and one of them in 4 years of grad school with old high quality racing bikes. They're only worth about $300 or so but they hold up amazingly well and are not a theft target like newer bikes. A good U-lock used properly and some security skewers and it's never a problem. Both of these bikes were both in universities in major urban areas. These were some of my old bikes that we had kept through the years, but you can find these all over on Craig's list, FB Marketplace or from those bike shops that recycle old bikes. These were bikes that had hand built wheels from the day, 5 or 6 speed cassettes, friction down-tube shifters etc... A side benefit is that they accept wider tires easily so it was simple to put on durable tires that could handle road defects etc...

That would be way smarter than putting money into a Walmart bike or even fixing this GMC thing. That bike would easily last your entire academic career. My son's bike (he's in school for a PhD) has been going 8 years now and hasn't missed a beat. That's a 1980 vintage Motebecane with that very low end campy drivetrain that they offered and handbuilt wheels on campy hubs.

j.

SpandexSpeeder

mynewnchome

It all depends on your needs and wants. Whatever works for you.

fietsbob

Made up of nothing weird , just got the cheapest of the parts available , ..

you need to buy thevtools and then similar parts , which will probably be better

ignore the voice in your head saying, " but it cost more than I paid for the bike" (or Not)

Of course it did, you bought a low cost bike .. it's a sum of it's parts ....





...

JohnJ80

jasnooks

You'll also need a lock ring spanner.
Park Tool (109917) HCW-5 Lock Spanner
https://www.amazon.com/dp/B000C17KRI..._MH3JCbJ16KMHR

And an installation tool for the bottom bracket, if you got a sealed beating cartridge style.
Bikehand Bike Bicycle Shimano Bottom Bracket Removal Remover Tool
https://www.amazon.com/dp/B00811WQJS..._YK3JCbCQSXAEK

SpandexSpeeder

I forgot to post an update. Long story short I was able to replace the BB and the bike rides great again. I had a change in work/life circumstances and ended up buying a Cannondale Synapse to replace the Denali but I am keeping it as a commuter bike.

Unfortunately I can’t post links yet but I was able to get everything from Amazon. I was able to repair the bottom bracket with the following part:

SHIMANO UN55 BB Square Taper Bottom Bracket (68x122.5mm) (about $22)


And I got the following special tools. I avoided buying the two special left and right hand side bottom bracket tools since I would be switching to the Shimano style.




Bikehand Bike Bicycle Shimano Bottom Bracket Removal Remover Tool ($10)





Park Tool CCP-22 Crank Puller ($15)


(a hammer and long screw driver would have worked in hindsight)




and I also needed anti seize grease, a 14” pipe wrench, a hammer, and 2” channel locks. A 2” washer, 5/8ths x 3” screw with nut with some WD-40 was also needed.




Taking the cranks off was a breeze. I used the 2” channel locks to take out the left bearing cup (side with the three key holes).





But the right hand fixed cup was a beast to get out. It wouldn’t budge with channel locks. I tried an adjustable wrench, nothing. Tried a Sheldon tool. Nothing. Tried heating it with a small blow torch. Nothing. Let PB blaster soak in over night and retried. Nothing.




Eventually I put the pipe wrench on it, used a 5/8” bolt with a washer through the fixed cup to keep the wrench from falling off, then I used a hammer to tap the wrench until it turned. Once it was broken free, it came right out.



So at the end of the day I was able to fix the bike for about $35 if you don’t count the crank tool. I’m pretty happy with that.

Jax Rhapsody

When I replaced the BB on my Genesis Roadtech(same thing but more roadbikey); I used a sealed unit for a mtb, because the width and gearing is mtb. I love the frame and everything around the frame is the bullspit. I built mine up to roughly a "$600" bike. It got stolen and I got a Denali to do the same.

Jax Rhapsody

Yes it will. The paint is really thick and it's aluminum. The fork is hiten steel, the frame is 4130 aluminum... aircraft grade oOoOoOo

Bonzo Banana

I rode a cheap heavy steel mountain bike at 26 stone, the first thing that went was the bearings in the front wheel and I had to true the 26" wheels more than once when I hit pot-holes. I lost weight rapidly but after riding perhaps a couple thousand miles in total which by then I was maybe 18-19 stone I replaced the caged bearings of the bottom bracket with new loose bearings and fresh marine grease. The bearings were only about a £1 delivered (probably ebay). The bottom bracket was as good as new. It can be a bit finicky adjusting the bottom bracket for no play. Pretty sure I rode it for about a week and then had to adjust it again but that second time lasted a very long time. I could of gone with a sealed bottom bracket but I really didn't need to, the original only needed fresh bearings and grease and it spinned much better with loose ball-bearings. I'm just making the point you probably could have bought it back to good working condition spending even less money. There are millions of bikes all over Africa getting huge abuse and being massively over-loaded and they don't have fancy sealed bottom brackets etc that wouldn't be cost effective to them.

JohnJ80

That’s not been our experience with about 12 years experience with bikes on campus. Aluminum parts corrode, lubrications gets washed off, etc.. chain isn’t aluminum, neither are the springs in brakes and derailleur. Cables aren’t. All of that suffers in weather. And if any of those things fail, your bike can become unrideable.

better bikes do better. Been there done that - for years.

Jax Rhapsody

The crappy parts will crap out, yes. Mine had wax coated cables along with the other mods. But things corroding, oxidizing, rusting is pretty much enevitable.

JohnJ80

Well good luck. Not how I’d solve the problem if reliability matters.

Go to a university and walk through the bike racks outside student housing in the fall and then again in the spring. It’s pretty obvious what works and what doesn’t.

Jax Rhapsody

Oh yeah, I know. I live near UofLs main campus. Wax coated ones is what the co-op has, I use the famous blue grease when I install them. Rub the cables down with a thin layer. Mine often sit outside if in use and I don't have the problems unless mine sit outside unused. I think some bikes there get parted out before they return back to the earth.

Bonzo Banana

4130 is chromoly steel. GMC Denali if aluminium is going to be 6061 aluminium or perhaps 7005 for older models. If steel likely to be a high tensile steel or one of the newer high carbon steels which they still call high tensile, very unlikely to be 4130 chromoly steel which is more expensive to manufacture than aluminium these days.

I think they call 6061 aircraft grade aluminium because it's less brittle and more fatigue resistant than 7005 aluminium.

wphamilton

There's always a crowd saying that, but they're mostly wrong. The BB is an easy, inexpensive upgrade on the Denali and well worth the trouble.

wphamilton

Right the fork is steel and quite heavy, frame is 6061. Both I think will last longer than you'd want them to.

Lemond1985

Congrats. You did it ... your way. And it worked!

Squeeze every mile you can out of that bike. Now that you've worked on it, it's become an investment of your time. The crank puller and bottom bracket tools will serve you well over the years, keep them in a safe place.