Med!c

So as you guys can see my frame cracked. I went to a bikeshop to see what they had to say and of course they are trying to sell me a bike. I said no thanks and asked if they could see how much a replacement frame would cost since it's out of warranty so I'm waiting on an estimate for that. Since the guy ignored me completely when I asked if it's repairable and rolled on through like I had said nothing I've decided to ask you guys as you dont have commission incentive.

So according to bikepedia the frame is 6061 aluminium. I'm going to take a leap of faith here and assume the information is correct and that the frame is indeeded not heat treated. According to wikipedia 6061 aluminium is weldable. So is there any reason why I cant just weld that crack up?

bobotech

You can't just weld aluminum like you can steel. It needs to be annealed and heat treated properly otherwise it will crack if you even have the proper tools to weld aluminum.

What kind of bike and how old is it anyway?

jimc101

From the look of the frame, and details in the post, it's a 2008 GT Avalanche, this matches bikepedia https://www.bikepedia.com/QuickBike/B...e#.UDgLddZlQ6Y.

For the cost involved in attempting to wed (if it could be done) it would be cheaper to just replace the frame.

Looking a the picture, the drive side chainstay isn't in great shape either, and really could use some protection from chain slap as well.

Med!c

Well on the chain side it's just the paint thats damaged. But I never thought that was a big deal. I guess I'll wrap it in something.

But if aluminium 6061 isn't a heat treated alloy why would you need to heat treat it afterwards? As far as cost goes I know some welders who could do the work. Plus I dont see welding would be an issue. Aluminium isn't like titanium where it needs to be gased on both sides while welding.

As far as a replacement frame goes, do you guys have any suggestions on what to look into? I think I'd like to go with a steel frame this time.

LarDasse74

6061 usually is heat treated.

The cheapest option (if you are buying new) will be an aluminum frame. I have also seen a lot more broken steel frames than aluminum, but most were back when steel was more common, and most were lightweight steel, which is likely built with a smaller safety factor than an aluminum frame of similar weight. I have broken several steel frames but never an aluminum one. Too bad yours broke after the warranty expired, as unless there was some damage to it that is almost definitely a defective frame, IMO.

Aluminum frames start around $100, maybe a bit less.
https://www.nashbar.com/bikes/Product...09_-1___202337

Steel frames that I have seen generally start around $500 or so.

FBinNY 

Then welding process introduces heat, and the problems of expansion and contraction causing internal stresses in the metal. After welding the structure needs to be annealed (a heating/cooling process). I wouldn't bother going that route. If you're at all handy you can wrap the stay with either stainless steel wire or fiberglass and make a repair that might outlast the rest of the frame.

With the stainless you can do a nicer job, but it'll be time consuming. Start by cleaning the crack and filling with JB weld. Then use a relatively thin wire close to .010"-.020" from a continuous spool and start about 3/4" beyond the crack and wind in a tight coil similar to how the loops are held on a fishing rod. Wrap until you've gone beyond the other end of the crack by the same 3/4 inch. When finished tie off by slipping the last loop under itself and pulling tight. Cover the entire job in a thin layer of JB Weld to stabilize the job.

The alternative is to use fiberglass mats and resin, and like the steel you can get a repair stronger than the original.

I've done both in similar applications (the wire without JB weld, and simply a thin coat of auto body filler to finish). If you work carefully you'll have a decent looking repair that will outlast the bike.

dedhed

I myself would contact GT and see what they might do for you. Maybe replace it free or a deal on a new frame. The worst they can do is say no and you're right where you are now.

https://www.gtbicycles.com/contact-us/

Med!c

Well on bikepedia it didnt say T6 so I assumed it wasn't heat treated.

The reason I wanted to go with steel was weldability. But you're post has been very helpful. This is pretty much the only bike I've ever had so my experience is none in regards to this stuff. I'll see what kind of price I get from this shop. They said GT has a loyalty program so I should be able to get 20% off. Plus this site seems to carry GT frames, plus more. Thanks for the link. I will probably stick to aluminium since budget is an issue here.

Rekless1

Its not the big a deal to re-heat treat it after the weld but then your talking about stripping the entire bike down to the frame anyway at that point.

Welding cost is going to run you $50-$75 min.

You may be able to have it brazed. There's low temp alu brazing rod that may work without upsetting the heat treating of the frame.

Either way , your going to be getting right up there near the cost of a new frame and if you have one crack now, how far are you from the next one?

Med!c

I guess nothing to lose here. I assumed they only deal with shops but it's worth a try. Thanks.

LarDasse74

Don't spend one penny more to get a brand name on your bike - all these bikes (including the original GT frame) are made by a handful of Chinese and Taiwanese contract manufacturers.

Med!c

So I was thinking.. do you guys think this has anything to do with too small of a frame being used? The frame is a small, and I'm 5'8" and weigh about 200 lbs. I really have to raise the seat high actually, and for a while have felt I could easily fit into a medium. But at the time of purchasing the bike the shop told me this is what fits me and i just kind of went with it.

LarDasse74

That will almost definitely not put extra stress on the chainstays. I have seen many frames damaged at the top of the seat tube due to a too-heavy rider with a too-high seatpost, but not the chainstays.

Med!c

Alright then. Well I emailed GT just to see if they are kind enough to send me a free replacement since according to their site they are all about customer service. Other wise I will just buy that nashar double butter frame you posted.

redtires

I gotta go with those who recommend against this welding idea here. I mean, if GT won't warranty the frame or give you one at a ridiculous price, I mean, heck you can pick up a decent aluminum frame from Price Point, Performance or Nashbar for less than $100 pretty much any day. And your GT isn't any better than any of those.

LarDasse74

BTW... why do you say the warranty expired? Are you not the original owner of the bike? Did they ask for a bill of sale and you couldn't find it? Did you contact the company before and they said there is no warranty because the bike was made before the most recent takeover of the company?

The shortest warranty I know of on a rigid frame is 5 years, and 2008 + 5 = 2013. By my count you have at least one more year.

JohnDThompson 

No. The location of the crack, on top of the crimped area of the chainstay, suggests to me that the crack was caused or at least promoted by the crimping process on the stay.

catonec 

dont forget about ebay. you can do really well on new and slightly used frames in alum or steel.

bobotech

I'm a little surprised at the fact that the warranty is expired myself. I warrantied my son's bike which was a 250 dollar Schwinn from Target a few months ago and Schwinn easily approved the warranty and replaced the entire bike. I can't believe that a higher end bike would have a less warranty than a dept store Schwinn. And for that matter, I thought that Schwinn and GT were under the Pacific umbrella?

fietsbob

I suggest the next bike be from a company that has a lifetime of the frame
for the original owner sort of warrantee.

though those are usually materials and workmanship, not Wear and tear in service
types of coverage..

cale

Wrap it up with a couple hose clamps and keep an eye on it. Unless you really want to buy a new frame. Worst case is it buckles. Maybe avoid the downhill parks. Lol.

rydabent

Yes---------I wouldnt do anything until you hear from the manuf to see what they might do for you. They might send you a new frame, and want yours to analyze.

saddlesores

interesting.....i got cracks in both chainstays on my diamondback wildwood, also a 2008
model. mine was purchased in china.

DB customer service folk claim the DB network in china is a different company. no warranty.

eyeomegasquared

Might look at the Surly Troll frame: https://www.treefortbikes.com/product...-Frameset.html

Med!c

Just thought I'd give an update. GT never replied to my emails, and the shop never contacted me back. lol. I guess they dont like me. I JB welded very generously and it's been holding up fine so far. So thats good. But I'm constantly keeping an eye on it just to make sure, hopefully it holds up well for another year, then I'll be getting new bike.