Giant Propel cracking noise

ic. · March 2016

A friend has a strange problem/issue with his 2016 GIANT PROPEL ADVANCED SL 2. He's not had it long, maybe 600km on it.

Since new, it's made a strange cracking noise. Basically, it clicks (sounds a bit like a slightly out of index rear mech) for a minute or so, then makes quite a loud cracking noise, then is silent. It stays silent for a while, before the process starts again

He took it back to the shop, who muttered something about thinking grease is making it's way out of the rear hub and onto the freehub pawls, causing the freewheel to skip

Personally, I think that's nonsense.

I know swapping out the rear wheel for a reliable one would test the theory, but he hasn't had chance.

He's not a user on these forums, so on his behalf I'm asking for any ideas you think might cause this?? I've yet to actually get my hands on the bike to check it over, but I've ridden next to him while it does it and it is a strange noise indeed and I can't get my head round what's causing it. Thoughts welcome, thanks.

Ste_S · March 2016

Working out when the cracking sound occurs - in and/or out of the saddle, pedalling and/or freewheeling is usually a good place to start.

If pedalling and occurring during both in and out of the saddle, I'll take a stab at the press fit bottom bracket wasn't installed properly

ic. · March 2016

Ste_S wrote:

Working out when the cracking sound occurs - in and/or out of the saddle, pedalling and/or freewheeling is usually a good place to start.

If pedalling and occurring during both in and out of the saddle, I'll take a stab at the press fit bottom bracket wasn't installed properly

Should have mentioned happens whilst pedalling, seems to be ay gear too.

BB installation issue is a good shout. Thanks for the idea

ic. · March 2016

Apparently the shop has already had the BB out and re-pressed it....

sungod · March 2016

slipping seat post can be quite noisy, only moves a minute amount each time

to eliminate remove it, clean it, put some assembly paste on it before refitting

ic. · March 2016

sungod wrote:

slipping seat post can be quite noisy, only moves a minute amount each time

to eliminate remove it, clean it, put some assembly paste on it before refitting

Thanks, but it's an ISP.

Also, compared to noise I've heard from a seat post, its a deeper, bigger, noise. Imagine a really loud crack, basically

dee4life2005 · March 2016

I had a cracking noise that sounded like it was pedal / crankset / BB related ... i.e. in time with pedalling. I replaced the pedals, stripped the crankset and regreased all the bolts and replaced the bottom bracket (hollowtech ii). After all that, it still made the cracking noises, and just as bad as before. A bit of roadside troubleshooting, as it was doing my head in, and it turned out it was the rear quick release needing tightened a little more. It seemed tight enough before, but not quite enough it would seem. Might be worth a shot before you start stripping things down and replacing stuff.

izza · April 2016

Have a look at the rear skewer. Sometimes with Giant Propel's the paint collects in between the two grub screws that hold the mech hanger on. This creates a bulbous lump between the skewer bolt which then sit non-flush to the frame and 1) leads to funny noises in time with pedalling and 2) bends skewers.

albash · April 2016

I had a similar problem (Giant TCR). paid for new bottom bracket, to no avail. it then got worse, I was assured it could not a frame crack. So to find the cause the bike was stripped down by the bike shop- a crack was found near the bottom bracket under the front derailleur. The frame was replaced by Giant though I still had to pay for the rebuild.

Giant Propel cracking noise

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