has anyone experienced turbulence-unstability while riding up 50 km in a giant propel advanced 1 , 2

Memo

Hi,


I purchased my bike on october 2016, since then i´ve being riding a lot, but have experienced lately that the bike when speeding up over 50km suddenly loose control and starts to shake, first time i thought was something wrong with the wheels but everything was well and in place. After few days the rear rim got broken, so i decided to change for new mavic wheels, it results that even with new the pair of wheels, same situation has happened 3 times already, fortunately able to control it.

I have taken to various mechanics but all conclude that all mechanical parts are ok. Lately the bike tail also is experiencing same kind of vibration-shake even when riding in flat terrain, seems like the wind is going to pull you down, i´m just wondering if anyone has heard or experienced something similar in order to learn if this might be cataloged as a design failure for claiming to Giant for the warranty.

Appreciate your comments.

Bobbinogs

Have you tried riding another bike to see if the issue is closer to home? You say you bought the bike at the end of 2016, did you start riding then?

Some riders get all tense at high speeds and, as well as getting the handling all wrong, then exacerbate the problem by adopting a funny position which they think is aero...With disastrous effect on the overall stability.

svetty

Does sound like speed-wobble. Try googling - lots of explanations and some solutions......

dodgy

Loose headset?

Matthewfalle

Overtight grip on bars as suggested above? Wiggly hip syndrome when pedalling fast? Utterly bizarre spacer/stem set up causing steering issues?

Can you post a pic of the front of the bike and or a vid of you riding so we can see?

davep1

I have the same bike, bought 5 months before yours, and have no problem like you describe. Are you sure the wheels are ok? QRs tight? Spin freely, no problems with the axles? Then the frame, is that definitely ok?

burnthesheep

Memo wrote:

I purchased my bike on october 2016, since then i´ve being riding a lot, but have experienced lately that the bike when speeding up over 50km suddenly loose control and starts to shake, first time i thought was something wrong with the wheels but everything was well and in place. After few days the rear rim got broken, so i decided to change for new mavic wheels

Can you explain this part more? Did you break a rim before or after you noticed speed wobble? Is the new wheel trued?

Even if you had speed wobble before, doing something or hitting something hard enough to break a rim isn't trivial. I know the shops checked it out, but I'd be sure the frame in the back is ok.

Either way, I have a 2015 PA1 and no issues. I've had it up to 75 km/hr multiple times on a small descent. I've sprinted down small inclines for a couple minutes at a time at 35 mi/hr which is close to 60 km/hr with no issues. I've also had it at 45 km/hr for 15 minutes in a tail wind.

Only speed wobble I've had was making the mistake of trying to leverage the handlebars in a sprint without knowing what I was doing and induced a wobble.

AK_jnr

30mph is surely way too slow to be a speed wobble. Got to be rider induced.

Memo

Hi all, thanks for taking time to write.

The rim was broken after first speed wobble, not as a result of an impact, seems for me more a defective in the joint blade where it come off slightly.

With the definition provided ' speed wobble ´ i have searched and there are several factors that influence the shake, among others, weight distribution of rider ´rear and front´ and the elasticity and geometry of the bike frame too.

There is no video to show you what happend.

In this circumstances I will claim to Giant as itis unacceptable and not safe to ride a bike having known it easily end up in a death wobble.

ayjaycee

Have you got a similar sized mate that you can temporarily swap bikes with? That way, if he can replicate the issue on your bike but had never seen it on his, it could point to yours. Alternatively, if you can replicate on his but it has never materialised for him, it could be pointing at your technique.

Good luck with with any claims on Giant. I suspect you will need it if that is your eventual route.

pblakeney

AK_jnr wrote:

30mph is surely way too slow to be a speed wobble. Got to be rider induced.

Nerves. To put it politely.
Or a broken bike.

cougie

Your rim broke without an impact? Whats a joint blade?

None of this is making much sense to me.