Giant Reign e+ Mount Bolt Issue (Yamaha Motor)

[Mjbiker]

Hi all,

I have been riding the awesome Giant Reign e+1 Pro (made 2020, purchased new 2021)! It's been a great fun bike both uphill and dowhill. The only complaint I have is listed below and I wonder if any of fellow Giant e-riders here have had similar experience to share.

After riding about 200 km, a creaking noise developped in the Syncdrive/Yamaha motor mount on the chainring side. Did lots of research online since Giant dealer didn't know what's causing it. A helpful Youtube video showed the source of problem and how to fix it by greasing the steel bushing/insert into the aluminum frame. The noise disappeared thankfully. The bike just passed 800 km with no issue or noise.

However during the fix, I noticed that the threads on the Torx 30T bolt were smoothened. Checked the other bolts out of precaution, the other short bolt which is located on the chainring side also showed similar issue. The long bolts on the oppsite side are fine (there are total of 4 motor mount bolts).

I reached to Giant dealer/distributor but they were no help. They said there is no recall. They only offered to provide one short bolt to replace one of the the worn ones. I replaced the other worn bolt with an excatly same aftermarket bolt. The issue is gone!

My guess is that either the original bolts were out of spec (soft) or the vibration/wear of dry ungreased steel bushing deformed the threads over time which also caused creaking noise.

I'd appreciate any thoughts here. Hopefully Giant would notice and fixe the issue on this great bike. I attached some pictures as reference.

Thanks,
MJ

 

[KuRi]

Thanks mate, very helpful information. Can you please provide the exact specs of these bolts?

 

[gbarfoot]

That looks like an overtightened stripped bolt to me.

 

[Mjbiker]

Thanks mate, very helpful information. Can you please provide the exact specs of thes bolts?

Sure, I will get back to you on that.

 

[Mjbiker]

That looks like an overtightened stripped bolt to me.

Could be. Stripped, overtightened or crossed threads. It must have happened in the factory or at dealer/distributor. The dealer insists that it is not their fault.

 

[andyb2]

if the bolt looks like that, I'd be concerned about the state of the thread on the motor

 

[04fuxake]

Interesting. On my Fathom, the bolts go right through the motor with a nut on the other side. I assumed they'd all be like that.

 

[Mjbiker]

if the bolt looks like that, I'd be concerned about the state of the thread on the motor

Checked the threads of the motor mount bushing on the same day, they were fine. That makes think that the bolt was out of spec and soft (improper heat treatment maybe?).

if the bolt looks like that, I'd be concerned about the state of the thread on the motor

 

[Mjbiker]

Interesting. On my Fathom, the bolts go right through the motor with a nut on the other side. I assumed they'd all be like that.

It's a 4-bolt mounting system. Two long and larger diameter bolts on the non drive train side, and two short and thinner bolts on the chainring side. The latter develop issues.

 

[KuRi]

How did you get the replacement bolts? Can you please share a link?
And what torque settings did you use?

Thanks!

 

[Mjbiker]

A local shop ordered it for me The mechanic doesn't remember the exact spec but, he thinks it was a Torx T30 head with M6 1 mm pitch. Regarding torue settings, he used the same torque as pivot bolt on the Maestro linkage which is written on the bolt.
Just a word of caution, measure the bolt dimensions before ordering a replacement since it may be different than mine.