Chain Stretch Issues!

[TomAllyn]

So as you all know I now have a BBSHD on my Breezer Uptown. I absolutely love it, but I'm now having issues already without even having 100 miles are the bike yet with severe chain stretch. This weekend I had my bike up on the stand and noticed that my chain was extremely loose. When I installed the chain I made sure there was about .25" play so as to not brake the chain. I only road 60 miles last week which is the first week of riding. It so lose I thought I must have done something wrong so I actually shortened by 2 links. I rode it 12 miles yesterday and this morning I was going to commute to work and noticed the chain had severe sag in it. This time I know for a fact it stretched, because I used my bicycle chain gauge. The first chain I bought that was supposedly an ebike chain got stuck on the chain ring.

What kind of chain do I need for this thing that will at least last several hundred miles?

[Bicycle365]

FWIW: I'm running a SRAM PC-1 and have had great life out of them. I would avoid KMC brand , they are cheaper than all the others and are what come standard on low end bikes, there's a reason.

[TomAllyn]

FWIW: I'm running a SRAM PC-1 and have had great life out of them. I would avoid KMC brand , they are cheaper than all the others and are what come standard on low end bikes, there's a reason.

Thank you very much.

[tomjasz]

It's not branding, it's the specific chain and it's specs. Even Wipperman has some dog chains. For those that swear by other chains be certain KMC doesn't make it under that label. They are HUGE!

KMC Chain Industrial Co., Ltd. is a roller chain manufacturer headquartered in Taiwan, R.O.C. with corporate entities in the US, Continental Chain Company, and Europe, KMC Chain Europe BV.^[2] They make cam driving chains, balance driving chains, oil pump chains, motorcycle chains, and industrial chains.^[3] They manufacture and market bicycle chains and master links under their own KMC brand and supply them to others, including Shimano.^[4] KMC chains are used in the Tour de France by riders such as Gustav Larsson, Swedish time trial champion.^[5] KMC was founded by Charles Wu in 1977,^[1] and was the largest bicycle chain manufacturer in the world in 2011.^[6]

[marjamar]

I have KMC chain. Came on the Motobecane Cafe Express 8 I bought a couple years ago. It's not stretched at all that I can see and is working fine with the BBSHD I put one a few hundred miles ago. I was curious and looked online here and it might be the Z-8. Here's a pic.

[TomAllyn]

Thanks everyone. I emailed KMC just before starting this thread and they have already gotten back to me. The chain they said I need is the KMC X8.93. So I just ordered it off Amazon.

[tomjasz]

Luna wisely uses KMC X9! On their builds!!

[Sebz]

Some of the KMC's are really good, so is wipperman! Some Sram too.... like any other brand there is some bad ones and really good ones!

[Sneakers915]

SRAM bought Sachs years ago, so I know they make their own chains.

Chains don't stretch, which is why they are used in drive applications, they wear. I'm not sure what is going on with yours, but 100 miles is nothing. Is it really dirty? A bad chain line? That will wear it much faster.

[TomAllyn]

SRAM bought Sachs years ago, so I know they make their own chains.

Chains don't stretch, which is why they are used in drive applications, they wear. I'm not sure what is going on with yours, but 100 miles is nothing. Is it really dirty? A bad chain line? That will wear it much faster.

I'm aware that chains technically do not stretch - its just a commonly used term applied to chain wear. Sure their are likely folks who actually think they stretch. A bad chain line is possible I'll have to check that tonight.

[Sebz]

True they don't stretch but the distance between 2 links does.

BIKE RADAR : Chain wear is commonly referred to as ‘chain stretch’, because the chain’s pitch grows in length as it wears. This is the most important type of chain wear, and the growth comes from the bushings wearing with the chain pins. Overtime, the inner diameter of these bushings increase and the pins groove out.

It’s often stated that a worn chain is when it reaches one percent growth from the original 0.5in (12.7mm) pitch.


But a stretch chain is just the common name for worn out chain, if it's worned out it will eat your cassette and chain ring!

[TomAllyn]

Is 6.35mm gap between the rear edge of the chainring and the front edge of rear sprocket enough to cause an issue? Do I need a different chainring? I used a straight edge and a tape measure.

I just received a email from Luna, I can improve it by a couple millimeters which will likely be fine. I may be able to improve it by another millimeter if the rear sprocket is installed with the dish going inboard as it can be faced outboard. That would give me an acceptable chainline.