Why am I finding it so difficult to find a 38T 11x1 Deore m5100 chainring?

[pgrbff]

My son has a Haibike emtb, a special for which there is no printed spec document.
I have purchased a new chain and cassette but cannot find a 38T M5100 chainring.
Could this be a Haibike specific part? I cant see it on the Shimano website.

 

[Mikerb]

In general terms any narrow wide 10 or 11 speed chainwheel will work but 38T is quite big for an EMTB which are usually 32t or 34t............the issue being clearance between the chainwheel and the chainstay. So Haibike may have used one with enough offset to provide clearance.
The main things are: Direct mount or spider?
If spider 4 bolt? BCD? ( bolt centres diameter)
Boost if the backend is 148/12 mm.
Steel or ally ( steel being better for an EMTB)

Are there any identifiers on the existing chainwheel? Brand ( usually the same brand as the crank) serial number?

On an EMTB the chainwheel is usually specified for whatever motor type is in the bike. So look for a chainwheel for that motor.

 

[pgrbff]

There are no identifying numbers, probably on the inside, I have asked Haibike many times for a spec for the bike and they say there isn't one. This means I spend hours searching for the correct parts which because of our location are invariably ordered online.
It has 4 point fixing and 10mm and 8mm hex in the centre of the crank. To be honest I have no idea at the moment how to remove it.
I'm toying with just changing the cassette and chain at the moment, the chain is stretched and some of the teeth on the cassette have been knocked.
I found a brief spec for the bike online, Italian bike shop, and it said Deore groupset so I assumed, probably incorrectly, Deore chain wheel. I have a feeling it is a Haibike part as the crank is Haibike.

 

[Mikerb]

OK so its 4 bolt on a spider not direct mount. Now measure diagonally from one bolt to the other...that is the BCD..it will be somewhere close to 104mm probably. To remove the chainwheel just take the chain off the chainwheel...maybe take off the chain guide if there is one........then undo the 4 bolts. The chainwheel should then come away from the spider. You may or may not have to remove the pedal to get it off ...try it first. Replacement is a reverse of that procedure.
The 4 chainwheel to spider bolts should be loctited and tightened to 10nm.

As before the chainwheel may or may not be a Shimano part but it will be a chainwheel suited to the motor in the bike....so a Shimano steps, Bosch CX, Yamaha etc as appropriate. Look for narrow wide, 38 t, 4 bolt , 10/11 speed, whatever the BCD is..e.g. 104 in steel.

 

[Gary]

without knowing the motor type or bike model it's impossible to give you a definitive answer but unless your bike has a hub motor it's highly unlikely to be a deore M5100 chainring as they have an asymetrical bolt patern to fit normal (not E bike) shimano cranksets. If it's a mid motor your chainring will be specific to the motors bolt patern or direct mount type.
If your chainring is 4 bolt measure your current chainrings bolt circle

Wolf Tooth - How to measure Bolt Circle Diameter (BCD)

Bolt Circle Diameter (BCD) is the diameter of the circle that goes through the center of all of the bolts on your chainring. On bicycle chainrings this dimension is usually measured in millimeters. It is critical to know the BCD of your crankset when you are selecting a new chainring for your bike.

www.wolftoothcomponents.com

and order any decent narrow wide or single ring 38t chainring in that bolt patern

 

[pgrbff]

without knowing the motor type or bike model it's impossible to give you a definitive answer but unless your bike has a hub motor it's highly unlikely to be a deore M5100 chainring as they have an asymetrical bolt patern to fit normal (not E bike) shimano cranksets. If it's a mid motor your chainring will be specific to the motors bolt patern or direct mount type.
If your chainring is 4 bolt measure your current chainrings bolt circle

Wolf Tooth - How to measure Bolt Circle Diameter (BCD)

Bolt Circle Diameter (BCD) is the diameter of the circle that goes through the center of all of the bolts on your chainring. On bicycle chainrings this dimension is usually measured in millimeters. It is critical to know the BCD of your crankset when you are selecting a new chainring for your bike.

www.wolftoothcomponents.com

and order any decent narrow wide or single ring 38t chainring in that bolt patern

It's a Haibike allmtn 2.5 and the groupset is Deore M5100 11x1. The crank is labelled Haibike. There is no spec because Haibike refuse to tell me and there is nothing on the website for this model. The motor is a Yamaha PM-X2.
At first, I assumed the chainring would also be Deore, but when I looked on the Shimano website there was no M5100 38T.
I have asked Haibike, because none of the Italian dealers I have asked has responded, but if past experience is anything to go by they won't be very helpful.

 

[Gary]

"Deore groupset" on any Emtb doesn't include cranks unless it's a Shimano motor. and then it would be STEPS or XT STEPS cranks arms. not Deore.
The chainring isn't fittted to the cranks. it's fitted to the motor and the chainring is 4bolt 104 bcd (Deore is 96 asymetric).
Asymetric rings aren't used on Ebike motors as the spider turns independently of the crank arms so all the *claimed* benefits of asymetric design are lost.
your Yamaha if it has a 4 bolt spider with chainring bolts more than likely uses a 104bcd patern too too.
but measure it.

 

[Mikerb]

It's a Haibike allmtn 2.5 and the groupset is Deore M5100 11x1. The crank is labelled Haibike. There is no spec because Haibike refuse to tell me and there is nothing on the website for this model. The motor is a Yamaha PM-X2.
At first, I assumed the chainring would also be Deore, but when I looked on the Shimano website there was no M5100 38T.
I have asked Haibike, because none of the Italian dealers I have asked has responded, but if past experience is anything to go by they won't be very helpful.

View attachment 79145

Try this one...it has BCD of 104....so measure yours to ensure a fit. The BCD is from the centre of one bolt to the centre of the other bolt diagonally opposite ..in mm.

FSA E-Bike chainring for Haibike with Yamaha from MJ 2016 | Bikester.co.uk