Getting installed on my Hydra today. The adapter is from Christini AWD Bikes and allows the use of 104BCD chainrings on the Ultra motor. I have a RaceFace 36T Narrow Wide ring that I’ll be using instead of the stock setup. The Christini and RaceFace ring is a lot lighter vs what came on the bike so it should spin easier. That with the smaller front ring should give me more torque but a little less top speed which I’m ok with. Only negative is you lose the chain guard. I’ll post more pics once the install is complete.
Christini 104 BCD Adapter and RaceFace Narrow Wide Chainring
- Thread starter Cuz Vinny
- Start date
Getting installed on my Hydra today. The adapter is from Christini AWD Bikes and allows the use of 104BCD chainrings on the Ultra motor. I have a RaceFace 36T Narrow Wide ring that I’ll be using instead of the stock setup. The Christini and RaceFace ring is a lot lighter vs what came on the bike so it should spin easier. That with the smaller front ring should give me more torque but a little less top speed which I’m ok with. Only negative is you lose the chain guard. I’ll post more pics once the install is complete.
I know a guy who's lookin for a chainring guard! Oh wait he already has one sorry. One of my buddys did the same thing as you as well. I think the stock ring will only allow you to go down to 38t. Just make sure you check for clearance. Might need shorter 2-piece mounting bolts to. You won't miss the guard I ditched mine right from the start. Now shorter crank arms might be in your future. Have fun.
The Christini adapter actually came with bolts which was nice. The frame design of this bike likes a large front ring. The 38T fits and is much smaller than what came on the bike, not sure I’d go smaller than that. Have to remove some links from the chain and try and adjust the chainline a little.
Merle Nelson
Well-Known Member
- Region
- USA
Sounds interesting. I notice I rarely ever go over 20 mph even when coming downhill. Low end climbing grunt is what I want the most.
Can't wait to hear how you like it on the trails Cuz Vinny.
Can't wait to hear how you like it on the trails Cuz Vinny.
So RaceFace chainring is on but the chainline is off a little. The adapter is made for boost spacing 148mm and apparently the Hydra is more like 142mm. Gears 1 - 6 isn’t an issue but after that the chainline gets a little wonky and with the torque this motor makes that’s not a good thing. With a Kindernay or Rohloff this setup would be perfect but with a cassette not so much. Live and Learn.
scrambler
Well-Known Member
- Region
- USA
- City
- Bay Area, CA
My understanding was that the Hydra rear dropout was 148mm
Well either the adapter is incorrect or the bike is. I’ll email Christini and confirm with them that what I purchased is for boost 148mm spacing.
Well I bought the adapter based on the description and the assumption that the Hydra has 148mm rear spacing. I’m pretty confident the issue is with the adapter and not the bike. My mistake, lesson learned.
One other thing I discovered is my Hydra had a 44T front ring. I changed to a 38T so even though only the first six gears of the cassette have a usable chainline the difference in ratios is so great sixth gear (21T) is just about equal to seventh gear (24T) with the 44T ring. This setup as it is may just be usable so I’ll test it before putting the stock chainring back on.
The lateral position of the motor is fixed so it has zero bearing on this refit. If the adapter offset is the same distance as the one he took off it should work.
Did your bike come with a chainring guard? Some of the ones Ive seen run the chainring on the INSIDE flat part on the spider and the guard on the OUTSIDE and if you are to far away from the motor that could be your issue.
Lay your original on a flat surface and lay your new one next to it and that will tell you. My buddy has a Biktrix with the 197mm rear end and his spider offsets WAY out to get the chainlink correct.
When going smaller in chainring size and keeping the same lateral distance from the motor you might have a clearance problem on your chainstay as you are making the circle tighter. Looking at your pic it looks tight already.
Just went out and measured mine ( Ultra on a Exess E-180 ) and the C/L of the chainring ( Wolftooth 38t ) is 59mm away from the flat round side of the motor housing measuring straight out. My bike has148mm dropouts ( Boost ) and I am running a Shimano 11 spd cassette ( 11-42 ) and I can use every one of my gears under load if needed. Normally hardly ever use the 2 largest gears but if I need them they work fine.
Did your bike come with a chainring guard? Some of the ones Ive seen run the chainring on the INSIDE flat part on the spider and the guard on the OUTSIDE and if you are to far away from the motor that could be your issue.
Lay your original on a flat surface and lay your new one next to it and that will tell you. My buddy has a Biktrix with the 197mm rear end and his spider offsets WAY out to get the chainlink correct.
When going smaller in chainring size and keeping the same lateral distance from the motor you might have a clearance problem on your chainstay as you are making the circle tighter. Looking at your pic it looks tight already.
Just went out and measured mine ( Ultra on a Exess E-180 ) and the C/L of the chainring ( Wolftooth 38t ) is 59mm away from the flat round side of the motor housing measuring straight out. My bike has148mm dropouts ( Boost ) and I am running a Shimano 11 spd cassette ( 11-42 ) and I can use every one of my gears under load if needed. Normally hardly ever use the 2 largest gears but if I need them they work fine.
Just checked the WW website and also the "unofficial Hydra thread by BB" and neither has any info on the rear drop-out spec size for the different wheel sizes. I'm guessing the 27.5" and the 29" use the same rear end and the 26" is different. FWIW they should also list the front drop-out sizes available or at least have specs on the forks they offer as you can get different size hubs for the same forks.
That should absolutely be listed as some of us build up from scratch and ya gotta know what's what.
That should absolutely be listed as some of us build up from scratch and ya gotta know what's what.
Merle Nelson
Well-Known Member
- Region
- USA
Well, it sure looks sharp.
The adapter is designed so you can run the chainring on the inside or outside of it. If you mount the chainring on the inside it hits the frame at the lower suspension pivot point. Most likely this is why the bike comes with a large 44T ring. The large chainring gives the clearance needed. With the ring mounted on the outside you have chainline issues.
Not to beat this thing to death but I was reading on another thread that Pushkar and Innotrace are marketing a model in Europe ( probably Germany ) by the name of Black Forest Bikes X3 Carbon E-Bike X3 and it lists the rear drop-out for that bike in the 27.5" size as indeed Boost at 148mm so there ya go.
There isn’t anything wrong with the bike or the adapter. It’s just they don’t work well together. If I had asked Pushkar before going ahead and just buying the adapter on a whim I’m sure he would have told me it wouldn’t work. The design of the Hydra frame requires a large front chainring in order to get the proper chainline. It’s as simple as that. I had zero issues with the stock setup. The 44T front ring when paired with a 11 speed cassette is perfectly fine for trail riding. Nothing ever goes easy when modding so lesson learned.
Even with the original spider that came on the Hydra I don’t think you can use a 38T ring as the chain will hit the lower suspension pivot. It’s the large 44T ring that gives the clearance so the chain won’t rub.
As a side note I found two companies that make 44T 104BCD chainrings so I may switch to one of them. Unfortunately both are on back order as of now.
It looks like the 38t you have on the new spider the pic of clears yeah? It's just the chainline that's wonky? Absolutely a 38t ring will mount on the original 130BCD spider. Will it clear the frame or chainstay? don't know. AND if the 38t is clear on the 104BCD mount it will work on the 130BCD original. 38t rings are all the same diameter it is just the mounting holes that differ.
Sounds like you are you to far out with your chainline with the new set-up correct?
Worst case go back to your original ring and fine tune your cassette cogs to larger sizes to get you the cadence and pedal torque your looking for.
Sounds like you are you to far out with your chainline with the new set-up correct?
Worst case go back to your original ring and fine tune your cassette cogs to larger sizes to get you the cadence and pedal torque your looking for.
I found a company that makes a 44T 104 BCD chainring that will work when installed on the back side of the adapter.
Similar threads
