Hydra Fatty Chain/Tire Rub Thread

[Cuz Vinny]

Ok, so one of the biggest issues I’m having with my new Hydra build is chain/tire rub when going into the taller gears. My current setup is 90mm wide Nextie Tri Spokes with 26X4.8 Maxxis Colossus tires. As it sits I can only get the first four cogs on the cassette before the chain rubs the tire. I next tried a set of Sunringle 80mm wide rims with Vee Tire Apache Fatty Slicks in 26 X 4.5 and the chain rubs the tire after about the first five cogs on the cassette. Now the Fatty Slicks run large so it’s not much different in width vs the Colossus tires. I thought going with a 80mm wide wheel vs 90mm wide would help but it’s not enough.

I am determined to use the Tri Spokes as I spent a lot of money on them and they look badass. So my next attempt will be a set of Surly Edna’s 26 X 4.3 on the Nextie’s. If that doesn’t work I’m going to try a set of 26 X 3.8 tires on the Nextie’s. Hopefully that works otherwise I’ll be super pissed.

Now before anyone says anything this has nothing to do with problems with the Hydra design or the bike itself. The bike appears to be designed around a 80mm wide rim and not for super wide massive fat bike tires. I tried to stuff the widest rim and tire combo I thought would fit and it doesn’t so I’ve got no one to blame but myself for the issue I’m having.

If any of you have a Hydra Fat Bike and are running 90mm wide rims and your not having chain/tire rub issues please post what tires you are running.

 

[scrambler]

Do you really need / use the lowest gears on an e-bike with that much power ?
Or you can ask them to build you a custom rim around the Kindernay Cage

 

[Cuz Vinny]

Do you really need / use the lowest gears on an e-bike with that much power ?
Or you can ask them to build you a custom rim around the Kindernay Cage

It’s the taller gears that I can‘t use and yes I need them. Using the taller gears puts less strain on the motor. Last thing you want to do is lug this motor when going up hill by being in the wrong gear. The taller gears let the motor spin which keeps it happy.

 

[scrambler]

The rear dropout on the hydra FAT is 197mm right?
What Cassette are you putting on there, and did you ask Nextie what is the max tire clearance for it?

 

[Cuz Vinny]

The rear dropout on the hydra FAT is 197mm right?
What Cassette are you putting on there, and did you ask Nextie what is the max tire clearance for it?

Rear drop out is 197mm and the cassette is a Shimano XT 10 speed.

 

[scrambler]

You can also may be get some extra space by shifting the front chainring to the outside as long as it does not prevent the chain from riding the sprocket.

 

[Cuz Vinny]

You can also may be get some extra space by shifting the front chainring to the outside as long as it does not prevent the chain to ride the sprocket.

So trying this made things ten times better. Moving the chainring outward will allow me to use just about all the gears except the last two. To over come this I’ll remove the two smallest cogs and use spacers to push the cassette outward. This way I’ll be giving up some top speed but I’ll have the use of the tallest cogs for climbing. Thanks for the tip!

 

[scrambler]

Glad it worked out
There should also be a little play in the swingarm, so you could try adding the spacers without removing the two small cogs and see if you can spread the swingarm enough.
If two spacers is too much stretch, you can add two spacers and remove only one cog. The swingarm should definitely be able to absorb that.
That is if the hub has room for 12 gears of course

 

[Cuz Vinny]

Glad it worked out
There should also be a little play in the swingarm, so you could try adding the spacers without removing the two small cogs and see if you can spread the swingarm enough.
If two spacers is too much stretch, you can add two spacers and remove only one cog. The swingarm should definitely be able to absorb that.
That is if the hub has room for 12 gears of course

It’s a ten speed hub. Losing two cogs isn’t a big deal for me. I’m using an XT cassette so it has individual cogs so I can play around and see which ones I want to remove. Might try two middle gears instead of the first two and see how that works out.

 

[Jon A]

Now before anyone says anything this has nothing to do with problems with the Hydra design or the bike itself. The bike appears to be designed around a 80mm wide rim and not for super wide massive fat bike tires.

I agree with the premise this shouldn't be frame related. If the motor and wheel are centered in the bike, I'm not sure how it could be. It should be an Ultra/197mm issue which is why it has me confused. On my E06 with 4.8's (Maxxis FBR) on 80mm I didn't have any issues either with the stock adapter/chainring or the Christini FAT adapter and Raceface chainring. The stock chainring was 40T and the Raceface is 36T, in both cases bolted to the outboard side of the adapter. I only checked the stock 9 speed with the stock chainring, the Raceface/Christini combo was with Sram 12 speed.

 

[Cuz Vinny]

I agree with the premise this shouldn't be frame related. If the motor and wheel are centered in the bike, I'm not sure how it could be. It should be an Ultra/197mm issue which is why it has me confused. On my E06 with 4.8's (Maxxis FBR) on 80mm I didn't have any issues either with the stock adapter/chainring or the Christini FAT adapter and Raceface chainring. The stock chainring was 40T and the Raceface is 36T, in both cases bolted to the outboard side of the adapter. I only checked the stock 9 speed with the stock chainring, the Raceface/Christini combo was with Sram 12 speed.

Two things were wrong, one I’m using a 90mm wide wheel and I had the chainring mounted on the backside of the adapter closer to the frame. I did it this way because thats how it’s done on my regular Hydra. With an 80mm wide wheel and the chainring on the outside of the adapter all of the gears could be used no issues.

 

[Jon A]

OK, that makes sense and should make people feel better--with the chainring mounted to the outside and wheels 80mm or narrower, everything works.

As a related aside, I've thought this issue may make the relatively obscure Prime 9 drivetrain: https://boxcomponents.com/collections/prime-9-filter

particularly well suited to fatbikes and E-Fatbikes specifically. You can still have the 11-50T range, but the 50T cog is located 6mm outboard compared with Sram/Shimano 12 speeds. If I didn't already have a bunch of fat wheelsets set up for 12S Sram I may have given it a try. I still may at some point. I love 12 gears on my manual fatbike, but I certainly don't need steps so small on my E-Fat.

 

[JakEmAll]

Ok, so one of the biggest issues I’m having with my new Hydra build is chain/tire rub when going into the taller gears. My current setup is 90mm wide Nextie Tri Spokes with 26X4.8 Maxxis Colossus tires. As it sits I can only get the first four cogs on the cassette before the chain rubs the tire. I next tried a set of Sunringle 80mm wide rims with Vee Tire Apache Fatty Slicks in 26 X 4.5 and the chain rubs the tire after about the first five cogs on the cassette. Now the Fatty Slicks run large so it’s not much different in width vs the Colossus tires. I thought going with a 80mm wide wheel vs 90mm wide would help but it’s not enough.

I am determined to use the Tri Spokes as I spent a lot of money on them and they look badass. So my next attempt will be a set of Surly Edna’s 26 X 4.3 on the Nextie’s. If that doesn’t work I’m going to try a set of 26 X 3.8 tires on the Nextie’s. Hopefully that works otherwise I’ll be super pissed.

Now before anyone says anything this has nothing to do with problems with the Hydra design or the bike itself. The bike appears to be designed around a 80mm wide rim and not for super wide massive fat bike tires. I tried to stuff the widest rim and tire combo I thought would fit and it doesn’t so I’ve got no one to blame but myself for the issue I’m having.

If any of you have a Hydra Fat Bike and are running 90mm wide rims and your not having chain/tire rub issues please post what tires you are running.

They look do look amazing. The width issue is what's held me back from going 27.5 x 4+ despite being told that there's clearance on the frame. I suspect going with a smaller tire will work for you, but it'll also lower your diameter. You'll have more of a half moon shape than a bubble on a frame.

 

[Cuz Vinny]

They look do look amazing. The width issue is what's held me back from going 27.5 x 4+ despite being told that there's clearance on the frame. I suspect going with a smaller tire will work for you, but it'll also lower your diameter. You'll have more of a half moon shape than a bubble on a frame.

If I ran say, a 26X4.0 or 26X3.8 on an 80mm wide rim it would fit with room to spare. As it sits, with the 26X4.8 on a 90mm rim, I can use all the gears except the last two. For me I’ll just remove two gears from the cassette and use spacers and that will fix the problem. Someone else is running 27.5X3.8 on 80mm rims and they have no clearance issues. That just may be the perfect setup for this bike.

 

[JakEmAll]

If I ran say, a 26X4.0 or 26X3.8 on an 80mm wide rim it would fit with room to spare. As it sits, with the 26X4.8 on a 90mm rim, I can use all the gears except the last two. For me I’ll just remove two gears from the cassette and use spacers and that will fix the problem. Someone else is running 27.5X3.8 on 80mm rims and they have no clearance issues. That just may be the perfect setup for this bike.

you’d only use those two gears on the steepest of hills. I’ve only used the lowest gears a few times and that’s on trails with fairly steep incline.