Ultra 1000 stock fat tire rubbing on right chainstay

Bikeyearround

New Member
Super excited to get my first Ebike, the Biktrix Juggernaut Ultra 1000.
Took it for my first right at night, I could not wait! It was making a weird squeaking sound. Thought is was the front fender but I couldn't find any area that was rubbing. Got back to the light of the garage and saw that the rear tire was rubbing so bad the writing on the tire had been rubbed off and there were rubber shavings all over the wheel and drive train. On a non-ebike I would have noticed this immediate with trying to ride as the rear wheel does not spin freely. The wheel is close to true and rubs on the right chainstay for the complete revolution of the wheel.
Customer service was initially very responsive. They asked me to send pictures of the rear hub. They reviewed the photos I sent and they responded: "It doesn't look like there are any washers between the hub and the frame. There should be 2-3 washers on both sides of the hub. Are those present? " I informed them there was one washer on the left side and none on the right two days ago, but haven't heard another response.
For now I'm stuck with a $3500 awesome bike that I can't ride without the rear tire shaving away. I'm starting to question if this frame might not really accommodate fat tires properly. Waiting on customer service to tell me what to do.
Is is really possible that the design of the frame requires "2-3 washers on each side of the hub" to accommodate a fat tire?
I've attached the link to pictures of the rear hub Biktrix requested I send them.
https://photos.app.goo.gl/WLb33rpE1wzM6fK38
 

smorgasbord

Active Member
The last two pictures seem to show that the tire isn't centered between the frame. I don't think it's a hub/spacer problem at all. You do need to loosen the hub nuts and then center the tire so it isn't rubbing. BTW, it looks like clearance is really tight there.

Also, you may need to readjust the brakes on the rotors after centering the tire in the frame - but may not. Check it in any case.
 

FlatSix911

Active Member
What tire pressure are you running on the rear?

Very high pressure can actually increase the tire diameter a fair amount.
 

TForan

Well-Known Member
Something is way off. I just checked mine and there is plenty of clearance on both sides.
 

FlatSix911

Active Member
Something is way off. I just checked mine and there is plenty of clearance on both sides.
Super excited to get my first Ebike, the Biktrix Juggernaut Ultra 1000.
Took it for my first right at night, I could not wait! It was making a weird squeaking sound. Thought is was the front fender but I couldn't find any area that was rubbing. Got back to the light of the garage and saw that the rear tire was rubbing so bad the writing on the tire had been rubbed off and there were rubber shavings all over the wheel and drive train. On a non-ebike I would have noticed this immediately with trying to ride as the rear wheel does not spin freely. The wheel is close to true and rubs on the right chainstay for the complete revolution of the wheel.

Customer service was initially very responsive. They asked me to send pictures of the rear hub. They reviewed the photos I sent and they responded: "It doesn't look like there are any washers between the hub and the frame. There should be 2-3 washers on both sides of the hub. Are those present? " I informed them there was one washer on the left side and none on the right two days ago, but haven't heard another response.
For now I'm stuck with a $3500 awesome bike that I can't ride without the rear tire shaving away. I'm starting to question if this frame might not really accommodate fat tires properly. Waiting on customer service to tell me what to do. Is it really possible that the design of the frame requires "2-3 washers on each side of the hub" to accommodate a fat tire? I've attached the link to pictures of the rear hub Biktrix requested I send them. https://photos.app.goo.gl/WLb33rpE1wzM6fK38

I agree that something is not right here... you should have far more clearance on chainstays.

Can you take another photo from the side to show how the rear wheel axle seats in the frame?

I doubt that a few a hub washers will make much of a difference in the frame clearance... a smaller tire may be required.

1566618974814.png
1566618933833.png
 
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mbouck

Member
What's the info on the tire they have mounted on the rear? Can you post a photo of the sidewall showing the brand/model/dimensions, etc.? From the photos it looks like there's a couple of millimeters clearance available between the chain stays. It almost seems like they have a too large tire mounted.
 

roshan

Active Member
I agree that something is not right here... you should have far more clearance on chainstays.

Can you take another photo from the side to show how the rear wheel axle seats in the frame?

I doubt that a few a hub washers will make much of a difference in the frame clearance... a smaller tire may be required.

View attachment 37070 View attachment 37069
Take the wheel out and reinstall it. While you're at it, could you check if the tire is seated correctly? Also, are you sure you only have 15psi in there? The clearance on the frame should be at least 1.5mm on each side.
 

smorgasbord

Active Member
Looking at the photos, the tire seems seated properly on the rims, and it doesn't protrude more than usual beyond them.

1.5mm is only 1/16" for us US folks. That seems REALLY small. Maybe this frame is better with 27.5" PLUS size tires?
 

mbouck

Member
Looking at the photos, the tire seems seated properly on the rims, and it doesn't protrude more than usual beyond them.

1.5mm is only 1/16" for us US folks. That seems REALLY small. Maybe this frame is better with 27.5" PLUS size tires?
I agree - I think the 27.5" and 29" wheels are much more appropriate to this chain stay width. I wouldn't want to run anything with less than 5mm clearance on both sides.
 

Bikeyearround

New Member
Take the wheel out and reinstall it. While you're at it, could you check if the tire is seated correctly? Also, are you sure you only have 15psi in there? The clearance on the frame should be at least 1.5mm on each side.
So I took the axle out. Removed the wheel and moved the one washer from the left side of the wheel to the right side of the wheel. Doing this centered the wheel better between the chainstays of the frame. Airing the tire down to 10 psi allows enough clearance for the wheel to spin. I will take more photos, but I don't think there is even a millimeter of clearance on either side.
 

smorgasbord

Active Member
I'm going to go out here on a limb and suggest that you have a bent frame (rear triangle).

Here's the rear view, with a yellow annotation:
1566685860274.png


And here's the side view. If you look at the reflections there appears to be a "disturbance" around the same area.

1566685915942.png


This might be damage from shipping.

Of course, trying to analyze this from a couple online photos, I could be completely and totally wrong.
 
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TForan

Well-Known Member
It looks bent to me. I can take a picture of mine , which has around an inch on both side but mine is the older design and I don't know if they are different. What a pain with a new bike !
 

Feliz

Well-Known Member
😲 that just isn't right, 1/2" or 12 mm should be the minimum, come on Roshan, step up to the plate.
 

Bikeyearround

New Member
I'm going to go out here on a limb and suggest that you have a bent frame (rear triangle).

Here's the rear view, with a yellow annotation:
View attachment 37101

And here's the side view. If you look at the reflections there appears to be a "disturbance" around the same area.

View attachment 37102

This might be damage from shipping.

Of course, trying to analyze this from a couple online photos, I could be completely and totally wrong.
Yes the frame does have a bend in it on the chain stay but the bend is symmetrical on both sides. So it appears to be a design of the frame and not something from damage in shipping. It just doesn't look like this design can fit the wide fat tires. When looking at from above both sides of the frame are bent in the same amount.
 

roshan

Active Member
Yes the frame does have a bend in it on the chain stay but the bend is symmetrical on both sides. So it appears to be a design of the frame and not something from damage in shipping. It just doesn't look like this design can fit the wide fat tires. When looking at from above both sides of the frame are bent in the same amount.
I'll check at our other bikes and get back to you on Monday. Since we designed this frame to accommodate 27.5/29 plus and 26x4, we made tolerances tight. But this looks almost too tight. Will get back to you on Monday. Apologies for your inconvenience.
 

Bikeyearround

New Member
I have attached some photos to show the current
it still looks bent to me. Mine is nothing like that.
I have attached some photos to show the currents chainstay design of the frame. with 5 PSI I have good enough clearance to ride the bike. I would love the ability to run a higher PSI for the road. I'm a little confused why they chose to have the chainstays bent in. This does not accommodate fat tires. This clearly looks like it is designed for much skinnier tires.
 

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