Chain rubbin on the wheel

GoldenMotor.com

Sherriftom87

New Member
May 16, 2012
12
0
0
CT
OK, so, im at a bit of a dead end. got a cranbrook the other day. The chain rubs the rear wheel. I cannot for the life of me figure out how to fix it. Ive searched the forum and havent found anything. This is the second bike Ive bought in 2 weeks because of mechanical issues(combined 3! weeks of this nightmare). i got the cranbrook because of the supposed ease of use. It is beyond brutally frustrating and if I have to take that god damned rear sproket off again ill be selling everything or smashing it with a sledge hammer. If anybody could give me ANY advice or tips or help I would be indebted to you.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
Can I lend you a 10 pound sledge and a digital camera? ;)

There are a lot of ways to over come the problem, and the only one easier and more effective that the ten pound sledge is to get skinnier tires.

You can offset the sprocket (chain won't line up)
Dish the wheel. (makes the bike ride funny, and takes awhile)
Try all manner of other frame bendings ect. (won't work).

Now if you do smash the bike, please, post pictures.
 

locell

Member
Jan 16, 2010
215
0
16
mesa
How are you putting on the back sprocket? If you look closely you will see it it not the same on both sides, mounting it one way will push the chain a little further out and the other way will push it in twards the tire.

Also, you can use the chain tensioner to position the chain

you could also run a skinnier back tire
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
How are you putting on the back sprocket? If you look closely you will see it it not the same on both sides, mounting it one way will push the chain a little further out and the other way will push it in twards the tire.

Also, you can use the chain tensioner to position the chain
Both of those suggestions can make the chain run out of line, which is way worse than the tire rubbing the chain.
 

Sherriftom87

New Member
May 16, 2012
12
0
0
CT
So if the chain is rubbing Im not gonna have a blow out? If not than awesome. I could go with a skinnier wheel, I have one, but that rear sprocket is the bane of my existence. If I switch the the sprocket around it'll hit the frame. But if its not that big of a deal for now ill just let it hit the wheel I do not care how white the walls are. I promise there will be pictures if it has to go that far.
 

locell

Member
Jan 16, 2010
215
0
16
mesa
Both of those suggestions can make the chain run out of line, which is way worse than the tire rubbing the chain.
Correct, it has to be perfectly aligned or you are ****ed when you pick up any speed/torque the way I test it is if it can roll backards AND forward its good. I use the tensioner as a fine-tune as well, it can lean in or out a hair and make a big difference on clearance. Im still curious on how he is mounting the back sprocket. On a cranbrook either way should work. Also is it the stock chain that comes with the kit? those are skinny and the #41 chains and **** are wider so they have more tendency to rub.
.cs.
 

Sherriftom87

New Member
May 16, 2012
12
0
0
CT
It's the chain that came with the kit. Got the kit from pirate cycles. Alignment is not an issue, only the chain hitting the tire. The rear sprocket is mounted so the chain is closer to the wheel. If I put it the other way it hits the frame and causes poor alignment. I like the wide look of the tire and really don't want to have to switch the sprocket to my other wheel for the 100th time.
 

locell

Member
Jan 16, 2010
215
0
16
mesa
.wee.
It's the chain that came with the kit. Got the kit from pirate cycles. Alignment is not an issue, only the chain hitting the tire. The rear sprocket is mounted so the chain is closer to the wheel. If I put it the other way it hits the frame and causes poor alignment. I like the wide look of the tire and really don't want to have to switch the sprocket to my other wheel for the 100th time.

Unless im understanding this wrong, you dont need to change the wheel or sprocket, just the tire.

.wee.
 

locell

Member
Jan 16, 2010
215
0
16
mesa
Would a tire 2.0 fit on the wheel of one with a 2.125?
Depends on your rim width - try it. It has to be easier than smashing the whole thing with a sledgehammer or ****ing with that sprocket. Some mid-sided rims are compatable with both sized tires.

My personal fix would be spreading the back axel width of the frame and adding a washer to the axel, and then flipping the sprocket over if needed.

The tolerances of the cranbrook vary wildly depending on a plethora of factors, they make the tolerances of "china girl" engines NASA compliant

http://motorbicycling.com/attachment.php?attachmentid=26206&d=1277785571

laff
 

Nashville Kat

Well-Known Member
Apr 20, 2009
1,503
55
48
Jacksonville, Florida
Pay no attention to these naysayers- this problem can probably be solved in several ways!

Yes- you CAN change the tires- any 26" with a DECIMAL number (as opposed to a Fraction) will fit. 2.25. 2.00 1.75 1.50 (NOT 1 3/8 or 1 1/2- Fractions)

I always recommend narrow tires myself- better roll, less vibration on the pavement, but you have to use good street tread or smooth- knobbys vibrate
Give your little motor as much advantage from narrow tires as you are comfortable with- unless you're really into a lot of rough riding- potholes or off road.


Yes- make sure the sprocket is dished AWAY from the frame and toward the spokes

I'm assuming you have a coaster brake- I haven't read this thread much yet- but you may at some point want to consider a freewheel wheel with handbrakes-

or there are expensive adapters here that work better than a ragjoint- still your problems are not insurmountable with the standard stuff- pictures would help us help you.
 

Nashville Kat

Well-Known Member
Apr 20, 2009
1,503
55
48
Jacksonville, Florida
Also -one moire BASIC thing to check- Is the MOTOR on straight- sight line it froim front and back- there should be equal amount of motor around the seat tube.

A motor not sitting straight can cause this-
Is the Wheel itself alligned- you've probably checked that by now.

It sounds like something OTHER than the kit or motor- Lots of people here use this bike and report no special problems with a China Girl 2 cycle kit.
 
Last edited:

Nashville Kat

Well-Known Member
Apr 20, 2009
1,503
55
48
Jacksonville, Florida
The OP says he doesn't like the skinny look-
but I mnyself would reccommend 1.75 or 1.5-

If I was still riding 26" Id probably use 1.5, and maybe even 1.25 on the front- but I'm just a city street ridin guy.

I have 700c wheels with 28 mm tires 91 1/8) on my 50cc
and 27 x 1 1/4 wheels on my 66 cc.

They pedal great and really roll with the motor- I can kill the motor and coast 2 or 3 blocks and do- all the time- I'd still just bike ride mostly if I weren't old and stiff.
 

locell

Member
Jan 16, 2010
215
0
16
mesa
Also -one moire BASIC thing to check- Is the MOTOR on straight- sight line it froim front and back- there should be equal amount of motor around the seat tube.

A motor not sitting straight can cause this-
Is the Wheel itself alligned- you've probably checked that by now.

It sounds like something OTHER than the kit or motor- Lots of people here use this bike and report no special problems with a China Girl 2 cycle kit.
I was looking at this huffy cranbrook that was bought a few years ago and one that was just recently bought and it uses some different components, the tubing is a different gauge, and there are other slight differences. Just sayin that a "cranbrook" may not be a "cranbrook". A half a bit off on the frame and a half a bit off something else is a whole bit off - with a skinny stock chain it for sure it cant be a bit off, it has to be "spot on"

.bf.
 
Last edited:

NoLicen0

New Member
Jul 1, 2012
12
2
0
Byron Bay
I Snapped a few cog keys in my gearbox , using wide knobbies, until i got the right combination of spacers for cog/tyre/tensioner positioning-chain torque