I'm going to remove the rear wheel from my Cota 247. I have a flat tire and I want to check the wheel and the rim. 

Any tips how to do it correctly? Do I need to release the rear brake? Do I need to take the chain off?  Do I need to mark any position of the wheel? 

Any help will be appreciated. I never done it before. 

 

Also- the previous owner told me it's a tube rear tire, but the tire (Dunlop D803 says tubeless) Could be it's a tubeless tire with add tube inside?

Thanks. 

 

Edited September 27, 20214 yr by Niro

Wow thats some rear brake return spring set up.

Now that you mentioned it.. I looked online on photos and looked at the parts manual and it looks very very odd.

Makes me think this is definitely not the original return spring. Now I'm wonder if this is the original brake cover or not. According to the parts manual, probably not..

It's normal to release the brakes to take the brake plate out of the hub.

You don't have to take the chain off the bike but do need to take the chain off the rear sprocket. After you undo the axle nut and the brake link, slide the axle forwards to slacken off the chain tension and it will usually come off the sprocket.

I see at least one missing rear wheel spoke.

Yes it's common to fit a tube in a tubeless tyre. That rim/tyre combination won't hold air pressure without a tube.

You will need to set the wheel alignment and chain tension when you put it back together. You can make a mark if you want, but are you sure it is set right at the moment?

That dodgy-looking brake return arrangement is to stop the brake sticking on so you may find that there are problems inside the brake hub that are causing it to stick on (missing/wrong spring, worn linings, worn brake drum). Looks like someone has extended the length of that brake arm too.

Brake arm on upside down.

 

I appreciate the information!

Is the part arrowed in the photo is the wheel alignment? I'm not sure the wheel is aligned. When you spin the wheel, when the bike on the stand, you hear for a moment that the wheel is softly grinding the chain guard. 

I'm planning to re- spoke the wheel. The spokes are very rusty. 

 

Edited September 28, 20214 yr by Niro

Quite likely that there's bit of a ding in the wheel causing it to rub the chain guard at some points (or tyre is mounted without being square on the rim). Not unusual. Can always tweak the chain guard a bit after checking.

Yes. The arrowed part is the chain/wheel alignment device.

It acts as a cam, rotating about the spindle and bearing against a peg just forward of the wheel axle.

The position should be the same on both sides.

Judging by the postion of the cams, it looks like either the chain is badly adjusted, or more likely the chain and both sprockets are worn out.

Photograph below is from my later 248 model, but the same principle. Note the notches in the outer diameter. 

This is the position with brand new chain and sprockets.

 

I see.. So it's should point downward? 

How can one tell if the chain and sprockets are worn out?