Tony N.

I have a 2 year old Mongoose that I purchased at Wally Mart for a camping bike. It has 28x1.75 tires on it that also says 700x45. Is that the same size or what should I purchase as replacement tires/tubes. Also the wheels seem to be just crap and the rear brake will not slide the tire no matter how tight so been thinking that since I use it mostly as a town/camping bike (ride it a lot more than I thought) I might upgrade the wheels and add an extracycle to it for utility so what do you all think? Should I replace the wheels with and the rear cantilever? What about disc brakes for the rear?
Tony

LarDasse74

See the Sheldonbrown.com article on tire sizes. Most 28" designations are the same rim size as 700C and tires can be used interchangeably. 700 X 32, 700 X35, 700 X 40, whatever, they will all work fine.

THere are many factors affecting brake performance. Unless you have steel rims, simply changing wheels will not do much. If you do have chromed-steel rims, then changing the wheels will help a whole lot.
First, though, make sure all your cables are running smooth. What type of brakes are they?
Also try replacing brake pads with a decent aftermarket set.

Swapping to disc brakes is generally expensive if a bike did not come prepared for the addition of discs with compatible hubs and frame.
Also, do you already have front disc brakes? I ask because if you are only adding one set of brakes, it should be in the front as this is where most of your braking should be done.

JanMM

That size tire is not spoken of as 28" in much of the US - 700 is the term commonly used. The other designation for that specific tire size is 622-45. Again, few folks speak of 622 tires/wheels.
622/45 = 28" x 1.75" = 700 x 45 (more or less) Refer to Sheldon as suggested above.

Tony N.

Thanks for the replies. Brakes are cantilever and the front brakes are fantastic but the rear are dogs. With the shoes so close that they rub, I can squeeze the lever all the way to the handle bar and it just does not put the pressure on the wheel needed. Can't locate the problem but it is like the cable is stretching and I know it is not.
Another question, since I'm riding it more as a town/utility/car light bike, I'm thinking about adding an xtracycle and upgrading the wheels so what do you folks suggest. If I had known how much I would be using it, I would have gotten a LBS bike but was thinking it would only be a bike that I would use while RV camping and would be exposed to all the elements. Actually I use it more as a town/commuter/shopping bike. Don't worry so much about it getting a little banged up while commutting/shopping/rain, stolen or hauling it around on the back of my rv. Bought it when my favorite Trek 800 was stolen off the back of my RV while we were eating at a Cracker Barrel. They actually removed the rear bumper and took the bikes and bike rack. :-0 That is why my camping bike is a Mongoose Wally bike. ;-/ I named it Wally. :-)

Retro Grouch 

Does the rear caliper open and close easily with your fingers? If so, that's probably not the problem. That said, I'm thinking that bike probably has ProMax brakes which I hate. If it was my bike and I was concerned about brakeing power I'd replace them with something from Avid or Shimano. They'll stay in adjustment a lot better.

Short of replacing the calipers there are a couple of intermediate steps you can take.
1. Better brake pads will almost certainly help. Kool Stop salmons are the gold standard.
2. Better cable housing will probably help too. Jagwire Ripcord housing is on the pricy side but it doesn't compress so it should improve your rear brakeing function.

phoebeisis

Remind me- what exactly does 700c stand for?
I'm guess it is the diameter of a tallish tire(1.5" tall sidewall) on a 622 rim- roughly 700mm.
So what the heck is the C?
Thanks
Charlie

Retro Grouch 

"C" is a measure of rim width - like in shoes.

Interestingly, it also affects rim diameter. If you visualize tire section as a circle, as you increase the diameter of the circle, the rim diameter has to diminish to maintain the 700mm outer tire diameter. Consequently a 700c rim has a larger diameter than a 700d rim.

motobecane69

there is nothing wrong with your rear brake. your not a 100lb kid anymore, your not supposed to be locking up your rear brake to do burnouts. rear brakes always have less stopping power and most people never even use the rear brake except when coming down the steepest of hills or when they are purposely only looking to scrub off a little bit of speed. swapping to disc will be way to expensive, you can get another entry level bike for a few hundred bucks that will come with discs std. as others mentioned, not only do y ou need a hub that you can mount a rotor too, the frame needs to have the attachment points for the caliper brazed on already, if not, then you are pretty much sol.

scroca

Rubbish.

prathmann

From your description that you can easily bottom out the rear brake lever I'd say the problem is with your brake cable housing. It's compressing when you apply the brakes and using up the cable movement that should be moving the brake arms instead. Replace it with some heavier-duty housing and you should have much better action from the rear brakes. But, as some others have mentioned, most of your braking power in a hard stop comes from the front brakes so the operation of those brakes is more critical.

Tony N.

I like to use the rear brake first and then feather the front and I'm really not into skidding the rear tire but it is real soft. I have other bikes and understand how the brakes should feel. With the brakes the way they are, it is almost like no rear brakes.
Thanks for the info and now I would like some response to the second part of my original question. Some suggestions on wheel replacement for the bike with consideration in how I'm using it and it's intended purpose.
Thanks again for all replies.
Tony

Retro Grouch 

What are you trying to accomplish?

Since you say the front brake works to your satisfaction I'm assuming you don't have chromed steel rims. If that's the case, I don't think replacing the rear wheel is warranted unless you are having an additional problem that you have yet to indicate.

Jeff Wills

Uh, no... take a look at Sheldon's page again. (Who'd have thought a dead man could be so informative?): https://sheldonbrown.com/tire-sizing.html#french

700A through 700D were all the same outside diameter tire but different widths. This means the wider tires mounted on smaller diameter rims. Over time, "700C" became the most common... but it truly doesn't define a dimension of any sort.

IanHelgesen

When you say cantilever brakes, do you mean the traditional center-pull type (https://www.sheldonbrown.com/cantilever-adjustment.html for examples)? If so, try raising the straddle cable hanger. Your problem could be caused by the brakes having too much mechanical advantage. If they're the linear-pull type, make sure your brake levers are a matched set. Using short-pull levers with linear-pull brakes could also cause your problem. Also, try replacing the pads, they could have hardened and lost their stopping power. While you shouldn't lock your brakes in practice, there is something very wrong if they don't allow you to (especially on the rear).

phoebeisis

I think you two are saying the same thing- wider taller sidewall tire- means smaller diameter rim to keep total diameter the same- Right??Wider tire SECTION means taller tire sidewall means shorter rim.
70mm(total) of tire height means 630mm of rim diameter 70+630=700
50mm(total) of tire height means 650mm of rim diameter-smaller tire bigger rim 50+ 650=700

"This means the wider tires mounted on smaller diameter rims."

"If you visualize tire section as a circle, as you increase the diameter of the circle, the rim diameter has to diminish to maintain the 700mm outer tire diameter." Consequently a 700c rim has a larger diameter than a 700d rim."

Retro Grouch 

Huh?

First he says that I'm wrong then he explains it by saying almost the exact same thing.

Jeff Wills

You said "C" is a measure of rim width. I would have said it defines the rim's diameter, which in the "French" system is dependent on the tire's section width.

frantik

i think it's better to use mostly the front, but obviously if the rear has no stopping power then it should be looked at

old single pivot side pull brakes sometime just don't have that much power

also look at cable routing.. i've noticed if the cable routing isn't perfect you can get a lot of "slop" when the housings move around as the cable tightens

garage sale GT

Try cleaning the rear braking surface with windex and flossing under the pads with a rag.

garage sale GT

Is the lever bottoming out against the grip? If so, you may need to adjust cable tension by letting out the barrel adjuster in the lever, located right where the cable enters the brake lever base and housing.