pedal bike question

Originally Posted by jim@55

its a diamond back overdrive ,

Sure it's not a diamondback override? It's a hybrid bike and its a 28 inch wheel.

Anything MTB and I'm your man jimbo - was competing up until last year.

[northwind]

Have you considered measuring it?

700c is the size you want. Basically there are two wheel sizes around, 26" which is used on most mountain bikes and 700c which is used on most road bikes. But don't try measuring them, that'll only confuse the matter! Sounds like you've either got a very unusual mountain bike or a hybrid.

Make sure you get the correct width as well. Standard mountain bike tire sizes over here are 26X1.95 inches. You'll want to stick pretty close to that or you'll risk damaging the inner tube.

well ive got tyres bought via e-bay(700*28 shwalbe blizzard kinda slicks thingy err,,,is it obv i know nothing about bikes??)and the question now is....will the inner tubes have to b changed at the same time to match the tyres ??tyres are as said-700*28- and the existing tyres are on original tubes -prob to match the same size ie 45...the existing tubes have a weird type of valve ,,its not a schrader valve ,its a narrow thing the kinda valve iv seen on a fancy road bike..the tubes are ok ,but ill change them if need be

Sounds like you have a presta valve. You can buy a pump that will switch from schrader to presta pretty easily. I prefer presta valves on my bike just because they are easier to get the pump attatched. They also will not release air if simply pressed like a schrader valve.

Not sure if there's a real price difference in buying a presta over a schrader...obviously not enough to make a difference to me when buying them.

As far as the inner tubes go, as long as the new tyre is similar is size to the old ones you shouldn't have to change them out. Just be careful not to pinch the tube when putting your new tyres on.

the 'old' tyres are 700*45c,and the new ones im gtng are 700*28c,theyre prob a bit narrower but thats ok ,the rims are fairly narrow (about 1+1/2 i think )but the tyres that are on it just now (oe i may add)are at a guess about3---3+1/2,so they look oversize already ,so i guess a narrower tyre should b ok ,and i guess the only way of knowing if the inner tube is ok for it is to try it ..(if its too big is it not the done thing to just stuff it in and pump away??)and yeah iv heard that 'presta/presto valve thing mentioned,so i take it their ok then??if its all good i can just leave them b

Originally Posted by jim@55

.and yeah iv heard that 'presta/presto valve thing mentioned,so i take it their ok then??if its all good i can just leave them b

Like I said, I have presta valves on my mountain bike it costs $1800 USD new so they must be good. My tires are also 2.3 inches wide, which is much wider than normal as well as some oversized inner tubes. (my bike is a giant reign 3, great bike recommend it to any serious mtn biker looking for perfect full suspension)

The inner tubes might have the width of tyres they're suitable for marked on them if you have a look. If not try them and see, but it could be that you need new tubes as the difference between a 28 and a 45 is quite big. Presta valves are fine if you've got a pump that is compatible with them, but are a bit more fiddly to pump up. They're narrower than schrader valves (car type) so if you do want to switch tubes to schrader check the valves will fit in your wheels first.