need help with tyre choice

contender1

Hello all this is my first post i signed up as my head is hurting after spending about two hours reading about tyre sizes and was hoping i could get some expert help.
Right i have a kona smoke with Rigida Cyber 10 wheels.

I currently have continental city contact tyres which have done around 1500 Miles they still look in reasonable nick but i have recently started to get a few punches and in the last week i have had the tyre actually come off the wheel twice when pumped up to 50 Psi they are rated at 58 psi max and i haven't had this problem before, so i was thinking maybe its time to change the tyres and inner tubes.

My current tyre has 28 x 1.75 which i believe is the imperial measurement

it also has 47-622 which i believe is the iso measurement

and the website spec said 700 x 47c

So i think 47c is the width of the tyre in mm and 28, 700 and 622 is the diameter depending where its measured from and what unit of measurement it is measured in, but could i select a tyre with a thinner width say 700 x 38c or something similar ????? as i have found tyres at the 700 x 47 / 47-622 but it really does seem to be limiting my options as they dont seem to be the most common size.

Thanks in advance for any help

davis

Blimey. You've done a pretty good job of deciphering the arbitrary measurements that manufacturers throw at us.

Yep, you can almost certainly go for a 700x38c. At a guess you can probably get down to 35c, but measure your internal wheel rim width with a micrometer or similar. Then have a look at http://sheldonbrown.com/tire-sizing.html, scroll down to the red/green chart (about 80% of the way down) and see what you can fit.

Tyres shouldn't pop off the rims, though. Ever. Are you sure your wheels are true (not bent)? Also, I reckon tyres should last much longer than ~1500 miles. I think I got about 12000 miles out of a pair (they outlasted two sets of wheels, and the bike) but that's pretty rare.

bails87

I had a pair of Conti Gatorskins on my road bike/commuter for ~3000 miles without any punctures or 'falling off'.

But yes, you could go down to a 700x35, or even smaller. I've got 25mm tyres on a 19mm rim without any problems.

contender1

Thanks for the reply guys i'll check the sheldon brown website and see what i can go down to.

The tyres were guaranteed for a year not to get a puncture and fair play i didnt get a single puncture in the first year i ride at least four miles everyday so i thought that was good but since the year has been up i've probably had about 5 punctures altogether which i thought was odd as there is plenty of tred left.

I took the tyre off yesterday and flipped it 180 degrees so that the little arrow goes the same way as the wheel rotates not that it should make any difference but i think that is how they were last time they were on i must have made a mistake last time i refitted them.

I wonder if there could be a bulge or something in the inner tube causing the tyre to come off mind you it stayed on allright today will have to wait and see, problem is im too paranoid to venture too far from home now untill i know this problem is fixed.

The Rookie

I bought my tyres half worn (for a fiver - yeh!) and they have done over 1600miles commuting since, rear tyre is getting a bit worn, front is just fine.

Simon

desweller

If the bead is coming out of the wheel rim then you should check your braking surfaces to make sure they're still parallel. If they've become dished then the rim is scrap I'm afraid.

Blue Meanie

Take some care/time refitting tyres/tubes, rears wear out faster so maybe swap front to rear. Tyres popping off is bad and scary when it happens, normally means a long walk home or you've wrecked the bead because of frequent use of a tyre lever.
Simple answer is new tubes and new tyres, but if your rim's splayed from use then it's new wheel time.
Or learn how to remove/refit tyres without tyre levers, it's not about strength, it's a technique thing and it saves the bead.
Even to an 'untrained eye' a damaged bead will pop off at recommend pressure.

Gussio

Blue Meanie wrote:

Take some care/time refitting tyres/tubes, rears wear out faster so maybe swap front to rear.

What is the view on swapping tyres from the back to the front? I've always been wary of doing this, because a front puncture can be so much more catastrophic than a rear one.

The Rookie

If the tyre is worn out, it's worn out, do it before the rear is toast and you'll delay having to change it for a while.

Simon

desweller

Gussio wrote:

Blue Meanie wrote:

Take some care/time refitting tyres/tubes, rears wear out faster so maybe swap front to rear.

What is the view on swapping tyres from the back to the front? I've always been wary of doing this, because a front puncture can be so much more catastrophic than a rear one.

I put the front tyre on the back, new tyre on the front and throw the old rear tyre away (unless I have a use for it).