confused by measurements tyres and tubes

[beatmeoutame]

Hi im having problems with my back bicycle wheel. I have recently acquired a raleigh criterium racing bike.First racing type bike i've owned. Bought a track stand to inflate my tyres with and inflated the back one to the recommended 80psi.

Cycled up my street and it popped. during this short time cycling i noticed the tyre rubbing on the brakes and noticed that the tyre had bulged and slipped off the rim, so I came to the conclusion that the brakes must have popped the tyre as the wheel went round.

Bought a new tube : Specialized presta tube 700x20/28c 27x3/4" - 1 1/8"

my wheel rim is Rigida steel rim: 18x622 28x15/8

the tyre which is on is Schwalbe Stelvio: 25-622 28x1-700 x 25c HS350

I fitted the new tube but everytime I inflate it pushes the tyre over the rim, even when i inflate to 15 psi and check its all sitting correctly.

Should the tyre be 18x622? Im not sure what all of the numbers on each piece mean either. The front wheel has the same type of tyre as the back. Im guessing I have just bought the wrong tube and should get a tube with 18-622

Any help will be much appreciated, I just wanna get out and ride the thing

 

[e-rider]

the tube is not the problem, the old tyre and wheel are!

old steel rims are well known for letting the tyre slip off, especially if it has a flat spot.

Is the tyre fairly new?

Make sure you 'seat' the tyre properly before inflating.

If the tyre size is 700x25 then a 700x20-28 will be the perfect match! It basically means that the tube can be used for any tyre size from 700x20 to 700x28. The 700 is the wheel size (which obviously doesn't change) and the 20 is the width of the tyre in mm ; you can choose to some extent what width tyres you want to fit, within limits of the rim width.

 

[ian turner]

Tsk look again.
The wheel is an 18-622 which is 700-18 so the tyres are too big including the one that was on when the OP was sold it
Possibly.

 

[beatmeoutame]

the tube is not the problem, the old tyre and wheel are!

old steel rims are well known for letting the tyre slip off, especially if it has a flat spot.

Is the tyre fairly new?

Make sure you 'seat' the tyre properly before inflating.

If the tyre size is 700x25 then a 700x20-28 will be the perfect match! It basically means that the tube can be used for any tyre size from 700x20 to 700x28. The 700 is the wheel size (which obviously doesn't change) and the 20 is the width of the tyre in mm ; you can choose to some extent what width tyres you want to fit, within limits of the rim width.

Thanks for your reply,

The tyre looks new to me it is hardly worn at all. I was making sure to try and get the tyre seated properly before fully inflating it.

do you think some better rims are in order? i've not got much money spare for these may look on freecycle or ebay or something

 

[beatmeoutame]

Tsk look again.
The wheel is an 18-622 which is 700-18 so the tyres are too big including the one that was on when the OP was sold it

thanks

oh really? so both tyres are slightly too big for the wheels? aah

but that means i will need to replace the tyres and they look almost brand new

 

[ian turner]

thanks

oh really? so both tyres are slightly too big for the wheels? aah

but that means i will need to replace the tyres and they look almost brand new

My lack of knowledge may be showing as 25 seems to be the upper limit for an 18 wheel.

 

[beatmeoutame]

My lack of knowledge may be showing as 25 seems to be the upper limit for an 18 wheel.

ok

but because its at the upper limit combined with the old steel wheel then this could explain why the tyre is coming off the rim hm

thanks

 

[ian turner]

ok

but because its at the upper limit combined with the old steel wheel then this could explain why the tyre is coming off the rim hm

thanks

See http://www.sheldonbrown.com/tire_sizing.html#width which actually suggests that they are too small or at least borderline as 17s manages 25s and 19s don't and yours is 18/19 by the looks of it.
Someone more knowledgable will be along in a bit

 

[e-rider]

my mtb rims are 17mm and they take huge 2.3inch tyres (60mm).

I'd say the rim width shouldn't be a problem

It's all in the bead seat diameter - if that is the same then it will be fine.

 

[HJ]

See http://www.sheldonbr...zing.html#width which actually suggests that they are too small or at least borderline as 17s manages 25s and 19s don't and yours is 18/19 by the looks of it.
Someone more knowledgable will be along in a bit

Someone more knowledgeable than Sheldon Brown?

 

[beatmeoutame]

Someone more knowledgeable than Sheldon Brown?

yea looking at the table of measures does help but i think i may need to buy new rims

 

[HLaB]

yea looking at the table of measures does help but i think i may need to buy new rims

Would a new 28mm tyre not be cheaper

 

[beatmeoutame]

Would a new 28mm tyre not be cheaper

do you think bigger tyre?

the one at the mo is 25-622 should I go to 28-622?

 

[e-rider]

don't listen to HLaB - you would need to get narrower tyres, but I still think your 700x25 will fit.

 

[e-rider]

and replacing the rims is not an easy task (for a novice) and would cost more than buying new wheels