HELP! New tyres not round / deformed?

[Mike!]

Today i got some Schwalbe City Jet to replace the knobbly's on my mountain bike (with new tubes)

Now fitting them but neither of them seem to sit properly on the rim, i don't have enough sidewall showing in places which means the whole tyre is not perfectly round and doesn't run true.

It's almost as if the tyres themsleves have been squashed and are not round (or flattened sidewalls or something).

I have tried reseating but it doesn't seem to help?

Is this a common thing or do i have a duff set of tyres

 

[Globalti]

Have you got a track pump? Pump them up to the maximum presure recommended on the sidewall. If that doesn't work, deflate and take them off, sprinkle with talc, rub all over and refit then pump up hard. Talc is the perfect dry lubricant for rubber.

 

[Mike!]

I have a Top Peak Master Blaster G (Mini) so i do have a gauge. Have been up to 80psi with one of them and it didn't seem to make any difference.

So are they just not being seated right when pumping up do you think?

 

[RecordAceFromNew]

Just in case, before pumping could you please tell us what are the old and new tyre size specs, and what is inner width of the rim (between the lips, see the drawing in this).

 

[Gerry Attrick]

Globalti is right. Always sprinkle talc on the tyre beads before fitting. It eases fitting and helps centre the tyre on the rim.

 

[02GF74]

that happens sometimes - I have some WTB tyres and specialized tyres that not only run a bit oval but have side to side wobbles as they cannot be centred - you can see the centre of the tyre move from side to side as the wheel is spun and go in and out.

These are mountain bike tyres and offroad I cannot feel them but do feel the bump on smooth tarmac.,

wierdly the schwalbe replacements I got - black jack I think - are perfectly round - yet are much cheaper than the ones I mentioned.

you can spend ages trying to tug the tyre into shape but to no avail.

 

[Mike!]

Have you got a track pump? Pump them up to the maximum presure recommended on the sidewall. If that doesn't work, deflate and take them off, sprinkle with talc, rub all over and refit then pump up hard. Talc is the perfect dry lubricant for rubber.

Well i don't have any talc (will be on my shopping list!) but just tried a small amount of washing up liquid around the edges and that seem to have doe the trick with the front wheel.

Now for the back but so far so good so thanks very much!

 

[02GF74]

hmmmmm, interesting - never tried the talc or washing up liquid ...... but pretty sure tht wouldn;t have helped with my specilaised tubeless tyres, ..... but may give it a go some time.

 

[Gerry Attrick]

I don't recommend washing up liquid, it contains salt and will corrode rims.

 

[Mike!]

Both tyres are on and nicely centered, many thanks again for the help.

All ready for my first ride into work tomorrow, i've just been for a quick test ride and i couldn't beleive the difference - it's like another bike all together!! Much quicker, smoother and quieter without that rumble of knobbly tires.

 

[rh100]

I had the same problem with Panaracer tyres on my MTB. Took them back to the shop complete with the wheels where they fitted them for me, took the poor guy nearly an hour He reckoned it was down to the wheels not being the highest quality.

Had to refit them several times myself afterwards, first time I used washing up liquid which leaves a sticky mess next time you have them off. Then I used talc which worked much better - to the point I started carrying a small tub in the pannier bag incase of roadside repairs.

On the side of the tyre - there is what Sheldon Brown calls the witness line, a narrow line that runs around the edge near the wheel rim, it should be equally spaced all the way around, if not fitted correctly you will see it dip into the rim. Sometimes lowering the pressure to about half way so its soft and massaging the tyre into place helps, then pump back to full pressure.

Most tires have a "witness line" moulded into each sidewall. This is a narrow ridge of rubber running around the side of the tire, just outside of the rim. Spinning the wheel and observing the witness line will help you locate the place where the seating might be off. Note, it could be OK on one side of the tire but not the other.

http://sheldonbrown.com/flats.html

 

[Globalti]

In the past I've had some success with almost deflating the tyres then rolling the bike along for a few yards.

People wouldn't use washing up liquid if they knew how much salt was in the formulation as a thickener. Anyway, what does it do to your brakes?

Talc every time.

 

[Mike!]

People wouldn't use washing up liquid if they knew how much salt was in the formulation as a thickener. Anyway, what does it do to your brakes?

Talc every time.

What brakes?