Tires don't stay on...

Valy

I've just changed the tires on my new bike - Specialized Hardrock Disk Comp 2010 to the ones I had on my other bike - the older of the two so to say.

So the rear one got inflated to about 60 out of 65 PSI just fine, but the front tire starts to bulge out of the rim at about 50PSI. I deflated it and had a look and there does seem to be a bit more out than the rest of the tire but the edges are still inside the rim.

I pulled tha valve through as far as it would go without having to use too much force but there is still a bit more distance from the rim compared to the rest.

Any suggestions?

nicklouse

sounds like you have not seated them correctly.

pics will help.

Valy

nicklouse wrote:

sounds like you have not seated them correctly.

pics will help.

I went around a few times squeezing them and there does not seem to be much different than before - I did inflate them after that and got the same result... Might get pics soon.

EDIT: Went around a few times and pressed the tire in and... WOOHOOO - it fit on and it now at about 63 PSI or so.

Went a few times up and down the street and there is a difference as the "stock" ones are like parachutes on tarmac.

now here is the next question - could some deformation to the rim have been caused by the tires slipping out like that? (I am like this about things... :oops:)

Shorty12

no

warrerj

What tyres are yo runnign at 60psi ???

Thats sounds WAY to high. I'm 14 st and run mine at 35 psi

Valy

Shorty12 wrote:

no

warrerj wrote:

What tyres are yo runnign at 60psi ???

Thats sounds WAY to high. I'm 14 st and run mine at 35 psi

Well it is not *that* high. For the road and paths it is alright and the higher the better really -it's only when you get to some really rough stuff when you want to actually decrease the pressures to 40-50 PSI. It would also depend on the tire of course.

Northwind

Valy wrote:

Well it is not *that* high. For the road and paths it is alright and the higher the better really -it's only when you get to some really rough stuff when you want to actually decrease the pressures to 40-50 PSI. It would also depend on the tire of course.

That's still pretty high for any sort of offroad never mind really rough stuff, 25-35 would be better with most tyres and average weight riders. Though YMMV of course. MTB tyres tend not to roll all that fast with high pressures on tarmac, and offroad it can sometimes make them slower- nevegals frinstance are slower on tarmac at 60 than they are at 40.

Valy

Northwind wrote:

Valy wrote:

Well it is not *that* high. For the road and paths it is alright and the higher the better really -it's only when you get to some really rough stuff when you want to actually decrease the pressures to 40-50 PSI. It would also depend on the tire of course.

That's still pretty high for any sort of offroad never mind really rough stuff, 25-35 would be better with most tyres and average weight riders. Though YMMV of course. MTB tyres tend not to roll all that fast with high pressures on tarmac, and offroad it can sometimes make them slower- nevegals frinstance are slower on tarmac at 60 than they are at 40.

I see... a bit odd about lower pressures being faster - at least in your example. I just don't ride too much off road if you will. I mainly ride on paths which are fairly smooth and lately I have been riding a lot on the road due to the snow.

prawny

I only put 40-45 psi in my MTB tyres if I'm going on the road with it. Im my teens I'd be lucky if I had 30 psi in them, never had any pich issues and I've always been 13st+

Dirtydog11

Valy wrote:

Northwind wrote:

Valy wrote:

Well it is not *that* high. For the road and paths it is alright and the higher the better really -it's only when you get to some really rough stuff when you want to actually decrease the pressures to 40-50 PSI. It would also depend on the tire of course.

That's still pretty high for any sort of offroad never mind really rough stuff, 25-35 would be better with most tyres and average weight riders. Though YMMV of course. MTB tyres tend not to roll all that fast with high pressures on tarmac, and offroad it can sometimes make them slower- nevegals frinstance are slower on tarmac at 60 than they are at 40.

I see... a bit odd about lower pressures being faster - at least in your example. I just don't ride too much off road if you will. I mainly ride on paths which are fairly smooth and lately I have been riding a lot on the road due to the snow.

Do yourself a favour read this

http://www.schwalbe.co.uk/shopdata/file ... fo2-GB.pdf

Especially the bit on rolling resistance.

joshtp

i run 24 psi in my back tyre on a HT! if im doing a lond road ride.... i go up to a whoping 35 psi.

cycleNoodle

you may have previously damaged your rim or there could be a fault in the bead of the tyre..

Valy

DD - I see, though the paths I ride on are quite smooth and there aren't many stones or pebbles in the way.

CN - The rims don't seem to be damaged nor do I recall them being damaged. Besides the tire stays on now. :P

But damn - some really low pressures you people have.

Northwind

Valy wrote:

I see... a bit odd about lower pressures being faster - at least in your example. I just don't ride too much off road if you will. I mainly ride on paths which are fairly smooth and lately I have been riding a lot on the road due to the snow.

I was really surprised too, what I think causes it (on tarmac) is that when the tyre's got more give it can flatten out onto the road, whereas when it's stiffened up at high pressure it goes from one knob to the next like a big cog, donk donk donk, so it basically makes your tyre less round. That might be cobblers though but it does seem to make sense

Offroad is a bit simpler, it's less work for the tyre to deform and roll over a lump than it is for the entire bike to go over a lump- this is easier to believe if you've ever pushed a wheelbarrow. Though the Schwalbe study isn't neccesarily totally representative, there are tyres that roll faster and grip better with a bit more air, Mountain Kings frinstance.

Valy

Northwind wrote:

Valy wrote:

I see... a bit odd about lower pressures being faster - at least in your example. I just don't ride too much off road if you will. I mainly ride on paths which are fairly smooth and lately I have been riding a lot on the road due to the snow.

I was really surprised too, what I think causes it (on tarmac) is that when the tyre's got more give it can flatten out onto the road, whereas when it's stiffened up at high pressure it goes from one knob to the next like a big cog, donk donk donk, so it basically makes your tyre less round. That might be cobblers though but it does seem to make sense
Yeah seems reasonable.
Offroad is a bit simpler, it's less work for the tyre to deform and roll over a lump than it is for the entire bike to go over a lump- this is easier to believe if you've ever pushed a wheelbarrow. Though the Schwalbe study isn't neccesarily totally representative, there are tyres that roll faster and grip better with a bit more air, Mountain Kings frinstance.

Indeed, though as I said before - the paths I ride on are farly smooth and there aren't many thugs to get in the way.

sniper68

Valy wrote:

But damn - some really low pressures you people have.

Or what really high pressure you're running at I'm 14st and run 30F and 34R.My mates 3 stone heavier and runs his about the same.

Valy

ibbo68 wrote:

Valy wrote:

But damn - some really low pressures you people have.

Or what really high pressure you're running at I'm 14st and run 30F and 34R.My mates 3 stone heavier and runs his about the same.

I tend to run close to the max stated pressure on the tire wall as I see it as higher pressure = less rolling resistance. And it seem to be the case, at least on smooth-ish surfaces.

sniper68

Valy wrote:

I tend to run close to the max stated pressure on the tire wall as I see it as higher pressure = less rolling resistance. And it seem to be the case, at least on smooth-ish surfaces.

That like most things is just a guide and a maximum.
Offroad high pressures = less grip.On the few tarmac sections i ride i don't notice rolling resisitance.Why have a MTB with knobbly tyres if you're worried about RR?Put some semi-slicks on it or get a roadbike/tourer/cyclocross etc.

Valy

ibbo68 wrote:

Valy wrote:

I tend to run close to the max stated pressure on the tire wall as I see it as higher pressure = less rolling resistance. And it seem to be the case, at least on smooth-ish surfaces.

That like most things is just a guide and a maximum.
Offroad high pressures = less grip.On the few tarmac sections i ride i don't notice rolling resisitance.Why have a MTB with knobbly tyres if you're worried about RR?Put some semi-slicks on it or get a roadbike/tourer/cyclocross etc.

Yeah I know. :P

It's just that lately path riding for me was out of the question, once they return though the tires I have now should be alright as there are a few rough sections on my routes, but mostly they are pretty smooth paths/bridleways.