PSI Advice please

[Saint]

I am not sure how much pressure to put in my tyres on my 2 bikes so wondered
if anyone can help.

My first bike is a Scott Roadster with 700 x 25 tyres. I have tended to try
and maintain pressures at about 110 PSI as I weigh about 15.5 stones and am
quite a big bloke. Trouble is that, at this pressure the bike bounces like
*********** and feels like quite a severe ride. A bit less is more
forgiving but I have a feeling it won't be enough to protect the rims/wheels
if I clout something unexpected.

Second bike is a Dawes Discovery 301, not sure about wheel size so maybe
someone can tell me (these measurements are really confusing!) but I am less
worried about this one as the tyres are a lot fatter than those on my Scott
and will take a lot more biff and bash - I would still like to know though.

Cheers

S

 

[Simonb]

Saint wrote:
> I am not sure how much pressure to put in my tyres on my 2 bikes so
> wondered if anyone can help.
>
> My first bike is a Scott Roadster with 700 x 25 tyres. I have tended
> to try and maintain pressures at about 110 PSI as I weigh about 15.5
> stones and am quite a big bloke. Trouble is that, at this pressure
> the bike bounces like *********** and feels like quite a severe ride.
> A bit less is more forgiving but I have a feeling it won't be enough
> to protect the rims/wheels if I clout something unexpected.
>
> Second bike is a Dawes Discovery 301, not sure about wheel size so
> maybe someone can tell me (these measurements are really confusing!)
> but I am less worried about this one as the tyres are a lot fatter
> than those on my Scott and will take a lot more biff and bash - I
> would still like to know though.

The recommended range of pressures should be embossed or printed somewhere
on the sidewall of the tyre.

 

[NC]

Saint wrote:
> I am not sure how much pressure to put in my tyres on my 2 bikes so
> wondered if anyone can help.
>
> My first bike is a Scott Roadster with 700 x 25 tyres. I have tended
> to try and maintain pressures at about 110 PSI as I weigh about 15.5
> stones and am quite a big bloke. Trouble is that, at this pressure
> the bike bounces like *********** and feels like quite a severe ride.
> A bit less is more forgiving but I have a feeling it won't be enough
> to protect the rims/wheels if I clout something unexpected.
>
> Second bike is a Dawes Discovery 301, not sure about wheel size so
> maybe someone can tell me (these measurements are really confusing!)
> but I am less worried about this one as the tyres are a lot fatter
> than those on my Scott and will take a lot more biff and bash - I
> would still like to know though.


Try good old Sheldon Brown for starting point recommendations:

www.sheldonbrown.com/tires.html

There is a table of recommended starting points for tyre pressures towards
the bottom.

If you're finding the 25mm tyres are a bit hard, you might want to try a
wider size.


Elsewhere on Sheldon's excellent pages, he'll explain the mysteries of tyre
size markings.



- Nigel


--
NC - Webmaster for http://www.2mm.org.uk/
Replies to newsgroup postings to the newsgroup please.

 

[Just zis Guy, you know?]

Avoid bibshorts.

Oh, PS/I/. As you were, then.

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University

 

[tony R]

"Simonb" <[email protected]> wrote in message
news:[email protected]...
> Saint wrote:
> > I am not sure how much pressure to put in my tyres on my 2 bikes so
> > wondered if anyone can help.
> >

>
> The recommended range of pressures should be embossed or printed somewhere
> on the sidewall of the tyre.
>
And don't forget the rims may have a maximum PSI rating too.

tony R.

 

[Simonb]

tony R wrote:
> "Simonb" <[email protected]> wrote in message
> news:[email protected]...
>> Saint wrote:
>>> I am not sure how much pressure to put in my tyres on my 2 bikes so
>>> wondered if anyone can help.
>>>
>
>>
>> The recommended range of pressures should be embossed or printed
>> somewhere on the sidewall of the tyre.
>>
> And don't forget the rims may have a maximum PSI rating too.
>
> tony R.

Good point. It is possible that this may actually be _lower_ than some
tyres!

 

[Velvet]

Simonb wrote:

> tony R wrote:
>
>>"Simonb" <[email protected]> wrote in message
>>news:[email protected]...
>>
>>>Saint wrote:
>>>
>>>>I am not sure how much pressure to put in my tyres on my 2 bikes so
>>>>wondered if anyone can help.
>>>>
>>
>>>The recommended range of pressures should be embossed or printed
>>>somewhere on the sidewall of the tyre.
>>>
>>
>>And don't forget the rims may have a maximum PSI rating too.
>>
>>tony R.
>
>
> Good point. It is possible that this may actually be _lower_ than some
> tyres!
>
>
ok, now I'm concerned My rims don't (afaik) have ratings on them.
Any ideas where I might find this info? Manufacturer website? Inside
the rim somewhere?

--


Velvet

 

[Simonb]

Velvet wrote:

> ok, now I'm concerned My rims don't (afaik) have ratings on them.
> Any ideas where I might find this info? Manufacturer website? Inside
> the rim somewhere?

Pete Biggs posted a link to the Mavic details a few weeks ago. I didn't
bookmark it.

Pete?

 

[tony R]

"Velvet" <[email protected]> wrote in message
news:[email protected]...
> Simonb wrote:
>
> > tony R wrote:
> >
> >>"Simonb" <[email protected]> wrote in message
> >>news:[email protected]...
> >>
> >>>Saint wrote:
> >>>
> >>>>I am not sure how much pressure to put in my tyres on my 2 bikes so
> >>>>wondered if anyone can help.
> >>>>
> >>
> >>>The recommended range of pressures should be embossed or printed
> >>>somewhere on the sidewall of the tyre.
> >>>
> >>
> >>And don't forget the rims may have a maximum PSI rating too.
> >>
> >>tony R.
> >
> >
> > Good point. It is possible that this may actually be _lower_ than some
> > tyres!
> >
> >
> ok, now I'm concerned My rims don't (afaik) have ratings on them.
> Any ideas where I might find this info? Manufacturer website? Inside
> the rim somewhere?
>
> --

My new (Mavic) rims have the rating printed on the label on the rims
themselves. To be honest this is the only reason I became aware this was an
issue - I fitted narrower tyres and their max. PSI is higher than the figure
on the rims. I'd merrily used the previous (also Mavic) rims for years
without giving it a second thought - although with the wider tyres I doubt I
exceeded any rating anyway. Mavic also have info on their website eg:
http://www.mavic.com/servlet/srt/mavic/asph-prod_fiche?product.id=64&lg=uk
Sorry about the long url. I'm not computer literate enough to make it
manageable.

tony R.

 

[Velvet]

tony R wrote:

> "Velvet" <[email protected]> wrote in message
> news:[email protected]...
>
>>Simonb wrote:
>>
>>
>>>tony R wrote:
>>>
>>>
>>>>"Simonb" <[email protected]> wrote in message
>>>>news:[email protected]...
>>>>
>>>>
>>>>>Saint wrote:
>>>>>
>>>>>
>>>>>>I am not sure how much pressure to put in my tyres on my 2 bikes so
>>>>>>wondered if anyone can help.
>>>>>>
>>>>
>>>>>The recommended range of pressures should be embossed or printed
>>>>>somewhere on the sidewall of the tyre.
>>>>>
>>>>
>>>>And don't forget the rims may have a maximum PSI rating too.
>>>>
>>>>tony R.
>>>
>>>
>>>Good point. It is possible that this may actually be _lower_ than some
>>>tyres!
>>>
>>>
>>
>>ok, now I'm concerned My rims don't (afaik) have ratings on them.
>>Any ideas where I might find this info? Manufacturer website? Inside
>>the rim somewhere?
>>
>>--
>
>
> My new (Mavic) rims have the rating printed on the label on the rims
> themselves. To be honest this is the only reason I became aware this was an
> issue - I fitted narrower tyres and their max. PSI is higher than the figure
> on the rims. I'd merrily used the previous (also Mavic) rims for years
> without giving it a second thought - although with the wider tyres I doubt I
> exceeded any rating anyway. Mavic also have info on their website eg:
> http://www.mavic.com/servlet/srt/mavic/asph-prod_fiche?product.id=64&lg=uk
> Sorry about the long url. I'm not computer literate enough to make it
> manageable.
>
> tony R.
>
>

Ah, ace! Just looked mine up (MA3's, for my sins) and the tyres'll give
out before the rims... or so they reckon, anyway ;-)

--


Velvet

 

[Pete Biggs]

Simonb wrote:
> Velvet wrote:
>
>> ok, now I'm concerned My rims don't (afaik) have ratings on
>> them. Any ideas where I might find this info? Manufacturer website?
>> Inside the rim somewhere?

No, I've never seen a pressure rating actually marked on or in a rim.

> Pete Biggs posted a link to the Mavic details a few weeks ago. I
> didn't bookmark it.

"Max pressures" are indicated on the main website. Go to www.mavic.com
and find your rim.

I wouldn't worry about them too much. They're conservative
generalisations, at best.

~PB