Pumping up road tyres..

[hoopdriver]

Have you never heard of irony?

 

[black'n'yellow]

Have you never heard of irony?

have you..?

Anyway, can you show me some evidence that competitive cyclists don't care about rotational weight - only dead weight..??

 

[hoopdriver]

I never said pro cyclists do not care about rotational weight. Sprinters certainly do. What I said was that rotational mass affect only acceleration, which it does. I said that the weight, in absolute terms, was of concern to competive cyclists in mountain races who naturally wish to shed weight from all parts of their bicycles. I said too that the weight differences between various narrow tyres makes little difference to the average rider's performance.

 

[black'n'yellow]

I said too that the weight differences between various narrow tyres makes little difference to the average rider's performance.

well, I'm an average rider - what size tyres should I be using..??

 

[hoopdriver]

That's not really for me to say, as I've never seen your bike, have no idea of its clearances and since i also have some doubts about this being a sincere question. Were I to recommend road bike tyres for my son, however I would suggest he go no narrower thn 25 and, if the prospective bicycle had the clearances, consider 28mm. Leaving aside the broad question of make and model of tyre, and sticking instead only to dimensions, it is safe to say that wider tyres such as these not only have better rolling resistence, they offer more comfort and better handling as well and whatever fractional weight penalty you oay is more than offset by the better rolling qualities - or at least that it would not make a material difference to most riders.

 

[ushills]

well, I'm an average rider - what size tyres should I be using..??

If your bike will take it, have a look at some of the wider Grand Bois tyres.

IMHO you will get a better ride from some lightweigh, supple carcassed 28mm tyres or larger.

I used to race, a long time ago, on 700 x 19C tyres in closed circuits and they were hell, yes they had high pressure in but they were skittish on the surface. I've recently move from 25c to 28c and the only difference I can feel is the improved comfort and grip, my speeds on the flat are the same and my average speed are also the same.

My recommendation go with a lightweigh, kelvar beaded 28mm or larger if you have the clearance,

 

[C Fairfowl]

In order to get 120psi you'll need to apply 120lbs of force on the pump plunger assuming it's area is 1" (pi r squared etc.) forgive me, but for most woman (and a lot of men) that is quite a lot if you are not used to this level of physical exertion - assuming the diameter of the pump is say 30mm in diameter and say the plunger dia. is 25mm that is 25/25.4 = 0.98 inches the radius = .49 inches, square that times pi thats 0.76 inches squared. 120lbs x .76 you'll need to excert 91 lbs of force to the pump handle to get 120psi, mutiply this by the number of pumping actions you'll need to achive the tyre volume and this is a LOT of work. Not so bad if you are using a proper pump - Joe Blow for example, but if you need a pump when you are out on the road you'll need to buy wisely or you have problems.

Before you try doing this, try (in a safe place) riding the road bike with low pressure in the tyres especially the front and you'll be surprised at the significant loss of handling especially when turning and you could snake bite the inner tube too if you hit a bump or pot hole.

I would not recommend you buy a hand pump without first establishing how effective it will be when YOU use it to pump up your tyres.

Good luck.

 

[hoopdriver]

Better still, don't pump up your tyres to 120psi. There is absolutely no need.

 

[C Fairfowl]

((Better still, don't pump up your tyres to 120psi. There is absolutely no need.))

Perhaps not, however, lower pressures will significantly increase your chances of loosing the front or back and falling off - especially on a road bike. So, all I'm suggesting is It's a good idea to choose a pump that gets you as close as possible to the Manufacturers "RECOMMENDED" tyre pressure and then testing the handling of the bike to assess the reduced handling at that pressure. Then if you are forced to cycle home in the wind and rain on a wet road there are no nasty surprises. My Norcom Straight handles fantastically on a dry road with 120psi, with half that pressure it's lethal even in the dry.

Better to be safe than sorry.

 

[hoopdriver]

Er...no. 95-100psi is plenty. More than that is just asking for a rough ride and potential blow out.

 

[presta]

For four and a half decades I just pumped my tyres by feel, when I bought a pump with a gauge a couple of years ago that feel turned out to be about 60-65psi. The maximum pressure is 85psi for my 35mm Marathons and about 90psi for the A719 rims, Schwalbe recommend 65psi.

I've had cyclists tell me I need at least 100psi, but I've also been told I pump them too hard. Someone who told me I need 100psi once pumped my tyre, and It was 3 parts of the way to coming off the rim after 20 minutes.

 

[hoopdriver]

It depends on the width of your tyres. Pumping a 35mm tyre to 100psi woukd be foolish indeed and well beyond manufacturers recommendations. When I said 95-100psi earlier i was referring to 23-25mm tyres, even 28mm.

The Schwalbe Marathon tyres, 40mm, on my expedition tourer have a max of 65psi and I keep to that.

The super high pressures some people put in their tyres - 120 to 140psi- is just foolish and dangerous.

 

[C Fairfowl]

OK, I give in. I'll experiment with slightly lower pressures but I'm not sure I'll feel any more comfort. Little comfort is was to be found on my Specialized road bike and I fear none is to be found on the Norcom Straight, anyway, If comfort was what I was after I would stay in bed on a Sunday morning or ride a hybrid or mountain bike. I'll be interested so see if there is any comfort gain and just out of curiosity see what the calorie count difference might be over a 3.5 -4 hour ride with lower pressures. I'll repeat my favourite ride for the next 4 to 5 weeks. Some of The roads around the Surrey Hills are atrocious so I just hope punctures don't start becoming a problem. Comfort on this, not any I've noticed.