Minimum Tyre Pressure

For discussions about bikes and equipment.
Rhodrich
Posts: 180
Joined: 10 Jul 2012, 11:17am
Location: Thames Ditton, Surrey

Re: Minimum Tyre Pressure

Post by Rhodrich »

niggle wrote:
*BTW how did you get to the 45/55% weight distribution figure?


My understanding is that with drop handlebars, this is about the weight distribution you'd expect. With a more upright style of bike, you'd expect more weight on the back.

Not having ever weighed my bike on a pair of scales however, I wouldn't really know! I guess having a saddlebag almost permanently fitted to the back, with my commuting kit in does increase the rear wheel weight.


reohn2 wrote:Well there's always one of these:- http://salsacycles.com/bikes/vaya/2015_vaya_2/overview/ :D


I'd love one! Sadly though, finances couldn't stretch that far, and I'm already at D-1 in terms of number of bikes. I'm already getting stick for having bought a Jack Taylor tourer that I very rarely use.....
Bicycler
Posts: 3400
Joined: 4 Dec 2013, 3:33pm

Re: Minimum Tyre Pressure

Post by Bicycler »

Rhodrich wrote:
reohn2 wrote:Well there's always one of these:- http://salsacycles.com/bikes/vaya/2015_vaya_2/overview/ :D


I'd love one! Sadly though, finances couldn't stretch that far, and I'm already at D-1 in terms of number of bikes.

Divorce - 1? :lol:
User avatar
al_yrpal
Posts: 11571
Joined: 25 Jul 2007, 9:47pm
Location: Think Cheddar and Cider
Contact:

Re: Minimum Tyre Pressure

Post by al_yrpal »

Rhodrich wrote:
niggle wrote:
*BTW how did you get to the 45/55% weight distribution figure?


My understanding is that with drop handlebars, this is about the weight distribution you'd expect. With a more upright style of bike, you'd expect more weight on the back.

Not having ever weighed my bike on a pair of scales however, I wouldn't really know! I guess having a saddlebag almost permanently fitted to the back, with my commuting kit in does increase the rear wheel weight.


Easy to test. Just put the front wheel on your bathroom scales when you and your gear are on it, then the rear wheel on the scales. That will give you a pretty good idea. I always run the 37mm tyre pressures on my Vaya at about 50 and 60 which gives a comfortable ride with very low possibility of p***s on Oxfordshires flint and pothole strewn roads.

Al
Reuse, recycle, thus do your bit to save the planet.... Get stuff at auctions, Dump, Charity Shops, Facebook Marketplace, Ebay, Car Boots. Choose an Old House, and a Banger ..... And cycle as often as you can......
reohn2
Posts: 45181
Joined: 26 Jun 2009, 8:21pm

Re: Minimum Tyre Pressure

Post by reohn2 »

al_yrpal wrote:
Easy to test. Just put the front wheel on your bathroom scales when you and your gear are on it, then the rear wheel on the scales. That will give you a pretty good idea.....
Al


But make sure the other wheel is chocked up to the same height as the scales with a book of block of wood,etc,otherwise you'll get a false reading of weight distribution.

Rhodrich
Weight distribution with drops depends how far stretched the rider is or how low the h/bars are in relation to the saddle.
-----------------------------------------------------------
"All we are not stares back at what we are"
W H Auden
User avatar
Mick F
Spambuster
Posts: 56366
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Minimum Tyre Pressure

Post by Mick F »

Using the bathroom scales method - plus a chock for the other wheel - my dropped handlebar bike came at 60% 40%
It made little difference if I was on the drops or the tops. It was ages ago when I did the test, so I can't remember specifics other than the ratio.

I think the weight distribution has a lot to do with frame geometry and your personal physicality.
Mick F. Cornwall
reohn2
Posts: 45181
Joined: 26 Jun 2009, 8:21pm

Re: Minimum Tyre Pressure

Post by reohn2 »

Mick F wrote:Using the bathroom scales method - plus a chock for the other wheel - my dropped handlebar bike came at 60% 40%
It made little difference if I was on the drops or the tops. It was ages ago when I did the test, so I can't remember specifics other than the ratio.

I think the weight distribution has a lot to do with frame geometry and your personal physicality.


IIRC your h/bars are lower than your saddle and you don't ride particularly upright on the bike.
-----------------------------------------------------------
"All we are not stares back at what we are"
W H Auden
User avatar
Vantage
Posts: 3052
Joined: 24 Jan 2012, 1:44pm
Location: somewhere in Bolton
Contact:

Re: Minimum Tyre Pressure

Post by Vantage »

I can neither find nor remember the weight figures for my bike, but unloaded (nothing but me on it) it was front heavy, and loaded (it varied a lot by how much loaded) it was rear heavy.
However, I read and this does make sense to me, weight distribution on a bike constantly changes according to whichever gradient you're cycling on and so the load on your tyres are forever changing.
I also have to wonder how pressures are affected on tyres with differing 'suppleness'. My Landcruisers and Voyagers which are almost identical in size feel sooooooooo different when run at the same pressure.
Bill


“Ride as much or as little, or as long or as short as you feel. But ride.” ~ Eddy Merckx
It's a rich man whos children run to him when his pockets are empty.
nirakaro
Posts: 1591
Joined: 22 Dec 2007, 2:01am

Re: Minimum Tyre Pressure

Post by nirakaro »

Bear in mind that probably the majority of cyclists throughout the world have never thought of measuring their tyre pressure. They just pump the tyres up until they feel reasonably hard, and repeat the operation when they feel soggy again. And mostly it doesn’t cause any problem.
User avatar
Mick F
Spambuster
Posts: 56366
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Minimum Tyre Pressure

Post by Mick F »

reohn2 wrote:
Mick F wrote:Using the bathroom scales method - plus a chock for the other wheel - my dropped handlebar bike came at 60% 40%
It made little difference if I was on the drops or the tops. It was ages ago when I did the test, so I can't remember specifics other than the ratio.

I think the weight distribution has a lot to do with frame geometry and your personal physicality.


IIRC your h/bars are lower than your saddle and you don't ride particularly upright on the bike.
Yep.
Correct.
Just like I said.
Weight distribution has to do with frame geometry and your own physicality.

I suppose I meant that "frame" included saddle position and handlebar height and reach.
Mick F. Cornwall
sreten
Posts: 347
Joined: 29 Sep 2013, 10:59pm

Re: Minimum Tyre Pressure

Post by sreten »

Rhodrich wrote:
I'm currently riding at the minimum recommended pressure of 70psi, both front and rear, and the ride on the bike is a bit bouncy, which also suggests that this is too high.

What would be the consequences of reducing the pressures to 52psi front, 64psi rear, which are below the minimum recommended pressures as stated by Continental? I don't want to destroy my tyres, or get pinch flats......

Thanks


Hi,

The front is too high, drop it to say 55 psi, keep the rear 70psi. Ride your bike. Pump
up the tyres when they are too low, which should be quite a while, say a week or so.

There is no chance of damaging your tyres or pinch flats. Imagine you weigh 100Kg ....

It won't take long to work out the lazy attitude to tyre pumping,
do it when needed, and go a bit over what seems to be the best.

rgds, sreten.

Personally I reckon about 55psi rear and 45psi front minimum for your weight.
Post Reply