# Tyre Pressure



## scouserinlondon (6 Jul 2009)

Now this could just be in my head.

But I've had my Trek Valencia for three weeks (was commuting on my wife's halfords carrera before that) and finally got the tyre pressures back up to maximum thanks to a track pump.

OMFG the ride was fast this morning. Was it just my legs liking the cooler air or do properly inflated tyres make _that_ much difference.


----------



## Gerry Attrick (6 Jul 2009)

It does make some difference, but unless you were running them at grossly low pressures, it would not make the tyres roll hugely faster.

You can have tyres too hard for your weight, and this can lead to poor roadholding on bumpy bends.

Have a look at this: http://www.vintagebicyclepress.com/images/TireDrop.pdf


----------



## scouserinlondon (6 Jul 2009)

Interesting stuff, cheers. The tire says it should be inflated to 110 psi. When I attached the pump it was way down, at around 80, so pumped up to just below the 100 mark and it's made quite a difference, particularly to stability.


----------



## Gerry Attrick (6 Jul 2009)

I use 700 x 23 tyres on my road bike which weighs about 18 lb. I am 11 stone. I find I can run my tyres at 90psi rear and 80 psi front very successfully. I have had no pinch p******res and the rolling resistance fells normal.


----------



## magnatom (6 Jul 2009)

That's an interesting article Gerry. Up until now I have had my back at about 110psi and my front at about 95psi (road bike on 25mm and with rider plus bike weighing about 95kg).

I think I'll drop the front a bit more. It recommends about 75 psi, but that seems a bit low to me. I'll try 85psi. It might help with my numb finger issue.


----------



## Gerry Attrick (6 Jul 2009)

One of my regular loops involves a country road which has been surface dressed a few times, but not for the last four or five years. Consequently the surface has broken up and become almost corrugated. The pressures I use almost nullify the horrendous vibrations I used to get even on a bike known for its smooth riding character.


----------



## magnatom (6 Jul 2009)

Aye, I have a carbon fork, but I still get a lot of road vibration (the roads are pretty poor in places). This article has given me the courage to drop the front pressure a bit. It might make a difference as I am pretty sure vibration is one of the causes of my numbness.


----------



## jimboalee (6 Jul 2009)

Here comes more mysticism. FOR ROAD BIKES.

You need close to 1 square inch of rubber on the road at the bottom of each tyre.

The weight split should be 60/40 rear to front.

If the entire bike & rider package is 200 lb, you should have 120 in the rear and 80 in the front.

Best to check your weight split, as 'in the tuck' can be a 55/45 R/F split.


----------



## ColinJ (6 Jul 2009)

Gerry Attrick said:


> One of my regular loops involves a country road which has been surface dressed a few times, but not for the last four or five years. Consequently the surface has broken up and become almost corrugated. The pressures I use almost nullify the horrendous vibrations I used to get even on a bike known for its smooth riding character.


That's exactly my experience in West Yorkshire. 

I have an oversized steel framed Basso and ride that on some pretty poor road surfaces. Steel is comfortable, right? Not when the tyres are pumped up hard it isn't! 

I always put about 10 PSI more in the rear tyre than the front (23s) and find 110/100 really uncomfortable. Pressures in the range 95/85 - 100/90 PSI are fine. I weigh nearly 15 stone but very rarely get punctures - I watch where I'm going, avoiding debris and potholes, never bouncing over kerbs. I unweight the bike going over potential problems like cattlegrids. The tyres still roll pretty well at those pressures. 

Below about 90/80 it feels as though I have a slow puncture, the bike starts to feel sluggish and I think I'd be likely to start getting snakebite punctures (pinch flats).


----------



## swee'pea99 (6 Jul 2009)

AFAIC the answer to the OP is an emphatic yes. Makes a helluva difference. Personally I go for speed over comfort - 25 min commute each way, so comfort's not really a big issue - and I (c.180 lb, bike + rider) go for 100/120. Works for me. Much below 100 and I certainly notice the difference.


----------



## XmisterIS (6 Jul 2009)

I weigh 12 stone and I always keep my road tyres pumped up to the max (120psi). I am getting some new tyres which will go to 160psi, and I intend to keep them at 150. It makes a lot of difference!


----------



## HJ (6 Jul 2009)

scouserinlondon said:


> ... do properly inflated tyres make _that_ much difference.



Yes


----------



## HJ (6 Jul 2009)

magnatom said:


> That's an interesting article Gerry. Up until now I have had my back at about 110psi and my front at about 95psi (road bike on 25mm and *with rider weighing about 95kg*).


----------



## magnatom (6 Jul 2009)

HJ said:


>




Oi! Don't edit my quotes! I'm a svelte 85kgs of cycling power!


----------



## Keith Oates (6 Jul 2009)

I keep my 700 x 23 tyres at about 100 psi front and rear and find the ride comfortable and not many pinch flats!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


----------



## Twanger (6 Jul 2009)

I gained 5 minutes on my journey in when I got a track pump. I can't get my hand pump to inflate more than about 65-70 PSI. That's because I am lazy and don't like pumping.


----------



## J4CKO (7 Jul 2009)

I do 110 in the rear and 95 in the front as I find it gets skittish in the wet if the front is much higher, me plus the bike and panniers must be around 280 lbs.


----------

