Tyre Pressure v Speed

[aces_up1504]

After a bit of a lay off the bike due to be lazy, I started commuting today. Only problem was I was a bit rushed, Knew my tyres were a bit soft from a squeeze test but not deflated, good god they made it hard work. I reckon if you want to get fit cycling this is the way.

So all back and inflated, I reckon it cost me around 2mph. Will find out in the morning.

 

[biggs682]

the wider the tyre surely the issue would get worse as well ?

 

[Supersuperleeds]

First thing I check when I have had a struggle is the tyre pressure, I am always forgetting to pump them up.

 

[aces_up1504]

Made around 1.5mph difference, but in terms of effort the difference is huge especially on uphill sections. Lesson learnt always check tyre pressure!!

 

[HLaB]

IME there's a critical pressure (if thats the right term); over hard tyres will be uncomfortable and make you slower unless the road is perfect but when they are too low they become 'sticky' (if thats the right term also).

 

[SpokeyDokey]

the wider the tyre surely the issue would get worse as well ?

I thought a 25mm tyre had a smaller contact patch than a 23mm everything else being equal and hence would roll faster.

 

[rams1de]

I thought a 25mm tyre had a smaller contact patch than a 23mm everything else being equal and hence would roll faster.

I believe that they'd have the same contact patch at the same pressure. But the longer shape of the narrower tyre means it loses more of its 'roundness' which creates a higher rolling resistance.

Narrow tyres benefit from operating at higher pressure and having less air resistance at speed which is why they are preferred by racers.

 

[madpensioner]

I would like some advice - i pump my tyres up to the limit stated of 140 psi - on good surfaces the performance is good however i recently did a 100 miler using repeated curcuits - i believe that the tiredness on completion was mainly due to bad road surfaces - would i have been better reducing the pressures - if so to what extent ?

 

[boydj]

High pressure like that means the tyre bounces around rather than deforming with the irregularities in the road surface. This makes it uncomfortable and slower. Depending on the size of the tyre and your own weight, tyre pressure should be somewhere in the region of 90 - 110 psi.

 

[Smokin Joe]

I would like some advice - i pump my tyres up to the limit stated of 140 psi - on good surfaces the performance is good however i recently did a 100 miler using repeated curcuits - i believe that the tiredness on completion was mainly due to bad road surfaces - would i have been better reducing the pressures - if so to what extent ?

Unless you weigh the same as an aircraft carrier 140psi is way too high, your tyres will feel solid.

 

[bpsmith]

I recently replaced wheels and tyres. I have GP4000S 25's on now. What pressure would you guys use?

 

[User16625]

I recently replaced wheels and tyres. I have GP4000S 25's on now. What pressure would you guys use?

I would use about 7-7.5 bar.

 

[madpensioner]

I recently replaced wheels and tyres. I have GP4000S 25's on now. What pressure would you guys use?

I think with the limited expearience ive got - you would be better off asking the people who have solved just that problem for me in the last few days - they are all on this forum

 

[Shaun]

Also, if you're currently using a hand pump and want to get that extra hardness for speed, try a track pump with a gauge.

 

[madpensioner]

Also, if you're currently using a hand pump and want to get that extra hardness for speed, try a track pump with a gauge.

Cheers Shaun - ive got one - i do believe its the only way achieve the correct/required pressures