Tyre pressures
#2
Senior Member
the best psi values are those above 0.
seriously now... this is quite easy to answer.
1. rear wheel is best pressured as to insure best rolling resistance. too high psi or too low increase RR. you should compare looking at the clock for a given wattage and compare psi values by this.
2. front wheel is best pressured as to insure best control of the bike, best grip available dry and wet. RR is very less relevant for the front wheel, control in braking and in turns is much more important when figuring out tire pressure.
so... there are no fixed values because everyone should adapt psi for given actual and possible/probable circumstances.
i'd say i very much like a 50mm rear tire or even a 60 (not yet mounted) with a 40mm front tire. this 50-40 combo is now what i use and somewhere in the future i plan to mount a 60 in the back. a narrow front tire is chosen not for being more aero or anything like that but for better grip when wet and more puncture resistant (a sudden puncture in the front wheel can be very dangerous) because i would not have a wide tire in the front with a low pressure.
so... 88kg bike+rider for this combo (29er) has the same pressure both front and rear: 2.5bar (36 psi).
this combo is useful for an electric bike with a hub motor and a rear rack mounted battery.
why so many started threads in the same day?... 6 total posts... this is very dubious.
anyway, there are many answers you can find to this very question if you search using the search function on this forum...
seriously now... this is quite easy to answer.
1. rear wheel is best pressured as to insure best rolling resistance. too high psi or too low increase RR. you should compare looking at the clock for a given wattage and compare psi values by this.
2. front wheel is best pressured as to insure best control of the bike, best grip available dry and wet. RR is very less relevant for the front wheel, control in braking and in turns is much more important when figuring out tire pressure.
so... there are no fixed values because everyone should adapt psi for given actual and possible/probable circumstances.
i'd say i very much like a 50mm rear tire or even a 60 (not yet mounted) with a 40mm front tire. this 50-40 combo is now what i use and somewhere in the future i plan to mount a 60 in the back. a narrow front tire is chosen not for being more aero or anything like that but for better grip when wet and more puncture resistant (a sudden puncture in the front wheel can be very dangerous) because i would not have a wide tire in the front with a low pressure.
so... 88kg bike+rider for this combo (29er) has the same pressure both front and rear: 2.5bar (36 psi).
this combo is useful for an electric bike with a hub motor and a rear rack mounted battery.
why so many started threads in the same day?... 6 total posts... this is very dubious.
anyway, there are many answers you can find to this very question if you search using the search function on this forum...
#3
Junior Member
Thread Starter
Join Date: Aug 2019
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
thanks for your reply most helpful
Simple reason why, is because I cant post images, cant do something else cant remember now until I have made so many posts. I think its 12 posts, just seem to be a silly thing, so hence why i have made so many posts
why so many started threads in the same day?... 6 total posts... this is very dubious.
#4
Cycleway town
Depends on the bike and it's tyres. I have a tandem on balloons, heavy rear hub, i'll bet my tyre pressures are a bit different than the next guy's.
#5
Senior Member
Join Date: Oct 2016
Location: Sacramento, CA
Posts: 458
Bikes: 2017 Surly Cross-Check. 2020 Specialized Turbo Vado 3.0, 2002 GT Dyno Roadster, 2002 Rans Stratus, 2020 Giant Fathom 2, 2011 Trek Pure Sport
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 171 Post(s)
Liked 85 Times
in
62 Posts
There is a range specified on the sidewall. I start with the max pressure on the rear wheel, and then reduce until it is not too harsh/ hard. Even softer on dirt or loose gravel roads. Inflate the front wheel to same minus 10% pressure. (eg. 60 psi rear, 54psi front) THIS IS JUST THE STARTING POINT. Adjust accordingly.
Different tires and different riding conditions dictate adjusting.
Different tires and different riding conditions dictate adjusting.
#6
Senior Member
Join Date: Dec 2011
Location: 98059
Posts: 182
Bikes: Treks and a Moulton
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Likes: 0
Liked 3 Times
in
2 Posts
> ..I start with the max pressure on the rear wheel, and then reduce until
> it is not too harsh/ hard. Even softer on dirt or loose gravel roads.
Keep in mind when dropping psi that tire pressure is an important factor in the wheel assembly's strength and rigidity.
> it is not too harsh/ hard. Even softer on dirt or loose gravel roads.
Keep in mind when dropping psi that tire pressure is an important factor in the wheel assembly's strength and rigidity.
#7
Senior Member
There is a range specified on the sidewall. I start with the max pressure on the rear wheel, and then reduce until it is not too harsh/ hard. Even softer on dirt or loose gravel roads. Inflate the front wheel to same minus 10% pressure. (eg. 60 psi rear, 54psi front) THIS IS JUST THE STARTING POINT. Adjust accordingly.
Different tires and different riding conditions dictate adjusting.
Different tires and different riding conditions dictate adjusting.
the maximum pressure is there so that you will know that for a given weight you should just take a larger tire and do not go beyond that pressure limit.
you should reduce pressure not necessarily by feel but by measuring speed or rolling resistance with the clock. rolling resistance can't be accurately discerned by regular people.
you might find that an even lower pressure is best than what you think is ok now - not being harsh enough is not a good enough assessment.
be sure to lower pressure comparing speed only for the rear wheel pressure adjustment and set the pressure on the front just by feel regarding the whole thing being stable in turns, braking, dry and wet. doing so one wheel at a time means more time but more sure results. also, ensure the tire size so that the right pressure for that size makes it possible to have the least risk of flats.
that's one of the reasons i recommend putting a narrower tire upfront especially if you have it on your hands; changing the rim width is not easily done.
a front tire no larger than needed for proper pressure and also not too much sideway flex for a given rim. rear is no big deal if it has more sideway flex.