Finally switching to 25mm tires..How may psi?

[tlittlefield]

Well after years of riding 23's I finally installed a pair of 25mm wide tires (Continental GP 400 S II) on my Tarmac.

I am thinking of 80 psi front and 90 psi rear, I weight 144.

Any input from anyone?

[AngryScientist]

a lot of people get bent out of shape about tire pressure. here's what i do: pump them up to the max you think you're comfortable with, say 100/90. ride. let the pressure drift for the next several rides. repeat. you'll eventually get a fee for what works best for you. don't overthink it, this is one of those things that costs you nothing to experiment with.

[fa63]

80 front / 90 rear is probably not too far off for you weight, especially considering that those Contis are known to measure much larger than advertised (mine measured almost 28 mm on 23 mm wide rims).

[azrider]

I weigh 175 and I am 80/90 front and back on 25's and 28's

[chiasticon]

255mm wide? I wouldn't go over 30 psi :D

[TEMPLE]

Finally switching to 255mm tires..How may psi?

Whoa! You riding a moonlander or something? Well, I guess you already know what "they" say about bigger cushions*...

*it's totally not true, by the way.

[palincss]

Here http://www.bikequarterly.com/images/TireDrop.pdf is a good place to start. Then experiment.

[tlittlefield]

Fixed the headline...

[oldpotatoe]

Well after years of riding 23's I finally installed a pair of 25mm wide tires (Continental GP 400 S II) on my Tarmac.

I am thinking of 80 psi front and 90 psi rear, I weight 144.

Any input from anyone?

I seldom use more than 90 psi on clinchers and I weigh .1 offa ton..80 psi both is where I'd start. If too 'squishy', add 5psi

[Lewis Moon]

I weigh 175 and I am 80/90 front and back on 25's and 28's

I'm 190 and I ride the 85/95 for everyday rides. I might go 95/100 for races.

[weiwentg]

Here http://www.bikequarterly.com/images/TireDrop.pdf is a good place to start. Then experiment.

That scale is suggesting that my front tire should be at something like 50 PSI. Not sure I trust it for myself. I am at the low extreme, of course.

[josephr]

not sure if this helps, but I'm at 200lbs, ride Gatorskins, and I like my tires on the firm side at 100/95...

[Matt-H]

a lot of people get bent out of shape about tire pressure. here's what i do: pump them up to the max you think you're comfortable with, say 100/90. ride. let the pressure drift for the next several rides. repeat. you'll eventually get a fee for what works best for you. don't overthink it, this is one of those things that costs you nothing to experiment with.

Good advice as usual from AS. I've done this and for my 150lbs found my sweet spot to be about 80f/85r on Veloflex 25 Masters.

[ripvanrando]

Try 60/80 pis, then 70/90psi and then 80/100PSi

i suspect 65-70psi on the front and 85-90 psi on the rear will be your sweet spot. You could do this test on one ride. Bring a small pump and a gage

Well after years of riding 23's I finally installed a pair of 25mm wide tires (Continental GP 400 S II) on my Tarmac.

I am thinking of 80 psi front and 90 psi rear, I weight 144.

Any input from anyone?

[cdn_bacon]

I'm 170 and run my veloflex/vittoria at 110 with no issues

[ripvanrando]

I'm 170 and run my veloflex/vittoria at 110 with no issues

have you ever tried lower pressures?

Having the same pressures on the front as rear is not logical in terms of minimizing suspension losses.

[bikingshearer]

Here http://www.bikequarterly.com/images/TireDrop.pdf is a good place to start. Then experiment.

I'm waaaaay off that scale. 275#, Conti 4000's, 120 psi. That works for me. But at 140#, you should be able to go with significantly lower pressures. Otherwise, I agree with the "experiment but don't overthink it" group.

[eddief]

we like it that way. no issues.

[Bob Ross]

Having the same pressures on the front as rear is not logical in terms of minimizing suspension losses.

I'm trying to think if there's anything I do that pertains to riding a bike that could be described as "logical"

...um, nope, I got nuttin'.

[ripvanrando]

I'm trying to think if there's anything I do that pertains to riding a bike that could be described as "logical"

...um, nope, I got nuttin'.

Riding is one thing

Setting it up to ride for a given purpose is an entirely different matter.

[spartanKid]

i'm 190 and i ride the 85/95 for everyday rides. I might go 95/100 for races.

+1.

[shovelhd]

A lot of it depends on rim width and bead depth. I have a set of 28mm wide carbon clinchers with 25mm GP4KSII that will pinch flat like clockwork if under 95/90, so that's what I use.

[palincss]

That scale is suggesting that my front tire should be at something like 50 PSI. Not sure I trust it for myself. I am at the low extreme, of course.

So experiment. Try it, see how it feels. Easy to add or subtract air, and no cost to experiment.

[Black Dog]

Same tires as you and same size. I am 155 pounds and I never run them above 85 rear 75 front. Fast and smooth.

[weiwentg]

So experiment. Try it, see how it feels. Easy to add or subtract air, and no cost to experiment.

No cost except maybe a pinch flat. I suspect the scale doesn't behave linearly at the extremes. I'm fine at 80 PSI.

[weisan]

What do you guys do with your tires and how do you ride, the last time i had a pinch flat was like 15 years ago, and I like low pressure cushy ride...I am sure now that I have said it I am gonna jinx myself...:beer:

[beeatnik]

I'm 170 and run my veloflex/vittoria at 110 with no issues

https://www.youtube.com/watch?v=iZq3i94mSsQ

[45K10]

https://www.youtube.com/watch?v=izq3i94mssq

Good one :)

[Fatty]

Probably start around 5 psi less than what you are running now.

[markoprotic]

I was running Bontrager RXL Tubeless wheelset for a little bit over 2 years. Tires were Bontrager R3 TLR 25mm. I'm 155 Lbs and I was setting mine at 90psi on the high side, ideal was 80-85 psi.
It was a nice smooth ride.
There were days when I went lower 50-60psi (short ride circa 5 miles from home to work, small test).

[jwalther]

I run the same tires at 80/90. 167#.

[shovelhd]

What do you guys do with your tires and how do you ride, the last time i had a pinch flat was like 15 years ago, and I like low pressure cushy ride...I am sure now that I have said it I am gonna jinx myself...:beer:

Come on out here. I'll set up my wheels with 80/80 and lend them to you. You can take a ride on them through our pothole-infested rural roads and see if you pinch flat. :beer:

[fuzzalow]

Different roads, different rims, different weights, actual tire versus marked tire, bike setup, rider fit & position contact point geometry, rider geometry location along the frame wheelbase.

All stuff that influences and changes the feel. So with all those variables, the tire pressure overlays all of that and changes some of the feel but not IMO to dramatically alter the experience from what you have fundamentally setup to have. To me it is not all that different from the current fashion and favoritism found in the whole 23-to-25-to-28-to-32mm tire section movement - an aging ridership seeking comfort in gear that might make for a cushier ride. Which is fine but means little when the rider's main shock absorber is found with his spinal discs and not in his tires.

So getting feedback from others about PSI is fun to banter but that's about it. Who really cares what PSI somebody else uses? Easiest thing in the world to change if you don't like what'cha got.

I pump to slightly less than 7bar as indicated on a 30 year old Silca track pump gauge - how much air pressure that really is that makes it into the tire only God knows.

[weisan]

Come on out here. I'll set up my wheels with 80/80 and lend them to you. You can take a ride on them through our pothole-infested rural roads and see if you pinch flat. :beer:
Shovel pal, let's do it! No, wait, aren't we planning to meet up anyway when I head out later this year to do D2R2? :D
It's time to call upon my gravity-defying iron monkey skills...

https://upload.wikimedia.org/wikipedia/en/thumb/b/b0/Iron-MonkeyPoster.jpg/220px-Iron-MonkeyPoster.jpg

[shovelhd]

:beer::banana::banana:

Unfortunately I was laid off last week and won't know about my employment/time off situation until your visit gets closer but no matter what this will be a priority.