what psi do you run on ur folders? 20" wheels and smaller

[trueno92]

Hey guys, just with making the transition to a smaller folding bike, I finally got my Schwalbe Marathon's mounted (thanks for all the help, guys + sporting life!) and they got about 75psi in there now. I really enjoy the ride and low rolling resistance, but its on a 16" wheel and was wondering what everyone else runs? no creaks or squeeks in the frame and things seem to be good.. anyone run 100 or more?

[werewolf]

My Schwalbe Marathon 20X1.5's say 45-100 PSI on 'em - that's quite a range! - so I've been putting in 100, maybe even a bit more.

[doco]

I have Marathon Plus's on all my folders

Swift=75 PSI
Moulton APB=100+

good choice on the Schwalbe's, bulletproof, nice riding tire

[invisiblehand]

Lately I have been running my Marathon Racers on the NWT at 60 and 68 psi for the front and rear respectively. The Big Apples on the Mini are run at 50 and 80 psi for the front and rear respectively. Note that I pump up the rear tire on the Mini high since it has a rear suspension.

[trueno92]

yeah the tires are really great, and im hoping i don't have to change them anytime soon (16" x 1.5 = $30 each! yikes)

The range is,indeed, 45-100psi - which is great! probably the highest max spec tire i have ever owned! lol

I was reading about 100psi but then with that being the MAX, i wasn't sure about the tire heating up in hot weather and having a blow out on a long ride on a sunny day..

[Mr. Smith]

Hey guys, just with making the transition to a smaller folding bike, I finally got my Schwalbe Marathon's mounted (thanks for all the help, guys + sporting life!) and they got about 75psi in there now. I really enjoy the ride and low rolling resistance, but its on a 16" wheel and was wondering what everyone else runs? no creaks or squeeks in the frame and things seem to be good.. anyone run 100 or more?

I run 16" marathons between 65-70psi and they're plenty fast for me at that pressure. Any more and I'd feel nervous. I spend part of my time on sidewalks, so I wouldn't go above that unless you're on only good tarmac or a light rider.

[MillCreek]

On my Dahon Mu XL with 20" Marathon racers, I am running about 65psi on both tires.

[psykoocycle]

DT, kendakwest 44 PSI
Birdy Marathon Plus 95-105 PSI

[LittlePixel]

My Brompton with Velocity Aeroheat (ISO 349 aka 16") rims and Schwalbe Stelvio folding tyres rolls happily at 110psi. Yes it's fast. Bit bumpy but fast.

[EvilV]

65 psi on the Merc 16 inchers and 100 psi on the 20 inch marathons of the TSR30. Both of these are the stated max of the particular tyres used. The fully suspended Moulton is smooth even with rock hard rubber under it.

[itsahobby]

70 psi front & rear seems best for me, but I do find the Marathon's seem to be a slow tire at any pressure.

Would Big Apples be any better (faster), or would they just be more of the same?

[jur]

Ever since I did roll-down tests and found tyre pressure to be towards the insignificant scale of things, I stopped worrying about it. My Downtube Mini's Big Apples 40psi, the Swift's Conti Grand Prix' at 90psi but long periods (months) sometimes go by without topping up. The R20 I have no idea, hard enough not to be bouncy or squirmy in corners, probably above 30psi.

[werewolf]

I always have run my bike tires and my motor vehicle tires at max. pressure, or a little above, under the impression that it reduces rolling resistance and likelihood of blowouts and increases tire life, only at the expense of a more comfy ride. My motor vehicle tires tend to last a long time. Haven't rode a bike enough in recent years to adjudicate tire longevity.

What sort of tests did you run, Jur?

[stevegor]

451 Stelvios at no less than 110psi
406 Comets at 90-100psi

[jur]

What sort of tests did you run, Jur?
I did some roll-down test from an incline, with different tyre pressures. I also had 3 different bikes and different tyres. The results were that tyre pressure made very little difference (a few % at most) to the roll-down time (which was about 40s IIRC), the differences were just about the same as the margin for error. The biggest difference came from different bikes or from an extreme, impractical aero tuck. So because I couldn't really see a proper difference, I concluded that tyre pressure was such a small contributer to overall pedalling effort that it's not worth worrying about it, and that even if the tyres feel different or faster, you can't trust those feelings. This general conclusion was confirmed by another forumer who had done similar, more systematic tests.

So all i worry about these days is that the tyres are not so soft as to cause pinch flats, and not so hard as to negate the advantage gained from pneumatic tyres over solid ones. Hence the Big Apples at about 40psi, so that the balloon effect does its job.

[pm124]

I did some roll-down test from an incline, with different tyre pressures. I also had 3 different bikes and different tyres. The results were that tyre pressure made very little difference (a few % at most) to the roll-down time (which was about 40s IIRC), the differences were just about the same as the margin for error. The biggest difference came from different bikes or from an extreme, impractical aero tuck. So because I couldn't really see a proper difference, I concluded that tyre pressure was such a small contributer to overall pedalling effort that it's not worth worrying about it, and that even if the tyres feel different or faster, you can't trust those feelings. This general conclusion was confirmed by another forumer who had done similar, more systematic tests.

So all i worry about these days is that the tyres are not so soft as to cause pinch flats, and not so hard as to negate the advantage gained from pneumatic tyres over solid ones. Hence the Big Apples at about 40psi, so that the balloon effect does its job.

Laboratory conditions exist because they eliminate variability, thus providing much more accurate results than real world tests. Real world tests exist because laboratory conditions aren't variable enough, and thus are not generalizable to the real world. Fortunately, a happy medium exists; testing similar routes with a power meter.

Don't take this the wrong way, but your roll down tests are not going to be even close to providing you with information on differences in rolling resistance. Your cheapest bike rolled best downhill simply because it was heaviest. Now, if you repeat the experience in a vacuum and get the same results, I'd be more inclined to believe them!

Nonetheless, I would be more content that you feel comfy on your bike than a tad faster!

[Pine Cone]

Your cheapest bike rolled best downhill simply because it was heaviest.

There was no mention of which bike rolled the best, only that tire pressure wasn't a factor.

What was stated was that tire pressure variation on the 3 different bikes didn't change the results.

"The biggest difference came from different bikes or from an extreme, impractical aero tuck." which doesn't sound like it is likely to be the cheapest bike.

A good laboratory experiment tries to explain as much real world variation as it can. I spent more than a decade as a research scientist and know a lot about the failings of simplistic lab tests and their lack of validity in many real world situations.

There is nothing inherently different in the way physical laws work inside a Certified Research Facility versus the the way they work in the rest of the world.

On rolldown tests I have done there are major differences in time and distance traveled with different riders, presumably because of weight and its,effect on inertia, but I think Galileo showed that mass alone doesn't influence acceleration.

With the same riders, rolldown tests show similar rankings for each rider with different tires and different bikes.

[Raxel]

120psi (maximum) for both stelvios and Conti GPs.

[jur]

Don't take this the wrong way, but your roll down tests are not going to be even close to providing you with information on differences in rolling resistance.
You are quite correct, 'other factors' dominated the result, completely obscuring the tyre pressure effects. The test was not good enough to detect those effects. That's why I no longer worry about something which is small in the scheme of things. For TdF racers who look for small advantages pressure is important, but not for me. It is not important for me to arrive at work 30s sooner. :)

[EvilV]

This table shows some proper tests done on different tyres and sometimes the same tyre run at different pressures. Taking the Conti Top Touring 406 running at either 70 or 90 psi, the time loss in the lower pressure test over a ten mile ride would be 15 seconds - not much, I'll grant you, but it does exist. At 20 miles an hour running both tyres on the softer setting will necessitate that you put in an extra 20 watts of power at the pedals assuming (which you can't) perfect efficiency in the transmission. Twenty watts would easily mean me pedaling twenty percent harder for the same speed - err - no thanks mate.

http://www.hadland.me.uk/rolrec10a.pdf

Information on the testing procedure:

http://www.hadland.me.uk/lafford.htm

[jur]

This table shows some proper tests done on different tyres and sometimes the same tyre run at different pressures. Taking the Conti Top Touring 406 running at either 70 or 90 psi, the time loss in the lower pressure test over a ten mile ride would be 15 seconds - not much, I'll grant you, but it does exist.
Wow. 15s in 16km, 30s in 28km - I guessed that I would be at work 30s sooner, I didn't think that guess would be so accurate! :)
Thanks for those links, I can almost quote them verbatim by now, having pored over those tables for years now! :)

[itsahobby]

That table confirms what I thought about the Marathon - it's a comparatively slow tire.

Big Apples were not rated, so I will ask again - how do the Big Apples compare with the Marathons?

[Raxel]

Big apples are low pressure 'baloon' tire so its rolling resistance will be huge. But you can pump it up to 100psi (if I remember correctly) and I suppose big apple @ 100psi will be comparable (or better) to most 1.5 tires @ 30-40psi.

[EvilV]

Wow. 15s in 16km, 30s in 28km - I guessed that I would be at work 30s sooner, I didn't think that guess would be so accurate! :)
Thanks for those links, I can almost quote them verbatim by now, having pored over those tables for years now! :)

LOL - you're right about the time, but I just think of that six watts difference per tyre on the contis for 20 psi. Also, the lower figure was still pretty high at 70 psi. I expect I could soak up half of my feeble available power by running them at 40psi.

Maybe your 'cavalier' attitude to this problem is down to your super human physique. Don't forget, we've seen how you win races on your twenty Jur, and power over all those southern hemisphere mountain rages on a touring folder, not to mention busting the cogs in your SA8 hub through sheer beastly pedaling force. If you have a ferrari engine under the hood a soft tyre may not make any difference to you - me on the other hand, I'm running a coked up prewar side valve that might put out an average 80 watts. Expending a quarter of that in running two softish tyres is not on my agenda, especially since my stirrup pump is so easy to use once a week.

:)


This post has been edited for errors on the wattage and pressure figures in the original post

[sprockets]

Big fat Maxxis Hookworms - max 120 psi. I run them at about 110. Bumps are a bit painful like that though.

[jur]

Big apples are low pressure 'baloon' tire so its rolling resistance will be huge.Actually, Schwalbe make a big song and dance about these having low rolling resistance. Big fat does not necessarily equal slow roller.

[EvilV]

Actually, Schwalbe make a big song and dance about these having low rolling resistance. Big fat does not necessarily equal slow roller.

I wonder how that works.

I read some reviews of the Dahon Curve whoch said how fast the tyres were even though they soaked up bumps as well as a suspension system (so it was said).

[awetmore]

Hey guys, just with making the transition to a smaller folding bike, I finally got my Schwalbe Marathon's mounted (thanks for all the help, guys + sporting life!) and they got about 75psi in there now. I really enjoy the ride and low rolling resistance, but its on a 16" wheel and was wondering what everyone else runs? no creaks or squeeks in the frame and things seem to be good.. anyone run 100 or more?

There is no reason to significantly overinflate most tires. It doesn't help the rolling resistance, and can increase it if the bike is constantly bouncing. It also reduces traction.

I run the Greenspeed Scorcher tires on my Tikit (the tires are 40-349 sized) at around 50-60psi. I re-inflate them when the pressure gets down below 40psi.

I hated the Schwable Marathons, especially in 349mm. They are a very harsh riding tire.

alex

[awetmore]

Laboratory conditions exist because they eliminate variability, thus providing much more accurate results than real world tests. Real world tests exist because laboratory conditions aren't variable enough, and thus are not generalizable to the real world. Fortunately, a happy medium exists; testing similar routes with a power meter.

Don't take this the wrong way, but your roll down tests are not going to be even close to providing you with information on differences in rolling resistance. Your cheapest bike rolled best downhill simply because it was heaviest. Now, if you repeat the experience in a vacuum and get the same results, I'd be more inclined to believe them!

Roll down tests can be done with lab conditions. The problem with rolling resistance tests done in labs is that they rarely reflect the rear world. The tires are usually tested on smooth drums that are around 6" in diameter. These bear no reality to road surfaces. The bicycle and rider are removed from the equation, even though those provide dampening and suspension.

I've been involved in the rolling resistance testing for Bicycle Quarterly. We use the same bicycle and rider for all tests. We use the same test track and time the center of the rolldown (ignoring timing from the start and end when the rider may wobble). The rider does the route 3 or 4 times and is timed by two people independently. We always use reference tires for the first and last rolldown to make sure that our times are consistent in a day. The timing is done at 5am when there is no detectable wind (using a very accurate wind meter) and in a certain temp range. The exact procedure and results are listed in BQ issue Vol 5 No 1. http://www.vintagebicyclepress.com

I think that this gives much more accurate results than a drum test. It also takes a significant amount of time.

[invisiblehand]

I wonder how that works.

I read some reviews of the Dahon Curve whoch said how fast the tyres were even though they soaked up bumps as well as a suspension system (so it was said).

EvilV ... the best explanation is on the Schwalbe website under the Tech tab.

Oh ... why am I making this difficult? :)

http://www.schwalbetires.com/tech_info/rolling_resistance

[EvilV]

EvilV ... the best explanation is on the Schwalbe website under the Tech tab.

Oh ... why am I making this difficult? :)

http://www.schwalbetires.com/tech_info/rolling_resistance

Interesting link there.

[werewolf]

I hated the Schwable Marathons, especially in 349mm. They are a very harsh riding tire.

__________________________

Could you recommend a tire that rolls better with equal flat-resistance?

Tire pressure. I easily weight over 100 pounds more than many riders on the same (20X1.5) tire - 150 pounds in the case of a small woman, so I would think that's another reason for me to keep the tire pressure all the way up at max - keep from bottoming out the tire.

On motor vehicles, anyway, I believe the #1 cause of tire failure is low air pressure in the tires, even more so in hot weather, like you get here. And it's pretty much accepted that high air pressure in motor vehicle tires = better gas mileage.

[werewolf]

I've always run my bike tires at the recommended pressure, namely the max. pressure. I've never encountered bike tires before that recommend such a wide range of pressures as these Marathons, but then I've been away from bicycling for a long time. Maybe tire pressure recommendations have changed whiel I was away, or maybe it's because I never rode on small tires before.

[jur]

Tyre pressure is an area of myth and hype.

myths:

the sidewall value is the recommended pressure. Not so, that is the max beyond which the tyre cannot be guaranteed to resist failure. This value is dependant on the carcass strength, the density of weave. The correct pressure depends on a the mass the tyre has to bear - must be high enough not to bottom out. Connected with this there is sometimes quoted a maximum mass. For a very light rider, optimum pressure is lower, as the tyre still has to 'give' a bit to absorb road irregularities.

The higher, the better. Not so, Alex already mentioned this. Beyond a certain pressure (110psi for typical roads) rolling resistance actually goes up again, since the wheel is almost as hard as the rim itself which would have appalling rolling resistance (unless on steel tracks).

The amount of drag caused by the tyres is proportional to speed. So if you're exerting 80W, it is not 20W you lose, rather it is a percentage of your power, perhaps only a few, less than what you lose through the drive train, and certainly much less due to wind drag.

[Raxel]

Tire pressure seems to be a personal choice. I always pump up to the max. pressure because I am kinda heavy and want to go as fast as I can. My GF prefers 1.5 marathon @ 60psi as it is much more comfortable than stelvio @ 100psi. But marathon did not suit my taste, even @ 100psi. Now she rides a full suspensioned moulton with conti GP @ 120psi and is happy with it.

[kraftwerk]

100 psi on my 451's Stelvio's. 80 psi, sometimes, when I am traveling in areas with broken glass.
I go as high as 110 psi for fast cruising

[14R]

100psi front wheel, 90 on rear.

[awetmore]

Could you recommend a tire that rolls better with equal flat-resistance?

Flats aren't a big problem for me, so I don't prioritize that when selecting my tires. That is a long way of saying "no" I guess. I haven't had a flat yet with my Greenspeed Scorcher tires and they have a much nicer ride than the Marathons.

On motor vehicles, anyway, I believe the #1 cause of tire failure is low air pressure in the tires, even more so in hot weather, like you get here. And it's pretty much accepted that high air pressure in motor vehicle tires = better gas mileage.

There is very little in common between bicycle tires and car tires. On most bicycles the tire is being used for suspension, while all common road cars have suspension.

[Fear&Trembling]

My weight 89kgs.

Bike: Trek F600 (unsuspended) ISO 406 wheels

Stelvios: R: 105psi F: 95psi
Kojaks: R: 90psi F: 80psi
Scorchers: R: 85psi : F 80psi
Marathon Racers: As for Scorchers.

[werewolf]

I'd like to try those slick Scorcher tires, Awetmore. The Marathons are kind of noisy. I'd been away from bicycling for along time. I can hardly believe the prices they are getting for bike tires now, more than car tires used to cost - and car tires have, what, about 1,000 times the material in them! The Scorchers are near $40 a piece.

[werewolf]

What ever happened to those bicycle tire scrapers we used to mount to brush off debris from the tire? Have they gone extinct? They're particularly effective with slicks.

[jur]

What ever happened to those bicycle tire scrapers we used to mount to brush off debris from the tire? Have they gone extinct? They're particularly effective with slicks.
They have been called of dubious value. I haven't seen those for sale anywhere.

[mrbrown]

65-75 psi on 20 x 1.5" Marathon Racers on my Dahon MU P24 (max 85 psi)

55-60 psi on 16 x 2.0" Big Apples on my Dahon Curve (max 75 psi). Too much and you lose the benefits of comfort from these tires.

90 psi on 26 x 1.25" Panaracer T-serv Messengers on my Hardrock (max 100 psi)

My LBS tells me not to hit the max, just keep it about 10% to 15% under.