Tire pressure! At what psi are you cruising?

I've had a flat recently ... I had myself to blame because I did not put any rim tape on my rims to protect the tube.

Today I fixed my flat and put some rim tape on my rim.

When inflating my tire I was wondering what the best PSI is to have a smooth and efficient ride.

I saw that my tire can handle up to 65 PSI . For now I have the rear tire on 40 PSI and the front on 35 PSI.

My bike has no suspension exept for a cheap seatpost suspension. I ride maxxis hookworm 2.5 tires with Maxxis DH 2.5/2.7 tubes.

At what PSI are you tires and please also mention what suspension you have?

40 psi on 2.35" schwalbe big apples. no suspension. Supposedly you can keep them as low as 20 psi for a softer ride and they will still roll well. I don't like them that soft, though.

If you are not driving a friction drive on your tyres, I would take them almost to the max rated - usually I run mine on 85 PSI Rear and 5 - 10 less on the front so about 75/80PSI. (my tires obviously are rated to 85PSI max). I have yet to build an ebike so this is my commuter mountain bike tyres I am referring to, but generally the higher the PSI the less tire deflection will occur and the more efficient the bike will be (although sometimes harsh if you don't actively raise yourself off the saddle for big bumps in the road).

I run 60 rear and 45 front on a set of maxxis hookworms. I run lower pressure in the front, just because it's a narrow rim, and I've had trouble with the bead seating properly on the hookworms. Otherwise 60 is perfectly fine.

I run at 40psi. Running at the max 65psi is too bumpy for my liking when at full speed on the road around town.

65 psi, but with full suspension. Slime works best at high pressure, and around here I always have a ton of thorn holes in tubes.

GPZRider said:

If you are not driving a friction drive on your tyres, I would take them almost to the max rated - usually I run mine on 85 PSI Rear and 5 - 10 less on the front so about 75/80PSI. (my tires obviously are rated to 85PSI max). I have yet to build an ebike so this is my commuter mountain bike tyres I am referring to, but generally the higher the PSI the less tire deflection will occur and the more efficient the bike will be (although sometimes harsh if you don't actively raise yourself off the saddle for big bumps in the road).

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What does friction drive have to do with it? I have friction drive and run my tires at 60 psi front and rear. I would go a bit more but I figure 5 psi below the recommended max on the tires works fine.

My simple stock tires (Trek Pure) are rated to 65 psi max, so I run them at 60 each.

I'm into speed more than comfort, since the bike is extremely comfortable already. I have no weight on my handlebars, and the seat post has suspension, so I really don't get bumped much. The bike does a bit, but not me.

i run my swiftor 2.1 at 55psi on a no susp norco katmandu and on my full susp i like 40psi

EVTodd said:

GPZRider said:

If you are not driving a friction drive on your tyres, I would take them almost to the max rated - usually I run mine on 85 PSI Rear and 5 - 10 less on the front so about 75/80PSI. (my tires obviously are rated to 85PSI max). I have yet to build an ebike so this is my commuter mountain bike tyres I am referring to, but generally the higher the PSI the less tire deflection will occur and the more efficient the bike will be (although sometimes harsh if you don't actively raise yourself off the saddle for big bumps in the road).

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What does friction drive have to do with it? I have friction drive and run my tires at 60 psi front and rear. I would go a bit more but I figure 5 psi below the recommended max on the tires works fine.

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I'm new to the forum, but I was under the impression that the general advice with friction drives was the run the tires slightly softer than normal to allow the friction roller/drive to bed into the tire slightly better increasing traction and reducing slip - is this not your experience?

I ride a BMX frame Urban Bike with no suspension other than a coil spring seat. I am currently running Maxxis Miracle tires front and rear, 20" x 2.1" at 90 pounds pressure front and rear. The tire is rated for a maximum of 110 pounds pressure. I find this high pressure helps to nullify the higher rolling resistance inherent in the smaller tire diameter. It also increases range and sharpens up the handling response. Downside is that the ride is far too rough off road. On pavement, it is acceptably smooth. This IS an "urban bike", and not a BMX/offroad.

I am currently developing a new BMX frame for front fork suspension and suspension seat post, with coil spring seat. I will run the Maxxis Miracle 20" x 2.1" rib tire on the front, and the Maxxis M-Tred 20" x 2.1" on the rear (same tire carcass and tire profile, moderate "traction tred" pattern). I will run the higher pressures on this new bike as well.

wdwrkr51

@rated front and back, 45psi, on a non-suss BMX, 20x1 3/8 tires. My push trailer has a 20x1.5 tire rated for 120psi but I run it closer to 35psi so it can grab a little better...it's flat now, and can't be repaired, so I'm planning to switch to a street tire and will probably double the psi (so about 70psi) and see how it goes.

edit; picked up new 20x1.5 street tire for the trailer rated 65psi and will probably run it 50psi.

GPZRider said:

I'm new to the forum, but I was under the impression that the general advice with friction drives was the run the tires slightly softer than normal to allow the friction roller/drive to bed into the tire slightly better increasing traction and reducing slip - is this not your experience?

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Welcome to the forum!

I've seen other people talking about running lower pressure with friction drive and it does sound logical but with a setup that's working correctly I don't think it's necessary.

I have close to 3000 miles on the tire I'm using friction drive on and it still has a lot more life.

Again, welcome to ES. Do you have a friction drive setup?

I run 60 in the front on some cheap Bell 'kevlar' road tire, and 25-30 out back on the cheapest MB tire I can find.

I do 50 lbs with my full suspension trike and Kevlar Walmart tires and it is a bit harsh on regular roads but the suspension helps for bigger bumps and dips. I like the better control at higher psi but I can see where if you have a bad back some Big Apples and a full suspension can help cushion the smaller bumps. The Big Apples at 30 lbs were a bit softer but wore out too quick for expensive tires.
otherDoc

more psi means better efficiency, and much less liklihood of puncture due to pot- holes, kerbs etc. On the down side the ride's a little harsher and you get less tolerance of spoke holes and damage to the outer cover. I run pretty high pressure but not maxxed out...
We max out the greenpower race cars, to well over 100 psi.
For a friction drive, lower psi gives more tolerance of wheel/tyre radial run-out (esp. for a fixed drive roller)

bobc said:

For a friction drive, lower psi gives more tolerance of wheel/tyre radial run-out (esp. for a fixed drive roller)

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If you have that much radial run-out then you need to correct the problem. Lowering tire pressure would just be a band aid fix.

I am running pretty high pressures for my friction drives @ 80-100psi, on the 700x23c tires. No issue with slipping, can transfer upto 7Nm.
With narrowish MTB tires I can get up around 13Nm, just followed the recommended pressures for the tires, nothing special.

For my hub motor bike (x408 dual suspension) I run Schwalbe Marathon Plus's 26" x 1.75", they are down around 50psi from memory.

- Adrian

Dual suspension bike. I run around 40psi front, 45psi rear on Specialized Compound Control tires. They are rated for 100psi. I tried lower pressure but didn't like the feel.

Gary

EVTodd said:

Again, welcome to ES. Do you have a friction drive setup?

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I do not yet, but I have already acquired materials to attempt a clone of adrian_sm's commuter booster. I work as a CNC miller, setting and running mills in a small engineering business so am hoping to not have too much difficulty with it all. I have also seen your build and have also been tempted to build something like yours IN BETWEEN my front fork legs ( I have pace rigid forks replacing my suspension - seems to be just enough room for the 63/74 motor). I'm still in the planning stage (and learning - what a curve!), messing around with CAD etc, I'm glad I found this forum, it appears to be a WEALTH of information. In particular I am finding a lot of information on the electronics side, which I am not so used to dealing with.

3 years ago I used to commute to work on my road equipped MTB 8.5 miles each way 3 - 4 days a week, there are 2 serious hills on the way in. I did this for about a year even in the depths of winter, however after an op I took a break, and have struggled ever since to get back into it. In replacement I now ride a small sports motorbike to work, and although it is the fastest form of transport yet (can do home to work in less than 20 mins, 35 mins ish by pushbike, and 25 - 45 by car, traffic dependant) I'm piling on the pounds and I miss being in the open air (full biker gear kinda takes that away).

I'm really looking for a riding experience as close to un assisted riding as possible, with just a way to up my average speed a bit, and help me on the hills, I do NOT want another motorbike! ideally I would like to reliably (wind or not) do my work commute in under 30 mins - whilst getting a small work out. And if it could end up good enough for 5 days a week, year round, then I would probably sell the motorbike all together.

Thanks for the welcome!

I have played around with the pressure on my Schwalbe Big Apples, and I find that they absorb bumps at the high end of the pressure almost as well as at the low end, so right now I am running them 60 PSI front & rear, they max at 65, but I want to leave some room for them to expand with hotter temps while still being under 65 PSI.

All my tires that I use are 90% of the time on the road, so I use them at or near the maximum pressure.

So !, what do we conclude for tire pressure ??
Seems like people are using everything from 25 to 100 psi for various reasons and different tires. !
My conclusion..and from experience... It isnt really critical !.
I like to think my tires at high pressure roll much easier...but i dont see it in W/hrs per mile or total range.
Conversely i like to soft ride of lower pressures, but worry about pinch flats..however i have yet to suffer from one !!

Floont said:

If you want greater speed and less resistance, high pressure is the way to go. If you need traction or are riding over rocks, roots and gravel or sand, the low pressure is a benefit.
FA

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Not many folks go "cruisin'" on rocks ,roots sand etc ( ref the thread title), but yes you are correct ( you would probably need different tires too)
But for "crusin' " on pavement with "street" tires.. there is still a compromise between the theoretical advantage of high pressure, ( not always obvious).. and the reality of a comfortable ride at low pressure ( with a hardtail frame) :?

Lots of variables so what works for me may not work for you.

I run 8 psi in my Maxxis FBR 26x4.8" and I run 100 psi in some of my narrow pavement only tires.

Only restrictions are don't exceed the pressure printed on the sidewall on the high end and don't go so low that the sidewall flexes excessively on the low end.

Schwalbe is one of the few manufacturers that give a minimum and a maximum inflation pressure on for their tires on their web site...not sure if both the min and max are printed on their tires .