Utility Cycling - Utility Bike Tires?

Hi,

What type of tires do utility bikes usually have and how much pressure do they typically hold?

I ride a 7 speed cruiser with wide tires rated at 40psi that I use mostly for grocery shopping. It feels a bit "mushy" when I have a load of groceries in my rear baskets (two side baskets and a milk crate on top).

Does this matter? Will it reduce the life of the wheel or bike in some way?

Should I (can I) inflate the tires to a higher pressure than they are rated for? How much?

Should I get different tires? What psi?


Thanks

Hi,

What type of tires do utility bikes usually have and how much pressure do they typically hold?

I ride a 7 speed cruiser with wide tires rated at 40psi that I use mostly for grocery shopping. It feels a bit "mushy" when I have a load of groceries in my rear baskets (two side baskets and a milk crate on top).

Does this matter? Will it reduce the life of the wheel or bike in some way?

Should I (can I) inflate the tires to a higher pressure than they are rated for? How much?

Should I get different tires? What psi?


Thanks


The rule of thumb on tire inflation per Sheldon Brown is 15% less from maximum. Other that that it's up to how conditions feel to you. If you need more float over the ground then reduce pressure if you feel that you have too much drag and the roads are smooth then increase pressure.

As for what tires are used on utility bikes it depends. As for your bike as long as you not getting pinch flats your pressure is fine also a lot of cruisers ride around on cheap rims that may not handle much pressure.

One thing to think about is that patching a tube can be far more trouble on a loaded bike. Percentage wise, armored tires ( like big apples) are not the weight hit they would be on a road burner.

I use Big Apples 26 x 2.35 on my Big Dummy and I put the max 55psi when I hall heavy loads, this way I know it hold 140 kg per tire. Also the tire will run cooler loaded at the max psi.

The rule of thumb on tire inflation per Sheldon Brown is 15% less from maximum.
Don't think Sheldon ever stated such a rule of thumb, and it would make little sense to give that recommendation without considering either the load being carried or the size of the tire. But he may well have reiterated Jan Heine's recommendation to adjust the pressure so that the tire sidewall height is reduced by about 15% when loaded :
http://www.bikequarterly.com/images/TireDrop.pdf
That recommendation was based on measurements of rolling resistance which showed that this resulted in the lowest tire pressure without incurring a significant rise in the resistance. There's an online calculator to determine this pressure after inputting the load on the wheel and the tire width at:
http://www.dorkypantsr.us/bike-tire-pressure-calculator.html

But I agree that the original poster will not cause any harm to her wheel or bike as long as the tire pressure is sufficient to avoid pinch flats when hitting bumps.

Some other guy (Brandt, maybe?) has a 15% sag theory. I think that's what your thinking of, Sirrus Rider.

Pretty much states that tires are at proper inflation if the squish 15% while loaded.

Jobst Bradt makes sense as he did a lot of rolling resistance experiments.

I use kevlar tires on both my bike and trailer. For my bike I run the tires around 65psi. I put them closer to the 80psi max if I'm carrying more weight than usual. I rarely fill my trailer tires to max psi for it make the trailer really springy when I hit bumps in the road.

Jobst Bradt [sic] makes sense as he did a lot of rolling resistance experiments.
But not these as I previously posted above (post #5) complete with a link to Jan's article.

But not these as I previously posted above (post #5) complete with a link to Jan's article.

Yep, that's the one for sure. I shoulda hit refresh after reading thread / before posting.

Some other guy (Brandt, maybe?) has a 15% sag theory. I think that's what your thinking of, Sirrus Rider.

Pretty much states that tires are at proper inflation if the squish 15% while loaded.

Jan Heine based his work on Frank Berto's research on optimal tyre pressures and they have worked together quite closely through many, many years.

I run Bell Dirtster 26x1.75, rated to 65 psi max, but I usually have 60 psi in them. They have kevlar flat protection and only cost $15/tire. Of course, I don't put a lot of weight on my bike (me + ~50lbs max tongue weight) because I pull a trailer.

On my R20 I've got about 800 miles on them with no problems. On my Kona (my primary trailer puller), I've got about 500 miles on them with no problems.

... I rarely fill my trailer tires to max psi for it make the trailer really springy when I hit bumps in the road.

Maybe lower pressure would be better for light loads, but I've found just the opposite for heavy loads, especially top-heavy heavy loads.

I find that when I'm carrying a top-heavy load (cement mixer, bins stacked two high, or even a washer and dryer because they're tall), I like to have max pressure in my trailer tires. Otherwise, bumps will cause the trailer to rock from side to side. Having a higher tire pressure helps control this, and limits it once it starts.

FWIW, I have carried light loads (just one of my children) to very, very heavy loads (350 pounds on one trailer with another 150+ pounds on a trailer behind it).

Lower pressure works for lighter loads and following that 15% deflection rule is effective for bicycles and trailers alike... too little pressure and you can pinch flat as well as have a bike that feels squirelly.

I,too,ride cruisers but I run my tires rock hard all the time to cut rolling resistance on the fat tires used on cruisers.

I find the rolling resistance at lower pressure make my cruiser feel like I'm dragging a boat anchor behind me!

26x2.3 big apples here as well. Normally I am around the 25-30 psi range but when carrying a very heavy load I will bump it up to 45 or so. Big apples are designed around much lower pressures through being a higher volume tire so those pressures would feel horrible on most other tires ridden on pavement. Oh and if I plan to be on a lot of bumpy dirt roads I drop them to 20ish.

The tires have been great for me, over 1k miles and they show very little wear and no flats yet and I have carried a 180lb person and a little gear on the back before.

I have Fat Franks 2.35" with the pressure usually around 30psi. This gives a very smooth and cushioned ride which I like. I think I do end up going a bit slower, but that is not such a bad thing.

I use big apples 26x2's.

I just do a visual inspection really. I don't pay attention to PSI. What really matters is the weight of your bike, yourself, and any additional load. I check to make sure there is a slight bulge in the rear tire, and more bulge in the front, where road vibration affects you the most. The extra give offers shock absorbance and the helps compensate for how air expands as the tire gets hotter the longer it rolls.

For me, weighing almost 200lbs and having a bike and load ~50lbs, this translates to a max of 40-45 PSI in the rear, 30-40 in front. When I had 1.5 tires, I would do about 55 PSI rear, 45 PSI front. I sometimes change the pressure according to my load, but again, I don't really pay attention to numbers and just do visual inspection.

The fat tires like big apples are designed to offer suspension, so pumping them to max PSI really doesn't affect rolling resistance, especially considering how rough typical city streets and country roads can be (I rarely experience smooth pavement). Only skinny road tires benefit from max PSI, and that benefit is largely reduced as the terrain gets rougher.

Cruiser bikes are supposed to have mushy tires, that is their suspension ..

Another word of warning for lowering tire pressures combined with bigger loads, not all sidewalls can take it. I've been running Kenda K-rad, (26x1.95) at ~45-50 lbs. After doing regular 20-40lbs pannier runs this fall, I've noticed that my sidewalls are popping threads. Good excuse to find some new rubber.

MTB tyres are designed to have tougher sidewalls and can be run at much lower psi... you can go by the tyre ratings to determine the low limit but factor in rider weight and load and make sure the deflection is not excessive.

My winter bike has tyres that run 40-65 psi with really stiff sidewalls I run them at around 50 psi and will up the rear pressure if I am pulling my trailer as I did tonight as I was towing 80 plus pounds.

http://www.ravingbikefiend.com/bikepics/2011norcowinterbike2.JPG

FWIW, Jobst Brandt thinks the 15% drop scheme is bunk because when climbing or descending a steep hill, nearly all of the weight will be on one tire, putting it at greater risk for a pinch flat. It hasn't let me down yet, though.

I've been running on Panarace Pasela tourguards 26 x 1.75 at 60psi. They have good flat protection, roll nice, seem to be handleing a combined load of 300lbs without any problems.

I run 26 x 1.75 with 65 to 70 pounds of pressure. Unless I am loaded. I'll let some air out of the tires and drop it to 55 to 60 for the load.

Maybe lower pressure would be better for light loads, but I've found just the opposite for heavy loads, especially top-heavy heavy loads.

I find that when I'm carrying a top-heavy load (cement mixer, bins stacked two high, or even a washer and dryer because they're tall), I like to have max pressure in my trailer tires. Otherwise, bumps will cause the trailer to rock from side to side. Having a higher tire pressure helps control this, and limits it once it starts.

FWIW, I have carried light loads (just one of my children) to very, very heavy loads (350 pounds on one trailer with another 150+ pounds on a trailer behind it).

I've carried near 300 Lbs. of groceries in my utility trailer, and very light loads, and higher tire pressure sure helped (both in the trailer and on the bike) with high weights. Low tire pressure led to LOTS more rolling resistance, and yes, the load shifting side-to-side was worse with low pressure.

Wider tires can be run at lower pressures because the increased footprint will support more weight. I run big apple 2.35 on snowcat rims and can run them at 25psi unloaded and I will add enough air to not risk pinch flats and to avoid squirrely handling when I carry a load. When I put my skinnier studded tires on in the winter, I need to bump up the pressure to arround 45psi.