seekermeister

I just took delivery of my new Worksman Port-O-Trike, which has 20" tires. I noticed one tire is significantly softer than the other two. Intending to air it up, I've been looking for information on what would be an ideal pressure to run in them, but there seems to be a wide variation in pressures, which leaves me confused. Obviously the trike doesn't need the super high pressure of higher speed bikes, but what is too high or too low?

BassNotBass

Tire pressures are first and foremost dependent on the tire's construction so adhere to the suggested pressures stamped on the sidewalls. From that point it's up to you to decide what pressures work best within the tire's ratings.

seekermeister

Thanks, that was the answer I needed.

jur

And yes you're right, load is distributed, so less pressure is good. Less than the sidewall maximum value. How wide are they?

seekermeister

1.75

jur

I would hazard a guess of 40psi max for the back, for a more plush ride. Depends on how much you are going to load it up. Obviously you wouldn't want to pinch-flat when hauling heavy loads.

BassNotBass

I have several low grade Kenda tires in 20X1.75 that state a max pressure of 35 and 40 psi. They utilize a very stiff rubber so they most likely are more resistant to pinch flats at relatively low pressures than a tire with a more supple rubber compound and thinner sidewalls. My Schwalbe Energizer Plus and Marathon Plus in 20X1.75 have a working range of 50-70 psi.

Again, the construction of the tire is what determines the pressures first and foremost... stay within the limits specified.

seekermeister

These tires are Shin, which are Chinese made. The inflation range is 35-50psi. About the only other thing I know from reading the sidewalls is that they are nylon. I'm thinking about getting some brand name kevlar tires, but it will probably be a little while before they fall into the budget. Originally, I intended to frequently max out the weight capacity of the trike, but I also just bought myself an old minivan, which I can use for hauling my heavier loads, so I doubt it will ever have to carry more than 200 lbs payload.

BassNotBass

That's good... in light of that I'd have to side with Jur's recommendation of ~40 psi. Start with that and play with various pressures until you find what works best for you.

seekermeister

This discussion has caused another question to start jumping around in my head. Until now, I've figured the reason for the lower weight limitation of folding trikes over their counterparts was simply that the folding joint was the weakest link, but considering the fact that both the Adventurer and the Jorvik claims an additional 50 pounds on the maximum capacity, and they don't look any different than any other folding trikes with which they complete, it would seem likely that there is another factor involved....maybe they use better tires? If a person did install better tires, allowing higher tire pressures, would it be safe to carry a heavier load than the manufacturer set as maximum?

catgita

If you are at max pressure and are still pinch flatting, the tires are limiting. Not likely.
Wheels may be be a limit, especially on a trike, but when overloaded they tend to have a short life rather than fail suddenly.
Frame limits are a combination of engineering and lawyer set limits. Also not a hard limit, and Clydesdales often exceed the ratings. Again, mainly indicates a shorter life, not a point of pass or fail. Warrantee may be void.
Same for many other parts.

But if you see the same frame rated differently when sold with different parts, you can compare and change parts accordingly.

seekermeister

Clydesdales...at first I thought you were talking about horses, until I did some checking.

osco53

My Dahon speed P8 with Its cheapo 20 X 1.75's state a max psi of 65
I'm 175ish and like 50 in the front and 55 out back. I ride on all kinds of city surfaces,, never a problem.

fietsbob

read the tire casing numbers there lies your answer .. cheaper tires wont handle high PSI.
Wider , higher volume, lower pressure..

seekermeister

When browsing some tires online, I noticed that most seem to have a small scale of rim sizes they will fit, rather than just one, but what about the other way around? What is the maximum width of tire that a specific rim (1.75) will fit?

fietsbob

keeping the rim width you have a secret, so people have to guess?


inside and outside is more useful measurements ..

seekermeister

Secret? I don't understand what you mean, I said it is 1.75. Or are rims sized in some manner I don't understand?

fietsbob

The rim aint an inch and 3/4 across Is It ? your are looking at the Tire

Since you are not able to respond with appropriate data . stick with what you have .


consult a Bike shop to see what you are asking this forum to blindly guess ..

seekermeister

Pardon me, if I assumed that the collective knowledge of the forum membership could comprehend the issue better than I could. Perhaps I should ask my questions elsewhere.

jur

Try 40psi,put a test load and see how it goes. The tyre should have some amount of widening/drop when seated with the load, not more than say 1/5th of the height of the tyre.

seekermeister

That is what I'll do. Thanks.

jobtraklite

I think what they are saying is you are giving the tire size. But they need to know the interior rim width. I use the following



which I downloaded a long time ago from Sheldon Brown's website, I believe.

invisiblehand

This sounds reasonable.