Tire Pressure

[Blueribbon]

My brother has a Mystery trike, H-D Softail (2009) with P205/70R 15 on the back and he has no clue what to run his tire pressure at. Any constructive suggestions would be appreciated.

 

[Steve on 3]

I run 24 in my triglide but not sure how that translates to his. His manufacturer website might have some info.. Sorry I could not be more help.

 

[HarleyPap57]

My brother has a Mystery trike, H-D Softail (2009) with P205/70R 15 on the back and he has no clue what to run his tire pressure at. Any constructive suggestions would be appreciated.

I have dropped my Air Pressure in the Rear Dunlop's that came on my '14' down to 22psi and it's made the ride WAY BETTER. I'm going to drop them down to 20psi tonight when I get off work and ride home with that to see if that makes any difference. Some people are running down to 18 and 16psi on their rear tires. Hope this helps a little.

 

[HDB0B]

Agree .... A lot depends on the stiffness of the sidewall. A stiff sidewall might go down to 16 or 18 psi .... versus a soft sidewall like a Goodyear comfort tread which would be in the 20 to 24 psi range. I like 22 - 24 on my Tri Glide Stock P20565R/15 Dunlops. 26 psi is the lowest number the Tire & Rim Association currently lists for automotive tires .... however we are much lighter vehicles.

Bob orag:

 

[roadking2]

TriGlides are solid axle and that makes a difference as far as ride comfort goes. If the trike he has is IRS, then 26 rear, 36 front is what most trikes call for and I believe that's what the TriGlide owners manual says. Mystery makes solid and IRS, so find out which he has and air it up accordingly. The reason solid axle owners lower it is mainly because the 26 psi makes the ride to rough, but that's a function of having a solid axle. They compensate by making their rear tires softer. One of the benifits of IRS is a smoother ride.

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Agree .... A lot depends on the stiffness of the sidewall. A stiff sidewall might go down to 16 or 18 psi .... versus a soft sidewall like a Goodyear comfort tread which would be in the 20 to 24 psi range. I like 22 - 24 on my Tri Glide Stock P20565R/15 Dunlops. 26 psi is the lowest number the Tire & Rim Association currently lists for automotive tires .... however we are much lighter vehicles.

Bob orag:

What does you owners manual say? Does it recommend 26, 36?

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[HDB0B]

FWIW:

"From Lehman Trikes:

There has been a lot of confusion and misinformation out there when it comes to tire pressures for trike riders. Most all trikes have a motorcycle tire up front and automotive tires in the rear. The motorcycle compliance label has a recommended pressure for both the front and the rear tires. Now that your motorcycle is a trike are these still the pressures to use? Since we are trying to clear up the confusion and misinformation… the answer is yes and no!


Let me explain more fully. We, Lehman Trikes, have always recommended that you maintain the same pressure the motorcycle manufacturer lists on the compliance label for the front wheel. There is no reason to change this pressure. That’s the "yes".


The "no" is a bit more involved. First of all, the two automotive tires like those installed on the rear of your trike are a completely different design than the single motorcycle tire they replace. Now for some history. Lehman Trikes has been building and riding trikes for 25 years. Our founder, John Lehman, and many of the dedicated trike riders that work here have experimented for years trying to find what air pressure in the rear tires gives you the best ride, handling and tire life. What they found and recommended for years was an air pressure in the 20 to 22 psi range worked best.


So why, if you look at a current Lehman Trikes Owner’s Manual or the Owner’s Manual for a H-D Tri Glide, do you see a 26 psi recommendation for the rear tires? When I came to Lehman Trikes several years ago one of the things I was asked to do was to confirm with the manufacturer of our tires that they would support our recommendation of 20 to 22 psi air pressures for our application. What I learned is that no tire manufacturer will recommend anything less than 26 psi for standard automotive tires.
Where the 26 psi number came from is an interesting and somewhat involved story. There is a regulatory organization called the Tire and Rim Association (T&RA) which, of course, standardizes specifications for all different applications for tires and wheels (rims). One of the things that they provide is a load carrying capacity for each tire size at different air pressures. In their old reference books they listed load carrying capacities for tire pressures all the way down to 20 psi. I don’t know what year they changed but in 1999 they still listed load carrying capacities down to 20 psi.


Do any of you remember the big public fight that went on between Firestone and Ford Motor Co a few years ago? As I recall, people were rolling over in their Ford Explorer’s and Ford and Firestone were vigorously pointing the finger at each other. The final out come was that it was determined that people were reducing the air pressure in their tires to improve ride quality. That would not have been a problem but they failed to increase the pressure when the vehicle was more heavily loaded. As a result, the T&RA elected to eliminate the lower pressure ratings from their reference books. In support of the T&RA, the tire manufacturers will not support running their tires at anything less than 26 psi.


So how much difference does it make? Why not just run them at a higher pressure? Running the rear tires on your trike at a higher tire pressure has a dramatic impact on how the trike rides and handles. For each additional psi of pressure you increase the rigidity of the sidewall. At maximum pressure the sidewalls of your tires are quite rigid. Rigid sidewalls will increase the occurrence of the low speed "head shake" inherent in all three wheeled vehicles. They will also transmit more of the bumps in the road to you and your passenger. As you reduce the tire pressure it allows the sidewall to provide additional "cushioning" when riding over irregularities in the road surface. Certainly you do not want to reduce the air pressure too far because that will adversely affect the handling of the trike.
The "cushioning" effect of the sidewalls is, of course, reduced if you are using a tire that has very little sidewall. For example, those 18 or 20 inch rims that look so cool on the back of your trike do all the wrong things for ride comfort and low speed head shake. A standard 15 or 16 inch rim with a properly sized, properly inflated tire will give you the best ride quality and the least amount of head shake.


The most commonly used tire on the rear axle of a Lehman Trike is the P205/70R15. As a point of interest, in the 1999 T&RA reference book it lists a load carrying capacity of 1146 lbs for a standard P205/70R15 tire with 20 psi of air pressure. "

 

[Sloufoot]

Yep 20-22psi ! NOT 15-18psi. But run whatever you value things at.......

 

[HarleyPap57]

FWIW: "From Lehman Trikes: There has been a lot of confusion and misinformation out there when it comes to tire pressures for trike riders. Most all trikes have a motorcycle tire up front and automotive tires in the rear. The motorcycle compliance label has a recommended pressure for both the front and the rear tires. Now that your motorcycle is a trike are these still the pressures to use? Since we are trying to clear up the confusion and misinformation… the answer is yes and no! Let me explain more fully. We, Lehman Trikes, have always recommended that you maintain the same pressure the motorcycle manufacturer lists on the compliance label for the front wheel. There is no reason to change this pressure. That’s the "yes". The "no" is a bit more involved. First of all, the two automotive tires like those installed on the rear of your trike are a completely different design than the single motorcycle tire they replace. Now for some history. Lehman Trikes has been building and riding trikes for 25 years. Our founder, John Lehman, and many of the dedicated trike riders that work here have experimented for years trying to find what air pressure in the rear tires gives you the best ride, handling and tire life. What they found and recommended for years was an air pressure in the 20 to 22 psi range worked best. So why, if you look at a current Lehman Trikes Owner’s Manual or the Owner’s Manual for a H-D Tri Glide, do you see a 26 psi recommendation for the rear tires? When I came to Lehman Trikes several years ago one of the things I was asked to do was to confirm with the manufacturer of our tires that they would support our recommendation of 20 to 22 psi air pressures for our application. What I learned is that no tire manufacturer will recommend anything less than 26 psi for standard automotive tires. Where the 26 psi number came from is an interesting and somewhat involved story. There is a regulatory organization called the Tire and Rim Association (T&RA) which, of course, standardizes specifications for all different applications for tires and wheels (rims). One of the things that they provide is a load carrying capacity for each tire size at different air pressures. In their old reference books they listed load carrying capacities for tire pressures all the way down to 20 psi. I don’t know what year they changed but in 1999 they still listed load carrying capacities down to 20 psi. Do any of you remember the big public fight that went on between Firestone and Ford Motor Co a few years ago? As I recall, people were rolling over in their Ford Explorer’s and Ford and Firestone were vigorously pointing the finger at each other. The final out come was that it was determined that people were reducing the air pressure in their tires to improve ride quality. That would not have been a problem but they failed to increase the pressure when the vehicle was more heavily loaded. As a result, the T&RA elected to eliminate the lower pressure ratings from their reference books. In support of the T&RA, the tire manufacturers will not support running their tires at anything less than 26 psi. So how much difference does it make? Why not just run them at a higher pressure? Running the rear tires on your trike at a higher tire pressure has a dramatic impact on how the trike rides and handles. For each additional psi of pressure you increase the rigidity of the sidewall. At maximum pressure the sidewalls of your tires are quite rigid. Rigid sidewalls will increase the occurrence of the low speed "head shake" inherent in all three wheeled vehicles. They will also transmit more of the bumps in the road to you and your passenger. As you reduce the tire pressure it allows the sidewall to provide additional "cushioning" when riding over irregularities in the road surface. Certainly you do not want to reduce the air pressure too far because that will adversely affect the handling of the trike. The "cushioning" effect of the sidewalls is, of course, reduced if you are using a tire that has very little sidewall. For example, those 18 or 20 inch rims that look so cool on the back of your trike do all the wrong things for ride comfort and low speed head shake. A standard 15 or 16 inch rim with a properly sized, properly inflated tire will give you the best ride quality and the least amount of head shake. The most commonly used tire on the rear axle of a Lehman Trike is the P205/70R15. As a point of interest, in the 1999 T&RA reference book it lists a load carrying capacity of 1146 lbs for a standard P205/70R15 tire with 20 psi of air pressure. "

Great information, Thanks for sharing it :Agree:

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So this morning I rode to work at 20psi. Looking at the trike from the back the tires actually look like radials on a car with just a little bulge at the bottom. The bike road extremely smooth and stable riding both back country roads between 50 and 60 and in the interstate at 70 to 75. No heat build up just straight and steady.

I remember from my days drag racing many years ago we always ran street tires but dropped the tire pressures way down, sometimes to 20 psi to get better traction depending on the track conditions. Only thing you had to worry about was breaking the bead loose on the starting line when the green light came on.

Knowing I'm not going to do any burnouts on my trike and so far it's rode and handled like it's on rails with these pressures I think I'll stay right there. May go to 22psi when riding two up but 20psi is great for just me onboard.

 

[Blueribbon]

All, thanks so very much. I'll pass this link on to my brother.