Rear Tire Pressure

[FirstTrike]

What air pressure do you run in the rear tires? On my 21 Tri Glide the manual says 26psi.

Thanks

[PosseRider]

What air pressure do you run in the rear tires? On my 21 Tri Glide the manual says 26psi.

Thanks

20-22 for me

[ultrafxr]

Same here.

[DOKK]

I'm one of the few that runs 26 in mine but I have also replaced the rear suspension and added a lift kit.

[hydraglide]

I'm one of the few that runs 26 in mine but I have also replaced the rear suspension and added a lift kit.

Same for me… rides great, gas mileage with my Stage 2 is quite acceptable.

IMO, when you start lowering the tire pressure, your gas mileage will decrease, and while your ride may “feel softer”, you run the risk of decreased cornering stability due to more “give” in the sidewalls… not to mention your tire life will also decrease.

[cubalz]

24 psi in mine

[Notgrownup]

I do 24 because we have some pretty good weight on the bike. I tried lower but didn’t feel it was wise. My gas mileage sucks enough already plus I have the comfort lift with 14” pro Action set up. It’s going on the lift tomorrow to tweak the shocks a bit.

[FirstTrike]

Same for me… rides great, gas mileage with my Stage 2 is quite acceptable.

IMO, when you start lowering the tire pressure, your gas mileage will decrease, and while your ride may “feel softer”, you run the risk of decreased cornering stability due to more “give” in the sidewalls… not to mention your tire life will also decrease.

Thanks for the reply. What cam did you use on your stage 2 and what did you do on the exhaust? I am thinking of doing a state 2 on my 21.

[ultrafxr]

I agree with all that has been said but I see no mention of weight. Tire pressure must be able to support the load it is subjected to in order to perform properly. See the attached article from Lehman trikes regarding tire pressure. They state that a load chart indicated a 205/70R15 tire will support 1,146 lbs when inflated to 20psi. Now our trikes have a 65 series tire not a 70 series but I really do not think that would make much difference.

The weight of the TG is 1,243 according to the HD specs. Adding for example a 200 lb rider, a 160 lb co-rider and 100 lbs of cargo nets 1,703 lbs total weight. No idea of weight distribution but I'll assume 60% on the rear which equals 1,021 lbs divided by two so each tire must support 510 lbs which is way below the load limit mentioned above.

I have no problem running 21-22 psi and did so on a recent 8,500 mile road trip running two up and fully loaded. No problems or issues. Each to his/her own but I'll stick with the reduced pressure for a better ride.

Here is the Lehman article:

WHAT IS THE CORRECT TIRE PRESSURE FOR MY TRIKE?

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 recommendedpressure for both the front and the rear tires. Now that your motorcycle is a trike are these still the pressuresto 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 themotorcycle 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 area 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 thatwork 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 to22 psi air pressures for our application. What I learned is that NO Tire Manufacturer will recommend anything less than26 psi for standard automotive tires.

LEHMAN TRIKES: 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 fortires and wheels (rims). One of the things that they provide is a load carrying capacity for each tire size at different airpressures. 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 ateach 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 notwant to reduce the air pressure too far because that will adversely affect the handling of the trike.

THE IMPORTANCE OF PROPER TIRE PRESSURE (CONT.)TECHNICAL HIGHLIGHTS:

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 andlow 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.

[Mykneesbehurtin]

Thanks for the reply. What cam did you use on your stage 2 and what did you do on the exhaust? I am thinking of doing a state 2 on my 21.

I did a stage 2 on my 17, but I didn't use all HD parts. Cam is a S&S 465 which is their torque cam, Fullsac Sportpipe head pipe, SE air cleaner,SE Street Cannon mufflers, S&S lifters along with a TTS tuner and full dnyo tune. My 107 went from 76 hp to 96 hp and from 90 ft lb torque to 106 on the torque. At 2300 rpm it has 102 ft lb torque, which for my riding style is perfect. Tons of low end for riding 2 up and pulling my trailer.

[headheaded]

Been running 22lbs. for years in my rear tires with no problems. Much better ride.

[Zammy]

I've been running 22# in the rears since we moved to a trike in 2015, nary a problem and we ride pretty darn hard in the twisties.

[hydraglide]

Thanks for the reply. What cam did you use on your stage 2 and what did you do on the exhaust? I am thinking of doing a state 2 on my 21.

I used the Harley “torque profile” cam… Exhaust I put on Khromewerks slip ons. Don’t forget the intake too. I used the Screamin’ Eagle Ventilator Extreme air cleaner.

Very happy with the final result.

[David792]

Thanks for the reply. What cam did you use on your stage 2 and what did you do on the exhaust? I am thinking of doing a state 2 on my 21.

Installed my stage 2 this past winter with all HD parts. I think it's a 447 cam. I run my rear tires at 24psi. Rode a big loop of 2000 miles through Canada and averaged 40 mpg. I know that sounds crazy, but we were 2 up and kept it between 60 and 65 to enjoy the scenery. When I go over 4000 rpm the mpg really starts to suck.