Just found this on Lehman Trike's stuff: For Your Info:
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.
Thank you good article.
Stallion #406 // 2013 Tri-Glide
I run my 2009 Triglide with 20lbs in the rear tires...with the Mrs. on board and fully loaded...runs great, holding the curves and when it's raining, sticks a lot better in the turns. Believe me, 20lbs works great. I weigh in around 235 and the mrs around 120. I believe Dennis runs around the same air pressure even pulling a trailer! So lower that rear pressure boys, your butt will appreciate it and it will handle much better.
just a thought..................
Diesel
Interesting, what does Harley, or the builder recommend? My trike is a 2005 GW with a Road Smith conversion. Road Smith recommendeds 26 to 30 lbs; 20 would probably make for a better ride, but I'm thinking I don't want to go that far under the recommended.
Harley recommends 26 in the rear, I ran 24 in the rear of my 2010 Triglide. Those of us with IRS trikes can run the higher rear tire pressures and still get a smooth ride, I run 28 which is the recommended pressure for the rear of my 2012 Hannigan. The straight axle on the Triglide has a bit of a harsher ride when it comes to bumps, so the lower tire pressure helps smooth it out a bit.
http://i1347.photobucket.com/albums/...pswnuweejq.jpg
Red Ultra Powered By Head-Quarters 120, Easy Clutch Pull By ClutchWIZ. 2012 GL1800 Hannigan. I've yet to ride a stock Harley which wasn't in need of a mechanical intervention.
Yes, you get the 'feeling' of those big bumps, but I think that's the nature of the beast.
Diesel,
Glad you re-posted this. I have been running around 20 PSI for several years on my 2011 TG. After I got the trailer I never felt the need to change. I started out just going down a couple pounds at a time and found the ride improvement was noticeable. Rode a while at 16PSI, then found 20 felt about the same so left it there.
Enjoy the rides folks,
Dennis
Wish I was comfortable with that on my Road Smith. If I'm feeling real brave sometime, I might run them down to 20 psi for 20 or so miles, see if they heat up.
Saw a lot of responses on this subject stating they're running the air pressure down around 20psi. I still have the stock Dunlop's on my '14' TG. I checked mine last night and they are still at 26psi. I decided to drop mine down the 22psi to see if that made a difference and boy was I surprised. This morning riding to work was WAY BETTER than before!!! Tonight when I get home I'm going to drop down to 20psi to see what if any difference that makes.
2014 Big Blue Pearl / Vivid Black, 1.5" Lift Brackets, Street Cannon Mufflers, 10" Wind Splitter Windshield, Daymaker LED Fog Lights, Passing and Fog Lamps work on both High and Low Beams, BAL-1R Rear Taillights, Dunlop American Elite Rear MT90B16 (34AE92) on Front turned backwards, Dynojet Power Vision Turner, De-Cat Headpipe just for a start.
That sounds Great! Remember back in 1999 the Tire and Rim Association said, "your tire at 20psi can support over 1150lbs safely. Our Trikes weigh in at 1180 and change so both tires are safe for 2300lbs at 20psi......you will really noticed the ride difference.....
Diesel
TBEAR
2010 Triglide Harley Davidson
V&H Exhaust,True Duals, Big Sucker Ac,,557 S&S Cam,SE Compensator 2014, oil cooler,EBC r.brakes,Progressive air-shocks,Floorboard extensions,rear fender bras, Dynoed,krome-werks 2+2 bars, and a sheep wool butt protector....