Very interesting, but I have noticed the same thing on two wheelers. I'm thinking the air pressure some use two or three wheels is the culprit. If one uses close to 10 lbs more and puts a tire made for the rear and reversed you would have a stiffer sidewall than one using a front radial with the proper pressure. Thanks for your input.I agree with what Jerry said!! I want that front tire standing up strong instead of rolling under on turns. I had the pleasure of riding north from Alpine to my home in SE NM with my wife and some other triking friends. The wind was blowing a gale from almost directly to the west, and most of that route home put us at just about right angles to the wind. We stopped in Pecos for a rest (boy, did we need it!!) I knew that I had been holding constant pressure on the bars to point the front tire slightly into the wind to be able to hold my position in my lane. Most of that route involved two laned road, and we road well apart from each other and tried to stay in the center of our lane toward the center line. The occasional gusts above the 50 mph wind would move you toward the edge of the pavement, and some of us found ourselves on the narrow paved shoulder a few times.
We parked at a convenience store after getting fuel, and three of us were sitting on the pipe barriers in front of the store where we had parked our machines. I noticed all three front tires on the trikes parked in front of me. My front tire had a very interesting mark in the center of it. The side of the tire facing away from the wind had a very distinct dark line running parallel to the center of the tread and located about a half inch or so away from the centerline. The contact patch of the tread with the pavement was clearly defined, and it was obvious that the tire had been running a bit sideways instead of rolling straight ahead as normal. I've noticed the contact patch mark after riding all day when wind was not a factor, and there is a consistently darker patch extending equal distance on either side of the centerline.
On this occasion, the dark line indicated the place where the most stress was being placed on the tire and it's location. The contact patch on the side of the front tire toward the wind extended to about halfway between the centerline and the edge of the tread and the mark got lighter as it approached the location where the mark disappeared. The edge of the mark was feathered out to nothing .... no dark line at the edge! All three trikes showed the same mark on their front tires. One of the trikes had a Dunlop radial tire (regular front tire) mounted. There was a definite difference in the location of the dark line and the feathered edge of the contact patch. The dark line was very nearly at the centerline of that tire, and the feathered edge mark was closer to the edge of the tread, way beyond where the contact patch normally extends when these tires are mounted on a trike that does not lean.
We discussed these interesting marks. I was obvious that riding in those conditions was placing constant and continual stress on the front tires in a similar fashion to the stress that would occur when a trike negotiated a curve at speed. When we had the opportunity to ride some four lane divided pavement (same conditions present), I asked the rider of each of the two trikes to ride up close enough to my left side in the lane beside me so I could watch their front tire for some distance. That radial tire on the front of the trike was obviously rolled more underneath the rim by the stress of the angular "crabbing" necessary to ride in a straight line against the wind. The bias ply rear tire on the front of the other trike looked very nearly normal, with only a small amount of deflection present.
Sorry for the longwinded post here, but I can tell you from this experience that I never ever intend to have another radial tire designed for the front of a two wheeler mounted on my trike! I am much more comfortable in my mind knowing that the bias ply rear tire with it's much stiffer sidewalls is mounted up there. It may be a stiffer and not quite as cushy a ride, but that is much more preferable to me than the thought that that more flexible radial might roll under and pop off the rim in a hard turn.
There is nothing scientific about this ... just my observation and my conclusions based on my observation in these circumstances. I am certain that I am no worse off with the bias ply rear tire mounted on the front than I would be with a regular radial front tire mounted or a radial read tire mounted. I strongly feel I am better off with the bias ply tire up there. The additional mileage given by the rear tire mounted up front is nice, but it's not the main reason why I want the bias ply rear tire up there. In my mind, it's a safety matter, and I would do this even if the mileage were the same for both types. Take this for what it's worth. Think about it and decide for yourselves. Each of us must ultimately take the responsibility for the choices we make, regardless of how many others may agree or disagree. Those folks are not riding our machine, but I am, and my wife rides with me!!!
!30/70x18 Here ya go: http://www.motorcycle-superstore.com/10979559/d/street-bike-tires#&&SearchParameters=53-0-0-0-0-1-24-1-6_1-11_1-7_15-8_5-9_4Are there any radial rear tires that will fit the front of the 1800. All I can find are bias but would like to try a Dunlop E-3 MT if there any made in the 130-70R-18. Any one know of such a critter?
Answer to your question is yes, against my better judgement, I let my mechanic talk me into running a Dunlop E3 radial on my MotorTrike, last year. It is now badly cupped, worn out and ready to be replaced with an MPA. I got 11000 miles out of it, but was not satisfied with the ride. As I get older, I don't ride as aggressively as I did 5 years ago, but it still felt like it wanted to "push", to use a NASCAR term, an every corner. It took my confidence away, just a bit, on tight cornering.Are there any radial rear tires that will fit the front of the 1800. All I can find are bias but would like to try a Dunlop E-3 MT if there any made in the 130-70R-18. Any one know of such a critter?