New rear tire: Now handling problem--advice please??

[glasswave]

Hola,

I´m down in Tierra del Fuego and just bought a new rear tire. I am on a Honda NX 400 falcon which comes stock with pirelli 120 - 90- 17´s. It is based on a Honda xr 400 motor and is made in Brazil. It´s an adventure touring style enduro. The bike is fully loaded.

In Ushuia managed to locate a Duro 4.60 - 17. It has 3 ply tread and 2 ply sidewalls. It was maybe 3/4 to 1/2 shorter and a tad narrower than the Pirelli. It has quite agressive tread, but not quite a full knobby. I had it mounted and it seemed fine, but today after crossing the mountains, I find that the front end becomes very light feeling and wants to speed wobble starting between 90-100 kph. Comes on very slowly, but get`s quite scarry over 100 kph, especially with the ever present cross winds.

Would you think this is being caused by the tire?

What solutions could I pursue w/o buying a new tire?

I had a little of the same trouble at first when fully loaded at around 110 kph with the stock Pirelli. I adjusted the rear shock to 3/4 stiff and it seemed to greatly the problem. Should I try to tighten it some more?

Is it possible that it`s unidirectional tread and it was mounted backwards? It had no arrows on the sidewall.

Will I have to buy a new tire? Could something else be causing this?

I don´t have many options for redistributing my load and she`s quite tail heavy?

Suggestions? Advice?

[Walkabout]

If it were me, I would restrain my speed and experiment with higher tyre pressure(s) to stiffen the walls of the tyre(s).
Make one change at a time to find out what does make a difference.

I would also look again at re-distributing luggage weight forward onto, say, the fuel tank.

[brettsyoung]

Could be poor fitting. I've had this happen twice to me in countries where big bikes are uncommon. You can check by riding slowly and looking over the handlebars - you should see the tyre out of square. You will also notice that, even at slow speeds, cornering is not as solid as it used to be. Alternatively, it may have been put on back to front. I don't know where you had the tyre fitted but be sure to go to a "real" bike shop to get it checked (I've rarely had success at BMW car shops that sell a few bikes - harley shops or shops that sell and service Jap chopper things are the go, they're usually run by bike diehards). I doubt they'll charge you.

cheers, Brett

[Dessertstrom]

Since you have said that you had a slight wobble before you changed the rear tyre I think you have a load distribution problem. As a test try leaning forward over the bars to see if it makes a difference, if it gets better then you need to rethink your load distribution or ride slower if you can't put some load up front.
I presume you have checked the head stock bearings for any play ?
Cheers
Ian

[oldbmw]

Originally Posted by Dessertstrom

Since you have said that you had a slight wobble before you changed the rear tyre I think you have a load distribution problem. As a test try leaning forward over the bars to see if it makes a difference, if it gets better then you need to rethink your load distribution or ride slower if you can't put some load up front.
I presume you have checked the head stock bearings for any play ?
Cheers
Ian

I will go along with this good advice, but also check both tyre pressures, and if necessary raise them by 5 lbs to see if it helps. My bmw is very load and front tyre pressure dependant.. I just today fitted new front tyre and this time installed a tube with it as I could never get the rim to seal properly on the bead.