Awwrite. I've been reading the responses. I am ready to step out on a limb here. I am willing to go so far as to say this. Gort wont be trying it. Apparently, there are some who, having done the homework & assesed the risks & ride variations sufficiently for at least one to make high speed passes thru mountains in a sure footed enough manner to not scare a man who admittedly is NOT physically able to tolerate any major impacts. This is waht the word Controversy entails, more than one side, neither with definitive information to say what simply must be. We are men. We do things. Some of them work, some work well, some not so well & some explode on liftoff. I plan on trying it.

And actually, no mods at all are required if you avoid the ridiculously huge tire Oldfeller used!  

No amount of expensive equipment or fancy engineering calculations can duplicate the real-world.  Simulation and approximation, and lab test conditions ARE NOT the real thing.

So what's better a radial tire or a bias ply tire?  M/Cs have both...

What gives better dry surface performance?  Which is better on wet surfaces?  Which is better on dirt?  How big a factor does tread pattern play?  Rubber compound?

Have I stirred the pot enough here?  

Denim, is this your bike and if so, how does it ride differently than with the stock tire?  This is a great opportunity to learn about handling, braking and softness or hardness in ride, using a very extreme sized tire.

Don't worry Oldfeller!  I've got my sights on a 155/80-15 Comp T/A.  I've taken measurements, and with my chain mod and 12.5" shocks, those tires will slide in there nicely with no other mods necessary!  

Gort, they can tell you all they want, but if you truly want to understand what bump steer really means and what rumba really feels like, there is only one way for you to really really know.

You gotta take a little walk on the wild side  ....

Gort the younger was a wild child, now he is older and wiser and has his regrets.

Ah, don't we all -- them regrets, that is.  

All old men still feel the same inside as they were in their twenties, just stuck inside much older bodies.   We make lots of stupid mistakes along the way (none of which were fatal,  for us anyway).

Them that are younger are still due a few mistakes, so let them have their fun (and let them have their funky tires and their strange bikes).

Us that are older will make up some even stranger strange things that allow us to carry on in as much as we can, anyway.

It's called life, you just keep on doing it as long as you can having as much fun as you can in between the regrettable parts.

Well, I guess I'm not sorry I started this topic up again after all.

Since I've already gone to the 11 1/2" (or 12 1/2" I don't remember) Harley shocks and am running them on the middle setting I don't think I'll have vertical clearance problems.

Sounds like I should probably go with around a 145/80 or 145/90 radial with a big 15" bike radial tube in it. Then go with the softest road gripping rubber and the roundest tread face edges.

As for tread face design I'm wondering if the standard blocky car type pattern, or the "V" cut sort of look I've seen on some would be better for tracking down the road; in water, sand or gravel. I take this bike everywhere there's something I want to see. Any thoughts on that point?

Jack

DO NOT PUT A CAR TIRE ON A BIKE RIM.  IT IS TOO DANGEROUS.

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barry68v10 PUT A TA 155/80r15 ON THE BACK OF HIS BIKE, DROVE IT A COUPLE OF MILES TO A SERVICE STATION AND BLEW IT UP (that's exploded it for you who haven't heard yet) AT 175 PSI TRYING TO GET THE BEAD TO SEAT.  HE HAD SPRAYED TRUCK BED LINER ON HIS SPOKES TO SEAL THEM AND GOT SOME ON THE BEAD AREA.

HE DID DAMAGE TO HIS HEARING AND SHREDDED HIS SEAT BAGS.

DO NOT TRY THIS MOD.

IT IS FORMALLY UNAPPROVED FOR LIST MEMBERS TO DO.

I FORMALLY RECANT THIS MOD AS IT IS TOO DANGEROUS TO YOU AND YOUR EARS AND YOUR HANDS AND YOUR EYES (AND TO YOUR SEAT BAGS).


(signed)

Oldfeller

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Tire Rack is the best place to do tire research concerning rain grip or whatever other characteristic you are looking for.  Tire Rack will also show you ALL the tires available in the size you are looking for.

Remember, USA DOT has very restrictive high temperature high load at high speed tests that tires MUST PASS to be sold in the USA -- not all tires you see on the internet can be sold in the USA because they won't pass DOT 139.
(a very durn restrictive test, BTW)

Tire Rack is where I go to look at tires -- then I try to find a way to avoid their shipping charges if at all possible.  They are not always the cheapest place either.  And if you do try to buy something there you had better know durn well what car that tire comes stock on or you get an electronic "No way, Jose" from them as they are very careful not to sell an "inappropriate tire".

http://www.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich&tireModel=Radial+...

The BF Goodrich TA 155-80r15 gets excellent marks for rain grip, hell, it gets excellent marks for everything except for the good marks for snow and ice.  It got excellent for hydroplaning resistance and mileage (wear) which you very rarely ever see together.  People slam tires real bad in those reviews generally, so the good to excellent reviews this tire got are "outstanding" compared for what people generally give a tire.

Poke around the site a bit -- it is an excellent resource for hunting up a strange tire.  Look up your existing tires you got on your car right now and see what sort of crap you really have according to the reviews.

Spending time on Tire Rack can change your tire buying habits ...