Mismatched tyres

[MSTRS:Me]

The correct recommendation on a car is radials to the rear

Dead horse, maybe, but I still don't remember it being that way...
(On a car) the tyre's sidewalls flex mightily in a corner. The tread on a crossply then peels up off the surface of the road, reducing the amount of grip. Whereas a radial keeps all the available tread on the road, maintaining the full amount of grip. Perhaps FWD/RWD makes a difference, but still seems to me that maintaining full potential grip is better at the front end?
Of course, none of this applies to bike tyres...(other than a rear-end slide is preferable to a front)

[koba]

I think the fact that there are a few pages of debate on the differences between crossplys and radials and all that show that KB isn't going to provide a crediable answer to Katmans initial question.

I'm sure you knew that when you asked it though...

I still wan't to know if there are radials that will fit on rims designed for crossplys.
I know 125 slicks will but thats not exactly a normal road tyre.

[McDuck]

There's two questions here, Did the custy 'ok' it before it was done (or ok it when the bike was collected), or not?
And of course, is it safe?

Was ok-ed over the phone after an assurance from the parts guy that it was a good tyre and would work well with the sport demon. As to saftey i am going by the fact that i went down on the first wet hill i had done on the combo, so i will go with no...

[Viscount Montgomery]

I'd say the 'yes or no' ply/radial mix scenario depends on the style of motorcycle, and there's always conjecture and statements of advice from people who think they know it all from scouring the net and reading manuals and rulebooks, but who have, at the end of the day, never actually ridden any motorcycle on a ply/radial combo. Now, I've run modern 17" 160/170 radials on the back of old modded musclebikes with the standard 100/110 width 19" ply tyre setup still on the front. Perfectly fucken safe, no handling dramas, fine scraping pegs on corners, stable and solid on hi-speed straightline blats, no unexpected slides in the wet, no uneven tyre wear. All under control and zero problems. Basically, just ignore the tut-tutting self-proclaimed experts and you'll be sweet.. PS, don't try fitting radials to too narrow ply-tyre rims, I squeezed a front 120/70 radial on to a standard ply 110 width rim just to see what would happen. The 120 radial distorted and turned to a 100 width with tall sidewalls - and turned from a stable tyre to a twitchy death-trap

[MarkH]

Was ok-ed over the phone after an assurance from the parts guy that it was a good tyre and would work well with the sport demon. As to saftey i am going by the fact that i went down on the first wet hill i had done on the combo, so i will go with no...

Have you E-Mailed the respective tyre manufacturers and/or motorcycle manufacturer to enquire about the safety of mixing those 2 tyres? If an expert could give you a definitive answer on this it would be worth presenting that info to the bike shop.

[koba]

OK, no one answered so I looked it up.

They do cross over in sizes but the radial do tend to be wider, especially on the rear.

[McDuck]

Have you E-Mailed the respective tyre manufacturers and/or motorcycle manufacturer to enquire about the safety of mixing those 2 tyres? If an expert could give you a definitive answer on this it would be worth presenting that info to the bike shop.

Not yet, will get on to it on monday thanks

[Kokopelli]

For what it's worth, I currently have a radial Anakee on the front and a crossply Shinko on the rear of my R1150GS (dual sport tyres). The handling is not as good as with matched tyres, but so far nothing drastic has happened. I found a few dry patches today and have run them to the edge.

The GS sits like on rails when cornering and I've got wide handlebars. The story might be quite different on a twitchy sports bike. I also rarely go faster than 120 km/h, but then I usually don't slow down much for corners either.

On gravel it doesn't make and difference at all as far as I could tell. I won't mismatch again, but I am also in no hurry to change tires for the next few thousand km's.