mixing tire brands

[elbandido]

Hi all, I was in desperate need of replacing the rear tire on my 2000 B6, and got the Dunlop K591 (The kind they use on the sportier Harley Davidson bikes), 160/70B17, which was the only available one at the dealership.  I run a Bridgestone Battle Ax BT-50F, 120/60ZR17 on the front, with probably about 5K miles on it.  

My question is, will I have handling problems having different brands?  

The previous rear tire was a 160/60ZR17, Bridgestone BT 56, I believe.

 

[B12Teuton]

Probably.
I would not do it.

With 5K on your front Battlax, you should buy a rear Battlax now.  They will probably wear out around the same time and then you'll be able to get a fresh set.

The Metzeler Z06 tires are very popular and I am an avid Metzeler fan.

[todius]

Mixing brands is not recommended, but you have mixed a bias-ply tire with a radial tire.    This should NOT be done.  I'd change the rear to a different tire as soon as you can.

[Red01]

Todius is absolutely, 100% correct!

NEVER mix radials & bias ply tires!
NEVER!!!


STOP riding on that combo NOW!

If that K591 was the only tire close to the right size in that dealership, not only should you have left it there, they shouldn't have sold it to you (if they knew what your bike was).

Here's what tipped us off, even if we weren't familiar with that tire model. The "B" in the size code means bias ply.

Dunlop K591 160/70B17

On your Bridgestone 160/60ZR17 the "Z" is the speed rating of the tire. Z is for speeds >149. The "R" as you've probably guessed by now is for radial.

With no speed rating on the Dunlop (unless there's more code following that you didn't give us), I wouldn't trust that tire above 99 mph (which is the lowest code).

OH, and swapping the front to a bias ply would be better than riding with one radial and one bias, the Bandit was designed for radials and will work MUCH better with radials than bias.

[elbandido]

according to the dunlop website the K591 is V rated, 149mph.  would i still be okay with this combo?   for all of your help.  i'm never going to go to that dealership again, i even asked them about the mixing of brands and handling problems, and they never brought up the idea of rubber compounds.  they said that i would be okay with the combo.   i told them i was specifically looking for the Bridgestones, too.  obviously they don't care about the customers safety, and just wantede to make the sell.  oh well, i've learned my lesson.
thanks again,

[PeteSC]

Mixing brands is a minor problem.   Mixing tire construction TYPES is a major problem!
  The construction and configuration of the belts is different bewteen BIAS and RADIAL tires.
  You're looking at the possibility of some strange handling, and harmonic stuff going on.  The bike probably won't throw you off magically when you hit 25 mph, but you've got tires on both ends of the bike kind of working against each other in ways they aren't supposed to!
  (My squidly interpretation!)
  Verify that you have 2 different types of tires on your bike, one bias, and one RADIAL......


From Dunlop

Bias and radial tires have significantly different dynamic properties. They deflect differently, create different cornering forces, have different damping characteristics, as well as other differences. In order for radial tires to be introduced into the two-wheel market, it was necessary to change certain characteristics of the motorcycle. The introduction of the radial tire led to such things as modified frames, new steering geometries and suspensions. Therefore, it is recommended that a motorcycle be used with the type of tire construction that it came with originally. If a change is to be made, then it should only be done if the motorcycle or tire manufacturer has approved the change. Above all, do not mix bias ply and radial tires on the same motorcycle unless it is with the approval of the motorcycle or tire manufacturer

What’s the difference between radial tires and bias-ply tires?
The main difference between radials and bias-ply tires lies in their construction. Tires aren’t just toroidal balloons, they are reinforced with cords of steel or synthetic materials such as nylon or Aramid. In bias-ply tires, the fibers are wrapped in an X pattern between the beads; in radial tires, the fibers are wrapped perpendicular to the tread. Radial tires have more flexible sidewalls than bias-ply tires, and thus absorb road irregularities better and have a comparatively larger contact patch when leaned over. Because of the flexible nature of a radial, these offer higher mileage compared with a comparable bias-ply for a given rubber compound. Since they absorb small road irregularities better, they ride more comfortably and are less likely to be upset by groovy pavement.
While radial tires perform better than bias tires, some older motorcycles can’t be fitted with radial tires because of differences in rim profiles. You probably won’t notice much of a difference anyway, so stick with boas tires if that’s what the motorcycle was designed for.
Why can’t I mix radials and bias tires?
The different ways in which radial and bias tires react to sideways loads can lead to unpredictable behavior while cornering. It’s bad enough to do this on a four-wheeler, but it can be even worse on a motorcycle. If you need to replace one tire and the same type is not available, then go ahead and replace both tires with the same type.

[Red01]

according to the dunlop website the K591 is V rated, 149mph.  would i still be okay with this combo?

Absolutely NOT!

It's not the speed rating that makes this a MAJOR NO-NO, it is the fact the K591 is a bias ply tire and your bike has radials.

A member a while back was complaining his recently purchased bike (used) was handling funky and told us what tires were on his bike. Turned out the bike had a mix of radial & bias ply tires. Once he corrected the problem, the funky handling disappeared.

While you CAN mix them, the results are quite unsatisfactory and should only be done if there is nothing else you can do... like you're stranded in BFE and you can't wait for the right tire - you've got to hobble home NOW, This sort of thing needs to be corrected at the earliest opportunity...