Can you run a radial on front and a bias ply on rear? Or should you keep both radials or both bias ply? I had a new rear tire put on 2 weeks ago, and now the bike just feels squirrely. I have a Battlax radial on front, and asked for a Battlax rear. But they put on an Exedra, (both are Bridgestone) but i think its a bias ply. It doesn't say its a radial anywhere.
Any ideas?

I don't know for sure.   I think the conventional wisdom is that it is unwise as it might make your two wheels do different things in certain situations....  but noone has ever described such a situation to me.

A bias front tire with a radial rear tire can be OK, but a radial front with a bias rear is generally considered not good.  As a matter of fact, it is illegal across the big pond to the east.  From Avon fitment guide:

(Note: In the UK it is illegal to fit a radial front tyre with a crossply or bias-belted rear tyre. It is also illegal to fit a bias-belted front tyre with a crossply rear tyre. Fitment legislation may differ in other countries, therefore national laws should be observed.)

There are many Excedra models and many Battlax models and some of each are bias and some of each are radials.  Exactly what tires do you have?

Battlax BT45 and Excedra G547G(OEM) are both bias while Battlax BT010 or BT014 are radials and all and many others come in the 110/70 GS500 front size.

You don't really want to mix tire types or threads because they will react differently.  In rain or wet, tread patterns can cause the front tire to more in one direction, while the rear tire moves in another direction.

Then you have to worry about how sticky the tires are and how long it takes them to heat up.  If one tire heats faster or is stickier, you'll have more traction issues...

But, like gsJack says it depends on the individual tires.

The front has a Battlax BT45 radial. I asked for the same thing on the rear, and what they put on was a Exedra G550. Nowhere on it does it say its a radial, so i'm guessing that its a bias. Either way its not what i asked for..

Quote from: Scorpio65Either way its not what i asked for..

I think you have your answer there...

Your best bet is to get the same tires front and back...  Then you don't have to worry about a mismatch.

Quote from: Scorpio65The front has a Battlax BT45 radial. I asked for the same thing on the rear, and what they put on was a Exedra G550. Nowhere on it does it say its a radial, so i'm guessing that its a bias. Either way its not what i asked for..

The BT45 is a bias ply tire and has replaced the Excedras as OEM on the GS500F models. I have searched the world over for a Bridgestone Battlax radial tire in the GS500 rear 130/70 size and it can't be found. Checked Bridgestone's US, Japan, and Euro sites since the MCN report stating they had Battlax radials on their test GS500F.  Maybe they made a few special ones for you and MCN.  

Seriously though, does your front BT45 say radial on it?  What is the size designation?  A 110/70H17 or a 110/70V17 would be a bias ply.  A 110/70ZR17 would be a radial.  Or a radial could be a 110/70HR17 or VR17, but the R would be in the size designation.  Some have thought the BT45R model designation meant radial till they looked at the BT45F on their front tire.  

The Excedra G550 is the Ninja 500 OEM rear tire and is also bias ply.  

They really should have given you a BT45 rear for your F model since itis a better tire than the Excedra and is what you asked for.

I'm sorry, the front is a 110/70/ZR17 radial. BT56F. And the back was a
Battlax 130/80/17 BT45. Now if the back was/is a bias ply and the front is a radial than (even if their the same brand) thats a bad thing , right? Or is it ok because their the same brand and tire design?
Sorry for all the questions, but i would like to know this.

Quote from: Scorpio65I'm sorry, the front is a 110/70/ZR17 radial. BT56F. And the back was a
Battlax 130/80/17 BT45. Now if the back was/is a bias ply and the front is a radial than (even if their the same brand) thats a bad thing , right? Or is it ok because their the same brand and tire design?
Sorry for all the questions, but i would like to know this.

I've tried a lot of mixes on my GSs in putting over 100k miles on them, but never one that bad.   :dunno:  That is as extreme as you can get, a ultra high performance BT56 sport radial on the front and a bottom of the line handling wise bias ply Excedra on the rear.  If I understand you now, you got a BT56 radial front and a BT45 bias rear on the bike when you bought it which was bad enough and then the change from a decent handling BT45 rear to a just adequate Excedra G550 bias rear has made it worse.  It's no wonder it now feels squirely. I really wouldn't push that mix too hard myself and would change something as soon as possible.

Even if they had put on the BT45 rear you requested it still would be a bad mix.  I think it's time to put on a radial rear with the BT56 front or a bias front with the Excedra rear to make the bike more stable before you get into trouble.

Although it's not considered as bad of a mix, I recall replacing a worn Metzeler radial Z4 front on my 97 with a half worn bias belted Dunlop GT501  and ran it with the still good radial Z2 rear and the bike felt like it was falling out from under me on the first couple fast turns.  I somehow adjusted to it and could not make it repeat this falling feeling for the 3k miles I ran them together.  It's things like this that make the tire mfgs warn about mixing tires.  Sometimes it works out and sometimes it has a tragic ending.

It really isn't good to mix tire types and/or tire brands till you have enough experience yourself with tires to make good choices.

soo maybe I missed something, is the BT45R a radial or a bias-ply, cuz my bike has a pair of BT45R tires, and I was just going to repaclace the rear with a BT45

Quote from: gsJackThe BT45 is a bias ply tire.........................Some have thought the BT45R model designation meant radial till they looked at the BT45F on their front tire.  

BTW, I just noticed the Bridgestone Fitment Guide now shows special BT45G models as OEM for the 04 and later GS500F models.  The rear G has slightly diff dims and there is 1/32" less tread on both the front and rear on the OEM BT45G models compared to the standard replacement BT45 F and R models.  Also wheel fitment is a bit diff.  Seems they always have to change the OEM tires into cheapos to save a couple nickels.

Thanks for all your help gsjack. But i have another question. I have not been able to find a radial tire for the rear, is there a brand/maker that offers a set ,front/rear that are radials? I ride mainly freeways durning the week, but on the weekends i'm starting to ride some twisties. and now that I know not to push these tires i will slow down.
Shouldn't the dealer know better than to mix tires?

There are lots of radial tires that will fit our 3.0 and 3.5" wheels.

The all out sport/ultra sport type tires start at 160 wide rear in many brands which are too wide for our rear wheel, but there are some 150/60 rear tires that while not approved for our 3.5" wheel are used by many, many riders with GS500s and EX500s (Ninja) which have had same size OEM tires and wheels since 94. Avon AV50 and AV60, Metzeler Sportec, Michelin Pilot Sport and Pilot Power,  and Continental Contiforce are available in the 150/60 size. There are no Bridgestones sold in this country in this size.

I've always considered sport touring tires best for myself because of my high mileage.  They last much longer than the sport/ultra sport tires in most cases and I've done many miles of spirited riding on them in the mountain twisties. I've used the Metzeler Z4frt/Z2rear combo and also the Avon AV45/46 sport touring radials.  The 2nd 130/80 Z2 I put on was cut badly after a month and I replaced it with a 140/80 Avon AV36 and then in the fall I put on a BT010 ultra sport front with the AV36 rear.  I mention this because this combo works for me, it's still on my 97 GS, and the Bridgestone BT010 is an ultra sport like the BT56 on your front.  I think I'd try the 140/80 AV46 (superceeds the AV36) with the BT56 front and then go AV45 front when the BT56 is used up.  

As far as mixed sets go, all of the 150/60 sport rears above would come in sets and there are many choices in good sport touring radials too. Considering both 110/70 and 110/80 fronts and 140/80 and 150/70 rears in sport touring radials; the Avon AV45/46, Dunlop D205, Metzeler Z6, Michelin PilotRoad, and Pirelli Diablo Strada come to mind.  The 150/70 rears are approved for fitment on our 3.5" wheels by some tire mfgs and not others.  Some will fit with adequate clearance and some might require grinding off a bit of the brake torque rod for good clearance.

Just a bit more on the fitment of the 150/60 rear on our 3.5" rim.  We have to remember that many things are not approved for use by the mfg in  this country because of the extremely litigous nature of our society.

Bridgestone doesn't list the 150/60 size in this country but they do in Japan and also appearantly approve of the fitment on the 3.5" rim there.

http://mc.bridgestone.co.jp/en/products/battlax/bt090.html

http://mc.bridgestone.co.jp/en/products/battlax/bt92.html

I haven't tried the 150/60 size because of the shorter life of the sport/ultra sport tires, but if the sport touring radials came in this size I'd try them because of the OD being about the same as our 130/70 OEM rears.  The 150/70 are about 1" larger and the 140/80 about 1.5" larger in OD resulting in raising the rear of the bike .5" and .75" approx over the OEM size.

If I lived anywhere near you I would buy you a beer, But I don't, so a Thank you will have to do..
Thank you for all your help..