120 rear tire instead of 130?

[bobthebiker]

now I know on the EX500, you can use a 120/70/17 tire on the rear and get better turn in, but can you do the same thing on a GS500? 

[galahs]

Are you serious! 

[bobthebiker]

when combined with  a 110 up front, you can actually get a really nimble bike.   if memory serves right, the 130 was slightly pinched in the rim on the EX, so a 120 is more ideal for better handling. I"ve never tried it, but I want to.

[Kasumi]

Trust me i moved from my first bike 50cc rieju and that had skinny bloody tires like tiny. That was nimble as hell but had no grip because there was no tyre to grip. Yes you can flick from side to side fast but they are unpredictable and so unsafe, i spent so much time going sideways because the tiny contact patch would hit something slippy and not have any other part of the tyre to grip.

Now im on my zxr400 with 160/60 - 17 tyre i don't skid, i don't slide unless im pushing it. Much more surface area on the road to keep me and my bike stuck to it. Sure it doesn't do S bends quite as nimbly and theres a bit more resistance when flipping from one side to the other as there is more friction but its a damn steady bike and doesn't bobble or slip like my skinny ass tyres on my first bike.

Your a loon if you want to put a skinnier tyre on a bigger bike. Tyres are designed to cope with the size of bike. If you go up a size then you don't do alot of harm unless you drastically change the geometry but putting smaller tyres on is suicide. Bikes come with the right tyre you definatly dont wana make it smaller.

[bobthebiker]

well, thanks for that answer. makes enough sense to me.

[Kasumi]

Sorry i came across abit harsh there. Sorry didn't mean to offend.

[bobthebiker]

Sorry i came across abit harsh there. Sorry didn't mean to offend.

it didnt seem harsh.  but it DOES make a lot of sense. glad someone has some experience in it to keep me from learning the idiot way.

[Kurlon]

Actually, what you may find is the 120 gives a LARGER contact patch than the 130 on that rim.  A narrower tire will be forced to spread out to seat the beads, flattening the profile.  The flatter profile will present more rubber to the road.  The question is weather or not you'll go off edge of the flatter profile before you hit maximum lean...

I'd say it's worth a try, get a cheapie 120 (Ideally a take off so you can do a looksee without spending anything) and see what the profile looks like.

[galahs]

Kurlon are you willing to accept the responsibility if he does use them, runs of the edge when cornering and ends up shiny side down.

I would be very careful offering un-tested opinion on equipment of such importance like tyres. 

[Kasumi]

I promise you that you shouldn't put a smaller tyre on your bike unless you you have significantly changed the bike in terms of weight etc... the whole point with a wide tyre is that you put them on heavier taller bigger bikes and they hold the weight better and provide more gradual lean from side to side so you can reach full lean without the bike "falling in" to the turn.

Motorcycle manufacturers may be cheap and may cut costs but one way or another your bike has the right tyre size for the stresses. Smaller tyres arn't as strong as larger tyres (comparatively as they would be on much lighter smaller bikes) and they don't provide enough grip nor will they provide enough lean angle. The manufacturers don't pick a tyre size out of their head and go "yea that will do we've got tonnes of that size" The bike is designed to incorporate a certain tyre size or they are forced to use the correct tyre size to match the bike they have built.

[gsJack]

now I know on the EX500, you can use a 120/70/17 tire on the rear and get better turn in, but can you do the same thing on a GS500? 

when combined with  a 110 up front, you can actually get a really nimble bike.   if memory serves right, the 130 was slightly pinched in the rim on the EX, so a 120 is more ideal for better handling. I"ve never tried it, but I want to.

Don't recall ever seeing a 120/70/17 rear tire, certainly isn't common.

What year EX500 are you talking about?

94 and later EX500 come with same size OEM tires and wheels as the GS500 uses.  The pre 94 EX500 had 16" wheels with a 2.5" wide rear, narrower than the 17" wheels on the later model EX and the GS which have 3.5" wide wheels.  The pre 94 EX500 came with a 130/80/16 rear.

Metz and Pirelli current recommended fitments for the pre 94 EX500 are 130/90/16 rears and it's pinched a bit on the 2.5" wheels like a 150/70 is on our 3.5 " wheels but is an approved fitment.  An available 120/80/16 would work on the older EXs but I wouldn't consider a 120/90 or 120/80 tire for the 94 and later 17" EX500 or the GS500.

[bobthebiker]

alright, thats what it was, it was first gen EX's I was thinking of.   the 120/70 is very common, its just a front tire size.  since our wheels are wider, I'm just going to stick with stock size.

[Kurlon]

The pre 94's did have narrower rims in addition to being smaller diameter?  Hrmm... thought that had to be a typo on the wiki.  Guess not.

And RE trying a 120 rear... I'd give it a go myself if I had access to a cheap tire to try.  As it is right now decent race rubber is looking like 150 and up in back, so I get to go the oversized route.

[gsJack]

Yep, the pre 94 EX500 tires and wheels are the same size as the Ninja 250, from Metzeler Fitment Guide:


• Type of motorcycle:   KAWASAKI
    • Model: 87-93 EX500
LASERTEC   
Front 110/90-16M/CTL 59V LASERF  - 32 PSI  - 2.15  INCHES 
Rear 130/90-16M/CTL 67V LASER  - 36 PSI  - 2.5  INCHES


• Type of motorcycle:   KAWASAKI
    • Model: 86-05 NINJA EX 250, 250R
LASERTEC   
Front 110/90-16M/CTL 59V LASERF  - 32 PSI  - 2.15  INCHES 
Rear 130/90-16M/CTL 67V LASER  - 36 PSI  - 2.5  INCHES

[gsJack]

And RE trying a 120 rear... I'd give it a go myself if I had access to a cheap tire to try.  As it is right now decent race rubber is looking like 150 and up in back, so I get to go the oversized route.

You can get a BT090 Pro rear race tire in a 140/70 size:

http://www.barebones.net/tires.htm

And it's sized for a 3.5" rim:

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

[bobthebiker]

Yep, the pre 95 EX500 tires and wheels are the same size as the Ninja 250, from Metzeler Fitment

just to be clear, it was 94 when the EX500 went into second generation. the 1993 and earlier models have the 16" wheels, drum brake in the rear, 36mm front forks, the brake rotor is on the left instead of the right, and the speedometer cable pickup is on the right.    second generation has 37mm forks, rotor on the right, speedo pickup on left, disc brake in the back and 17" wheels are the most significant mechanical changes. 

bodywork and gauges are also a change, as is the ignition system between the two.

[gsJack]

Thanks, fixed typo.

[Kurlon]

You can get a BT090 Pro rear race tire in a 140/70 size:

That looks like just the ticket for the GS, thanks!

[wildbill]

I just put Pirelli sport demons on my bike. Put the normal 110 up front but opted for a 140 in the rear. Love the feel of it so far.

[bobthebiker]

being that I have a second rim to toy with, I may just get a new 130 and put it on, be done with the whole thing.  Kenda K671's are actually a pretty nice tire for sport touring, and AWESOME for commuting.