Tire Sizes

[tykho]

Any of you guys have 140-70-17s on the back of your bike? I'm buying a set of the Pirelli Sport Demons and I was thinking about going up to a 140-70-17 on the back since it's one of the recommended sizes, but I don't know if there's any real benefit.

[Iroquois]

I've always run the 140-70-17's.... It's probably in my head but it just feels safer.

[burning1]

The sport demon is available in 130/70/17; buy that. A 140 weighs more and won't provide any noticeable improvement in grip.

Yes, a 140 should fit. Clearance between the brake linkage and the wheel may be a little tight, however.

[mister]

I just put a Sport Demon on the back - 130. And I don't know if it's in my head or not, but the bike leans better with it. Feels better leaning (that is) than the BT45s. Don't know about mileage yet, though.

Michael

[jwgeorge]

I am running a 140-70-17 Avon Road Rider rear tire with no problems! And I run a 120-70-17 Avon Road Rider on the front. Makes the steering a little heavy, compared to my buddy's Yamaha R1.

Jay

[black and silver twin]

I have sport demons in stock size right now and there awesome. I was considering getting 140-70-17 next time though, not for cornering grip but for cornering clearance (its taller than stock) and for slightly taller gearing. I have a 15t sprocket and I like how its lower than 16t but its too low for top speed. plus it would look slightly wider which is good.
I did however wonder lust how much heavyer the 140-70 is than the 130-70.

[Toogoofy317]

I got battleax Bt45 150's on and I luv it that way. My MPG has not gone down if anything gone up.

Mary

[gsJack]

A 140/70 is about one pound heavier than a 130/70.  The chain lube on my rear wheel and tire weighs more than that.   

[gsJack]

Only Metzeler and Pirelli give tire weights in their tire guides and there is an obvious error in the weight given for the 140/70 Demon so I looked at Tires Unlimited who give shipping weights because they base shipping costs on weight.  

The Demon shipping weight is 130/70 14#, 140/70 15#, and 150/70 16#.  On the other hand their newest Angel sport touring radial weighs only 14# in the 150/70 size and their newest Diablo Rosso supersport radial weighs only 13# in the 150/60 size.  A good reason to run radials on a GS500 streetbike?

For years I took the position here that the oem 110/70 and 130/70 sizes were the best choices as far as GS500 performance goes and there was no good reason to go larger except to get better tires like the sport and sport touring radials generally available in the US in 150/60 and 150/70 minimum sizes.  When I got my first GS years ago I found my first radials, a Z4/Z2 combo, to be a very big improvement particularly in the wet.  Improvements in both compounds and profiles of the latest bias sport touring tires have since levelled the playing field a great deal and I just don't see the extra cost of the radials to be justified now on a bike like the GS500 for my usage.

I find the wider/larger rear tires do look better on the GS, maybe I'm in my 2nd childhood now.    Also more importantly I find the larger rear tires with their greater weight ratings are giving me greater tire life.  The approx 15k miles I got from a Roadrider 140/70 rear was a record for me for bias sport touring tires and the 150/70 I'm currently running seems to be giving even more miles.  At 12k miles I measured tread depth and projected tire life to about 18k miles.  Time will tell, it's gonna take all summer to wear out that 150/70 Roadrider.

My all time favorite handling tires for the GS's so far for all around street use have been the Lasertec front with the RoadAttack rear.  That RoadAttack 150/70 only weighs 13#.  

[importslife]

I got battleax Bt45 150's on and I luv it that way. My MPG has not gone down if anything gone up.

Mary

Mary are you still running gs swingarm and wheel w/w o mods for that tire

[tykho]

Yea, I didn't think a 150 would fit, I ended up ordering the 140 Demon Sport.

[jeremy_nash]

the pre-98 katana uses the same rear wheel as the gs, and runs a 150-70-17 metzeler me33 stock

[gsJack]

The Metzeler ME33 was a front tire only used with their ME55 and ME99 rear tires all of which have been superceeded by their new Lasertecs which have similar tread patterns to the 33 and 55 tires.

The early Kat 750 did indeed come from the factory with a 150/70 rear radial on the same 3.5" wheel used for the GS500s.  About half of the tire makers OK a 150/70-17 radial tire on a 3.5" wheel and almost all OK their 150/70 bias ply tires on a 3.5" wheel.  None approve fitment of a 150/60 supersport on a 3.5" rim in this country.  It's interesting to note the BT45 bias tire originally came in the 150/70-17 size in both H and V rated models and the H was approved and the V was not on the 3.5" rim.  Seems they only list the V rated now in that size.

Even more interesting to note is although I've never seen Avon approve fitment of a 150/70 radial on a 3.5 wheel in their general spec charts look at their fitment guide and you'll see they recommend their latest Storm 2 150/70 radial for the early Kat 750.   

[Yev]

Are you guys running the 150 without modifications?

[tykho]

Are you guys running the 150 without modifications?

That's what I was about to ask, I would definitely go with the 150 for aesthetic appeal.

[gsJack]

A normal size 150/70 rear tire comes close to and sometimes touches the brake rod on the GS.  I ran a 150/70 Lasertec rear for 10k miles without any mods but it came close.  Later I ran a 150/70 RoadAttack that was supposed to be the same size and it just touched the brake rod and I put a bend in the square cross section brake rod simply by taking it off and hitting it with a BFH right on the inside spot that the tire touched, a quick and easy mod.  I am currently running a 150/70 rear Roadrider that has ample clearance all around with the bend I previously put in the brake rod.

I say normal size above because I've more recently discovered a couple of Shinko bias tires that have a 150/70-17 rear tire that is actually wider than a normal 160/60 would be, most unusual.  A 160/60 requires further mods to get clearance for the chain and chain guard.  According to Shinko specs their 150/70 741 tire is 6.53" wide and their 150/70 712 tire is 6.45" wide.  A normal 150/70 is 5.9" (150 mm) wide and a normal 160/60 is 6.3" (160 mm) wide, all dimensions based on normal rim widths.

http://img.photobucket.com/albums/v443/jcp8832/CalcTireDims.jpg