Yet another tire thread

[bwringer]

< klrmode="on" >

Everyone still buying from these guys as the place of choice?

http://www.americanmototire.com/catalog/index.php?cPath=33_892_905

I need a set soon (and probably a set for the KLR too - what do you run their Brian? I'm coming to the end of life on a pair of Heidenau Scout K60's with about 9-10,000 on them.)

Lately I've been buying all my tires (sorry, "tyres") from Rocky Mountain/Jake Wilson (they're the same company). Their prices are under or within a dollar or two of the prices at American Moto Tire ("American" is right there in the name, so I guess they have to spell it "tire"). But the main reason is that they have a 5% rewards program, so I at least get some benefit from the vast sums I spend on rubber.

Anyhoooo... I've been through two sets of Metzeler Karoo 3 on my KLR, and they've been fantastic. Very aggressive tread that seems to work well off-road, and they stick wonderfully well on pavement, even in the wet. Reasonably priced (currently $158) a set, and pretty good life for a tire this aggressive (although not nearly as long as the Heidenaus). They even handle quite well when they're nearly worn out, which is unusual for knobby tires. They're noisy (some people care; I don't) and like any knobby there's a noticeable bit of rolling resistance.

The Heidenau K60 lasts a long time and works well off pavement, but from what I've observed and heard, they're a bit slippery on pavement and scary in the wet; the rubber is a bit too hard.

It's just about new tire time for my KLR as well, and I've been thinking about trying a set of the Shinko 804/805 knobbies in the name of Science. The online feedback is very good, and pricing is similar, perhaps a bit less. ($156/set right now, although the rear is backordered.)

The Shinko 244 works quite well and at $94 a set, they're the undisputed bargain leader for the KLR.

Michelin stopped making my favorite "pure" knobby, the T63. These were phenomenal, but wore out quickly. They're trying to get people to use the new Anakee Wild which just happens to cost about $70 more a set.

</ klrmode="off">

OK, hijack over -- back to your regularly scheduled GS programming...

[Nessism]

Handling will be MUCH improved with a 100/90-19 up front. And, as mentioned above, 130/90-17 in the rear.

The Spitfire S11 is very old design dating back to the late '80s/early '90s, and frankly never was that great a tire in the first place. There are MANY excellent choices in much more modern rubber nowadays, and I think you'll be very pleased with your revitalized GS850.

For your light usage, I'd bet the Shinko 712 or 230 would be just the ticket. My bike is currently wearing the Shinko 712, and I don't recall any complaints about the pace in the Missouri rally. Both handle great and stick well in the wet or dry, they handle great beginning to end, and they're an incredible bargain. The one downside is that they don't last as long as some other choices. However, that's not really a factor for you unless you like the way the bike feels so much that you end up riding a lot more.

Other great choices include:
Avon AM26 RoadRiders (careful -- the front 100/90-19 can be used front or rear, so some catalogs get confused and list it with the rear tires)
Bridgestone BT45 Battleax
Continental GO!
Michelin Pilot Activ
Metzeler Sportec Klassic
Pirelli Sport Demon

The only ones I'd avoid are the Kenda Challenger (horrifying in the wet), the Bridgestone Spitfire S11 (short-lived, and they turn nasty as they wear), the Dunlop 404 (short-lived, and they also turn evil as they wear), and the Metzeler Lasertec (eye-wateringly expensive, short-lived).

Great post here. Should be a sticky for the Newbie's.

100 front and 130 rear are tried and true sizes for the shafties. No reason to question further.

[bwringer]

Thanks for the quick response! I don't think I'm overthinking this decision as the tire combination will have an effect on the handling characteristics. I don't take this particular motorcycle out all that often but when I do, I push it pretty hard on winding roads so it would be nice if the tire combination I end up ordering doesn't result in heavy/awkward handling through curves.

Most imperial to metric conversion charts that I've found show a 1/4" of range eg: 3.25" to 3.5" x 19 = 100/90-19 for the front and similarly, 4.25" to 4.5" x 17 = 120/90-17 for the rear. Based on rim charts, it looks like 100/90-19 is the widest recommended tire for a 1.85" rim and the widest recommended tire for a 2.5" rim is 120/90-17. I guess I've just been lucky riding around with tires too wide for the rims for the past 9 years?

I've been reading through a lot of previous tire related posts but haven't been able to find who first determined that the best metric conversion of the original 4.5-17 rear tire is 130/90-17. Was the conversion & subsequent consensus based on measurements of an original set of tires or was there some guesswork involved? Maybe the consensus on the rear tire size is wrong?

I think the consensus came about for a couple of reasons.


For one, there are very, very few choices in 120/90-17. At the moment, I can find only three rear street tires in this size:
IRC Durotour
Bridgestone BT45
Avon AM26 (actually a front that can be used on the rear).

The Bridgestone and the Avon are fairly recent. For many years, the IRC was the only choice in this size. There don't seem to be any street tires currently available in 4.50X17.


Secondly, the 130/90-17 has been used hard for millions of miles of thousands of GS shafties. It's pretty well proven that it handles perfectly well. We've also proven that handling is much better with a 100/90-19 up front instead of the 110/90-19. I have no idea why, but it's common to find that some past shop or owner has stuffed a 110 on the front of a shaftie where it doesn't belong (the GK does use a 110/90-19, and has the correct wider wheel and forks) -- I suspect many of these started from a shop selling whatever they have on the shelf, not what's correct.


All that said, I don't know of any direct comparisons between a 120/90-17 rear and a 130/90-17 in the same brand. And it is true that the GL models with 130/90-16 rears came with 2.75" wide rear wheels. The G models came with 4.50X17 rears and 2.50" rear rims through 1983. Whether 2.50" rim is "correct" for a 130/90 tire is debatable -- some tire/rim charts show this as OK, some do not.

Anyway, 130/90-17 gives you a lot more choice and is correct or close enough for the rim width, and has been proven in real life use to work quite well on GS shafties. I will continue to use 130/90-17 rear tires on my GS.

[Steve]

Based on rim charts, it looks like 100/90-19 is the widest recommended tire for a 1.85" rim and the widest recommended tire for a 2.5" rim is 120/90-17.

Bwringer has given the best description of what works and why, I will just add that the '82-and-up GS1100G and GK have a front wheel that is 2.15" wide. Seems the GL kept the 1.85" wheel, probably to maintain that "chopper-esqe" look. I have a set of 1100G wheels on my 850, but I did it for the look of the different spoke pattern, not because the wheels were wider. Can't say that I noticed any difference in handling with the wider wheel. Used the same tire on both wheels to minimize the variables.

.

[CC2099]

I think the consensus came about for a couple of reasons.

For one, there are very, very few choices in 120/90-17. At the moment, I can find only three rear street tires in this size:
IRC Durotour
Bridgestone BT45
Avon AM26 (actually a front that can be used on the rear).

Secondly, the 130/90-17 has been used hard for millions of miles of thousands of GS shafties. It's pretty well proven that it handles perfectly well.

Well, that could be how the consensus came about. Most people here have been exchanging information with each other for quite a long time but as you've probably already guessed, I'm one of those people who always questions "common knowledge". I find that it's become far too easy these days to echo & thereby amplify misinformation.

OldVet66 has a differing opinion which was posted back in 2013: http://www.thegsresources.com/_forum/showthread.php?211522-81-GS-850-G-Shaft-Drive-Rear-tire&p=1904257#post1904257

130/90, 100/90 is a bad combination. 130/90, 110/90 however, is excellent, or as said before 120/90, 100/90. Increasing the back only, causes it to fall into the turns and take longer than it should for the back to catch up with the arc of the turn, not very confidence inspiring. I have run them both ways and know what it does. I am also running Shinko 230's.

This post seems to support my initial thoughts on tire size combinations - if the front tire width remains constant then as the back tire width is increased, the angle into the pavement is increased resulting in more pressure on the front tire and heavier steering.

[Nessism]

Most people here have been exchanging information with each other for quite a long time but as you've probably already guessed, I'm one of those people who always questions "common knowledge". I find that it's become far too easy these days to echo & thereby amplify misinformation.

Welcome to the GSR. I'll be sure to NOT respond in any of your threads. Don't want to spread any "misinformation."

[CC2099]

Welcome to the GSR. I'll be sure to NOT respond in any of your threads. Don't want to spread any "misinformation."

If you have an opinion on the discussion that has been taking place here, you should have stated your opinion and supported your position (if that's possible) rather than being rude. "To measure is to know" - that's interesting. Are you living up to your slogan?.. I'm not sure if you've read any of the previous posts where I specifically asked if anyone measured the original 4.5-17 tire.

I don't know what you took offense to in my post but I wasn't accusing anyone of spreading misinformation - all I was saying was this happens all the time and people don't even realise they're taking part in the echoing and amplification of incorrect information because they just accept what someone else said as the truth without question. Truth is supported by facts, not hearsay nor speculation. If you have some facts to share, I'm all ears.

[Nessism]

I seriously doubt anyone measured one of the original tires since they are 35 years old at this point and 99% of the bikes still surviving don't have the original rubber anymore. It doesn't matter anyway. The 100/130 tire sizes are PROVEN by hundreds of GSR members here. That's all most of us need to know. Since you have all of 8 posts right now it begs the question of why you did you join here anyway? If common truths that the folks here follow need to be proven to you why even waste the time of joining?

[CC2099]

I certainly didn't join to start a flame war if that's what you're wondering. I joined in order to ask questions. I was hoping for answers to be supported by facts. Just because hundreds decide to jump off a cliff doesn't mean everyone else should follow. People used to believe all manner of things. I'm sure that if you went back to the days when people used to believe that the Earth was flat, everyone you met would give you the same answer when asked about the shape of the Earth. Thanks for your OPINION on tire size.

[mmattockx]

I was hoping for answers to be supported by facts. Just because hundreds decide to jump off a cliff doesn't mean everyone else should follow.

No, it means that many hundreds of riders have tried the combinations mentioned and not found them wanting.


Mark

[GSJim]

I had a Metzeler ME99 120/90-17 on the back of my GS650G for a few weeks. It felt good but I didn't get a chance to give it a good run because it was destroyed by a handful of sheet metal screws two weeks after it was installed. The dealer had a 130/90-17 in stock and I have been using that size ever since.

Jim

[Nessism]

Hey CC2099, I've got an idea for you: how about starting a thread about the best oil for a GS! That topic is always fun.

[bwringer]

I certainly didn't join to start a flame war if that's what you're wondering. I joined in order to ask questions. I was hoping for answers to be supported by facts. Just because hundreds decide to jump off a cliff doesn't mean everyone else should follow. People used to believe all manner of things. I'm sure that if you went back to the days when people used to believe that the Earth was flat, everyone you met would give you the same answer when asked about the shape of the Earth. Thanks for your OPINION on tire size.

The solution to your curiosity and skepticism is obvious: advance the cause of Science yourself. "Science" is why my GS850G is currently wearing a set of Shinko 712s, in fact -- I wanted to push their limits and see how well they worked for myself. (Pretty darn well so far, although I doubt they'll make 3,000 miles.) I did the same with a set of Shinko 230s a while back.

Since 120/90-17 is now available in the Bridgestone BT45 and the Avon AM26 RoadRider, then you should buy new rear tires in both sizes and a front tire in 100/90-19, take them to a track day or to the mountains for THOROUGH knee-out, no-chicken-strips flogging, change the tires halfway through, and report back.

If you're not willing to do that (or send me a few free tires to test... ), then we're left with relying on the experience of hundreds of other riders.

[bwringer]

I had a Metzeler ME99 120/90-17 on the back of my GS650G for a few weeks. It felt good but I didn't get a chance to give it a good run because it was destroyed by a handful of sheet metal screws two weeks after it was installed. The dealer had a 130/90-17 in stock and I have been using that size ever since.

Jim

The ME99 is long gone, and Metzeler does not currently make a rear tire in 120/90-17.

Although in the case of your 650G, the original rear tire was 4.25-17 (not the 4.5-17 found on the larger shafties) so there's less gray area -- 120/90-17 would be more correct than 130/90-17, and some charts suggest 110/90-17 would be the closest match, although this is not a size that exists anywhere.

[CC2099]

The solution to your curiosity and skepticism is obvious: advance the cause of Science yourself. "Science" is why my GS850G is currently wearing a set of Shinko 712s, in fact -- I wanted to push their limits and see how well they worked for myself. (Pretty darn well so far, although I doubt they'll make 3,000 miles.) I did the same with a set of Shinko 230s a while back.

Since 120/90-17 is now available in the Bridgestone BT45 and the Avon AM26 RoadRider, then you should buy new rear tires in both sizes and a front tire in 100/90-19, take them to a track day or to the mountains for THOROUGH knee-out, no-chicken-strips flogging, change the tires halfway through, and report back.

If you're not willing to do that (or send me a few free tires to test... ), then we're left with relying on the experience of hundreds of other riders.

Yes, I am interested in doing a test. I don't want to waste money buying 2 different sets of tires but.. if I could find another GS850G rider nearby with the 100/130 front/back setup, it would be great to swap and go for a ride on each other's bike. We could both then report back with our subjective experiences.