Dropping Bias tread from a GS650L, shafty

[Jedz123]

Hey team.
I've seen ZR rims and tires fitted to the bigger bikes (750, 1100 and 1150's). I'm looking to find a means to get ZR tread on my 650. At speed in the twisties the stock bias tread and wheel size combo is creating an interesting feel in the turns. The suspension on the bike is pretty good. I think I need to swap out the front springs for the L springs dive a bit too easily, other then that the new rear shocks and front end is pretty solid... The rebuilt brakes are currently very adequate for shedding speed with this little bike. The tires are pretty great for cruising but pretty not so great in the turns. Tires are perfectly balanced BUT they currently have tubes even though the bike sports tubeless rims. The bike came with a new Dunlop American on the rear and new IRC GS-11 on the front. I really want some better tread for the twisties... The rear feels "alright" but the front tire does not respond well in the turns... Especially after 4 or 5 hard turns with spirited acceleration and deceleration.
So I was thinking when I ripped up the mountains today what tires or wheel options would compliment the small revvy engine and its extremely flickable and light frame but not compromise the comfort of the bike.
I've been out if the GS game for a good chunk, is there good (bias or radial)tires to run these days on these stock tubeless rims? If I decide to swap over to ZR(if possible with this little shafty) what wheel options do I have? I can't find ZR tires for this little guy with these rims...
Anyway Input is always appreciated.
-Justin

 

[tkent02]

What size tires are on it now?

 

[Jedz123]

The Front IRC GS-11 is in inches... 3.5 H19 I believe the stock tread is 90 90 19.

The rear Dunlop American is a MT 90 B16 H47?... Looks like a 130 width .

 

[tkent02]

So they must be decades old?

 

[Nessism]

Get some Sport Demons and call it done. There is no inexpensive solution on how to move to a wider rear wheel.

 

[Jedz123]

Nope they are pretty new Tkent. The American is stamped 1615 and IRC is stamped 4814. It was one of the first thing I checked out when I got the bike. Tires were practically new with those new hair nobs still on them, well on the very large chicken strips(they dont exist anymore). I just browsed eBay and you can still grab these tires new... The IRC comes in inch size. It's a replicant tire to replace the stock Firestone's that came on the CB's. Apparently to give that factory fresh look to vintage machines.

Who said I was seeking an inexpensive solution Nessiem? . I'll check out the sport demons. I'm guessing I would need to replace the swing arm for a wider tire huh...

 

[Nessism]

There are companies that can widen the wheels.

 

[SVSooke]

There are companies that can widen the wheels.

Maybe but how far could the be widened without hitting the shaft?Not much is my guess,defiantly not enough to fit radial tires. Thinking on it further didn't I see that Continental makes radials in vintage sizes.For Jedz I'd think a set of Sport Demons might be the easy answer.

 

[Jedz123]

The Continental Attack is made in a radial that would fit the front but nothing that would fit that 16" in the back rim. I would like to think the Sport Demons ran tubeless will be a world ahead with what I have right now in the front and rear. The rear is ok, I'm just dumbfounded why the PO had the shop but tubes in a tubeless tire on a tubeless rim... (rear) the IRC is a tube type, that thing is smooth to ride on but break 70mph or get hard in multiple turns and it will let you know it's really not up for the job. It works well though and rides very smooth at cruising speed.

I wasn't sure if I could swap to a 850 rim or not with this bike. Ive read the 850 had a 17" out there which will allow me to run a radial in the both front and back.

 

[Guest]

I'm just dumbfounded why the PO had the shop but tubes in a tubeless tire on a tubeless rim...

Why do you say you have tubeless rims? Simply being cast does not make them tubeless, they must also carry the 'MT' designation and I don't think any of the GS wheels ever had that.

I wasn't sure if I could swap to a 850 rim or not with this bike. Ive read the 850 had a 17" out there which will allow me to run a radial in the both front and back.

No GS 17" wheel will be wide enough to run a radial tire, you need a minimum width of 3.5" for all the 130 and 140 rear tires I have seen.


Mark

 

[ShadowFocus603]

Jedz I have Dunlop 404's on her 750L running tubeless and it will get down and boogie in the turns. The rear was done last year and the front was done last week. I haven't had an opportunity to really push it since I HATE the bars (and she loves them, go figure) but I have been able to reduce the chicken strips to less than an inch or so front and rear in short order. We are running 100/90-19 front and 130/90-16 in the rear.

 

[Jedz123]

Why do you say you have tubeless rims? Simply being cast does not make them tubeless, they must also carry the 'MT' designation and I don't think any of the GS wheels ever had that.

Mark they have the words cast "Tubeless Tire Applicable" on the rims... I know most GS bikes have tube style mags but these are indeed the tubeless style rims... I have had a few GS bikes that could run tubeless. 2 out of the 3 GRs I had also could run tubeless. The few spoked rimed GS (and 3rd GR) I've had could not.

Thanks for the input Shadow, I'll likely run Sport Demons tubless as recommended. The IRC was nice but after a +100 mile ride two up the tire felt odd at speed or in the turns. It'll be looking to grab some tread after I get the tires set for the Connie first. I got another BRP trip to ready her for at the tail end of next month.

 

[Steve]

You don't have to look for 850 wheels, the 650G had 17" rims on the back. It was only the L bikes that had 16s.

You mentioned something about replacing the swingarm for a larger wheel/tire combo? Good luck with that. The left side of the swingarm houses the shaft. There is no practical way to make the swingarm bigger to accomodate a wider wheel/tire. You are pretty much limited to the 130 width, it would be best to just find the best-gripping tire in that size.

As mentioned, the Sport Demons are good. Avons are pretty decent, too. Bwringer was pleasantly surprised at the grip available with the Shinko Tour Master 230, but found they did not last long enough for him. The Avons lasted about twice as long and cost less than twice as much, for a lower cost per mile. Not sure where the Sport Demons fall in there.

.

 

[tkent02]

Sport demons don't last as long as Avon RoadRiders, but are very sticky. Avon RoadRunners are a so so tire, nothing special, not even remotely as good as the RoadRiders.

Unlike on cars, I haven't seen much advantage to radials on bikes, they don't last any longer, not much if any stickier than GOOD bias ply tires. They are a little bit lighter if you consider that an advantage.

 

[Guest]

I run the Bridgestone Bt45's on my 1000G and like them, I tried a set of Shinko's and the bike handled like a truck, lost all of it's nimbleness. I highly recommend the BT45's ( and I ride the bike hard)

 

[Jedz123]

You don't have to look for 850 wheels, the 650G had 17" rims on the back. It was only the L bikes that had 16s.

You mentioned something about replacing the swingarm for a larger wheel/tire combo? Good luck with that. The left side of the swingarm houses the shaft. There is no practical way to make the swingarm bigger to accomodate a wider wheel/tire. You are pretty much limited to the 130 width, it would be best to just find the best-gripping tire in that size.

As mentioned, the Sport Demons are good. Avons are pretty decent, too. Bwringer was pleasantly surprised at the grip available with the Shinko Tour Master 230, but found they did not last long enough for him. The Avons lasted about twice as long and cost less than twice as much, for a lower cost per mile. Not sure where the Sport Demons fall in there.

.

Just dabbling with the idea... The bike is so low powered I would't mind "being stuck" with the 130 anyway.

I'll look into Avons, I ran Shinko 009 (ZR) Ravens quite often on my other "New" school Japanese liter standards and had good results with them but with the girth of the Connie, it would eat them up in a couple thousand hard miles, always wearing the side of the tire out before the middle. I now run the Michelin PR4GT on the Concours, That's a decent tire, not the best in the turns I often have wheel spin while exiting under hard acceleration and slide during hard braking pre turn sometimes causing a slight slide in hard cornering, this is mostly Un-loaded. Loaded it grips well and the Connie is a wheelie machine out of the turns. Takes a while to heat up the tire. I do notice poor grip if the tire is cold but when heated they perform pretty well and I can get the rear of the bike lined up with pre turn sliding or powering out. They do last very long... I have over 6K miles on this rear now and it's got 40% tire left I'd say. Still very rounded but I ride in the turns hard. The front though... Is spent. Like I said, the sides of the tires are first to go on this bike but grabbed some good miles out of it.

Anyway I'll likely run something other then a Shinko on the GS.

Sport demons don't last as long as Avon RoadRiders, but are very sticky. Avon RoadRunners are a so so tire, nothing special, not even remotely as good as the RoadRiders.

Unlike on cars, I haven't seen much advantage to radials on bikes, they don't last any longer, not much if any stickier than GOOD bias ply tires. They are a little bit lighter if you consider that an advantage.

They have less rolling resistance, My VTX had better mileage with radials before I swapped it over to Bias. The ride is more plush with the bias and they do respond differently (less precise) in the turns, it might be because the VTX1800 is a HUGE bike and the radials are better built for that application (and it came out of the factory sporting radials) but I did notice a ride difference from the Radial to the Bias. I actually prefer the ride on the bias with my VTX, Gas took a few points but it seems to eat up bumps easier and cruise nicer. It was pretty jarring with the radials.

I run the Bridgestone Bt45's on my 1000G and like them, I tried a set of Shinko's and the bike handled like a truck, lost all of it's nimbleness. I highly recommend the BT45's ( and I ride the bike hard)

Thanks Jim! I would like to be able to eat up some hard turns with you folks at our next meet but with this IRC on it now I would have to back off after a few miles. The tire distorts and feels differently after it get's hot (maybe too hot). The tubes are part of the problem too... The rear though feels fine. I need to get the bike off the tubes and onto a tread with decent life but far better handling.

Thanks for the input guys!

 

[bwringer]

You're overthinking this.

Spoon on some good modern rubber in the correct stock sizes, finish sorting out the front end (you mentioned it still needs springs), and enjoy.

Pirelli Sport Demons are very well-regarded, but are short-lived.

I prefer the Avon AM26 RoadRiders, since they stick just as well, they last, they're V rated, and they work brilliantly in the wet. And they don't turn evil near the end -- they're very consistent as they wear. The Avons have a very light, nimble feel -- I believe they have a slightly "pointier" profile that suits olde heavy bikes quite well.

And yeah, install new valve stems and run them tubeless.

The handling limits of these machines are in the frame, not tire grip -- frame flex limits your antics long before modern bias-ply tires will give up. There's no need to futz with wider wheels/tires.

 

[Guest]

And yeah, install new valve stems and run them tubeless.

Where are you buying valve stems for conversion to tubeless?


Mark

 

[Sandy]

Like bwringer said, just stick on some decent rubber and if the rear feels good just setup the front. It'll most likely need a set of springs, proper fork oil for your riding style and maybe even a fork brace. I'm running Dunlop GT501s on my 1000, BT45s on the 750 and both bikes behave very well with the bias ply tires. I'm sure the Sport Demons or Avons and a few others would be every bit as good as what I'm running, just a matter of sizing, price and longevity. Going to the 17" rear would probably be a good thing for tire selection. Once setup properly if ridden hard any bobbles and wobbles is probably frame related and not really fixable.

 

[bwringer]

Where are you buying valve stems for conversion to tubeless?


Mark

The OP mentioned that his rims are marked "tubeless applicable" but someone installed tubes.

You need metal motorcycle valve stems -- the ones made for cars are too fat, and you can't use rubber snap-in stems either.

Here's an example of what you're looking for -- not sure where you'd get them in Canoodia:
http://www.motorcycle-superstore.com/44692/i/bikemaster-chrome-tubeless-valve-stem

Note that these are the same diameter all the way down (about 8mm or 5/16") -- valve stems made for cars have bigger threads near the base.