Tyre advice for shafties

[49er]

It's time to replace the rear tyre on my 850. The PO had fitted Pirelli rubber all round. The rear is 130/90 17" and it's width just clears the shaft tube by 2mm. I would like suggestions from members who have fitted other brands and feedback on their stickiness and wet weather performance. Mileage isn't a big issue but grip is. Also, I don't want to buy a tyre only to find that it won't clear the shaft tube. I'm keen to stick with the 130/90 size, but the actual width appears to vary from different manufacturers. If the tread patterns are radically different, I may have to change the front as well.
Cheers
Ian

[neil w]

Try Pirelli Sports Demons, I ran them on my 1100 katana, (100/90 v19 front and 130/90 v17 rear).
They are the modern equivalent of the old phantoms and metzeler Me33/Me99's , excellent wet and dry weather grip and sporty for crossplys plus the rears looked like lasting up to 4000 miles and the fronts 6000 plus.
Only changed them when I upgraded to GSXR running gear

[Planecrazy]

I'll second the "Sport Demons!" When I changed my 1100G from Dunlops to the Sport Demons it was like riding a completely new bike!!

Enjoy!

[salty_monk]

Mine has Dunlops on it... Elite II same size. TPO said he used to get about 8,000 miles out of them more out of the front.

They seem ok to me but I have nothing to compare them with & don't ride that hard.

Dan

[Dink]

Nother vote for Pirelli Sport Demons.

Dink

[80GS1000]

Yet another vote for the Sport Demons. Great traction wet or dry, and really let you lean it over.

If I weren't doing the radial tire conversion, I'd have put on another set of the SD's.

[49er]

Thanks for the feedback guys. Looks like the "Sports Demons" will get the nod.
80GS1000.
Nice looking Wes Cooley example. Are you keeping all the original bits so it can be converted back to original specs at a later date?
Did Wes run airbox or pods on his race bikes?
Cheers
Ian

[80GS1000]

Thanks for the feedback guys. Looks like the "Sports Demons" will get the nod.
80GS1000.
Nice looking Wes Cooley example. Are you keeping all the original bits so it can be converted back to original specs at a later date?
Did Wes run airbox or pods on his race bikes?
Cheers
Ian

Ian-

Thanks for the compliment. Currently, that bike is a Photoshop mockup/prototype - the real bike is currently being built and looks like this as of right now. I am keeping the original parts so that it can be returned to original someday if desired. Although with the improved handling, brakes, and engine performance, that may never happen. I'm also trying to keep any permanent, irreversible mods to a minimum.

The Yoshimura GS1000 had velocity stacks.

Here are some good articles and pictures of that bike:

http://slcelectronics.com/GS1000_Build/Yoshi-Article/

http://oldskoolsuzuki.info/patrick/projects/knarf_gs1000/clink/

http://oldskoolsuzuki.info/patrick/projects/knarf_gs1000/wes_cooley_80/index.htm

[49er]

Well, I invested in a set of Sport Demons. I thought that the handling would be more consistant with the same rubber at both ends.
What a great set of tires. My tire fitter races bikes and set the tire pressures at 34psi front and 36psi rear. This was higher than I had been running on my previous Pirelli's (28/32). I wasn't averse at trying this setup as I had read debates on tyre pressures on another forum, before deciding to buy the SD's. The handling and braking has improved probably in the vicinity of 30%.
I have bought a later set of front brake calipers and now only need to replace the discs to complete the package. Then there's the progresive springs and improved damping, followed by...............................etc, etc.

[tomcat24551]

Ian, why don't you try the new calipers with the existing, non-slotted discs?
The solid discs appear to be slightly thicker than the slotted ones but, otherwise, I don't see why they wouldn't fit. I can't see why a few holes would improve braking performance all that much. (The slotted discs do look a little more attractive however.) There's method in my madness: If it works for you, I'll do the same. The '79 stock brakes are poor even with GG pads.

Also, do you really think 36 psi is necessary? I think 32 psi keeps a rounder profile on the treadface. Of course, if you're constantly in excess of 100 MPH, you don't want to overheat the rubber.

Just a few ideas. Thanks for the recent pictures of the cam bearing mods.

Tomcat

[Dink]

36 psi is the Pirelli recommended pressure, I run 36 front & 42 rear.
Obviously the tyres are designed to be ran at a higher pressure.

Dink

[themess]

36 psi is the Pirelli recommended pressure, I run 36 front & 42 rear.
Obviously the tyres are designed to be ran at a higher pressure.

Dink

Tire manufacturers usually say to use the air pressure recommended by the vehicle manufacturer. The vehicle manufacturer also specifies the size and shape (profile) of the tire. Air pressure changes the tire's profile. If the tires are at 36 psi and the total weight (rider + bike) is 720#, the contact patch will be 20 square inches. If the air pressure is 24 psi, the contact patch will be 30 square inches. The size of the contact patch changes the profile and the handling geometry.

[49er]

Ian, why don't you try the new calipers with the existing, non-slotted discs?
The solid discs appear to be slightly thicker than the slotted ones but, otherwise, I don't see why they wouldn't fit. I can't see why a few holes would improve braking performance all that much. (The slotted discs do look a little more attractive however.) There's method in my madness: If it works for you, I'll do the same. The '79 stock brakes are poor even with GG pads.

Also, do you really think 36 psi is necessary? I think 32 psi keeps a rounder profile on the treadface. Of course, if you're constantly in excess of 100 MPH, you don't want to overheat the rubber.

Just a few ideas. Thanks for the recent pictures of the cam bearing mods.


Tomcat

Tomcat, I'm planning on mounting the later calipers as a trial to the standard discs after I have fitted a seal kit to them. I will also re-surface the discs. I did that to the rear disc when servicing the rear caliper and master cylinder. The rear end is behaving quite well now.
I don't hammer my biker that often, but have found that when I do push it hard through corners, the extra tire pressure improves the side wall stability. I believe this benifit out weighs any slight lose of patch area because of the increased psi.
When we go with the manufacturer's recommended pressures, we may be missing out on improved handling due to the fact that tire design and composition have changed dramatically since 1979. It always pays to keep an open mind on these issues.
Dink, thanks for your feedback on the Pirelli recommended psi. That rear 42psi of yours sounds a little high though!!!

[80GS1000]

Glad you like the Sport Demons. What a great bias ply tire.

[Dink]

Dink, thanks for your feedback on the Pirelli recommended psi. That rear 42psi of yours sounds a little high though!!!

Remember these are an "upto the minute" tyre design, manufacturers recommended pressures do not apply; in fact I have always got a recommended pressure from the tyre distributer, BTW 42psi is recommended pressure for sustained two-up high speed riding;there is a lot of empty roads where I live. Try 40psi, these are "new tech"tyres designed to run at higher pressures, reduced rolling resistance whilst maintaining contact patch etc.

Dink