It's been a while since I've been on this site. Fortunately, I've been busy enjoying my GS500F a lot, having worked out some kinks and completed some "quiet mods" that increase safety and comfort for commuting/touring. But it's that time again . . . I need new tires.

Now, the BT45's have been fine, but every time I get to the point where I have to replace both tires, I contemplate my desire to try Avon's. The AV's (Azzaro) get great reviews and come highly recommended for the GS by this and other forums. However, we all bemoan the fact that the AV line is reputedly being discontinued in favour of the ST (Storms) which unfortunately do not come in a rear tire size that fits a 3.5" rim. In Western Canada where I live, the AV's just don't exist and the distributor can't even supply them. Personally, I like the technical specs of the Storm's better and would buy them in a heartbeat.

http://www.avon-tyres.co.uk/motorcycle/?page=tyres&method=showspecs&id=25
http://www.avon-tyres.co.uk/motorcycle/?page=technical&subpage=tech_symbols

I've personally written and talked to Avon pleading them to make a ST rear 140/70/17, like they did for the AV line. But unless they hear from a enough interested parties, it's unlikely they'll produce one. So . . . I'm asking anyone on this site who is interested in trying or using Avon Storm tires to contact Avon through their website http://www.avon-tyres.co.uk/motorcycle/?page=contact and petition them to make a rear tire that will fit our bikes.

Perhaps, by using the power of the web, we can convince them to consider adding a rear tire size to their ST line that will work on the GS. Maybe if we can get enough people to write in, we can figuratively, and literally, create an "Avon Storm" !

The VX800 was a standard style bike with the Intruder 800 V-twin engine.  It had 3.0x18" front and 3.5x17" rear wheels.  Avons recommended fitment from their fitment guide for this bike:

VX 800, U (1991 - 1997)
Front Tyres
» Storm-ST
Size 110/80ZR18 (58W)
2.3 bar (33psi)
Rear tyres
» Storm-ST
Size 150/70ZR17 (69W)
2.5 bar (36psi)

http://www.avon-tyres.co.uk/motorcycle/?page=fitment&method=fitments&manufacturer=57&id=1304&model=800&year=

Personally, I wouldn't hesitate to try a 150/70 Storm rear on my GS with my 3.5" oem rear wheel.  I've run both a Lasertec and a RoadAttack so far in the 150/70 rear size, ran them both with 110/80 Lasertec fronts.

Currently I'm running 110/80 and 140/70 Avon AM26 Roadriders and find them very good tires for the GS.  Very good tire life with good performance.  I'm considering trying a 150/70 Storm rear with the AM26 front next.

As far as I know Avon never made the Azaro in a 140/70 rear size but did make one in a 140/80 size which has a preferred rim width of 3.5", just right for the GS.  The Storm replaces the Azaros in most sizes but they still make Azaros in 6 sizes that aren't made in Storms which include the 110/80 and 140/80 sizes suitable for the GSs.  I ran a pair of Azaros in those sizes and they were very good tires on my GS.

The Tire God has spoken 

 


Another thanks from all of us im sure Jack! You are a great asset to the forum .

Hey, Jack. Thanks for that additional info and the correction on the AV sizing. You're right, they were a 140/80, not 140/70.  Just getting mixed up in the numbers.

My turn now . . . ST's aren't listed in a 110/80 on for a 17" rim, only an 18" rim.  However, would you be suggesting a 110/80 on the front and 150/70 on the rear because the reduced rear rim width will force the 150/70 to have a more pronounced profile that would match closer to an 110/80 profile? I'm guessing that if the tire is rated to fit a 4 - 4.5" rim, that putting it on a narrower rim will affect the profile.

I did contact Avon by phone/email and they did not recommend putting the 150/80 on the 3.5 GS rim. They were pretty clear about that, and if I remember correctly, it was more to do with the outward pressure and fit to the bead. They couldn't guarantee that the bead would stay put. But then even if it would work, they'd have liability concerns so they would never go outside their published recommendations anyway. Good to see you're running a similar mix of profiles on your bike, but the 140/70 in the Roadrider is rated to fit a 3.5". I'll have to give some consideration whether to give the ST a try anyway.

I'm also giving thought to the Katana 600 rear wheel conversion that is so well documented on this site. That would work with the ST 150/70 and open up more tire options. I'd probably make a separate custom brake caliper bracket so it could be switched back to stock easily.

The 88-97 Katana 600/750 had the same 3.5" rear wheels as the GS500 has.  The  98-06 Katana 600/750 had 4.5" rear wheels.  The preferred rim width for 150/70 or 150/60 rear tires is 4.0".  Avon's current fitments:

GSX 600 F, Katana (1988 - 1997)
Front Tyres
» Azaro-ST
Size 110/80ZR17 (57W)
Rear tyres
» Azaro-ST
Size 140/80ZR17 (69W)

GSX 600 F, FU, Katana (1998 - 2006)
Front Tyres
» Storm-ST
Size 120/70ZR17 (58W)
Rear tyres
» Storm-ST
Size 150/70ZR17 (69W)

GSX 750 F K-S, Katana (1989 - 1997)
Front Tyres
» Azaro-ST
Size 110/80ZR17 (57W)
Rear tyres
» Azaro-ST
Size 150/70ZR17 (69W)

GSX 750 F, Katana
Front Tyres
» Storm-ST
Size 120/70ZR17 (58W)
Rear tyres
» Storm-ST
Size 150/70ZR17 (69W)

Interesting isn't it, or should I say amusing isn't it?   

Personally I take the tire maker's fitment guides as valuable input but as you can see they're adjusted to accomodate the tire sizes they have to sell.  Good old sales dept engineering I would say.

The oem 110/70 and 130/70 size tires work just fine on the GSs but there are no radials available in those sizes.  The only good reason to go to wider tires is because the sport touring and supersport radial tires generally start at 150/70 and 150/60 sizes.  But the wider tires do look good on the GS don't they?

You should read the bias ply tire comparo test from the UK Bike mag that was linked here recently before you decide on which Avons to try:

http://www.smugmug.com/photos/421778173_r5kSp-X3.jpg
http://www.smugmug.com/photos/421778222_97mdg-X3.jpg
http://www.smugmug.com/photos/421778267_oz9pS-X3.jpg
http://www.smugmug.com/photos/421778306_bGmAr-X3.jpg

Yes, that is interesting. But the bottom listing GSX 750 F does not indicate a year. I wonder if that's a '98 or later model that would have a 4.5" rim. Seems everything that does show a year up to '97 is either Azzaro or Roadrider.

I'm going to head down to my local salvage place next week and see if they have a '98 or later wheel. Guess I'm just not willing to put to test fitting something that's not recommended while taking a corner at 90k with my wife on the back. If I was the only rider, maybe. But she likes to go for rides once in a while to and that changes everything for me.

Thanks Jack! I'll be checking back to reread this info when I tire of my tyres for sure!

That last listing is obviously for the 98 and later Kat 750 and they just missed putting the dates on it.  They show the 120 front and that change was made for 98 and later too when they changed the Kat front wheels from 3.0 to 3.5" wide along with the rear wheel change from 3.5 to 4.5".  I'm not trying to sell 150/70 tires on 3.5" rims but just saying I don't see the need for narrower sport touring radials in this limited market.

I found Conti much more agreeable when I posed the same question to them concerning the 150/70 radials on the 3.5" rims that you questioned Avon about, their e-mail reply to mine:

Dear John,
Our head technician in Germany confirmed that you will be OK to run a 150/70ZR17 in either ContiForce or Road Attack on your 3.5" rim.  I have attached some detailed information on the Road Attack for your review.

Safe Riding & Best Regards,
Greg Reich
Continental Tire North America, Inc.
Sales Manager/Motorcycle Tires
-------------------------


Your inquiry / Anfrage:
Your previous guides listed a 3.5" rim as suitable for your 150/70/17 ContiForce tire. Since the RoadAttack came out you show a 4.0" minimum rim width for both the ContiForce and RoadAttack tires in the 150/70/17 size.

I'm interested in trying the RoadAttack and wonder if it is a less suitable fitment than the Contiforce was on the 3.5" rim.  A number of tire makers approve this fitment like the Z6, Diablo Strada, and BT020 for example.  I'm running a 150/70/17 Lasertec now and am quite satisfied with the performance but would like to get the longer tire life I previously got from Metzler and Avon sport touring radials.

My local tire supplier has the RoadAttacks at a favorable price and I have been seeing very good reviews on them.  Would much appreciate your views on this fitment.

Thank you,
John Paul

Well, Jack . . . as usual you come up with some interesting info.  Certainly the Conti response gives some food for thought. I've been trying to find the email replies I got from Avon,  but even being a stingy old email pack-rat who seldom deletes emails, unfortunatley I can't seem to locate them. Must have purged when I was in email jail at some point. Hey, good eye on the front tire size identification of the post '98 Katana info.

I still think I'd prefer to go the rear wheel upgrade route if I can, but that will hinge on how easily and inexpensively I can get my hands on a wheel and whether it'll need the rotor, etc. Shipping is a killer and most ones I've seen on the Internet are out of the US, so shipping is as much or more than the wheel! Hopefully I can find one locally. If not, I'll give some consideration to just trying the 150/70 on the rear. I suppose every tire and rim combination is different though, so it's a $200 gamble.

Quote from: scottpA_GS on January 22, 2009, 06:50:51 PM

The Tire God has spoken 

 


Another thanks from all of us im sure Jack! You are a great asset to the forum .

+ 1 trillion

A 2000 750 Katana wheel and rotor are on their way . . .  Found one online including shipping for $200. I figure that's only about the cost of a rear tire, so why not go for it. If there is a chance I'd be gambling $200 fitting the 150/70 on a stock wheel anyway, then I might as well spend that much making sure it goes on a wheel that it was spec'd for.

I'm grateful for Turd Ferguson's writeup http://gstwins.com/gsboard/index.php?topic=25426.0 You can bet I'll be using that article to help me get through the modification. (who would name their kid "Turd" anyway?)   If the mod wasn't that straightforward, I probably woudn't go through the expense and trouble, but it will also open up some other tire possibilities.

Thanks for all you're helpful info, Jack. I suppose it may be a limited market like you say, but if they made one for the Azaro, which they are discontinuing, I wish they made one for the Storm to replace it. I still think if enough people send in the request, they may consider it.

The Storm line replaces the Azaro line but they still make the Azaros in 6 sizes they haven't made the new Storms in and that includes the 110/80-17 and 140/80-17 sizes that fit the GS500s as I said above.

A quick check shows the AV46 Azaro rear tire in the 140/80-17 size is available from AMT, MAW, Southwest, and Tires Unlimited and has a 3.5" preferred rim width.  I don't think Avon has plans to discontinue this tire.

Only other sport touring radial tire still available in the 140/80-17 size I can think of offhand is the Dunlop D205.  I was referring to the 140/70-17 size you were requesting in your first post above in saying there was a limited market here in North America.  There are many Moto Guzzi that use the 140/80.

Metzeler promotes a tire "upgrade" program to put larger rear tires on big cruisers.  They have Stage 1, Stage 2, and Stage 3 fitments that vary from no mods required for Stage 1 to extensive mods required for Stage 3.

Every time we get into a discussion like this that brings out questions of the safety of putting either 150/70 or 150/60 tires on the GSs 3.5" wide wheels I think of this.

Honda's 1100cc Shadows came with 170/80-15 rear tires on a 3.5" wide wheel which is a standard approved fitment for that size ME880 tire. Their approved no alteration Stage 1 upgrade is a ME880 200/70-15 tire on the stock rim but in their tire charts the standard permitted rim widths are 5.50-6.50" for this tire.

Guess that's good enough for a cruiser.   

You're right, the Azaro's seem to still be made and still somewhat available, just not in Canada. I've not been able to find anyone who stocks them or says they can get them in on order. Even when they talk to the distributor. Ordering from the US is usually a dead end because they won't ship to Canada or the cost of shipping makes them rediculously expensive.

Avon advertises that the Storm "replaces" the Azaro, so if they are not discontinuing them, that might be one of the biggest marketing fumbles they'll ever make. All over the web and in the shops people say the Azaro is being discontinued, to be replaced by the Storm. Most online stores don't have very many sizes of Azaro available, which looks to me like they're just trying to clear out remaining stock.

I really like the technology built into the Storms and in every reference I've read about, people who has had them liked them. So I'm going ahead with the Katana wheel upgrade which arrived yesterday. I'll be checking whether the Storms are in this morning and getting them mounted if so.

Cheers - Brian

Well, the 750 Katana rear wheel modification on the GS500F is complete and I've put some kilometers on the Storms. What a difference! 

Handling has improved significantly. I'm sure some of the difference I'm feeling is due to going from almost worn out tires to fresh ones, but the surefootedness of the Storms in dry and wet seem much better than the Bridgestone BT45's. I'm more confident on these tires and they seem to have smoothed the ride out as well. From the get-go the leans feel stable and the rear doesn't feel like it want's to wander a bit like the BT45's did.

I'm also thinking the 4.5" rear rim width has something to do with it. A 1" inch increase on the rim while only a 20 mm increase in width of the tire must add to the stability I'm sensing, particularly on the leans. IMHO this is the size of rear wheel that should have been stock on the GS. It rides better and looks better. Not sure any wider of a tire is necessary, but given how the Storm's feel, I'll probably never no because I won't be using anything else unless they prove to wear out too quickly. I average 25,000k a year, so the wear factor is fairly important to me.

I still wish Avon created a 140/70/17 for all those riders who can't or wouldn't do the rear wheel mod, but for me, this was the way to go  and probably the best modification (right up there with the heated grips).