How to shop tires

[Admiral Beez]

I?d like to replace the tires on my 1982 Suzuki GS650G, specs in the manual are 3.25H19 on front, 4.25H17 on the rear, both tubeless. But I don?t see these specs on tire websites.

 

[Nessism]

100/90-19 front
120/90-17 rear

Avon Roadrider's are hard to beat.

https://www.americanmototire.com/

 

[Big T]

You can get a 3.25 -19 in the Avons.
I just did.
In metric, a 90/90 would be closer

 

[hank2]

Those correct sizes for the GS650G seem to get harder to get all the time. Avon seems to have dropped the AM26 Roadrider sometime last year. They have one they now call the Roadrider MkII. No alpha-numeric brand that I have seen. The 100/90/19 is an easy size to find from many brands making classic bias tires. Avon and some others also make the inch 3.25/90/19 front, including the Avon RR MkII. Mostly for the old airhead market. Avon doesn't have a rear tire anywhere near the size needed though. Only 17 rears now are 140 or 150 70/17. The Bridgestone BT46's ( was BT45) is one of the very few available in a 120/90/17 rear. There are more tires available in 130/90/17, but that's going oversize. I really liked the BT45 on my GS650 and another bike in the past and couldn't ask for more.

There are also several brands that make a rear 120/90/17 bias tire in ADV type tires. Continental is one of them. Mostly 90/10 ( on road/off road) I picked up a new BT46 rear some months ago from Dennis Kirk, but haven't mounted it yet. My rear BT45 is about done @ 4500 mi. Beware, there are many 120/90/17 bias front tires, generally no bueno on the rear.

 

[grcamna2]

Those correct sizes for the GS650G seem to get harder to get all the time. Avon seems to have dropped the AM26 Roadrider sometime last year. They have one they now call the Roadrider MkII. No alpha-numeric brand that I have seen. The 100/90/19 is an easy size to find from many brands making classic bias tires. Avon and some others also make the inch 3.25/90/19 front, including the Avon RR MkII. Mostly for the old airhead market. Avon doesn't have a rear tire anywhere near the size needed though. Only 17 rears now are 140 or 150 70/17. The Bridgestone BT46's ( was BT45) is one of the very few available in a 120/90/17 rear. There are more tires available in 130/90/17, but that's going oversize. I really liked the BT45 on my GS650 and another bike in the past and couldn't ask for more.

There are also several brands that make a rear 120/90/17 bias tire in ADV type tires. Continental is one of them. Mostly 90/10 ( on road/off road) I picked up a new BT46 rear some months ago from Dennis Kirk, but haven't mounted it yet. My rear BT45 is about done @ 4500 mi. Beware, there are many 120/90/17 bias front tires, generally no bueno on the rear.

Can you confirm the BT46 Rear is available in size 120/90x17 ? I looked over a month ago but didn't see that one. thanks

 

[hank2]

grcamma2, Yes it is. I purchased one from Dennis Kirk online early this year. That was one of the lower prices I saw for it. I have found that not all tire sellers have the 120/90/17 BT46 rear listed, including some of the larger ones. I think I paid about $126. with free shipping.

 

[Guest]

Pretty much all true. The numeric sizing system is a relic of bygone days, it's mostly metric designations now.
/
Yes, the actual conversions get you to 82mm in front and 108mm at the rear, which would lead you to think about 90/90-19 up front and 110/90-17 on the rear. Going up one size at both ends will get you to the 100 and 120 recommendations that Nessism offered. The 120 can be difficult to find, you can move the rear to a 130 with minimal impact.

Avons are a good choice for many here, especially if your riding style is a bit more "enthusiastic". If your riding level is a notch or two down from that, or if you don't put on that many miles per year, Shinko 230 Tour Master or the 712 are also pretty decent. Their performance is a lot better than the price of admission might lead you to believe.

 

[Admiral Beez]

My local supplier has these https://fortnine.ca/en/metzeler-me-888-marathon-ultra-front-tire

But what does the last number mean? 100/90-19 I understand, but what?s 57H and 62H? The 57H is a little cheaper.

100/90-19

 

[Admiral Beez]

My bike currently has Shinko 130/90-17 on the rear and 100/90-19 on the front.

 

[hank2]

My local supplier has these https://fortnine.ca/en/metzeler-me-888-marathon-ultra-front-tire

But what does the last number mean? 100/90-19 I understand, but what’s 57H and 62H? The 57H is a little cheaper.

100/90-19

The 2 digit number refers to a load rating index. Higher number is higher weight capacity. The letter, like "H", is that tire's speed rating. There are many. H= 130 mph rating, a minimal rating for street motorcycles. Of the two examples, assuming they're the same size, is the lower rated one a tube type?

 

[LAB3]

Everyone seems to have their favorite place to buy tires, mine is eBay. Just do a search on the particular size you need and chances are the lowest will be chapmoto.com unless someone has a a few closeout or NOS in stock.

 

[Admiral Beez]

The 2 digit number refers to a load rating index. Higher number is higher weight capacity. The letter, like "H", is that tire's speed rating. There are many. H= 130 mph rating, a minimal rating for street motorcycles. Of the two examples, assuming they're the same size, is the lower rated one a tube type?

So what’s H57, top speed 57 kph? Hopefully that 57 mph, but still that’s way too slow.

 

[Admiral Beez]

Everyone seems to have their favorite place to buy tires, mine is eBay. Just do a search on the particular size you need and chances are the lowest will be chapmoto.com unless someone has a a few closeout or NOS in stock.

How do you prevent getting really old tires?

 

[Nessism]

How do you prevent getting really old tires?

Buy from a high volume dealer

 

[Grimly]

So what?s H57, top speed 57 kph? Hopefully that 57 mph, but still that?s way too slow.

This is a metric site, but the translation is painless.
https://www.tyreleader.ie/tyres-advices/car-tyres-load-and-speed-indexes
The same load and speed ratings apply to car and bike tyres.

 

[Admiral Beez]

This is a metric site, but the translation is painless.
https://www.tyreleader.ie/tyres-advices/car-tyres-load-and-speed-indexes
The same load and speed ratings apply to car and bike tyres.

Thanks. I see H on the list, 210 kph. What does H-57 vs H-61 mean, as found on the seller?s website mean?

 

[LAB3]

Buy from a high volume dealer

Yep! I've ordered several tires from chapmoto and never got one over a year old. Some of the other sellers may be selling older tires, especially if advertised as NOS (New Old Stock) so don't be afraid to ask. Last winter I found a SMOKIN' deal on Dunlop Elite 4's that where three years old, with the number of miles I ride a year they'll probably be six years old by the time they're ready to be replaced (That wouldn't have happened without Covid keeping me in one spot this summer)

 

[Guest]

Beez, the Letter is the speed rating, the numbers are the load rating.

Speed rating (quick googly from FortNine site):
https://fortnine.ca/en/motorcycle-tire-speed-rating

Load rating (quick googly from FortNine site):
https://fortnine.ca/en/motorcycle-tire-load-capacity

I just went through what you are for my GS850. Lots of info on the web for converting inch wheel sizes to the current metric sizes.

Basically your 3.25-19 inch size = 82.5/100-19 metric. (82.5mm wide x 100%high x 19inch wheel)(19 inch wheel? what? metric??-yeah, love it)
Rear 4.25-17 = 108/100-17 metric

This link seems to make sense for fitting tires to rim size (check on your wheel rim for a listed size: probably 1.85-19 and 2.5-17?):
https://dropbears.com/motorcycles/utilities/tyrerim.htm

The next question is whether you need tube or tubeless tires which is a whole other thread! I expect your 1982 is tubeless (I can't confirm). If they are, and you need new air stems, they may not be the same as car tires. My '79 GS 850 has 8mm bolt in motorcycle stems. Car tire are wider press in stems. Someone else comment?

So, my thoughts are these,

Front:
https://fortnine.ca/en/avon-roadrider-mkii-front-rear-tire (100/90-19) ,or
https://fortnine.ca/en/bridgestone-battlax-bt-46-front-tire (100/90-19)

Rear:
https://fortnine.ca/en/avon-roadrider-mkii-front-rear-tire (120/90-17) ,or
https://fortnine.ca/en/bridgestone-battlax-bt-46-rear-tire (120/90-17)

Stems:
https://fortnine.ca/en/k-l-long-valve-stems-32-8251

If yours need tubes, the FortNine has Michelin tubes to fit.

I ordered the Bridgestone for mine and they look good but not yet installed. Check the Bridgestone and Avon sites regarding which models can take a tube if you need tubes. The Bridgestones I ordered can be tube or tubeless and I'm planning to mount without tubes though my front rim does not say "tubeless". It's interesting stuff!

Good luck!
-Dylan

 

[grcamna2]

Yep! I've ordered several tires from chapmoto and never got one over a year old. Some of the other sellers may be selling older tires, especially if advertised as NOS (New Old Stock) so don't be afraid to ask. Last winter I found a SMOKIN' deal on Dunlop Elite 4's that where three years old, with the number of miles I ride a year they'll probably be six years old by the time they're ready to be replaced (That wouldn't have happened without Covid keeping me in one spot this summer)

I don't like buying tires that are past a certain date(it's molded into the sidewall of every tire)and a high-volume seller is a good bet that you get a fresher tire.

 

[Admiral Beez]

Beez, the Letter is the speed rating, the numbers are the load rating.

Speed rating (quick googly from FortNine site):
https://fortnine.ca/en/motorcycle-tire-speed-rating

Load rating (quick googly from FortNine site):
https://fortnine.ca/en/motorcycle-tire-load-capacity

I just went through what you are for my GS850. Lots of info on the web for converting inch wheel sizes to the current metric sizes.

Basically your 3.25-19 inch size = 82.5/100-19 metric. (82.5mm wide x 100%high x 19inch wheel)(19 inch wheel? what? metric??-yeah, love it)
Rear 4.25-17 = 108/100-17 metric

This link seems to make sense for fitting tires to rim size (check on your wheel rim for a listed size: probably 1.85-19 and 2.5-17?):
https://dropbears.com/motorcycles/utilities/tyrerim.htm

The next question is whether you need tube or tubeless tires which is a whole other thread! I expect your 1982 is tubeless (I can't confirm). If they are, and you need new air stems, they may not be the same as car tires. My '79 GS 850 has 8mm bolt in motorcycle stems. Car tire are wider press in stems. Someone else comment?

So, my thoughts are these,

Front:
https://fortnine.ca/en/avon-roadrider-mkii-front-rear-tire (100/90-19) ,or
https://fortnine.ca/en/bridgestone-battlax-bt-46-front-tire (100/90-19)

Rear:
https://fortnine.ca/en/avon-roadrider-mkii-front-rear-tire (120/90-19) ,or
https://fortnine.ca/en/bridgestone-battlax-bt-46-rear-tire (120/90-19)

Stems:
https://fortnine.ca/en/k-l-long-valve-stems-32-8251

If yours need tubes, the FortNine has Michelin tubes to fit.

I ordered the Bridgestone for mine and they look good but not yet installed. Check the Bridgestone and Avon sites regarding which models can take a tube if you need tubes. The Bridgestones I ordered can be tube or tubeless and I'm planning to mount without tubes though my front rim does not say "tubeless". It's interesting stuff!

Good luck!
-Dylan

Thanks Dylan, that helped a lot. Tubeless. Do you need new stems when you change tires? My rear is 17 not 19.