Dual Sport Tire Size Questions

[Bruno]

My 81 GS850G calls currently has 100/90-19 on the front and 130/90-17 on the rear. Both are tubeless. I am looking to do more riding on gravel roads, so I am looking at 70/30 dual sport tires. I'm finding it to be quite challenging to find the right size because, obviously, these tires weren't intended for my bike.

So, would it be better to go with a tire that is the same size with a tube in it? I do believe the bike came with tube tires (from the manual). Or better to go with a tire the has a lesser height dimension such as a 130/80-17 which would be tubeless? Also, could one run a 110/80-19 in the front or would that be too wide for the rim?

Looking at a set of Shinko 705s.

Thanks!

[Steve]

Tubes will be no problem.

Stick with the /90 tires, not the /80.

Stick with the 100 on the front.

.

[Bruno]

Thanks again, Steve.

[rphillips]

Personally I never want another tube in anything I own. I've never enjoyed the thought of removing the wheel, breaking the bead, removing & patching the tube, then getting it all back together without pinching the tube, then putting the wheel back on the bike, all while out on the side of the rd. Give me tubeless & some plugs, to get me back home, or to a shop, then fix it properly. Just my opinion.

[Grimly]

My 81 GS850G calls currently has 100/90-19 on the front and 130/90-17 on the rear. Both are tubeless. I am looking to do more riding on gravel roads, so I am looking at 70/30 dual sport tires. I'm finding it to be quite challenging to find the right size because, obviously, these tires weren't intended for my bike.

So, would it be better to go with a tire that is the same size with a tube in it? I do believe the bike came with tube tires (from the manual). Or better to go with a tire the has a lesser height dimension such as a 130/80-17 which would be tubeless? Also, could one run a 110/80-19 in the front or would that be too wide for the rim?

Looking at a set of Shinko 705s.

Thanks!

The factory tyre originally fitted to the rear of the 850 was a 4.50 - 17, which metricates to a 114mm x 17. Now, assuming an aspect ratio of 90%, as by then 100% AR tyres were firmly in the past and the 'norm' AR was 90%, this means the modern size of 130/80x17 is an exact match.
Usually, riders replaced the factory tyres with 130/90-17, but those weren't an exact size to the OEM fitment.
Proof here... plug in some numbers and have a play.

https://www.tacomaworld.com/tirecalc?tires=114-90r17-130-80r17

I've just fitted a dual-sport GoldenTyre GT201 130/80-17 radial to my 850, I'll see how it pans out once I've broken it in. The odd review I've found of that one is quite favourable.
Only reason I use that is because it was available dead cheap as NOS, plus there's an occasional bit of gnarly broken road surface around here, and the dual-sport nature of a semi-knobbly might be of some use.