Does size matter or is it how you use it? (tyres/tires)

[englishmanbo]

I have an emergency purchased 160/60zr17 Dunlop Road Smart 3 on my st 1300 rear instead of 170/60zr. I need a new front as well and am considering getting a matching pair but would change the rear if it will improve safety/handling. Does it matter to run a smaller size?

I have read an old thread discussing fitting a larger than standard 180/55 in place of 170/60, not a smaller one.

Backstory is weird, I had a nail through the rear tyre. It deflated the tyre enough to result in it slipping of the rim (breaking the bead) in a mid corner blowout. Today (the following ride) big puncture in the front tyre, 100km/hr, felt the steering go, slowed to a stop and the tyre was dead flat. Required 4 plugs to fill. Both were very dodgy situations, lucky to still be upright and bike unharmed. So...

Side note, the tyres were from the previous owner and probably too old, despite still having tread, rubber has a shelf life.

 

[mudduc]

During my racing days, I can attest that the rear tire width did have a noticeable change in handling. My experience was with the 190 vs 180 rear tire on a Ducati 916 and also a CBR900RR. I very much preferred the easier turn-in effort and more nimble feeling of the 180.

I can't give you specific feedback on the differences in handling for the 160 vs 170 rear on a ST but would be willing to bet a change could be felt and handling will be different at all points of corner control; turn-in, mid-turn, exit. However, I can't say how you, personally, would feel about the change.

My advice would be to ride out the life of the 160 while paying attention to how you like the feeling. Then go to the 170 when you next need new shoes and see how you like that. Both will give you plenty of traction and good handling (as long as you keep a margin away from the absolute limit of traction) but I'm sure they will feel different. Let us know your preference when you have it.

Later,
Kent Larson from Minnesota

 

[caldercay]

I would ensure the load rating falls within the requirements, and if it is, stick with it until the next tire change.

 

[dwalby]

During my racing days, I can attest that the rear tire width did have a noticeable change in handling. My experience was with the 190 vs 180 rear tire on a Ducati 916 and also a CBR900RR. I very much preferred the easier turn-in effort and more nimble feeling of the 180.

I had similar experience with my FZR1000, I ran 180s and 170s on it and preferred the easier turn-in of the 170, which was a rounder profile vs. the wider/flatter profile of the 180.

Looks like the 160/60 has a 69 (325kg) load rating to the 170/60 72 (355kg) rating. If you're riding fully loaded 2-up that might matter, but for normal one-up riding it shouldn't make any difference. From a table I found online it looks like both 170/60 and 160/60 use the same STD rim widths, so that part seems OK.

 

[englishmanbo]

Thanks, I will go ahead and just get a new front.