rear tire size

[zebulon]

should I go to 160/60 or 160/70?

One thing about this, all the guys that have tryed the 160/60 instead of 160/70 on their 1100 Sport ie where really happy about this.

 

As there is a lot of weight on the rear on our bikes the 70 is too high and the tire suffers a lot of torque power so you have a rear tire that deforms when hot or hard drive !!!

 

If you like to ride sometimes hard don't put the 70 but the 60 one

[Baldini]

Errr...

 

I've been thinking. Spoke to tyre supplier, tells me aspect ratio is measured width shoulder to shoulder/height bead to shoulder. Profile on optimum rim should be same...So...170 on 5.5 rim should have flatter profile than 180 on same, aspect ratio is not relevant...So why does 170 lean in quicker & feel more in tune with front (which is a much rounder profile)? My logic says the 180 should roll better cos it's profile should be rounder...is it simply width that holds it up? I've been thinking about John T's question about running off tread on a 170...? Both 180 & 170 seem to run to edge of tread very quickly...at much shallower lean angle than front.

 

Can anyone explain what's going on here...?

 

KB,Cymru

[Lex]

Can anyone explain what's going on here...?

 

No but I can take a guess. As I posted earlier on this thread, the closer the tire sizes are to matching front and back the more smoothly and easily the bike will roll into or out of a lean. My guess is the small change in profile in being over ridden by the more similar size. It could also be magic, I'm far from a tire engineer.

 

If you like to ride sometimes hard don't put the 70 but the 60 one

 

It may be that I don't ride hard enough to notice the difference but I've been very happy with the 160/70 BT 020 on my '01 Sport. If it is a matter of force I'd say I would have noticed it, between my weight (260 #/ 120 Kg) and my habit of leaving corners fairly hard I think I work the rear tire more than most. I went with the "70" to speed up the steering slightly (about as much as dropping the triple clamps 10 MM) and to keep the speedo/ odometer a little closer to accurate. Right, like you can use accurate and Veglia in the same sentence.

 

FWIW, I'd be pretty impressed by a rider who could tell the difference between the 70 and 60% aspect ratio in a blind test. I guess the bottom line is personal taste and most folks seem the be happy with the 60% tire. I just wouldn't want anybody to rule out the 70%, it also has a few advantages.

 

Pay your money, take your choices,

 

Lex

[gthyni]

A wider tyre is pinch and the profile is changed and get less rounded.

I think it is better to buy the correct width and choose the profile you

want by picking a tyre model.

Lock at these sport and sport touring tyres and compare the profile:

 

 

The rounder profile of the ST tyre (Pirelli Sport Demon) make it more stable and

less agile than the sport/racing tyre (Pirelli Diablo).

Pinching the ST tyre makes it behave more like a sport tyre but it is not

designed to be used like that and therefor a less than optimal solution,

[Baldini]

Still not clear to me. Given same tyre type (Diablo) on a 5.5" rim, will I come to edge of tread at less lean on a 170 than a 180??? Can you lean over further without running off edge of tread on a 180 than on a 170 on 5.5" rim?

 

Anyone know?

Thanks, KB,Cymru

[gthyni]

The profile will be sharper profiled with a wider tyre,

 

BUT if you seen a real sport tyres I don't think

you can lean more than the profile allows even

with a width that matches the rim width.

 

The difference will be that a sharper profile with

less rubber to the tarmac will be more agile but

again there is a thin line between agile and unstable

and I think a sport tyre of correct size is agile enough

for most riders.

 

180s is not very wide for a 5.5" rim but a 190 would be a bit pinched.

 

I am putting Pirelli Dragon Corsa:s (120/60-17 + 160/60-17) on this spring,

would have chosen Diablos but a got an irresistable price on the older Dragons.