Rtfm
 

I've just ordered new tyres in anticipation of my June MOT (be prepared!). I checked the sizes currently fitted - the front is a 120/60 x 17 and the rear 160/60 x 17.

In the process of returning from the garage and chatting to my neighbour I promptly forgot the sizes so I dug out the manual where it says the front is a 120/70 x 17 and the rear 160/60 x 17.

Apparently, the AL7 takes a different front tyre size compared to a curvy and for the last 11,000 miles I've been running the wrong size profile tyre (oops).

I knew the /60 or /70 described profile but was unsure what it meant other than being the tyre "height". For those like me who didn't know it is the aspect ratio and is a percentage of the width.
A 120/60 means the tyre has a height of 120 x 0.6 = 72mm whereas a 120/70 has a height of 120 x 0.7 = 84mm.

I would imagine that a /70 tyre should be slightly more comfortable with it having a higher profile and more sidewall flex but whether it would be noticeable is moot.

Re: Rtfm
 

Your speedo will probably be more accurate with the 70-profile tyre fitted as the front wheel will make fewer revolutions per mile travelled ...

Re: Rtfm
 

Does the AL7 speedo still run off the front wheel then?

Re: Rtfm
 

you will notice a difference in the two profiles not so much on comfort but on my SV650s the 70 turns in a little easier on bends. And it did affected my speedo reading quite a lot....

Re: Rtfm
 

I just checked the manual - it uses the ABS ring/sensor for the speedometer.

Maybe this explains why I was getting such incredible fuel consumption figures? Based on the radar speed warning signs (I don't know how accurate they are) I have to ride at 32mph to get a 30mph indication - assuming this is linear (and it probably isn't) and I was getting 85 mpg, then 30/32 x 85 = 79.6 mpg.
Which seems more realistic.

Re: Rtfm
 

You'd have similar handling characteristics to raising the stantions a few mm up through the yokes, or raising the rear, which steepens the fork angle, making it keen to tip in.

Re: Rtfm
 

That and I think the smaller radius profile of the 70 tyre makes it drop over easier and I prefer it but it probably depends on each bike, suspension set up and, of course, rider preference.....

Re: Rtfm
 

80mpg...really? That's bloody mental

Re: Rtfm
 

You can get over 90mpg from an AL7 if you really really want to.
Re tyre sizes, has to be remembered that the SV650AL7 is really a restyled Gladius/SFV and it had a /70 front.

Re: Rtfm
 

I almost find that impossible to believe, that's ridiculously good. But surely must be at about 60mph on a nice open motorway for a long ride. I reckon it'd struggle to better my sv1000 in town. I get about 22mpg out of it haha!