The New And Improved Unofficial R65 Forum V2

General Category => Totally Off-Topic Discussions, Rants, Tire & Oil Threads, Etc. => Topic started by: Bob_Roller on June 29, 2009, 02:03:08 PM

Title: Tire Sizes
Post by: Bob_Roller on June 29, 2009, 02:03:08 PM

I'm looking for new tires for the V65 Guzzi, and I'm having a difficult time finding a correct rear tire .

Bike manual calls for 100/90-16 front, and 120/90-16 rear .

I'm not having much success with the rear tire .

So my question is, there are 100/80-16 front , and 120/80-16 rear tires available .

Is this going to alter the handling of the bike, or even recommended ?

Title: Re: Tire Sizes
Post by: msbuck on June 29, 2009, 03:52:31 PM

The /80 is just a lower profile tire.  Quicker handling!  ;D
 Plus it puts you closer to the ground (I'm always looking for those /80 profile tires for my beemer and can't find them anymore.  :(  )

Title: Re: Tire Sizes
Post by: Bengt_Phorqs on June 29, 2009, 03:59:25 PM

It is a lower profile tire and would fit the wheel, however would it have any significant effect on the speedometer reading, ie. a faster reading than actual?

Title: Re: Tire Sizes
Post by: msbuck on June 29, 2009, 04:26:30 PM

Quote

would it have any significant effect on the speedometer reading, ie. a faster reading than actual?

You're worried about that with BMW speedos???   ;)  Oh yeah, this is a Guzzi it's going on....

Probably no more than having your tire pressure 5psi lower than spec.  In theory, if you started out with a 100% accurate speedometer and a new tire, the speedometer error would begin to accumulate as the tire tread wears down from it's original 6/32" depth (or so) down to the 2/32" depth at which point you are advised to replace the tire.

Oh yeah, all this depends on the speedometer getting it's reading from the front tire and not the transmission.  So, I wouldn't worry about it.  I never noticed a discernible difference when I ran the low profile (my speedo bounces pretty good...  :P )

Title: Re: Tire Sizes
Post by: Lucky_Lou on July 01, 2009, 04:35:41 PM

Quote

It is a lower profile tire and would fit the wheel, however would it have any significant effect on the speedometer reading, ie. a faster reading than actual?

Pye x D the reading will be higher than actual speed but you will need the overall diameter to work it out you will probebly only be looking at about 1.5% not enough to worry about.
In the UK the rule of thumb for speeding tickets is 10% + 2mph will earn you a ticket ie 35 in a 30 or 57 in a 50 unless the cops are haveing a bad day.
Lou

Title: Re: Tire Sizes
Post by: Semper Gumby on July 05, 2009, 08:31:15 PM

You might check out the Avon web site.  The have a MT90-16 that might work as well as the 120/80-16 rear.  They also have a 110/90-16 front which may be as close as you are going to get.

http://www.avon-tyres.co.uk/motorcycle/roadrider

Good luck.

Title: Re: Tire Sizes
Post by: Bob_Roller on July 05, 2009, 08:51:31 PM

I contacted the local tire shop where I do all of my business, Southwest Mototires ( http://www.swmototires.com /), in Tucson,AZ. and that was their recomendation as well .

Title: Re: Tire Sizes
Post by: Bengt_Phorqs on July 06, 2009, 02:59:27 PM

Bob, I just did a search for the 120/90-16 rear and came up with a Kenda from this outfit. http://www.oldbikebarn.com/Kenda-K657-Sport-Challenger-120-90-x-16-Rear-Tire?leadsource=M7989 Don't know anything about them but it looks like tires are available.  Also saw Bridgestones from here  http://www.allbikesupershop.com/part.aspx?partfamilyid=18612&partid=660486&x=27685&scid=FROOGLE