96 900ss/cr - upgrade from 4.5 to 5.5 rear rim - Page 3 - Ducati.ms - The Ultimate Ducati Forum
Reply
 
LinkBack Thread Tools Display Modes
post #21 of 43 (permalink) Old Jul 27th, 2017, 8:24 pm
Senior Member
 
Join Date: Jan 2007
Posts: 113
Thanks psyopper and ducvet for clearing that up.
450RT is offline  
Sponsored Links
Advertisement
 
post #22 of 43 (permalink) Old Jul 27th, 2017, 8:45 pm
Senior Member
 
samadhi's Avatar
 
Join Date: Jun 2016
Location: Sacramento, CA, USA
Posts: 228
Thank you everyone for the clarity of holy measures! So I will simply flip around the front sprocket and call it a day =)
RockAZ likes this.
samadhi is offline  
post #23 of 43 (permalink) Old May 31st, 2019, 3:23 pm
Senior Member
 
Join Date: May 2019
Location: Yuma, Az., USA
Posts: 518
... just out of curious concern, what does the unsprung weight difference measure out to be? I'm speaking of the stock 4.5"/160 combo vs the 5.5"/170 (or even 180) ensemble comparison.

I have to imagine that going from the 4.5/160 to the 5.5/180 increases rotational weight as well, which might have an influence on acceleration rates, along with additional unsprung weight.

When I used to race SCORE off-road/desert events (back in the 1980s ... y'know, before fire was discovered) the general rule of thumb was handling was affected by a ratio of 1:10. Meaning for every one pound of unsprung weight added it "felt" as if ten pounds of sprung weight was added.

Anyone know what those weight differences are (spec'd above)?

Thankies!!

Never Quit, Die Falling Forward
1996 900 CR. ... LOW ZOOT
Rex Coil 7 is online now  
 
post #24 of 43 (permalink) Old May 31st, 2019, 5:03 pm
Senior Member
 
dspear99ca's Avatar
 
Join Date: May 2013
Location: Penticton, BC, Canada
Posts: 1,260
Quote:
Originally Posted by catilover View Post
haha the fat cati!!

no with a 180 rear you get more tread on the sides when leaning so have more grip my theory anyway haha plus it looks better :P :P :P :P :P
My experience (longtime 900SS owner) is that you don't have anywhere near enough horsepower to break that rear wheel free on that bike unless you are riding on the ragged edge on wet sandy corners. So 180 vs 170 for increased contact patch isn't really a viable reason. With the 170 rear your turn-in is easier, and the tire itself (unsprung mass) is lighter. Win-win-win.

Where you lose, of course, is that you can't find 170 tires anymore. I had an SP so I'm not sure about fit on a CR but I'd guess a 180 would fit... otherwise everyone would be running 170's, which they are not... just about every one I've seen has a 180 tire on the back.

Plus that phat tire does look da' boss.

'09 Multistrada 1100s
dspear99ca is offline  
post #25 of 43 (permalink) Old May 31st, 2019, 5:29 pm
Senior Member
 
Join Date: Nov 2008
Location: DeLand, Florida, U.S.A
Posts: 157
Garage
I dont know about not being able to find 170 tyres any more mate, I got 1 in last week for my 91 900ss, I normally work on BMW's and alot of them use a 170 rear tyre--I have yet to have a problem finding rubber----and as to size of tyre I race on a 130 80 18 rear--far skinnier then a 170 or 180, and I probably can go around that corner faster then you can on your 170 or 180 the contact patch size is basically no different between the sizes.Ride on what you feel comfortable on but the 180 will be slower in the transition then the 170--unless you change the rear shock to one a hair tallier or you can jack up the preload on the rear if you have a preload adjustment-there are lots of things that can be done for handling etc--but mine I leave basically stock and it will handle just fine, unless you are putting the bike on the track or ride hard enough to drag your knee;s thru the twisties all the time--leave it alone, Your bike can probably do more then you are capable of

1991 Ducati 900ss, 1991 Ducati 907ie. 1978 Yamaha SR500, 1979 Yamaha RD400 Daytona Special, 1973 Truimph X-75, 1975 Triumph T-160, 1976 Triumph T140, BMW's too many to list
rennsportmotorrad is offline  
post #26 of 43 (permalink) Old Jun 1st, 2019, 7:16 pm
Senior Member
 
Join Date: Jan 2007
Posts: 113
Fred is right just swap rims .You have everything you need. Sprocket flipped. Speedo will read (10 mph higher with a 180).
450RT is offline  
post #27 of 43 (permalink) Old Jun 1st, 2019, 7:23 pm
Senior Member
 
Join Date: Jan 2007
Posts: 113
Anyone know where to get the correct front speedo hub gear?
450RT is offline  
post #28 of 43 (permalink) Old Jun 1st, 2019, 8:06 pm
Senior Member
 
Sherpa23F's Avatar
 
Join Date: May 2017
Location: Denver, Colorado, USA
Posts: 493
Garage
Quote:
Originally Posted by 450RT View Post
Speedo will read (10 mph higher with a 180).
Sorry, maybe I'm completely stupid, but can you explain this to me?

How do you know that it would be 10mph? if you're going 5mph it's going to say 15mph? At 100mph it's going to say 110mph? Also, wouldn't a larger tire reduce the indicated speed as opposed to raise it like you're saying since a larger rolling diameter makes fewer revolutions at a given speed?

I would love to be understand this better since I have a 180 rear on my Supersport.

1996 900 SS/SP #C22, 1996 916 Corsa (ex-Ferracci), 1998 916 SPS #774, 1999 748R, 2001 996R (US), 2001 996R (Euro), 2002 998R #481, 2011 848 EVO, 2008 1098R #262, 2014 1199 Superleggera #213
Sherpa23F is online now  
post #29 of 43 (permalink) Old Jun 1st, 2019, 8:31 pm
Prolific Poster Award
 
Join Date: Jul 2010
Location: Grass Lake, Mi, USA
Posts: 5,454
Images: 4
Iím not sure how a front wheel driven speedometer would be affected by a change in rear tire size. I must have missed class that day.
psyopper and RockAZ like this.

'96 Ducati SS900CR, '07 S4RS, '06 Busa, '77 Bonny,
'00 Superglide, '85 Sportster, '78 SR500
duc96cr is offline  
post #30 of 43 (permalink) Old Jun 1st, 2019, 8:59 pm
Senior Member
 
Sherpa23F's Avatar
 
Join Date: May 2017
Location: Denver, Colorado, USA
Posts: 493
Garage
Quote:
Originally Posted by duc96cr View Post
Iím not sure how a front wheel driven speedometer would be affected by a change in rear tire size. I must have missed class that day.
That was my next question...

1996 900 SS/SP #C22, 1996 916 Corsa (ex-Ferracci), 1998 916 SPS #774, 1999 748R, 2001 996R (US), 2001 996R (Euro), 2002 998R #481, 2011 848 EVO, 2008 1098R #262, 2014 1199 Superleggera #213
Sherpa23F is online now  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ducati.ms - The Ultimate Ducati Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in













Similar Threads
Thread Thread Starter Forum Replies Last Post
99 900ss engine upgrade Ducatinv Supersport 8 Oct 8th, 2009 7:47 am
900ss swingarm upgrade Badman Supersport 2 Jul 24th, 2009 12:11 am
Rear shock upgrade? gorma900 Supersport 21 Apr 17th, 2009 6:08 am
Upgrade 900SS suspension or ST4 Secgeek Sport Touring 3 May 13th, 2008 8:48 am
1993 900SS Shock Upgrade BenjaminR Supersport 11 Apr 16th, 2007 12:11 pm

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome