160mm or 170mm width rear tire? - Wrist Twisters
 1Likes
  • 1 Post By CB700S
 
Thread Tools Display Modes
post #1 of 31 Old 06-18-2015, 09:35 PM Thread Starter
Tirone
 
Join Date: Nov 2014
Location: Woodside, California
Posts: 58
Rep Power: 1
 
160mm or 170mm width rear tire?

So I'm thinking of going narrow for my next rear tire. I looked it up and at least according to generic tire/rim charts, 160 and 170 width tires are fine on a 5.5" rim (that is the stock 2003 919 size, right?).

I have worked my way up to the 919 via bikes with narrow rear tires. The cx500 was just as heavy, but on a 120mm rear, it felt like a ninja 250 throwing it side-to-side in tight turns. When I sold the cx500 I told the buyer truthfully that I could still ride the cx500 faster than the 919.

I mostly ride tight mountain roads, and rarely hit 50 mph in turns. I just don't think I push the bike enough where the extra width really matters, even on trackdays.

Anyone else run 160 or 170 width tires? Thoughts?

Manzanita is offline  
Sponsored Links
Advertisement
 
post #2 of 31 Old 06-18-2015, 10:06 PM
Why's everything on fire?
 
CB700S's Avatar
 
Join Date: Mar 2011
Location: Dallas
Posts: 2,355
Rep Power: 1
 
Garage
Normal low stress commuting will use up all but a 5mm strip on each side of the stock 180 section, so you have that much as reserve.

160 or 170? You have NO reserve. You will need to fit 4" long peg scrapers to make sure you don't exit the bank limits of the tire.

1986 Honda Nighthawk 700S
2002 Honda 919
CB700S is offline  
post #3 of 31 Old 06-18-2015, 10:09 PM Thread Starter
Tirone
 
Join Date: Nov 2014
Location: Woodside, California
Posts: 58
Rep Power: 1
 
So I don't get it. How can I take the same turns faster on other bikes with 120 or 130 mm wide tires, then?

Manzanita is offline  
 
post #4 of 31 Old 06-18-2015, 10:12 PM
Why's everything on fire?
 
CB700S's Avatar
 
Join Date: Mar 2011
Location: Dallas
Posts: 2,355
Rep Power: 1
 
Garage
Quote:
Originally Posted by Manzanita View Post
So I don't get it. How can I take the same turns faster on other bikes with 120 or 130 mm wide tires, then?
I've got a 1986 CB700SC with a 130/90-16 rear tire. Feels faster rolling through on the 700 than it does on the 919 - but in reality, and checked by GPS, the 919 is faster in any corner I can find. It's just got less drama.

If you use modern cornering techniques, you will quickly find the 130-tired bike hits its limits fairly fast, even in relaxed street riding.

Keep in mind too, the rear tire width doesn't affect steering speed much at all. Steering speed is more controlled by numerous variables in the front end, such as wheel diameter, rake, etc., etc. Also, handlebar width makes a *big* difference.

1986 Honda Nighthawk 700S
2002 Honda 919
CB700S is offline  
post #5 of 31 Old 06-18-2015, 10:46 PM Thread Starter
Tirone
 
Join Date: Nov 2014
Location: Woodside, California
Posts: 58
Rep Power: 1
 
Okay, so what does it feel like to hit the limit of a 130mm wide tire? I've taken both my 500cc Ascot and cx500 to the track and hit corners at speeds I will never approach on the street, catching up with guys on 600cc sport bikes (granted, in C group).

So I had to go back to my trackday videos and time the 919 versus the Ascot: in a section of 8 turns I did it in 1:08 on the 919 and 1:15 on the Ascot (and I was getting blocked on the Ascot, good for a second or two, maybe). The 919 has twice the horsepower as the Ascot. My general take is that the limits of (semi-?) modern sportsbikes are so much higher than the skill level of most riders--I was not approaching the limit of 130mm tires. I have been passed by a supermoto guy on skinny tires going---I don't know--30mph? faster than me in a turn. Maybe he was near the limit of his tires, but I have a long way to go to reach the limit of a 130mm tire... on the track. The Ascot on conti radials gripped to the track like glue at the speeds I was going.

Certainly, many ninja 250/300 riders on 140mm tires can kick my butt on the track without breaking a sweat. But somehow a 160mm tire on a 919 will limit me on the street?

Manzanita is offline  
post #6 of 31 Old 06-19-2015, 12:45 AM
Why's everything on fire?
 
CB700S's Avatar
 
Join Date: Mar 2011
Location: Dallas
Posts: 2,355
Rep Power: 1
 
Garage
Quote:
Originally Posted by Manzanita View Post
Okay, so what does it feel like to hit the limit of a 130mm wide tire? I've taken both my 500cc Ascot and cx500 to the track and hit corners at speeds I will never approach on the street, catching up with guys on 600cc sport bikes (granted, in C group).

So I had to go back to my trackday videos and time the 919 versus the Ascot: in a section of 8 turns I did it in 1:08 on the 919 and 1:15 on the Ascot (and I was getting blocked on the Ascot, good for a second or two, maybe). The 919 has twice the horsepower as the Ascot. My general take is that the limits of (semi-?) modern sportsbikes are so much higher than the skill level of most riders--I was not approaching the limit of 130mm tires. I have been passed by a supermoto guy on skinny tires going---I don't know--30mph? faster than me in a turn. Maybe he was near the limit of his tires, but I have a long way to go to reach the limit of a 130mm tire... on the track. The Ascot on conti radials gripped to the track like glue at the speeds I was going.

Certainly, many ninja 250/300 riders on 140mm tires can kick my butt on the track without breaking a sweat. But somehow a 160mm tire on a 919 will limit me on the street?
Yup, because the 919 has several times the horsepower of a Ninja 250 while weighing more. This causes more stress on the tire and requires a larger contact patch to keep from breaking traction. Put a smaller than 180 tire on the back and you better not touch the throttle until you're completely through the turn and back upright or you're going to lowside.

The suspension geometry and everything related to it is designed for a 180 on the 919. The older bikes were designed to have narrower tires to begin with, but even then they can't go narrower than what they were designed for. Some idiot on the Nighthawk forums put a 110 on the back of his 700S despite the members telling him not to. He promptly lowsided it within a week and ended up totalling the bike.

Also, are you running the stock bars? Those things have a shorter lever arm than the bikes you're used to like the CX and the Ascot and that causes the rider to exert more effort to turn. I fitted some spare 700 bars (which are appreciably wider) to my 919 and it's only slightly more effort to turn than the 700 now.

1986 Honda Nighthawk 700S
2002 Honda 919
CB700S is offline  
post #7 of 31 Old 06-19-2015, 06:05 AM
(Quintus) Pilus Prior
 
badmoon692008's Avatar
 
Join Date: May 2013
Location: Neenah, WI
Posts: 2,227
Rep Power: 1
 

Awards Showcase
Extraordinary Ride 
Total Awards: 1

I think the better question is what do you think you will gain?

Love is the feeling you get when you like something as much as your motorcycle - Hunter S. Thompson
I just mı̸̸̸̸̸̸̸̸̸̸̸̸̸̸̸̸̨ade you wipe your screen.
-2009 Suzuki GSX-R 750 Race Bike
-2007 Honda 919
-1995 Nighthawk 750 (Tboned)
-1983 KZ 440 (Sold)
badmoon692008 is offline  
post #8 of 31 Old 06-19-2015, 06:56 AM
Brain stolen again?
 
Bigdaa's Avatar
 
Join Date: Jan 2006
Location: Goleta, California
Posts: 17,358
Rep Power: 1
 
I think you are trying to out think the bike designers with a simplistic approach and understanding of cause and effect. You have double the HP on the Hornet and it will notice a reduced contact patch. Plus the profile of the narrower tire on a wider rim is changing the geometry and propelling you into areas hitherto unknown.

I couldn't recommend the approach to anyone outside my own curious self and I'm not taking.

Good luck with your ti-curiosity.

的 said I never had much use for one.
Never said I didn't know how to use it."
Mathew Quigley
Bigdaa is offline  
post #9 of 31 Old 06-19-2015, 08:23 AM Thread Starter
Tirone
 
Join Date: Nov 2014
Location: Woodside, California
Posts: 58
Rep Power: 1
 
Good point about needing a wider rear to handle more torque. But is a 6% difference going to be that drastic?

The point would be to get the bike to flip side-to-side faster--it is not the handlebar effort I am feeling as sluggish. The cx500 is just as heavy but can flip through corners much faster.

Manzanita is offline  
post #10 of 31 Old 06-19-2015, 08:35 AM
Brain stolen again?
 
Bigdaa's Avatar
 
Join Date: Jan 2006
Location: Goleta, California
Posts: 17,358
Rep Power: 1
 
Quote:
Originally Posted by Manzanita View Post
Good point about needing a wider rear to handle more torque. But is a 6% difference going to be that drastic?

The point would be to get the bike to flip side-to-side faster--it is not the handlebar effort I am feeling as sluggish. The cx500 is just as heavy but can flip through corners much faster.
You were pretty used to the CX500, weren't you.

的 said I never had much use for one.
Never said I didn't know how to use it."
Mathew Quigley
Bigdaa is offline  
post #11 of 31 Old 06-19-2015, 08:37 AM
GLG-20
 
Superdog's Avatar
 
Join Date: Aug 2009
Location: Huntsville, AL
Posts: 1,365
Rep Power: 1
 
Garage
Have you tried lowering the front at all? If not, raise the front forks in the triples by 5 mm or so. It will make the steering quicker.

'96 DR650, '01 SV650, '10 Aprilia Tuono 1000R
Superdog is offline  
post #12 of 31 Old 06-19-2015, 09:46 AM Thread Starter
Tirone
 
Join Date: Nov 2014
Location: Woodside, California
Posts: 58
Rep Power: 1
 
Maybe if I install the cx500 engine in the 919 frame...

Manzanita is offline  
post #13 of 31 Old 06-19-2015, 01:13 PM
Brain stolen again?
 
Bigdaa's Avatar
 
Join Date: Jan 2006
Location: Goleta, California
Posts: 17,358
Rep Power: 1
 
Quote:
Originally Posted by Manzanita View Post
Maybe if I install the cx500 engine in the 919 frame...
Anything is possible........

的 said I never had much use for one.
Never said I didn't know how to use it."
Mathew Quigley
Bigdaa is offline  
post #14 of 31 Old 06-19-2015, 04:02 PM
Brain stolen again?
 
Bigdaa's Avatar
 
Join Date: Jan 2006
Location: Goleta, California
Posts: 17,358
Rep Power: 1
 
I just came across this:


The 10 Worst Handling Motorcycles of All Time

Notice Number 4..............

的 said I never had much use for one.
Never said I didn't know how to use it."
Mathew Quigley
Bigdaa is offline  
post #15 of 31 Old 06-19-2015, 04:06 PM
Why's everything on fire?
 
CB700S's Avatar
 
Join Date: Mar 2011
Location: Dallas
Posts: 2,355
Rep Power: 1
 
Garage
Yup, the CX500 and 650 were pretty bad.

1986 Honda Nighthawk 700S
2002 Honda 919
CB700S is offline  
post #16 of 31 Old 06-19-2015, 04:41 PM
Brain stolen again?
 
Bigdaa's Avatar
 
Join Date: Jan 2006
Location: Goleta, California
Posts: 17,358
Rep Power: 1
 
I am wondering why attempt to emulate it?

的 said I never had much use for one.
Never said I didn't know how to use it."
Mathew Quigley
Bigdaa is offline  
post #17 of 31 Old 06-19-2015, 04:44 PM
Why's everything on fire?
 
CB700S's Avatar
 
Join Date: Mar 2011
Location: Dallas
Posts: 2,355
Rep Power: 1
 
Garage
Quote:
Originally Posted by Bigdaa View Post
I am wondering why attempt to emulate it?
Because he mistakes "changing bank angle quickly because the top heavy bike is actually falling over in a corner" for "agility"? :P

1986 Honda Nighthawk 700S
2002 Honda 919
CB700S is offline  
post #18 of 31 Old 06-19-2015, 09:58 PM
Community Moderator
 
g00gl3it's Avatar
 
Join Date: Jun 2009
Location: Idaho
Posts: 11,622
Rep Power: 1
  

Awards Showcase
Wrist Twisters Event Attendance Wrist Twisters Event Attendance Wrist Twisters Event Attendance 
Total Awards: 3

Maybe work on bettering the suspension first? I would think that with VERY good suspension on the 919, you could run it like it were on rails compared to just trying to 'get down' a little more with a thinner tire. ('getting down' = more corner speed).

And yes, I just opened up the suspension topic again,

2009 Aprilia Tuono - Ginger
2001 XR650R BRP (Big Red Pig)
2006 Honda 599 - Ex wrecked it :-D
2007 Honda CB900F (sold)
2006 Honda VTX 1300C (sold)
YouTube Channel
g00gl3it is offline  
post #19 of 31 Old 06-20-2015, 07:24 AM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,900
Rep Power: 1
 
Quote:
Originally Posted by g00gl3it View Post
Maybe work on bettering the suspension first? I would think that with VERY good suspension on the 919, you could run it like it were on rails compared to just trying to 'get down' a little more with a thinner tire. ('getting down' = more corner speed).

And yes, I just opened up the suspension topic again,
Mmmmmmmmmmm, suspension, 919 on rails. YES ! Bring it on.

mcromo44 is offline  
post #20 of 31 Old 06-22-2015, 04:52 PM
Why's everything on fire?
 
CB700S's Avatar
 
Join Date: Mar 2011
Location: Dallas
Posts: 2,355
Rep Power: 1
 
Garage
Quote:
Originally Posted by Manzanita View Post
So I don't get it. How can I take the same turns faster on other bikes with 120 or 130 mm wide tires, then?
Here's an example of what you can do with a 919:

Islandboy likes this.

1986 Honda Nighthawk 700S
2002 Honda 919
CB700S is offline  
post #21 of 31 Old 06-22-2015, 07:36 PM Thread Starter
Tirone
 
Join Date: Nov 2014
Location: Woodside, California
Posts: 58
Rep Power: 1
 
My 919 front forks were rebuilt by Catalyst Reaction with 0.9 springs. I replaced my rear shock with a Ohlins. Huge improvement, very nice.

I don't think I'm off-base to suggest that wider tires will make a bike slower side to side. Pretty much no says anything different. I can definitely feel it, having owned bikes with 120, 130, 150 and 160mm rear tires, and the 919, at 180.

Manzanita is offline  
post #22 of 31 Old 06-22-2015, 07:53 PM Thread Starter
Tirone
 
Join Date: Nov 2014
Location: Woodside, California
Posts: 58
Rep Power: 1
 
Quote:
Originally Posted by CB700S View Post
Yup, the CX500 and 650 were pretty bad.
Stock cx500 suspension is a joke. I had Racetech emulators, 0.9 springs, upgraded brakes, upgraded rear shocks... I went from a ninja 250 to a bandit 400 to a cx500, and have also had two honda ascots, but I use the cx500 as my standard. I've done trackdays on all these bikes. 3 trackdays on the cx500.

I paid 12k for the Zero, and *that* is bike with poor handling (... decent suspension, bad handling...). Mid-corner, it's like your balancing on a ledge... ridiculous. Went from a 150 to a 160 in back (pointy Pirelli to a round PR3) and went from 110 to a 120 in front (PR4) and it's better, but I think there is something fundamental about the geometry (not enough trail?) that makes it super twitchy.

Do the math, 180 to 170 is 5.6% narrower. Not that radical, but maybe will make the bike quicker side-to-side?

Manzanita is offline  
post #23 of 31 Old 06-22-2015, 08:05 PM
Left of Centre
 
K1w1Boy's Avatar
 
Join Date: May 2011
Location: Auckland, NZ
Posts: 3,714
Rep Power: 1
 
How many miles have you done on the 919, compared to the other bikes you have owned?

The other thing to consider is that it sounds like this is your first 4-cyl bike. I don't speak enough science to be able to describe it at all, but as well as the outright mass of the machine and the rear tyre size, you might also need to keep in mind the step up in whatever the forces are that are generated by the crank running all the way across the frame that resist turning...

http://www.renj.com/stability-cornering.aspx

K1w1Boy is offline  
post #24 of 31 Old 06-22-2015, 08:54 PM
Why's everything on fire?
 
CB700S's Avatar
 
Join Date: Mar 2011
Location: Dallas
Posts: 2,355
Rep Power: 1
 
Garage
Quote:
Originally Posted by Manzanita View Post
My 919 front forks were rebuilt by Catalyst Reaction with 0.9 springs. I replaced my rear shock with a Ohlins. Huge improvement, very nice.

I don't think I'm off-base to suggest that wider tires will make a bike slower side to side. Pretty much no says anything different. I can definitely feel it, having owned bikes with 120, 130, 150 and 160mm rear tires, and the 919, at 180.
The guy in the gymkhana is running a 180 rear tire (people have asked). He doesn't seem to have any problem with quick lean angle changes.

A wider tire does make it slower, but not to the point you're saying you're getting. My 919 runs through corners faster than my 700 and actually changes lean angles faster. The difference is that you have to apply a bit more more muscle to get the 919 to do the same thing (via countersteering) because of the front end geometry, wheel size and prior to my replacing the handlebars, the lever arm of the stock bars.

1986 Honda Nighthawk 700S
2002 Honda 919
CB700S is offline  
post #25 of 31 Old 01-19-2016, 08:05 PM
Tirone
 
mtoronto's Avatar
 
Join Date: Nov 2015
Location: Annapolis
Posts: 8
Rep Power: 1
 
I have quick question, my rear tire is 180/55/17, is it ok to put a 180/60/17 on my 919? if so what are the pros/cons? I was going to buy some track take off tires that are great shape super cheap is the reason i ask....

mtoronto is offline  
post #26 of 31 Old 01-20-2016, 07:14 AM
I'm going riding.
 
scrat's Avatar
 
Join Date: Jul 2008
Location: West Fargo, ND
Posts: 1,274
Rep Power: 1
 

Awards Showcase
Veteran 
Total Awards: 1

Quote:
Originally Posted by mtoronto View Post
I have quick question, my rear tire is 180/55/17, is it ok to put a 180/60/17 on my 919? if so what are the pros/cons? I was going to buy some track take off tires that are great shape super cheap is the reason i ask....
It should be fine, the tire will be a smidge taller and may slightly change the feel of the bike, but nothing major or detrimental for street riding.

30,000 mile 919 survivor. No plans of stopping the abuse any time soon.
scrat is offline  
post #27 of 31 Old 01-21-2016, 11:09 AM
Dead Wrong
 
Effe's Avatar
 
Join Date: Nov 2010
Location: Istanbul
Posts: 383
Rep Power: 1
 
Garage
Quote:
Originally Posted by Manzanita View Post
But is a 6% difference going to be that drastic?
%6 is a big difference in every aspect of a motorcycle.

Dead wrong
Effe is offline  
post #28 of 31 Old 04-08-2017, 12:02 AM Thread Starter
Tirone
 
Join Date: Nov 2014
Location: Woodside, California
Posts: 58
Rep Power: 1
 
Manzanita is offline  
post #29 of 31 Old 04-08-2017, 06:24 PM
Tesserarius
 
Join Date: Jul 2016
Posts: 755
Rep Power: 1
 
You may have some luck with different brands of tires. Are your tires worn, and squared off?

But l really don't think that you are going to have a lot of luck making a 919, not act like a 919.

Here is the answer you seek.
Attached Images
File Type: jpg IMG_1639.jpg (235.8 KB, 17 views)

Sniper-x is offline  
post #30 of 31 Old 04-08-2017, 08:48 PM
Tesserarius
 
nathanktm's Avatar
 
Join Date: Oct 2013
Location: Floral Park
Posts: 696
Rep Power: 1
 

Awards Showcase
Wrist Twisters Event Attendance Wrist Twisters Event Attendance Wrist Twisters Event Attendance Wrist Twisters Event Attendance 
Total Awards: 6

This is as TL;DR as I can make it while still being convincing. There are multiple reasons to my knowledge why the hornet uses tires at the size it does. To keep things simple, the larger rear tire will increase the size of the contact patch and long story short you will have more grip. You are correct, a smaller tire handles better and makes the bike require less lean to hold the same line, BUT a heavier bike with more power simply cannot get away with this. On a smaller tire, you will have:

Cold shearing, where the cold rubber literally gets ripped off the tire due to so much force going into such a small contact patch.
Tire overheating, both localized and overall, due to the small contact patch being instantly overheated and the smaller tire overall not having the surface area to dissipate the heat.
Suspension - As you may not know, tires make up a huge component of the suspension, and to keep it short, putting a small tire on a big heavy bike compromises that. You would need more pressure to make up for the smaller tire, which further exaggerates the contact patch issue.
Overall wear - not much to say here, you have less tire running a higher temp. it's obviously going to wear out faster.

Now to be honest, do I think you'll crash if you put on a 160? No. Maybe if you were really pushing it on a track balls to the wall you'd start to see why a wider tire is necessary. If you wanna try a 160, i'd say go for it.


Disclaimer: I am not a tire expert, I'm just sharing my OPINIONS
And to explain that video, that bike is specifically designed to turn left, and those guys on sportbikes are probably sandbagging because it's an event to show off the left turning bike =(

nathanktm is offline  
post #31 of 31 Old 04-09-2017, 10:30 AM Thread Starter
Tirone
 
Join Date: Nov 2014
Location: Woodside, California
Posts: 58
Rep Power: 1
 
Red face

I just had to post that video to this thread when I saw it. I guess I am trolling my own thread!

Anyways, since I wrote my original post I changed from Michelin CTs to Continental Sport Attack and pretty much the problems I was feeling went away. I don't think it's necessarily CTs in general but maybe the ones I had were worn down the center or somehow funky. Visually these tires seem to have the same profile, but maybe the sidewall flex or internal construction gives them a different turn-in profile, not sure...

It just took seeing with my own eyes guys flying by on the track on skinny tires to realize that 10mm of tire will likely not hurt me on the street, or on the track at the pace I run. Just posted here to see if anyone had already done it and what the result was...

So I looked up this: https://en.wikipedia.org/wiki/Auto_Race_(Japanese_sport) and the thing is that the guy on skinny tires started at the back, which means he was expert or more experienced, whereas the sport bike riders were less experienced. And clearly the guy on skinny tires was at the limit of grip where the sport bikes were not... but still! : )

Manzanita is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Wrist Twisters 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










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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 Off
Pingbacks are Off
Refbacks are Off

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