Guest Pete McCrary Posted June 11, 2008 Share Posted June 11, 2008 Has anyone tried running a 170/60 on the rear of their 6th Gen VFR? I was at a rally recently where some people were running 160/60's on the back of ZRX1100's and raving about how quick they turned in. These weren't slouchy riders either, but guys were regularly teach at track day sessions. Only problem I've come across in my search to contemplate this experiment is that for some reason the number of 170 series tires is very limited. Most of the major tire manufacturers skip over the 170 profile size. They go 160, 180, then 190. Link to comment Share on other sites More sharing options...
Guest Posted June 11, 2008 Share Posted June 11, 2008 Has anyone tried running a 170/60 on the rear of their 6th Gen VFR? That's the OE size on the rear of a 3rd and 4th gen (at least). I have run a 180/55 on the rear of my 3g, and then switched to a 170/60 and I do prefer the handling with the 170/60 on the back. Traction is not an issue either. I have found fewer supersport options but had no issues finding Pirelli Diablo Stradas and Conti Road Attacks, both of which suit the VFR exceedingly well. S Link to comment Share on other sites More sharing options...
wera803 Posted June 11, 2008 Share Posted June 11, 2008 I've run a 170 on the back of my 5th Gen. A little quicker steering, but nothing too dramatic. Link to comment Share on other sites More sharing options...
Member Contributer 2FAST4U Posted June 11, 2008 Member Contributer Share Posted June 11, 2008 I don't have time to do the math right now, but keep in mind the size of the rear wheel will directly affect your gearing. A wheel whose overall diameter is larger than stock will lower your gear ratio while the opposite is true of a smaller wheel. Your bike would feel livelier with a lower gear ratio and more sluggish with a higher gear ratio. I know a guy that did something similar to his Honda Shadow 1100 (what I used to ride) and although the change in size wasn't drastic by any means, he said he definitely noticed the difference. Whatever you decide, best of luck to you. Link to comment Share on other sites More sharing options...
Member Contributer CitizenOfDreams Posted June 12, 2008 Member Contributer Share Posted June 12, 2008 Just a reminder: a 170/60 tire is LARGER in diameter than a 180/55 tire. Link to comment Share on other sites More sharing options...
Guest Posted June 12, 2008 Share Posted June 12, 2008 Just a reminder: a 170/60 tire is LARGER in diameter than a 180/55 tire. I was wondering if that was the case. To my knowledge, there is no tire manufactured to a spec of 170/55. I think it may be an interesting experiment. I know a 170 tire should be more than sufficient for a VFR. My ST1300 uses a 170 series tire and it weighs about 150-200 lbs more and has about 20 more HP. I think the use of 180/55 rear tire on the VFR may be a styling touch by Honda as much as anything. Everybody likes that giant fat looking rear tires on their bikes. Problem is, those giant, fat rear tires don't turn in as quick and require more counter steering. Another thing to consider is that you only ride on "half" or one side of a tire in a turn. Purely by the numbers, a 170 tire is 10 mm narrower than a 180, but as you can only use one side of the tire at a time, in reality it is only 5 mm narrower. I think it may actually offer a little more traction. I can take my 180 rear tire all the way to the edge on the street but just barely. I'm running Pirelli Diablos and you can see they've gone all the way to the edge but the little Diablo pitch fork symbols are still there so I know I'm not using the edge hard. Flattening out the tire by running a 170 on a 5.5" rim might actually put more rubber on the road in a street situation. On my KTM Duke II, I run a 160/60 on a 5" rim and it uses the tire all the way to the edge. Really like the feel of it. I can take the front and rear tires all the way to the edge on that bike on the street. If I do the experiment and go the 170 route, it looks like I will be limited to Pirelli Diablos, Conti Attacks, or some Dunlops. I know nothing about Dunlops - which one is suppose to be the go fast model? Link to comment Share on other sites More sharing options...
Member Contributer 2FAST4U Posted June 12, 2008 Member Contributer Share Posted June 12, 2008 Just a reminder: a 170/60 tire is LARGER in diameter than a 180/55 tire. True. The difference in overall diameter is .2362" to be exact. Also, a more accurate way of stating what I said is that it changes the final drive. Keep in mind, it is a certainty this mod will throw your speedometer off. Whatever you decide, best of luck to you. Link to comment Share on other sites More sharing options...
Veefer800Canuck Posted June 12, 2008 Share Posted June 12, 2008 180/55 = 99mm tire height from pavement to rim 170/60 = 102mm " " " " " " " " " " " " " " " " " So, the rear of the bike will be raised 3mm. This, combined with the narrower width will (in theory) make the bike steer quicker. As for gearing difference, it's negligible. 3% increase in gearing. Link to comment Share on other sites More sharing options...
Member Contributer SAFE-T Posted June 12, 2008 Member Contributer Share Posted June 12, 2008 A 3mm increase in rear ride height is just about what you need to return a VFR to stock geometry with an RC51 front end....hmmmm Link to comment Share on other sites More sharing options...
Member Contributer CitizenOfDreams Posted June 12, 2008 Member Contributer Share Posted June 12, 2008 180/55 = 99mm tire height from pavement to rim170/60 = 102mm " " " " " " " " " " " " " " " " " As for gearing difference, it's negligible. 3% increase in gearing. [smartass]Actually, that would be 0.95%. Got to count the diameter of the entire wheel, not just the height of the rubber part.[/smartass] Link to comment Share on other sites More sharing options...
Veefer800Canuck Posted June 12, 2008 Share Posted June 12, 2008 180/55 = 99mm tire height from pavement to rim170/60 = 102mm " " " " " " " " " " " " " " " " " As for gearing difference, it's negligible. 3% increase in gearing. [smartass]Actually, that would be 0.95%. Got to count the diameter of the entire wheel, not just the height of the rubber part.[/smartass] Blame it on nightshift. I'm sleepy. 170*0.6=102(mm) 102*2=204 204/25.4=8.03" 8.03+17=25.03 inches total diameter, tire and wheel assembly 180*0.55=99(mm) 99*2=198 198/25.4=7.795" 7.795+17=24.795 inches total diameter, tire and wheel assembly 25.03/24.795=1.00947 Link to comment Share on other sites More sharing options...
Guest Posted June 12, 2008 Share Posted June 12, 2008 Just a reminder: a 170/60 tire is LARGER in diameter than a 180/55 tire. True. The difference in overall diameter is .2362" to be exact. Also, a more accurate way of stating what I said is that it changes the final drive. Keep in mind, it is a certainty this mod will throw your speedometer off. Whatever you decide, best of luck to you. I use a GPS for a speedo reading anyhow. I'll probably combine this project with an increase in the rear sprocket so it looks like a SpeedoHealer is in my future. Link to comment Share on other sites More sharing options...
Guest Posted June 12, 2008 Share Posted June 12, 2008 180/55 = 99mm tire height from pavement to rim170/60 = 102mm " " " " " " " " " " " " " " " " " So, the rear of the bike will be raised 3mm. This, combined with the narrower width will (in theory) make the bike steer quicker. As for gearing difference, it's negligible. 3% increase in gearing. I'm gonna do some careful measuring of everything before I undertake this so I can start out with the rear end in the exact same height location after I install the 170 tire. Luckily, I run a Penske shock so I can get the ride height dialed in to where I want it. An interesting aside to all of this - I talked to the same guy who turned me on to this idea about why I had no chicken strips on the rear tire and had about half an inch on the front tire. He said this was an indication of the rear being too low. I got under the VFR and with the Penske it took about 10 minutes to lengthen the shock about a quarter of inch. Took the bike back out on my favorite stretch of north GA road and the front chicken strip went down to about 1/16-1/8th of an inch in just 15 miles. There is something to tuning the suspension by looking at the chicken strips. I use to ride an SV650 before I got the VFR. It's been my experience that a lot of Japanese bikes really respond well to having the rear end raised. Not so much for the quicker steering, but for a more planted feel from the front end. Link to comment Share on other sites More sharing options...
Guest Posted June 12, 2008 Share Posted June 12, 2008 Pete, By chance was the rally that you were at the YTRAP ZRXOA at Skeena Creek in Suches, GA? I was there Th. night through Sun. morning on the VFR. Link to comment Share on other sites More sharing options...
Guest Posted June 12, 2008 Share Posted June 12, 2008 Pete, By chance was the rally that you were at the YTRAP ZRXOA at Skeena Creek in Suches, GA? I was there Th. night through Sun. morning on the VFR. That was me. Where were you staying? I didn't see any other VFR's there. My best friend and I always rent a house about a quarter mile down Skeenah Gap Rd so we don't stay at the camp ground. Ken R (the guy that does all of the tire changing) is the one that gave me the idea/input on running a smaller rear tire and helped me out with reading my chicken strips. Ken and I go back a long way. Ken, KD (the guy that stays with me), and I all have Duke II's also. Link to comment Share on other sites More sharing options...
Guest Posted June 13, 2008 Share Posted June 13, 2008 We stayed in the main house upstairs. When at the campground, my bike was parked right at the entrance across from the house. We were only at the campground in the evenings/night. I do not know Ken, other than meeting him there but he was working like a mad man Sat. afternoon before the dinner. A few guys were using other peoples used tires just to make it back home. Sorry we didn't get the chance to meet. Link to comment Share on other sites More sharing options...
Guest Posted June 13, 2008 Share Posted June 13, 2008 We stayed in the main house upstairs. When at the campground, my bike was parked right at the entrance across from the house. We were only at the campground in the evenings/night. I do not know Ken, other than meeting him there but he was working like a mad man Sat. afternoon before the dinner. A few guys were using other peoples used tires just to make it back home.Sorry we didn't get the chance to meet. Were you riding a yellow 5th Gen? I saw one at Dale's one of the days we were up there. I've only missed two ZRXOA rallys since I started going about 8 years ago. Last month was the first time I actually got to go up there from Sunday to Sunday. The ZRXOA is definitely a wild and crazy bunch. I have been a member since '99 when I owned a ZRX1100 (long since gone). We only had one person go down - I think that was a new record for us. Who did you ride with while you were there? What's your preferred riding style? Laid back or WFO? We'll be back up in Sept for the Hal Cline Memorial Rally. Maybe we'll get a chance to hook up then. Link to comment Share on other sites More sharing options...
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