5.5" Rear Rim on SV 650

[MAZZ77X]

Asides from the larger selection of tire choices what would the benefit be of running a bigger wheel?

I just noticed on the WERA Board they they are allowing this for there Supersport class this season and wonder what advantage riders on bikes equipped with this mod may have.

Thanks

[roadracer162]

Definitely more meat on the ground. Certainly a better choice of rubber when using the Michelin cup

[MELK-MAN]

+1..
better choice of rubber and MORE rubber on the ground (but still not TOO much) equals GOING-FASTER!!!
Many of the lt wt guys are even using 190 tires on some of the stronger bikes but not so sure 190 is needed. I loved the 180 michelin cup on a ds1000 ducati i raced at Homestead in december.  The principle is the same for the 600 guys going from 180 to 190's. If the bike will still flip back and forth, you can get to full throttle SOONER with more contact patch.

[twilkinson3]

THere is zero advantage to a 180 over a 160 on a ss bike, the current standard swap is a gsxr rear rim and the weight between the two is the same....it does provide a wider array of rear tires to use from more manufacturers as most are slowly stopping production of race rubber in the 160 width - I had sent in a rule change request for the sv's to be allowed to run a 5.5 in LW SS much like apaprently Wera has done but never heard anything back

[kvanengen]

twilkinson3, I am going to respectfully disagree.

At Black Hawk Farms raceway (1.95 mile track) I found a 1 second improvement in lap time when pulling off my stock wheel and installing the gsxr wheel with a 180 tire. This was done on an 84hp sv. Certainly more power than an SS bike, however, it's no SB... It's important to note that I tested the tires on the same day when the track conditions were the same. You will also find better tire life out of the 180's. There has been more R&D done on 180's than 160's, therefore, if I had to guess you're going to get better results out of the 180 any way you want to spin it.

Also, when going from the stock rim to the gsxr there will be no suspension of geometry adjustment needed. Just bolt it up and ride.

With what I know about the gsxr rim swap would I do it on a SS bike?? Absolutely! It is a very low cost modification for large gains.

[twilkinson3]

Still a subjective measure Kev, and on a higher hp bike I would expect it to make a bit of a difference as a stock gen 1 sv might make 72hp at best....and you are far from the average SV racer lol

My point was more in the quantitative vein - a gsxr 06-07 rear rim with a sv rear brake disc and a 180 tire weighs just about the same as a stock sv rear rim with the same rear brake disc and a 160 tire  (I actually have both as well) and the profile difference at 20mm wider isn't that much, as you said there is zero difference in the geometry setup

Is it possible the extra width on a tight twisty track helps in some fashion - I will concede it's possible....on a Road America like track tho....doubt anyone would ever notice the difference with the same rider in the saddle

I'm in favor of CCS looking into adopting a rule similar to the one Wera put in place this year for the SV simply on the basis that the tire selection available in 160 widths is dwindling fast and all the other CCS "lightweight" bikes can run a 180 rear.  Think we are now down to Dunlop (maybe) and Pirelli for race rubber and I don't expect this trend to reverse.

Either way an interesting conversation no?

[kvanengen]

Terry, Take this lightly. It's all in good fun, bud.

Interesting conversation, Yes! To be clear, because text does not allow tune to come over, I'm not arguing with you. This is just for fun and most of all to give MAZZ77X another way to look at his tire choice.... So, let me just state that you are straight up wrong, Terry :) It's cute that you're getting into a setup discussion with me even though you know where my info comes from. (Ed Key and Guy Bartz)

Let me explain in a way that truly matters, on the track, in practice. What is the goal when exiting a turn to assure optimal drive and to confirm you are using every bit of available power? Wheel spin. Exiting every turn (there are always exceptions) you want to accelerate until your rear wheel spins ever so slightly coming off the turn. (I can't express through text what I mean by ever so slightly) I call that "dancing". I believe Mr. Key coined that term. The next time you exit a turn without feeling the rear wheel spinning ever so slightly ask yourself, "Did I leave power on the table". That goes the same for uncontrolled wheel spin.

Ok, let me now explain my point. Even on a bone stock 68 hp sv you have the ability to spin the rear when exiting a turn. It's not as easy as it is on a SB; however, very possible. So, if you're running a 160 and spinning the rear, then you go to a 180 and you no longer have the ability (spinning the rear on a stock bike with a 180 has found to be challenging) on a stock bike to spin the rear that tells you one thing, you have increased your traction.

If it were me on a SS bike with the ability to run a 180 I would not hesitate to do so. Imagine being in mid carousal and having the ability to roll on as hard as you possibly can without losing traction.
With that said, let me ask this question. Let's say you're heading out for a race on a stockish (160) sv. You have two tire options, one option is a fresh 160, and the other is a 160 take off with a few races on it. Which one would you rather go with? The used tire? Or the tire that offers more grip? I would argue the tire with more grip. With that said, why in the world wouldn't someone not run the 180/5.5 if it was available.

Let me end this by destroying your theory by paraphrasing what the man who has the most well set-up sv around. Mr. Key once told me the same thing that I am telling you. "Running a wider rim with a 180 will be good for roughly 1 second per lap without making any other changes". You can't possibly tell me that both Ed and I are wrong on this.

[tug296]

Along these same lines, is anyone running a 200?

[tug296]

I should have added -on a superbike, not an SV 650.

[roadracer162]

Makes a lot of sense.

[bruce71198]

Good points Kevin, we switched to the 5.5 rim this year but won't see the results till we get to BHF. Mazz, Ben Probst has some caliper brackets and spacers made up for this swap, all you need is a wheel and your SV caliper.

[kvanengen]

Let me prefix this by saying thank you for not taking my last post out of context. It was not meant to attack anyone's views or opinions. Simply an interesting topic.

After posting my opinion I thought it over and whether or not it was 100% correct or should I have articulated my point differently. To make a small correction to my previous post, I could very well see bolting up the 5.5/180 and not seeing a 1 second gain. However, that would only be if you're not pushing the limits of the 160 in the first place. The rider needs to be able to use the power he has prior to requiring additional traction. Although, I'll stand firm that if you're a solid lightweight rider and traction is a bit of an issue (which is likely to happen) the 5.5/180 conversion is well worth it. I and everyone else who has done it have seen benefits.

This is how I justified my response. I asked myself one question. That is if I were on a bone stock sv with a 160, then bolted up a 5.5/180, would I be able to find 1+ second around a 2 mile track. I believe the answer is absolutely. Truth be told, I would like to test that. If someone has a stock bike out there and willing to let me borrow it, please let me know.

Additional traction, greater tire options, and longer tire life. How is that not a good idea.

As for a 200. Great question. I have never seen it done. If I had to guess clearance would be an issue. Just a guess though. If you find someone who has done it please let me know. I'm curious on how that would work.


OK, I'm done. :) Have a great day!