After reading every race prep document I can find on the 1098 swingarm length. Many from here. I decided to go long and experiment. The RS and BST arms are thousands of dollars. My donor SF swing arm in black with all the parts for spare was $200.00 shipped. The real question is not really will a long ass swing arm be the secret bullet, but it will give me a way to experiment with chassis length, rake and trail, all sorts of gear options and my dream of a 200/60 slick. So far in order to get the stock bike to turn I have had to add rear height and lower the front (raise forks in clamp). The bike also wants a lot of spring. A whole lot of spring and resulting rebound dampening. Ohlins has helped me get close. I have made the modifications to the brake adjuster and worked with the extra 10mm of swingarm length. No real gain for tire size. would work fine with 180 slick and tire warmers. I want the big tire. Not just for aesthetics. I think the extra height will allow the suspension to be pulled back down in the rear and get the rake change from the tire and obviously get the big ass tire! The bike also spins up the rear tire in long fast round corners. Only a problem on the street in rain. It can be controlled with a little rear brake. Thumb brake someday. I also think the change in gearing from the edge grip to the tall center of the Pirelli will benefit acceleration and maybe help with wheelies. I am curious if anyone else went higher on their gears. I am using 14x36 and 15x36 experimenting with the final ratios the taller tire will get into. The bike loves the higher gear and downshifts are much smoother. She gets mounted tomorrow. Any experience from you folks with 27-29mm triple clamps and RS swingarms I would love to hear it. Here are some swingarm length numbers from Abdyb
I had a 1098S that didn’t steer very well. It had a habit of running wide on corner exit. At the time the fix was new upper and lower triples to reduce the offset, but that also entailed moving the rad back to prevent the front tyre from contacting under heavy breaking. I never tried it on mine; too expensive and radical. Instead I chopped it for a sweet-handling RSV4. No more blisters on my hands at the end of each track-day. A flat link at the back was also supposed to help, but that entailed shortening the shock. Mine came with an 80 N/mm spring with loads of pre-load which made the rear harsh even for me (140 lbs). So I fitted a stiffer spring which helped a lot.
Remarkable change. Complete comfort and stability in fast sweeping turns. Brakes and turns in. Allows far more throttle coming out. Not one ill or unexpected thing during first 100 miles. Allows you to be farther back on the seat in 1st gear corners with great feeling for what both tires are doing. Now we see if i get beat going into or out of corners. I have never been comfortable with long wide open throttle sweeping curves that lead to fast straights. The shorter swingarm did not help at all. The SF showed me just how much throttle I was leaving off in the turn.
Okay - I have a 200/60 brand new pirelli and have mounted it onto both the factory length 1098 swing arm. The tire touches the swingarm exactly the same on both the stock and the longer streetfighter arm. Later this week I will have an RS arm to compare it to. The wheel can be adjusted for good clearance with the clotted brake mount and the change of gearing or chain length. The obvious fix of fixes is to reshape the swing arm. You can see the oval area cut out and a new shaped plate welded back in. I cannot wait to get all three arms on the bench to see the difference. The 200/60 yields lots of ride height an the adjustment rod can be shortened for a rear height correct for the track and the triple tree offset. So where am I going. I want two swingarms one short and one 35mm longer for faster sweeping tracks. Both modified for the 200/60. If planned well even the new 200/65 might work. No matter what it will require 3 or 4 chain lengths to deal with gear combinations. for now I am using 2 clip type links and adding extra chain links. So many combinations. I am almost there. A complete gear and swingarm swap takes less than an hour.
The saga continues. I have the 200/60 mounted with 15/36 sprockets. OMG - This tire is tall. Dropped the rear adjuster 1.5 cm. As yet have made no other adjustments. WOW! The tire is an SC3 and acts just like it should. Heats up quick. works with wide range of tire temps and pressures. I have just over a cm of tire clearance at the swingarm. Yes the brake adjuster has been slotted for more travel. It is obvious now that the stock short length and the SF long length both need to be cut to create clearance. Does anyone out there know if a 200/60 or 200/65 will clear on a BST carbon or the Italian magnesium arm. FYI - I purchased 30 mm triple clamps so more later
Why are you not using a ride height datum tool and then just maintaining the height at the same number Secondly to fit a 200 rear tyre both 1198 and streetfighter arm need a bit chopping away..., easy peasy.,, If you look on the pierobon site even tge do it now!
Andy The giant picture above is the Pierbon product. A "bit of chopping". You could have given me that little tidbit before. I am truly surprised you did not tell me to check the manual. And easy. Have you cut into a swing arm? I have and what you find requires a little engineering and some metallurgy. You just don't get it. Do you know where the extra length is in any of the swingarms? Do you even have a clue how to measure adjuster rod length and calculate the change in ride height? My money is on you take all your work to a dealer or "You got a guy". Please contribute.
I would say if you wanted the font of all knowledge on how to modify a streetfighter arm to fit a 1098 or even a 998. If you wanted someone that has cut chopped and welded several arms in the correct place to get a 200 60 tyre to work. if you wanted someone that could evidence all the work involved with detailed pictures. If you wanted someone with the knowledge of how it compares to say the RS arm or the rarer bursi arm in terms of wheelbase and the impact that has on swing arm angle. if you wanted someone that understands the impact off this modification on weight bias and suspension preload. If you wanted someone that understands rocker ratio and what works best including even the part numbers on what bottom eye is required on what rear shock... then out of all the posters on all the forums I would be up there with this information and evidence of how to do it.. but ill leave it with you and you obnoxious attitude.
You're here for advice. I my opinion, you pissed off the only fella on here, that I know of, who has done the modifying and understanding of what is required to do these conversions. I've no doubt he has all the photos and info that you need. I guess you need to look elsewhere now for that info.
Start from the beginning and ask @andyb in a non sarcastic way and I'm sure he will help you with what you need to know.
I just blocked him. I can do without his Font. At no point has he responded to any question asked. I have no patients for his tone, and yes I have read many of his posts. So please If you can contribute please do. If your curious please query. But if you are here to tear down, belittle, and horde great Ducatisti knowledge. Please just block me or choose not to type.
Four pictures. The cutaway shows the internal brace after machining for That beautiful hand hammered cover plate. The holes in the plate allow welding to contact the internal web. The last picture is the rough cut exploring the internal web. I have seen a number of plates welded back in, but that Pierbon is beautiful. I have three arms to experiment with. The first will be all hand work. Then to work it out on CNC. A curved rectangle blended in will suffice for now.
SEV: I already have a stock arm with 200/60 working great. But only one gear option 15/36. The us sites have been helpful but nobody here buys a Magnesium swingarm and talks about how its made. I was really bummed when I had four arms on a table and found that all the length was added behind the height adjuster and the front of the tire. Even the new bikes have folks carving on the stock swingarm. Here is a picture. You can see the extension. This is for a new v4 and they added the same 35mm that an sf arm adds to a 1098. Ignoring for now the triple tree and wheelbase. In reference to hitting the hard part. The hard part is no body has measured any of the arms with a three point tool on a surface plate. The true hard part is I want a 5000.00 magnesium arm from Italy. But would you not be pissed off to find it was a modified SF arm! More to come, Thank You...
This is what I expected to see when I compared the arms. Length added to the rear of the arm. The "RS arm I had looks nothing like this".
At least you have one of @andyb pictures. All the information is out there, from Andy, on here and MS. I have a RS arm and also a modified SF arm by Andy. He has all the lengths of them all. The SF is longer than the rs..
Your solution is an RS swingarm. Though I'm sure you already know that but don't want to fork out the cash for the swinger and the bits that go with it. (Would still be cheaper than a mag swinger) Who cares about magnesium, or any other material... If you want a longer mag arm, approach a company that makes them, get the specs, discuss the options and pay your monies. They're easy to find on the web. If you want to fabricate your own, seek assistance and knowledge of others who've been there and done it. Chop, weld, chop, weld until your satisfied what works for you.. The Pierobon swing arm will only help you with tyre size/rubbing and marginally assist with turn in. Your wheelbase will, more or less, remain the same. For what it's worth, if your trying to solve the problem of your bikes handling in the wet on the street because the rear wheel is spinning up on the track in a long turn (or vice-versa), you have much bigger problems than a longer swingarm.. Get a 30mm offset triple clamp, drop the top clamp 3 rings on the forks (ohlins), re-spring them for your weight.. Get an RS swinger, flat-link, adjuster, shock and spring it accordingly. You'll have the handling you seek and there's sooo much information in these forum to help you!!
