A little help with my Ducati 1098...

I'm new to racing this year and am part of the ASMA racing series near Deming, NM.

I recently added a 520 conversion and dropped a tooth in front (14) and added a two in back (40). When I fitted, sized and tensioned everything up I had a well-worn 190/55 installed. No issues there.

When my Tire supplier at the track said he would be stocking the Pirelli 190/55's for the upcoming season and instead was carrying the new 200/55's, I didn't skip a beat and had one installed on my rim. I had a tough time getting the tire installed but didn't make the connection that it was rubbing until I tried to push the bike manually. So he swapped it out for an older 190/55 that he just happened to have and it fit without issue. Although, after coming in from a few laps around the track the clearance between the tire and the swingarm is small enough that my tire warmers are snug going through the tight spot near the swingarm.

After that weekend, I ordered everything I needed to add a link to my chain to give me that extra space I needed to fit the larger tire. However once I broke the chain and moved the eccentric link to the 'sweet spot' (the approximately 4-5 o'clock position on the hub), I had one rung left on my rear sprocket with the chain tensioned properly. By rung, I mean I'd need a link with 3 pins or a master link and a half.

Has anyone had similar issue with their 1098, 1198 or 848? Would you think stepping up to a 42 or back down to a 38 would be better for the situation?

 

We've had it happen on a 1098 here at the shop.. Tire clearance can be a pain for sure.. one of our racers basically had the exact same thing happen, but he had a TINY amount of clearance at pit speeds and below, but as soon as he started rolling the tire would grow and rub the swingarm pretty severely.. Im not sure how they ended up addressing it though.. Ill see what I can find out for you.

 

Thanks, I appreciate the help!

 

@ Mongo - I miss-typed my initial write up, my tire supplier is NOT stocking the 190/55's. I'm extremely happy with the performance of the Pirelli DOT's I'm using and would like to stick with it.

 

If you want to keep that gear ratio just get a gearing chart and use smaller sprockets that give you the same ratio and that will allow you to slide the rear wheel back. Or just add links to the existing chain.

 

IMO, the proper gearing is more important than a few extra mm of wheelbase. Even if you are fast enough to notice the change, there will always be that tradeoff with an eccentric. Pick your gearing, tension the chain, and make sure have some tire/swingarm clearance (I'd guess at least 9mm or so). I think the rear ride height is the thing you need to worry about when you get everything situated.

Keep in mind that I lap a racetrack about as fast as paint dries...

 

Same thing happened to me on my 600rr. 190/55 fit fine but a 190/65 rubbed the shock linkage. I added two links to the chain and it fits fine.

 

What's different in this case is that you can't slide the rear wheel back. Ducs have an exxentric hub that ffects ride height anytime you want to adjust the chain. I've got it worked out for my 848, but it finally took me having three different chain and sprockt combos for the tracks I run.

 

You can machine the slot on the brake caliper bracket to gain a few more degrees of motion in the eccentric. That can give you 5mm or more extra clearance.

I used 15/40 gearing on my 1098 and achieved the longest possible swingarm length that way. The only downside is no additional adjustment is left over for much chain stretch.

 

Thats the way to go .It will hold a 200 no problem:up: