Should I re-spring my Duc Supersport?

[Mario149]

So.....a few months after picking up a very lightly used Superport S, I got around to playing with the suspension today. Given that I am, ehem, very "powerfully" built (to the tune of 113kg), pretty much every bike I've had (apart from the K1300S) hasn't ridden correctly on standard settings.

Have watched Dave Moss in the past and re-watched a lot of his stuff today and it was very useful, so I set about fiddling. Long story short, as far as I can tell, the springs are way too soft on the bike. I set the sag - rear is fine at 30mm but I had to compress the spring about 8mm or something silly. And with all the pre load on the front wound on, sag is still 33mm. And under hard braking, I come within about 5mm of bottoming out. On and emergency stop, I prob would. Is this a major issue?

With cold oil, I got the bike rebounding lovely and evenly front to back - needs a bit of a tweak after a test ride and hot oil, but nothing major. Does potentially feel like it needs some compression taken off the front though, which is only going to exacerbate potential bottoming out.

What are people's thoughts? Given that I don't ride the bike very hard, can I get away with it? Or should I really just pony up for stiffer springs? If so, where do I go for them?

[naetype]

Springs are cheap as chips. Get a new spring for your weight. Simples.

[tom_e]

I'm slightly lighter than you around 107kg but changing the stock springs on my SV made a huge difference I'm no street Rossi but even just bimbling about it transformed the handling.

Obviously not the same bike and the SV is known for being badly undersprung stock but definitely worth a couple of hundred quid to switch to something sprung for your weight.

[Biker's Nemesis]

Yeah, change your standard springs for your weight, I have just had mine done as standard its set for a maximum of 13 stone and I have a couple of stone over that.

I have had them done many times for both road and track bikes.

[Kawasicki]

If you are that close to bottoming out the fork then yes!

[Mario149]

Thanks all. Popped round to my local place today to ask about what can be done. They recommended rather than them just sticking in new springs, they would send everything off to an expert they know so he can do it in case fork oil etc needs to be changed. Said it would cost a bit more than them doing it, but best spend a bit more and get as much benefit as poss. Hopefully they'll get back to me with some numbers next week.

Any ideas on cost anyone?

[catso]

My experience of Ducatis is that they are generally sprung way too heavy at the front compared to the rear, especially single-seater models. The 'Biposto' (2-seater) versions have heavier rear springs that more closely match the rate at the front.

This is based on being anything other than a 'racing-snake' but in all cases the fronts seem to be disproportionately too stiff for the rear.

I'm no lightweight (though lighter than the OP) but had to fit lighter springs in the forks on both of mine to make the suspension work properly.

I'd get in touch with somewhere that specialises in suspension. I get mine done at K-Tech; http://www.ktechsuspension.com/ IIRC new springs were around £70 and they fitted them FOC (to forks removed from bike) whilst I waited.

[Mario149]

So, I called K-Tech while waiting for my local place to get back to me, and they said they didn't stock anything for the Supersport S. I suspect it's because it's too new.

However, some googling has revealed details of the Ohlins on the bike:




I've had a play on the Race Tech site (http://www.racetech.com/VehicleSearch) to see what sort of percentage increases in spring rate appear when I plug in my details for a bike of similar weight and riding style e.g. Street Triple R. Several searches for similar bikes appear to yield a spring rate in crease for front and back of 25% over standard.

So 130N/mm for the rear and 10N/mm for the front

Using this chart I found for the rear:




....and this reference I found in an Ohlins pdf for the front (different forks possibly, it's not clear, but same springs):



....it seems I need:

For the rear: a 1092-49

For the front: a pair of 4744-10

Thoughts?

Think I'll give K-Tech a ring again and see if they have equivalent springs.

[catso]

I'd be surprised if the springs aren't common to many other bikes/forks (unless they're a new fork design?).

Supersport are obviously lighter sprung than the SBK models? I've got some 1198S Ohlins forks that I had resprung from 11 to 9.5 (to use on 916) and some 916 Showa resprung from 10 to 9.5 (for 916) and then to 9 for use in a Monster (lighter bike than 916).

Of the spare springs I've got here (Ohlins 11, Showa 10 & K-tech/Showa 9.5), the Ohlins are a smaller diameter and shorter than Showa but even the 2 sets for the Showa springs are different lengths so I'm not sure how critical dimensions are as long as they fit?

[Mario149]

Yeah, I'm not wedded to Ohlins springs in particular - there just seems to be very little info available out there on what else will fit. Spoke to K-Tech again, they still can't help even with my new info, told me to just contact an Ohlins distributor which is what I'm going to do next.

This all seems harder work than it should be!

[Baldchap]

K-Tech will do you a great job if they can supply the parts. Never heard a bad word.

The factory tour is really interesting, too.

[Steve Bass]

Speak to FTR suspension in Braintree. Excellent Ohlins dealer