Ducati Monster Motorcycle Forum banner
1 - 18 of 18 Posts

·
Premium Member
Joined
·
102 Posts
Discussion Starter · #1 ·
Ok guys need some comments on my foggy to track bike conversion.

I found a set of totally trick magnesium triple clamps for a 996 that are 53mm upper and lower diameter. I'm selling my stock TiNi S4 SHOWA forks [50mm & 53mm] and was looking for a set of 996 Ohlins.

Murphy's Law - found a set of 999 Ohlins for an unbelievable price. They are 53mm upper and 56mm lower diameter.

If you look at the photo of the triples can I bore out the lowers from 53 to 56mm or an I risking breakage?????? I know nothing about the properties of Magnesium. Have good machine shops locally so i'm not worried about the quality of the work.

If no, can I mix a 999 lower yoke with a 53mm upper????

Totally confused.

HELP
 

Attachments

·
Premium Member
Joined
·
102 Posts
Discussion Starter · #2 ·
Too late.... just bought the Ohlins.

Price was too cheep to think about. 8)

No longer theoretical questions..... HELP
 

Attachments

·
Registered
Joined
·
8,800 Posts
I wouldn't bore out the Mag lower from 53mm to 56mm.
 

·
Registered
Joined
·
8,800 Posts
Also, I'm pretty sure the SBK triples have more offset than the Monster is comfortable with.
 

·
Premium Member
Joined
·
5,761 Posts
They only thing easy is the diameter of the triples. They should fit the 53/56 Ohlins forks perfectly.

Triple offset is too extreme. The magnesium triples usually are 30mm. You won't be able to change this.

999 forks bottoms have 15mm rotor offset. You will need new 15 offset rotors as your rotors are 10mm.

We might have a set of billet Ohlins triples for an S4 and some 15mm offset rotors in stock.
 

·
Premium Member
Joined
·
1,200 Posts
I used an AMS/Doug NAsh lower triple. It had adjustable offsets, so I could compensate. I had to use the most forward set of offsets.The stock distance from stem center to fork center is too short. I also had to cut off the steering stops. I then added stops on the ignition key/ plate bracket. I drilled a hole in each side, used a button head allen with nut on one side, locknut on backside. The stops now contact the upper triple, and are adjustable too. I have 2 PIAA driving lights for headlights, a SBK triple has no provisions for the headlight mount.
 

·
Premium Member
Joined
·
102 Posts
Discussion Starter · #8 ·
MOTO, & guys

Thanks so far for the info.

TRIPLE OFFSET - what is the ideal offset for this bike as a track machine?? If the Mag triples are 30mm and they may be too much what is stock?

BRAKE ROTORS - assuming the will need 15mm offset versus the 10mm that I have wo makes rotors at 15mm and the 5 bolt mounting which I believe is different than the 6 hole of the 749/999 rotors?

PM me on what you have that will work based on your experience.

Pushka
 

·
Registered
Joined
·
930 Posts
intense.
 

·
Registered
Joined
·
8,800 Posts
I *think* the stock Monster offset is 25mm.

CycleCat would know, as they make lots of billet triples.
 

·
Premium Member
Joined
·
102 Posts
Discussion Starter · #11 ·
??? the triple offset is confusing. Am I wrong in assuming the larger the offset the more stable the bike is with a slower turn in?

Stock Monster has been quoted as 25mm in one of the posts above, the mag units are 30, but on an S4RS the offset is 35mm ! Many Triple clamps advertise the 27mm as being ideal on the 996 and 999 series. The only other variable is steering head angle to the equation.

Comments?
Suggestions?

Pushka
 

·
Registered
Joined
·
8,800 Posts
Pushka said:
??? the triple offset is confusing. Am I wrong in assuming the larger the offset the more stable the bike is with a slower turn in?
You are wrong.

Larger offset means less trail, so it is less stable/quicker turn-in.
But it's more complicated than that, as it also effects how 'neutral' it steers when leaned over.

Pushka said:
Stock Monster has been quoted as 25mm in one of the posts above, the mag units are 30, but on an S4RS the offset is 35mm ! Many Triple clamps advertise the 27mm as being ideal on the 996 and 999 series. The only other variable is steering head angle to the equation.

Comments?
Suggestions?

Pushka
I was working from memory in my previous post. Occasionally that's not reliable... :p

I've just measured a set of aftermarket triples on an S4.
They appear to be 30mm offset, but I can't do a real accurate measurement at this time.
Tomorrow I should be able to get an accurate measurement of these, and a stock one as well.
 

·
Premium Member
Joined
·
102 Posts
Discussion Starter · #13 ·
Hey Speeddog,

Just froze my a$$ off on the deck measuring my stock S4 triples and yes they are 30mm [ it's Canada and the forecast is snow tonight :'( ]. I'm back where I started with this post and looking at boring out the incoming lower Mag triple assuming they are the right offset. On a good note I just found out an ex-racer Ducati buddy does Finite Element Analysis for an industrial machining company so the triple will go to him for the final verdict assuming they are 30mm offset.

Now to the brake disc issues. I was backwards in my last post and the S4 has 6 bolt rotors but I have no idea what the stock rotor offset is versus the offset required for the Ohlins?

Are S4 vs 999 forks using the same axle sizes?

This will get worse before it gets better :)

Pushka
 

·
Registered
Joined
·
8,800 Posts
moto said:
-----------------snip----------------
999 forks bottoms have 15mm rotor offset. You will need new 15 offset rotors as your rotors are 10mm.
-----------------snip----------------
Apparently, you will need 15mm offset rotors with a 6-bolt pattern.
You'll have to speak with moto to get more details.

S4 is a 25mm diameter axle. I've no idea what the 999 uses.
The Ohlins axle may be different from the stock 999.
 

·
Premium Member
Joined
·
1,966 Posts
That lower triple looks like a Febur item and as it is available with a 56mm bore, you should be able to bore out the unit you have.
 

·
Premium Member
Joined
·
102 Posts
Discussion Starter · #17 ·
Good point on the magnesium needing to be treated. I've done some math and the incoming mag triples look to be 35mm offset which are 5mm more than stock.

The S4RS triples have a 35mm offset with Ohlins. Does the RS have the same basic frame geometry, and specifically the same steering head angle etc? If it's close I don't see the big deal with going up 5mm as it will match the RS which by all accounts handles great.

????

Pushka
 

·
Premium Member
Joined
·
102 Posts
Discussion Starter · #18 ·
Hey guys,

Two great sites that explain suspensions, geometry, rate vs trail, offset, etc

http://en.wikipedia.org/wiki/Rake_and_trail

http://www.tonyfoale.com/ ...thanks Ducman851

I'm starting to get it. S4RS has a 35mm offset which reduces the trail to 90.07mm My S4 came stock with 30mm offset and 102mm of trail. Both share a 24' steering head angle. Another speculation - my S4 will virtually duplicate the S4RS number with 35mm offset triples.

....or am I totally F'd ? [laugh]

JP
 
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top