Ride height adjustment on a SFV4S

SuperDomestique said:

I'd go with increasing preload first. It's the easiest. Adjusting shock ride height may be feasible in situ but you have to have all the right tools to get in there and even then it'd be tough. Realistically, it'd be easier just to pull the shock out and do it that way (which is also not an easy feat).

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Agreed increasing preload is the easiest, but preload affects sag and in general (per several very experienced AFM racers in the Bay Area and per Dave Moss) it is not advisable to use preload to adjust ride height (besides maybe slightly increasing it when going from the street to the track on the same bike to make the bike steer more aggressively and less neutrally).

Also I don't want to drop the front more as in general I don't want to reduce ground clearance. My original question was around how difficult it is to get to the ride height adjuster at the bottom of the shock and what the stock settings are on other bikes as I got my bike used (even though I highly doubt ride height had been messed with anyway).

SuperDomestique said:

But shouldn't a 26.5º head angle make the bike steer more quickly?

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To my understanding, bigger rake angle (a bike feeling "raked out") means the bike feels more like a chopper and less agile and can increase a bike's tendency to understeer both on entry and exit with the added benefit of more stability.

Having messed with geometry on my previous bikes quite a bit my impression is that non-superbike/supersport bikes tend to have more rake and trail to have more stability (perhaps as they might target a slightly less experienced or aggressive rider on average). I prefer my bikes to feel almost nervous and super prone to dive in a turn with a slight tendency to oversteer on the gas on exit. The SF feels the opposite to me.

Alekos said:

Agreed increasing preload is the easiest, but preload affects sag and in general (per several very experienced AFM racers in the Bay Area and per Dave Moss) it is not advisable to use preload to adjust ride height (besides maybe slightly increasing it when going from the street to the track on the same bike to make the bike steer more aggressively and less neutrally).

Also I don't want to drop the front more as in general I don't want to reduce ground clearance. My original question was around how difficult it is to get to the ride height adjuster at the bottom of the shock and what the stock settings are on other bikes as I got my bike used (even though I highly doubt ride height had been messed with anyway).

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Sag is just a number. I wouldn’t worry about it too much.

Alekos said:

To my understanding, bigger rake angle (a bike feeling "raked out") means the bike feels more like a chopper and less agile and can increase a bike's tendency to understeer both on entry and exit with the added benefit of more stability.

Having messed with geometry on my previous bikes quite a bit my impression is that non-superbike/supersport bikes tend to have more rake and trail to have more stability (perhaps as they might target a slightly less experienced or aggressive rider on average). I prefer my bikes to feel almost nervous and super prone to dive in a turn with a slight tendency to oversteer on the gas on exit. The SF feels the opposite to me.

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I deal more with bicycles so I’m more familiar with head angle instead of rake angle which seems to be a motorcycle thing. Whoops

it gets better...

where do you thing rake angle is measured.....through the steering head!

Alekos said:

To my understanding, bigger rake angle (a bike feeling "raked out") means the bike feels more like a chopper and less agile and can increase a bike's tendency to understeer both on entry and exit with the added benefit of more stability.

Having messed with geometry on my previous bikes quite a bit my impression is that non-superbike/supersport bikes tend to have more rake and trail to have more stability (perhaps as they might target a slightly less experienced or aggressive rider on average). I prefer my bikes to feel almost nervous and super prone to dive in a turn with a slight tendency to oversteer on the gas on exit. The SF feels the opposite to me.

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You can raise the rear and it will help turn-in. Raising the rear shortens the rake (and the trail). But also adds anti squat which is the reason you lose traction at the rear ultimately if you get carried away. You raise the fork tubes and it will help turn in. Raising the fork tubes shortens the rake (and shortens the trail). Or like me you can do both. This will make the turn in tolerable but the front doesn't really like to be lowered (by raising the forks) because the change in the CG (makes the bike heavier to pick up out of the corner). The frame was designed to be at 24.5 with neutral set-up. And like you I will give away rear traction to get the bike to turn harder. But neither should be necessary with the Pani head bushings. The bike should turn harder and you will have the bike at the original CG and the rear at the original ride height so traction isn't compromised. And if you need it to turn yet faster you can get there.

SuperDomestique said:

I see what you're saying. I stand corrected. But shouldn't a 26.5º head angle make the bike steer more quickly? I guess the added trail could offset this (but doesn't seem like a lot)? Either way, changing these headstock bushes is no easy feat. I'd be exploring every other avenue before changing them.

SF headstock bush set
View attachment 52268

Here's what Trevitt says about corner troubleshooting
View attachment 52269

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Thanks Super. I was just trying to make everyone aware of what Ducati had done.

andyb said:

it gets better...

where do you thing rake angle is measured.....through the steering head!

View attachment 52271

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I’d argue that these headstock bushes control “head angle” (or steering angle however you want to call it) rather than rake. These bushes are inserted into the frame and therefore determine head angle. From my understanding rake is a function of offset in the suspension NOT at the chassis.

So there’s nuance which isn’t your forte

This is how bikes geometry is defined
https://calfeedesign.com/geometry-of-bike-handling/
Deviation from this thinking is dumb if that’s the case for motorcycles

bagger is making this assumption unless this has been documented by Ducati. No offense, but I’d trust Ducati’s info over speculation despite how much incorrect stuff that they do. I’d also be wary of determining a measurement from what was stamped into the headstock bushes. This could refer to some angle other than rake. Rake and trail could also stay the same and Pani but the SF needs different headstock bushes because the swingarm/pivot/gearing/etc are different between the 2 bikes. Therefore, it needs different bushes to get it back to the 24.5°/100 trail.

The only way to get a true geometry would to literally do the measurements on your own. Also, all this stock geometry goes out the window when you sit on the bike and sag and weight and all kinds of factors get introduced to the system.

If you increase ride height at the rear then you will decrease trail, increase anti-squat and the bike will turn in quicker, its a good idea to approach this systematically. YOu can do this dynamically or statically depending on the characteristic you're adjusting. Bear in mind that if you are not so experienced you will benefit by making quite big changes- say 8mm at a time in measured ride height so you can feel it, but take notes and count threads so you can go back to stock.You dont need to know too much about the finer points of suspension setup but you do need the same stretch of road that you can use each time you make a change. Adjust, ride, review, take notes, rinse and repeat etc focusing on the characteristic you want to improve bearing in mind that a setup for a fast pace is going to be different to normal riding. In the end it comes down to feel which is why the nerd arguments of the definitions of rake etc are a bit of a sideshow. Dont ignore tire wear and pressure either, as for how to get to the adjusting nut you need to get down and dirty

What feels good to you may be way off for others, on the 1299 I had a 60 profile tire, 5mm longer shock and forks raised 4mm to get the turn in feel I liked but on the V4 its been front springs, oil level and playing with free sag.

yes the steering head angle not the outer tube welded in the frame and yes this can be at a different angle to the outer part of the frame look at a ducati RS set up....

or even look at a 996 etc 23.5.24.5 rotate insert 180 degrees to adjust as std, meaning the steering head tube is angled differently to the outer part of the frame. Or get a parallel insert to make it 24 degrees..thats inline with the outer part of the frame.

It's almost like a company who has access to endless amount of information should be trusted more than a random on the internet.

SuperDomestique said:

bagger is making this assumption unless this has been documented by Ducati. No offense, but I’d trust Ducati’s info over speculation despite how much incorrect stuff that they do. I’d also be wary of determining a measurement from what was stamped into the headstock bushes. This could refer to some angle other than rake. Rake and trail could also stay the same and Pani but the SF needs different headstock bushes because the swingarm/pivot/gearing/etc are different between the 2 bikes. Therefore, it needs different bushes to get it back to the 24.5°/100 trail.

The only way to get a true geometry would to literally do the measurements on your own. Also, all this stock geometry goes out the window when you sit on the bike and sag and weight and all kinds of factors get introduced to the system.

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I would agree that ultimately it needs to be measured with the sag included. I think it would behoove all to do some basic calculations so you can understand the actual change in geometry versus ride height changes at either end. I went thru and considered what Ducati would have to do to the rest of the bike to tilt the head 2 degrees such that they'd have to add offset bushes to return it to 24.5. (and then why would you mark them 26.5?). Ultimately to change the head angle 2 degrees the SA pivot would need to be raised about an inch. The SA pivot height is what you're moving to achieve a rake change when you change rear ride height.

baggerman said:

I would agree that ultimately it needs to be measured with the sag included. I think it would behoove all to do some basic calculations so you can understand the actual change in geometry versus ride height changes at either end. I went thru and considered what Ducati would have to do to the rest of the bike to tilt the head 2 degrees such that they'd have to add offset bushes to return it to 24.5. (and then why would you mark them 26.5?). Ultimately to change the head angle 2 degrees the SA pivot would need to be raised about an inch. The SA pivot height is what you're moving to achieve a rake change when you change rear ride height.

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SF forks are 5 mm shorter than Panigale (at least V4S). Did you account for wheelbase and swingarm length?

It's the movement of the SA pivot that matters. When the rear is raised the SA pivot moves up. The triangle you need to consider is the one defined by the line between the SA pivot and the front axle centerlines. The fork length axle centerline to the top of the triples defines the next line and from the top of the triples to the SA pivot defines the last. The 5mm shorter tubes would drop the front a little but nowhere near a 2 degree change. I'll measure my bike when I reassemble with the changed pivots but I'm probably a month plus out. I would greatly appreciate if you have access to a Pani if you could measure the center to center length of a Pani swingarm as the Pani and SF have different part numbers (the casting is actually different). This may be caused by a change in length, torsional rigidity or maybe the shock mount. I get the SF to be about 24.5 inch center to center. I was going to buy Stevens SA but the check I sent took a walk about (I think Steven's maid threw it out by mistake). Since changing the head to 26.5 degrees would lengthen the wheelbase the SF SA may be the same length but if the Pani SA is significantly shorter I will probably change it. Thanks.

Measured my bikes swingarm lengths end to end as center to center would be impossible without disassembly.

'21 SF - 710mm
'22 P - 690mm

Wasn't measured with a vernier caliper but it's as near as 20mm difference in length.

Official website indicates the SF wheelbase is 1488mm, P V4 is 1469mm... 19mm. This is inline with my measurements if the difference in wheelbase is solely attributed to the difference in swingarm lengths.

So you could use a street fighter SA on a pani v4 as a cheaper alternative to a pierobon arm +20 instead of +35

andyb said:

So you could use a street fighter SA on a pani v4 as a cheaper alternative to a pierobon arm +20 instead of +35

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How much is a Pierobon SA?

The SF SA is right around 2,000 Euros.

EBay here SF SA circa £750
Pierobon I bet is around £2500-3000 plus the wait and import tax!

andyb said:

So you could use a street fighter SA on a pani v4 as a cheaper alternative to a pierobon arm +20 instead of +35

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How is this even relevant to the original topic?

SuperDomestique said:

How is this even relevant to the original topic?

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It needed something to provoke a pedantic .... into action….. well done!