Ride Forever Exclusive: suspension workshop with Dave Moss
A new Ducati Monster 821, a twisting highway and suspension guru Dave moss in attendance with his tool kit. It was educational. Honest.
Imagine your perfect riding day. Here’s one possibility: you've not long taken delivery of a brand new Ducati. You head out to a twisting country road you know well, in the sunshine. And who else is there but one of the world’s most respected suspension and set-up experts? With every little machine adjustment, you ride the twists, turns, ups and downs before stopping back at a shady café to debrief, review and tweak some more.
As luck would have it, that’s what we managed to do with renowned suspension and set-up guru Dave Moss. Dave should need no introduction. His suspension wizardry is sought out all over the world, especially in the USA where he now lives. Dave does around 240 track days a year, helping those attending get their machines riding perfectly. And when he's not helping others, he's racing–on a R6 450 triple, or a screaming CBR250RR–or contributing something new to his App, website and library of Youtube videos.
1200S (rear) has full Öhlins adjustment; 821 (front), not so much
Giving it all away
A lot of Dave’s vast knowledge is spread around electronically for free (start at the website, feelthetrack.com) but nothing beats attending one of his workshops or getting set-up advice at the circuit. Savvy New Zealand riders have cottoned on to this and his annual trips downunder always sell out. We were fortunate enough to hook up with Dave Moss towards the end of his NZ tour and arrange an exclusive day fettling the Ducati.
So here’s what we did, what was learned and all the setting changes we evaluated on the day.
Simple is good
A lot of modern ‘bikes have fully adjustable suspension front and rear: spring preload, low-speed compression and rebound damping, and some even have separate high-speed compression and rebound adjustment.
The only conventional adjusters on the 821 are spring preload and rebound damping at the rear. In some ways this simplicity is good because it focuses everything on the fundamentals: sag, spring rates, geometry, even tyres. It’s easy to go chasing a ‘better’ set up with everything six-way adjustable, but often you’re just papering over the need for a more important change.
Starting over
In the course of road tests and reviews I’ve ridden three different 821 Monsters, a 1200 Monster and, briefly, the 1200S.
From early on, I was a little unhappy with how this one handled. It wanted to run wide under power, while the front end felt a bit light and there was too much weight transfer under power and braking. I put the ‘running wide’ tendency down to a squatting effect at the rear, so I wound on about two turns of spring preload and rammed the rebound damping up to 0.5 of a turn out to compensate. This was a guess based on synthesising the manual’s guidance for ‘Sport’ riding and the pillion setting, given it was for a fully-kitted rider weight of 80kg (I’d be nearer 100). It seemed better to me, with less tendency to run wide, although the front end lightness and weight transfer seemed the same. Dave could tell immediately that the rebound was too slow.
As a starting point, Dave took everything back to stock settings (15mm preload, 1.5 turns out). These are Dave’s notes on assessing the bike, including my feedback.
Stage 1. Measurement and evaluation
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2015 Ducati 821 Monster
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Ergos |
Forks |
Shock |
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Dave’s diagnosis: “Too much squatting under acceleration will make it run wide out of corners. Front’s softness under braking was the result of too much rear sag and too much weight transfer forward on the brakes.” |
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To see Dave measuring and setting sag, click here.
Stage 2. First changes, evaluation and hot measurements
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Change and Evaluation |
Hot Measurements |
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Shock Change |
Ride Evaluation |
Forks |
Shock |
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Add two turns of preload.
At the same time the tyre pressures were set to 34psi rear, 33 psi front (based on personal preference). Rebound at factory setting: 1.5 turns out. |
“Weight transfer acceptable; no major issues on acceleration, deceleration or braking.”
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Dave’s diagnosis: “Only 2mm change at the shock, warm, which is what you’d like to expect of a new unit. Less rebound damping seems to be allowing the + 2mm preloaded spring to return to its top height sufficiently quickly and under control. From here, we’ll try faster and slower shock rebound, looking for more stroke.” |
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Caution, genius at work
Stage 3. Further change and evolution
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Shock Change |
Ride Evaluation |
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Dave didn’t tell me what (if anything) he changed for this. It was a blind evaluation. Rebound 2.0 turns out. |
“Crap. Doesn’t want to hold line under power, can't get on the throttle. More weight transfer; pitches forward. Turn-in is vague and harder to judge. Absorbs bumps fine but gives me no confidence.” |
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Dave’s diagnosis: “Too little rebound damping allowing the spring to rebound and top out. This is altering the effective steering geometry as it goes, changing the line and reducing rider confidence from turn-in right through to applying throttle. Fast rebound is allowing more weight transfer.” |
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SHOCK CHANGE |
RIDE EVALUATION |
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Again, Dave didn’t tell me what (if anything) he changed. Rebound 1.0 turns out. All other settings unchanged. |
“Much better. Easy to get on the gas, predictable turn-in and plenty of confidence. Weight transfer better again. Absorbs bumps okay but maybe not as good as setting #1. Or is it better? Can't tell.”
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Dave’s diagnosis: “It looks like optimum rebound is in the range of 1.0 to 1.5 turns out. But we’ll try more, to be sure.” |
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SHOCK CHANGE |
RIDE EVALUATION |
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By this time Dave told me what the other settings were, and he advised that he was setting the rebound to 0.5 of a turn out, which is where I had it. All other settings unchanged. |
“Nearly as bad as #2. Harsh, crashes over bumps, particularly when there’s a series of them. Wants to run wide on bumpy corners. Banged me out of the seat twice. More weight transfer, making the front seem softer again under braking. |
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Dave’s diagnosis: “Too much rebound damping means the shock is too slow to regain its height, and this is most pronounced with a series of bumps - the ride height at the rear is getting progressively compressed, making the geometry more like a chopper so the bike wants to run wide. The compressed rear suspension is harsher, knocking the rider out of the seat, and the variance this creates leads to more weight transfer.” |
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HANDLEBAR CHANGE |
RIDE EVALUATION |
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The stock handlebars are raked backwards and, for me, this means the outer part of the heel of my hand is what makes contact with the bar. (It should be a comfortable and even contact across the mid palm.) This has the effect of making me bring my elbows in to the body, to reduce the pressure on the outer part of the hands. This is the reverse of what you want: with your elbows out slightly, it’s more comfortable and you get more leverage. The bars were rotated slightly forward in an effort to reduce the pressure on the outer palm. |
“Nah, worse. It’s too much of a stretch to the bars, forcing an unnatural leaned-forward riding position. Worse still, when in a natural position, the bars are far away. So you're in a weak position to make a counter-steer push on the inside bar. So much so, I was pulling on the outer bar instead.”
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Dave’s diagnosis: “Preferred stock setting. New flat/straight bars needed given torso and arm length.” |
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FORK CHANGE |
RIDE EVALUATION |
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By this time, Dave’s experience was strongly suggesting one tiny change to the front end. Dropping the front by 3mm was the suggestion, but Dave was sure any more than that would be too much. So, with the rear in our ‘happy place’ (+2mm preload, 1.5 turns out rebound), that’s what we did. |
“Extremely planted and confidence inspiring. Good feel from the front. I can put the bike where I want it and the forks seem stronger with less weight transfer.”
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Dave’s diagnosis: “Dropping the front transfers a little weight forward, like increasing the preload. The front end damping had seemed good from the outset, with rebound not going into a second stroke. Without going to extremes, this has just sharpened the feel without changing how the back is working.” |
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Conclusions and next steps.
It was hard to judge whether 1.0 or 1.5 turns out was the optimum rebound setting. Maybe it’s 1.25? That’s something to evaluate on another day. What is clear, and no amount of fiddling with preload and damping adjustment would correct, is that the rear spring is too soft for the rider weight. And a set of flat, straight handlebars is a must.
What was shockingly clear (pun intended) was just how much difference a half-turn of damping can make. Dave explained that it’s down to the taper of the needle in the damping valve. A thick needle with a steep taper means even a quarter-turn makes a big difference to the oil flow. A long, thin needle, in contrast, means you can turn and turn it to little effect.
The changes to rebound damping made a huge difference to the Ducati. With the right setting it was possible to be greedy with the throttle while the bike remained stable and perfectly on line. A further half turn out, it was custard.
It’s also clear that changes in one place can have an effect elsewhere. Changing preload will likely require changed damping. A change at the rear can affect the front, and vice versa.
Ducati's advice now supplemented by that of Dave Moss.
The other 25% of your suspension
Another big aspect is tyres. We spent a half hour in a tyre shop pulling tyres off the shelf and examining the differences in sizes, profiles and the stiffness of the tyre construction. The real eye-opener was the differences between tyres from the same manufacturer. For example, the Michelin Pilot Road 3 (a personal favourite) and the Pilot Road 4. The latter has notably stiffer sides to the carcass. So would you run the same pressures? Metzler Sportec and Roadtec? The Roadtec actually has the ‘sportier’ profile. Two ‘identical’ tyres from different batches can be different in overall height by a few millimetres. What’s that going to do to your ride height? Your gearing?
It’s understanding these details and complexities, and making sense of them, that ensures Dave’s expertise is so sought after. I was genuinely amazed at how he strings all this together and makes it understandable.
If you have a Ducati Monster 821, you’re around 6ft and weigh around 93 kg, there’s no reason why the settings above shouldn’t give you a decent base to work from. But remember: it’s about the individual. How you feel about a setting may be different to another rider, though its hard to argue with the need for properly controlled suspension action.
Hopefully the process we followed will help any rider go about evaluating how their machine is set up and the difference any change makes. If there’s one thing to take away from all this, it’s make small changes, one at a time. And if you're unsure, check out feelthetrack.com for Dave’s advice.
