Fork upgrade for Hyperstrada

mentalist · Mar 18, 2014

I don't seem to get the dive on front suspension that you all complain about.
I think the low version must have stiffer front springs, even on the track day braking really hard I never noticed it. The shorter travel must have something to do with it, Less air gap, different spring rate???

gatdammit · Mar 18, 2014

Plus back is lowered. wouldn't that shift CG? It's possible stock height has weight more forward/up.

twozzie · Mar 18, 2014

I never experienced excessive dive on mine, just overall harshness and twitchyness (is that even a word?)

zippy49 · Mar 18, 2014

twozzie said:
(Disclaimer, I have no idea about suspension nomenclature or any affiliation to the companies below. This is just some feedback on my experience)

Finally took the bike to Evolution Suspension in San Jose, CA. I spoke in depth to Rob the owner about the issue with the forks and availability of the Andreani. I also spoke to David at Fastbike about the Andreani's and what needs to be done to get them fitted.
After 2 days Rob had reworked the existing forks as the best solution for me (I dont like to bugger about with the suspension). Upgraded springs, repacked shims, new oil, new valves or whatever (he has some pictures I will add showing the old and the new).
He said the old forks had way too soft springs (I'm 165lb inc gear) and Ducati had packed them down to make them stiffer. he also said the holes to let the oil flow were way too small so when the fork compressed, it didn't really do much as the oil had no where to go and so the force came through the handlebars. He also said that with not too much cost increase, the valves could be changed to let the suspension do what it was suppose to do and no idea why Ducati didn't do / hasn't done this.
I took the bike for a quick ride, aimed for potholes and train tracks and the bike was super compliant, most, if not all of the "grainy, harsh feedback had gone" only issue was it did rise up once and hit me on the butt but that may have been over agressive riding over the train tracks. I'll collect the bike this week and give it a full test ride this weekend. Rob can tweak as necessary after my ride.

I'll keep ya posted

Sounds like you got the same results as I did. It's always nice to have your experiences and opinions validated. Could you ask Rob what spring rate he came up with? Pathetic that the stockers could not handle even a flyweight like you! (He said with a hint of jealousy).

Racetech told me that they measured the stock rate at 0.63 mm/kg.
They chose 0.85 for my 180 pounds in gear, same as they recommend for most middleweight sport bikes.

gatdammit · Mar 18, 2014

Did they open the valve port to allow more fluid to flow, as well? You mentioned the tech spoke of it but didn't say if they resized.

twozzie · Mar 19, 2014

I asked Rob what was done and as the forks do different operations as you know, he put a 9mm/kg in one side and a 8. something in the other, (no idea which) overall he went to 8.75.
I've attached his picture of the valves/Piston, NEW on the left, OLD on the right. You can clearly see the holes are no where near big enough to flow the oil on damping.

[URL=http://s701.photobucket.com/user/uktech1/media/Shop%20stuff/DSCN6770_zps6ad02a5d.jpg.html]

[/URL]

First ride on the freeway it felt a little squirrelly but the roads are crap anyway. This weekend I'll run my regular route and see what gives. Rob was concerned about brake dive but so far this is not an issue.

zippy49 · Mar 21, 2014

twozzie said:
I asked Rob what was done and as the forks do different operations as you know...

Twozzie, actually the RHS does all the damping and the LHS does nothing. But those spring rates (the units should be kg/mm) sound just about right. Nice to hear someone else has done more or less the same as I did. I think you'll be pleased.

Could be worse - the YSR50 I once raced only had a spring in one side!

HyperPedro · Mar 23, 2014

mentalist said:
I don't seem to get the dive on front suspension that you all complain about.
I think the low version must have stiffer front springs, even on the track day braking really hard I never noticed it. The shorter travel must have something to do with it, Less air gap, different spring rate???

Like yours Mentalist, my Low version does not seem to have excessive dive under brakes, but it was twitchy under hard acceleration, a characteristic well controlled with the addition of a steering damper.

michdave · Mar 23, 2014

What is everyone running for their air chamber / oil levels? Andreani called for 140mm. I set it there and the fork would bottom to easily. So I bumped it up 20ml once; better but still bottomed. Bumped it up again by 20ml, and it's better"¦but will still bottom. I don't want to put too much in though"¦

(sorry if you've seen this twice, I did post on Ducati.ms)

zippy49 · Mar 24, 2014

michdave said:
What is everyone running for their air chamber / oil levels? Andreani called for 140mm. I set it there and the fork would bottom to easily. So I bumped it up 20ml once; better but still bottomed. Bumped it up again by 20ml, and it's better"¦but will still bottom. I don't want to put too much in though"¦

(sorry if you've seen this twice, I did post on Ducati.ms)

Can't you get the spring rate from Andreani? That's got to be right first. If it's less than 0.80 kg/mm or so you will need stiffer springs. They aren't all that expensive. If you are really heavy you'll need more like 0.95 kg/mm.

Since your cartridges are completely different from stock, my numbers will not necessarily apply. But RT set my oil level at 110mm. Preload is only 10mm. And I have been checking sag & travel with a ziptie, it's still at least 30mm from bottoming.

michdave · Mar 24, 2014

Sorry, I left out details.

The original / standard kit from Andreani comes with .78kg/mm. These were a bit soft for my liking and the bike had too much sag so we ordered up and installed .88kg/mm. Those got the sag numbers I was looking for. But the kit called for that air chamber gap of 140mm.

I can't really measure where it is now without completely removing and dissembling the forks (which if you've done on your bike, you know how much fun it is….LOL). But I wouldn't think those small fluid changes brought it any higher than 130mm. Likewise, as you said, with completely different internals, the volume difference really can't be measured between mine and a stocker.

I've been told not to change what Andreani recommends, but I'm not riding around a damn bike that bottoms at the slight hint of a wheelie….especially on a bike designed to be somewhat like a motard. (sorry to vent…just frustrated with this thing)

zippy49 · Mar 24, 2014

Wow those numbers sound so close that I wonder what else could be wrong. This is not rocket science. Could something be loose that feels like bottoming? Honestly I have not been even close to full travel. But I have not done any serious offroading...

michdave · Mar 25, 2014

I have checked and double checked. I've also used the zip-tie method (as well as seeing the "oil ring") too see if the fork was actually bottoming. Plus...the nasty headshake that happens when it does bottom out is a dead giveaway. LOL

I'm going to run up to the shop this weekend I think and speak with them. The owner there has been racing/building race bikes for 20+ years. I think i may just speak with them or even give him the darn thing to ride. Either that, or I may just keep adding oil until the problem stops. I guess the worst that could happen is I would blow a seal.

It's just confusing. In all the "normal" riding conditions, the fork preforms flawlessy. But with a wheelie, it's like the fork just gives out.

We'll see.

zippy49 · Mar 25, 2014

I'll admit that I am no "stunta." My wheelies are limited to lifting the front wheel an inch or two when accelerating in first or maybe second, and not really on purpose. However I've hit some huge potholes, thought I'd bent a wheel a few times.

But if you saw the Cycle World video, those guys were wheelieing their brains out on standard Hypermotards. Their forks did not seem to bottom! Maybe it was the 20mm extra travel, but maybe not. Have you tried adding more compression?

FWIW, one more item in my fork setup - 5W oil. Stock was 7.5W.

ChrisMag · Mar 25, 2014

twozzie said:
I asked Rob what was done and as the forks do different operations as you know, he put a 9mm/kg in one side and a 8. something in the other, (no idea which) overall he went to 8.75.

More than likely, it was a .9kg/mm and a .85kg/mm spring. Those rates are pretty common. They're soft, similar to a stock CBR600RR, but stiffer than something like a KLR.

ChrisMag · Mar 25, 2014

michdave said:
It's just confusing. In all the "normal" riding conditions, the fork preforms flawlessy. But with a wheelie, it's like the fork just gives out.

We'll see.

Well, it's not a SM with 8" of fork travel and a twin-tube cartridge fork, nor is it a superbike fork with a 1kg/mm spring installed.

As you raise the oil level, the air gap shrinks. As a result, the fork's effective spring rate will become progressive earlier in the stroke. Above a certain oil level, it will become effectively impossible to use the entire stroke of the fork.

To a point, this is good as it will protect you from mechanically bottoming over bumps or under emergency braking "“ you've created a hydraulic bottom rather than a mechanical one. Conversely, this can be bad as ride quality can suffer, available suspension travel becomes restricted to soak bumps, thus transferring too much into the tire and chassis, and rebound will not be linear throughout the stroke, as this is a function of the effective spring rate relative to hydraulic damping.

The important thing to know is what you are trying to achieve.

Do you want a plus ride with decent bottoming resistance? The solution might be a softer spring, modest compression damping and a higher oil level.

Do you want dive and bottoming resistance and consistent rebound through the stroke, at the expense of a plush ride? You might be better off with a heavier front spring, less preload and a lower oil level with good compression damping and initial stroke control by way of a mid-valve stack (typical of road-racing cartridge kits).

There's no ideal solution for all scenarios (yet). BMW, Ducati and KTM are all bringing in semi-active suspension in an attempt to solve the riddle. I personally would prefer a slightly softer front-end to help me transfer weight on-demand while on the HS. My RSV4 is the opposite "“ heavy spring rates at both ends to control pitch and to keep ground clearance from being a problem when corner speed and lean angles are high on a track. It's a compromise.

If you're happy overall with the feel of the fork, but are bottoming doing wheelies, maybe the solution is to practice wheelies on a different bike, or at least try to roll into the gas a little as you set the front down.

The bottom line is, do what you're doing"¦ small incremental changes.

twozzie · Mar 25, 2014

ChrisMag said:
More than likely, it was a .9kg/mm and a .85kg/mm spring. Those rates are pretty common. They're soft, similar to a stock CBR600RR, but stiffer than something like a KLR.

Yup, that seems about right.
Rode the bike at the weekend, was much improved over the stock shocks, potholes etc were now non existant and the bike seemed more planted in the corners which is great. However I seemed to feel more of the undulations in the road, I'll give it another few rides and then report back to Rob.

ChrisMag · Mar 25, 2014

What did the stock springs measure in terms of rate?

twozzie · Mar 25, 2014

ChrisMag said:
What did the stock springs measure in terms of rate?

.65mm/kg

michdave · Mar 25, 2014

ChrisMag said:
Well, it's not a SM with 8" of fork travel and a twin-tube cartridge fork, nor is it a superbike fork with a 1kg/mm spring installed.

As you raise the oil level, the air gap shrinks. As a result, the fork's effective spring rate will become progressive earlier in the stroke. Above a certain oil level, it will become effectively impossible to use the entire stroke of the fork.

To a point, this is good as it will protect you from mechanically bottoming over bumps or under emergency braking "“ you've created a hydraulic bottom rather than a mechanical one. Conversely, this can be bad as ride quality can suffer, available suspension travel becomes restricted to soak bumps, thus transferring too much into the tire and chassis, and rebound will not be linear throughout the stroke, as this is a function of the effective spring rate relative to hydraulic damping.

The important thing to know is what you are trying to achieve.

Do you want a plus ride with decent bottoming resistance? The solution might be a softer spring, modest compression damping and a higher oil level.

Do you want dive and bottoming resistance and consistent rebound through the stroke, at the expense of a plush ride? You might be better off with a heavier front spring, less preload and a lower oil level with good compression damping and initial stroke control by way of a mid-valve stack (typical of road-racing cartridge kits).

There's no ideal solution for all scenarios (yet). BMW, Ducati and KTM are all bringing in semi-active suspension in an attempt to solve the riddle. I personally would prefer a slightly softer front-end to help me transfer weight on-demand while on the HS. My RSV4 is the opposite "“ heavy spring rates at both ends to control pitch and to keep ground clearance from being a problem when corner speed and lean angles are high on a track. It's a compromise.

If you're happy overall with the feel of the fork, but are bottoming doing wheelies, maybe the solution is to practice wheelies on a different bike, or at least try to roll into the gas a little as you set the front down.

The bottom line is, do what you're doing"¦ small incremental changes.

Chris,

Currently I'm running .88kg/mm springs which are significantly stiffer compared to the stockers. I also have the Andreani double cartridge kit installed; making the stock forks now fully adjustable (i.e. preload, rebound, compression).

The shop I purchased them from weren't instilling full confidence in the advice they were giving"¦so I had to jump ship. I called Ducati Winchester and spoke with the owner, who has been wrenching and racing for 20+ years, primarily on Duc's and a fully certified Ohlins (Andreani and Ohlins are in collaboration in Italy) dealer, "¦yada, yada"¦.

He said that every other Hyper they're worked the suspension on, ran 100-120mm oil level. So"¦I'm pulling the forks as we speak and bumping them up to 100mm. We'll see what happens.

Fork upgrade for Hyperstrada

Similar threads