DDC Suspension

[Ukbmw]

Would be nice to switch to softer setup for the road then stiffen it back up for track

 

[Monners]

I had a couple of long chats with Dave Croft yesterday. Take this post as a discussion starter rather than all the answers as I'm using it to get things straight in my head but I think I've covered it all.

- Yes the length of the spring changes but the travel stays exactly the same. It doesn't matter how many coils you add or take away, the spring travel will always remain the same. It can compress until adjacent coils meet. The forks however have a cushion at the end of the travel so they dont do so.

- Spring theory - if you remove a coil the spring becomes stiffer! Sorcery if you ask me!!


They CSP30 high end forks that I bought have a through rod type system as opposed to the traditional oil or the newer gas based systems that people are using (eg Kawasaki on the ZX10). The gas systems have a benefit in corner exit, whereas the traditional oil systems have a benefit in the initial take up in the braking area. I need to go over the exact reasons some more to understand it but its due to the way the way the oil flows, etc. The idea of the CSP30 is that there is no trade off and you get the best of both worlds since there's no start/stop of flow in either direction since the rod is floating.

Mupo say they would implement the 911 system in the CSP30 forks but unfortunately the size of the working parts means there's no room to add the 911 adjustable spring mechanism.

If there's anything else anyone wants me to ask Dave then fire away as I'm learning a lot chatting to him.

 

[Monners]

...and here's something that may cause some controversy regarding all the people doing suspension setup at the tracks and races and pushing on the front and back of the bike to check balance, speed of rebound, etc. The suspension is built to support the bike and rider braking from 200mph to 20mph in ~100m (?). How can you possibly apply enough force to check the suspension by pushing down on it at standstill, all you are seeing is the initial take up?........

 

[Ukbmw]

...and here's something that may cause some controversy regarding all the people doing suspension setup at the tracks and races and pushing on the front and back of the bike to check balance, speed of rebound, etc. The suspension is built to support the bike and rider braking from 200mph to 20mph in ~100m (?). How can you possibly apply enough force to check the suspension by pushing down on it at standstill, all you are seeing is the initial take up?........

I couldnt agree more.
The forces under braking and accelerating are alot more than any human can push.
I had my mupo shock setup for my zx10r and my weight. They fitted a 115 spring on it which is quite beafy.
I couldnt pump it up and down by hand.
I just rode it about and gave it some clicks here and there until i gave it 3 more clicks on the rebound then bingo. It felt great.
Not convinced any hand puming is gonna work when your running heavy springs. But they can read tyre wear patterns and adjust it to suit.
Im not sure what spring to fit on my gen3 as ive just bought a new ddc shock to play with.
I think another 115 spring would work spot on for track riding but my old zx10r used to be dreadfull on the road over bumps

 

[alex]

...and here's something that may cause some controversy regarding all the people doing suspension setup at the tracks and races and pushing on the front and back of the bike to check balance, speed of rebound, etc. The suspension is built to support the bike and rider braking from 200mph to 20mph in ~100m (?). How can you possibly apply enough force to check the suspension by pushing down on it at standstill, all you are seeing is the initial take up?........

Thats usually to check the rebound speed, not the compression. Its the bounce at the top of the stroke.

- Alex

 

[alex]

Great info Dave, thanks for getting it. Learned something there.

The CSP's sound similar to the Bitubo pressurized system, is that correct?

- Alex

 

[Monners]

.... The gas systems have a benefit in corner exit, whereas the traditional oil systems have a benefit in the initial take up in the braking area. I need to go over the exact reasons some more to understand it but its due to the way the way the oil flows, etc.

I think I might have got this the wrong way around. The gas systems have rebound disadvantages which would make them tend to run wide on exit?
http://www.mupo.it/product/18/0/284/kit-cartridge-csp30
'The through-rod system guarantees the reliability of a sealed or pressurized cartridge without any rebound disadvantage typical of gas-based systems.
In this product, the rod enters and exits the body of the cartridge, thus avoiding the cavitation problems typically found in other cartridges.'

 

[Monners]

Great info Dave, thanks for getting it. Learned something there.

The CSP's sound similar to the Bitubo pressurized system, is that correct?

- Alex

It does look like two different solutions to address the cavitation issues. I dont think the Biturbo is doing a through rod type design, looks like its got a mechanism at each end of the rod?

 

[bmwbadboy]

Resurrecting this thread as I'm slowly thinking to upgrade DDC.

I have 2016 model, with OE DDC and 2D sensor. Absolutely no issues to report about suspension after Dave Moss helped to tweak it. Tire wear looks perfect, can't say anything bad about handling of the bike at all. I'm not BSB rider, but am able to do 1:40 at Donny.
So the only adjustment that I do to suspension is front pre-load to fit different tracks. If the track is kinda flat I'm at 9.5 turns (from fully opened), otherwise I'm closing it 1-2 turns.
I do not touch rebound/compression on front or back, since they were setup. Again just to iterate, tire wear at my pace is excellent.

Some say front is vague on short tracks. I can't say I ride short tracks, but at Donny/Silverstone/Spa/Almeria/Snetterton/BrandsGP I didn't feel it.

But I have this unsettling feeling that if I push a bit harder, OE suspension wont work and collapse. Hence thinking to get Ohlinx NIX cartridges and TTX GP shock.


Any thoughts or suggestions ?

 

[alex]

If you don't feel its holding you back then is it worth doing?

Also, I wouldn't default to Ohlins... there's other options to think about like Maxton, K-Tech, Mupo and Bitubo.



- Alex

 

[Monners]

Brands GP is a short twisty track that will definitely show you if you have a problem with the stock suspension. If you are fine at Brands and doing 1'40'' at Donny then there's no major problem using Stock DDC suspension and it will definitely go a few seconds under 1'40'' and has been used at Superstock level. I think you will struggle to get much more out of it without problems as that is a decent time. If you are looking to upgrade give me a message as I can get very good deals on Mupo. Be aware that upgrading to race suspension means you will have a lot more work getting the setup right than the stock stuff that has a wide window. It also needs adjusting more at different tracks. I know from your posts that you like to play with the setup but I suspect you will have problems finding a base setup as the BMW is quite tricky and has taken me a while to get working right.

 

[bmwbadboy]

Brands GP is a short twisty track that will definitely show you if you have a problem with the stock suspension. If you are fine at Brands and doing 1'40'' at Donny then there's no major problem using Stock DDC suspension and it will definitely go a few seconds under 1'40'' and has been used at Superstock level. I think you will struggle to get much more out of it without problems as that is a decent time. If you are looking to upgrade give me a message as I can get very good deals on Mupo. Be aware that upgrading to race suspension means you will have a lot more work getting the setup right than the stock stuff that has a wide window. It also needs adjusting more at different tracks. I know from your posts that you like to play with the setup but I suspect you will have problems finding a base setup as the BMW is quite tricky and has taken me a while to get working right.

Let's strike out Brands GP for now, I'm not fast there as I only did GP once.

I guess I need to get more experience before doing any changes. Will better spend moneys on coaching now.

 

[Gobert]

I'm running the DDC suspemsion with the 2D front sensor and have had the forks resprung by MTC - aftter what I read, I was expecting no feel and poor performance but to be honest it's fine at the pace I ride. Tyre wear is good and while I'm not quick - 1m 54s at Oulton today -it's good enough for me.

 

[bmwbadboy]

I'm running the DDC suspemsion with the 2D front sensor and have had the forks resprung by MTC - aftter what I read, I was expecting no feel and poor performance but to be honest it's fine at the pace I ride. Tyre wear is good and while I'm not quick - 1m 54s at Oulton today -it's good enough for me.

How much do you weight suited ? I often read/hear that OE forks are set for 85kg rider and hence can be soft.

I'm running 9.5 turns preload (from fully open) and that's probably a lot. I'm thinking to at least re-sprung the forks too.

 

[Gobert]

How much do you weight suited ? I often read/hear that OE forks are set for 85kg rider and hence can be soft.

I'm running 9.5 turns preload (from fully open) and that's probably a lot. I'm thinking to at least re-sprung the forks too.

I'm about 82kg in my gear - 74kg in normal clothes - and he fitted 10nm springs. He also machines the preload spacer for a wider range of adjustment and changes the size of the air gap.

 

[Ash34]

Resurrecting this thread as I'm slowly thinking to upgrade DDC.

I have 2016 model, with OE DDC and 2D sensor. Absolutely no issues to report about suspension after Dave Moss helped to tweak it. Tire wear looks perfect, can't say anything bad about handling of the bike at all. I'm not BSB rider, but am able to do 1:40 at Donny.
So the only adjustment that I do to suspension is front pre-load to fit different tracks. If the track is kinda flat I'm at 9.5 turns (from fully opened), otherwise I'm closing it 1-2 turns.
I do not touch rebound/compression on front or back, since they were setup. Again just to iterate, tire wear at my pace is excellent.

Some say front is vague on short tracks. I can't say I ride short tracks, but at Donny/Silverstone/Spa/Almeria/Snetterton/BrandsGP I didn't feel it.

But I have this unsettling feeling that if I push a bit harder, OE suspension wont work and collapse. Hence thinking to get Ohlinx NIX cartridges and TTX GP shock.


Any thoughts or suggestions ?

My coach is a BMW brand ambassador so gets given a car and bike. He rides the 2018 RR on track which is completely standard apart from a Brembo front master cylinder and rear sets. The rest of the bike is stock, with lights, horn, 525 chain the whole lot. At the Hungaroring (our nearest track) he is fastest guy there and that bike blows away all of the race bikes including a Ducati V4R. I would say the standard suspension is more than adequate.

 

[alex]

That's good, but the issue is vagueness and thats rider specific, if you don't get the feedback you want/need its hard to go faster if you're not an elite rider.



- Alex

 

[scooby]

My coach is a BMW brand ambassador so gets given a car and bike. He rides the 2018 RR on track which is completely standard apart from a Brembo front master cylinder and rear sets. The rest of the bike is stock, with lights, horn, 525 chain the whole lot. At the Hungaroring (our nearest track) he is fastest guy there and that bike blows away all of the race bikes including a Ducati V4R. I would say the standard suspension is more than adequate.

it's hard to compare against the pro's though,we have coaches over here in the UK that run standrad stock bikes,but still blitz the general trackday community regardless of what latest+greatest bikes they have,talent and ability will always trump "bike bling",but that doesn't mean improving elements on a bike over stock wont make the general rider better,as long as it used properly,or set up properly (suspension especially) it gives more confidence,which in turn allows you go faster.