Author [ES] [CA] [PL] [PT] [IT] [DE] [FR] [NL] [DK] [NO] [GR] [TR] Topic: Dymag Wheels and the Quickshifter  (Read 1948 times)

0 Members and 1 Guest are viewing this topic.

Offline marcparnes

  • XR Pro
  • ***
  • Posts: 105
  • Country: us
  • Bike: '18 S1000XR
  • Town: SoCal
Dymag Wheels and the Quickshifter
« on: April 12, 2018, 03:38:20 AM »
I recently installed a set of forged aluminum Dymag wheels which are much lighter than the stock wheels. Everything has worked out great but I have one nagging issue that I'm not sure how or if I can solve relative to the quickshifter. To me it now upshifts more harshly than it did with the stock wheels. There are two issues that contributes to this, the first obviously being the lighter MOI due to the lighter weight. Much less flywheel effect. The other one is a bit more concerning and that is the much smaller cush drive rubbers compared to the big ones in the stock wheels. I think this is the biggest factor. I spoke with the shop foreman at  Dymag and he is aware of the issue but has no solution. Turns out they only have one model of cush drive that they use for everything. He said that one customer actually drilled some small holes in the rubbers themselves in order to soften them up a bit but he didn't suggest doing that as they will just wear out faster. The original BMW rubbers are huge and have quite a bit of shock absorption while the Dymag ones are tiny little donuts in comparison and probably don't do much of anything. I noticed that the BMW HP wheels also use round donut shaped rubbers but they appear to be much larger. Don't know that for a fact so I will order one to compare it for size and hardness. Just for the hell of it I cleared the shifter adaptations and retaught them but that didn't change anything. I'm a bit concerned about the shock getting to the trans now besides the fact that it just isn't as pleasant shifting as it was before. Seems like Dymag should have reckoned with this but it doesn't seem like they did. If the shift times could be modified that would probably help but I'm not considering adding some extensive add-on box just for that. Has anyone run into this before? Any thoughts?

Marc
'18 S1000XR Premium
'15 BMW R1200GS Low

Offline smithy

  • XR Master
  • ****
  • Posts: 789
  • Country: au
  • Bike: 2017 S1000XR
  • Town: Sydney.
Re: Dymag Wheels and the Quickshifter
« Reply #1 on: April 12, 2018, 04:35:24 AM »
Do you know if the GS-911 has the ability to "adjust" the quick-shift ignition cut timings..?? I have the Rapid Bike EVO module fitted to mine and it has this "ability", my 3>4 shift was a bit notchy so I adjusted the ignition timing for the 3>4 shift to suit and it's quite a bit better now.

If so it might be worth experimenting with them to see if it helps.

Smithy.
When I die, I want to go peacefully in my sleep like my Grandfather....not screaming like the passengers in his car..!

Offline marcparnes

  • XR Pro
  • ***
  • Posts: 105
  • Country: us
  • Bike: '18 S1000XR
  • Town: SoCal
Re: Dymag Wheels and the Quickshifter
« Reply #2 on: April 12, 2018, 04:41:41 AM »
The GS-911 doesn't appear to have that ability. I do think that would help though. A bit more cut time would probably ease the shift.

Marc
'18 S1000XR Premium
'15 BMW R1200GS Low

Offline smithy

  • XR Master
  • ****
  • Posts: 789
  • Country: au
  • Bike: 2017 S1000XR
  • Town: Sydney.
Re: Dymag Wheels and the Quickshifter
« Reply #3 on: April 12, 2018, 08:50:27 AM »
*Originally Posted by marcparnes [+]
The GS-911 doesn't appear to have that ability. I do think that would help though. A bit more cut time would probably ease the shift. Marc

Precisely....that's exactly what I did using the Rapid Bike EVO. We're only talking a few milliseconds here and there though..

Smithy
When I die, I want to go peacefully in my sleep like my Grandfather....not screaming like the passengers in his car..!

Offline Salem

  • XR Member
  • **
  • Posts: 76
  • Country: nl
  • Bike: S1000XR
Re: Dymag Wheels and the Quickshifter
« Reply #4 on: April 13, 2018, 02:12:59 PM »
Interesting.. The spring effect of the rubbers will reduce transmission output shaft speed and affect the quickshift. Harder rubbers, less movement. While on the rear wheel the effect might only be a few degrees, it's increased by the chain (or final drive)  ratio of 2.647 (45/17).

@Smithy: I start to wonder if BMW uses ignition cut out time, which I expect to be a number around 100, or number of ignition cuts, which ought to be a number around 8. You seem to be the only one having changed this, and have the answer to this

I can post an Excel on quickshift with my logic, but need to check it first against a known BMW value

Offline smithy

  • XR Master
  • ****
  • Posts: 789
  • Country: au
  • Bike: 2017 S1000XR
  • Town: Sydney.
Re: Dymag Wheels and the Quickshifter
« Reply #5 on: April 13, 2018, 11:39:06 PM »
*Originally Posted by Salem [+]
Interesting.. The spring effect of the rubbers will reduce transmission output shaft speed and affect the quickshift. Harder rubbers, less movement. While on the rear wheel the effect might only be a few degrees, it's increased by the chain (or final drive)  ratio of 2.647 (45/17).

@Smithy: I start to wonder if BMW uses ignition cut out time, which I expect to be a number around 100, or number of ignition cuts, which ought to be a number around 8. You seem to be the only one having changed this, and have the answer to this

I can post an Excel on quickshift with my logic, but need to check it first against a known BMW value

I believe they do use time rather than number of cycles....they vary from 1st-2nd and 2nd-3rd etc.....the shorter the gear the longer the ignition cut....on average they're ~65 milliseconds. They vary a couple of milliseconds either way depending on what pair of gears are being changed....the down-change cut is slightly longer due to the need for the rpm to increase via the "blip" to match gear speeds etc...

Smithy.
When I die, I want to go peacefully in my sleep like my Grandfather....not screaming like the passengers in his car..!

Offline skapan

  • XR Member
  • **
  • Posts: 83
  • Country: ca
  • Bike: BMW S1000
  • Town: Toronto
Re: Dymag Wheels and the Quickshifter
« Reply #6 on: April 14, 2018, 12:27:25 PM »
Marc, did you also adjust the chain tension when you installed the wheels?  I had BST's on mine without any effect on the quickshifter, but I have noticed in the past that chain tension can have an effect. Just a thought.

Online SimonUK

  • XR Pro
  • ***
  • Posts: 263
  • Country: us
  • Bike: S1000XR,S1000R
  • Town: Upstate, SC
Re: Dymag Wheels and the Quickshifter
« Reply #7 on: April 14, 2018, 12:57:25 PM »
Also noticed no difference in QS performance when I was running Rotobox CF wheels(this is on my R, but same engine, similar shifter).

Offline marcparnes

  • XR Pro
  • ***
  • Posts: 105
  • Country: us
  • Bike: '18 S1000XR
  • Town: SoCal
Re: Dymag Wheels and the Quickshifter
« Reply #8 on: April 14, 2018, 01:54:39 PM »
*Originally Posted by skapan [+]
Marc, did you also adjust the chain tension when you installed the wheels?  I had BST's on mine without any effect on the quickshifter, but I have noticed in the past that chain tension can have an effect. Just a thought.
Yes, I'm very careful about maintaining chain tension.

Marc
'18 S1000XR Premium
'15 BMW R1200GS Low

Offline marcparnes

  • XR Pro
  • ***
  • Posts: 105
  • Country: us
  • Bike: '18 S1000XR
  • Town: SoCal
Re: Dymag Wheels and the Quickshifter
« Reply #9 on: April 14, 2018, 01:56:25 PM »
Sounds to me like the the wheels you guys are mentioning must have had more effective cush drives as that is the main difference between the Dymags and the stock wheels.

Marc
'18 S1000XR Premium
'15 BMW R1200GS Low

 


dysfunctional