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Golf R OEM spring rate and length + rear motion ratio?

jmblur

Go Kart Champion
Location
Massachusetts
Car(s)
2017 Golf R
Anybody have this information? Can't find it anywhere (and what I do find is conflicting). Front motion ratio I'm assuming is about .97, but rear?

Trying to figure out a semi-custom setup and this info is crucial. Thanks!
 

Mini7

Go Kart Champion
Location
Charlotte, NC
I measured my motion ratio before my Ohlins install. Can’t help with the R spring rate info.

.97 for the front isn’t quite right from memory. I will need to find my notes.
Rear is .64 or .68 something like that.

If I forget to circle back here, please PM me a reminder.
 

Mini7

Go Kart Champion
Location
Charlotte, NC
Front Motion Ratio = .789
Rear Motion Ratio = .642
 

jmblur

Go Kart Champion
Location
Massachusetts
Car(s)
2017 Golf R
Front Motion Ratio = .789
Rear Motion Ratio = .642
.79 seems WAY low for a macpherson strut setup (they're almost always .99+/-.03). The strut is attached directly to the knuckle so the biggest difference in travel is based off of camber and caster. Caster dominates here, since it's 7 vs 2-3. Cos7deg (wheel direction vs strut direction) is .99. there's a bit more geometry to consider here but it's all fairly minimal in effect.
 

Mini7

Go Kart Champion
Location
Charlotte, NC
I was surprised myself when I measured. Plan on rechecking my measurements tomorrow. Still have my stock LCAs so can get a more accurate measurement than when I measured under the car.

The shock is well inboard of the lower ball joint. See the attached photo. I pulled my CSS swivels out to measure. Centerline to centerline its a 99mm difference. That’s a fraction under 4”.

Front motion ratio is lower than you think.

What spring rates are you considering?

FBD3B26D-E333-4689-8E61-3BCAB2D17200.jpeg
 

jmblur

Go Kart Champion
Location
Massachusetts
Car(s)
2017 Golf R
The distance shouldn't matter much since the knuckle moves as a unit - if the wheel bearing moves up 1inch, the bottom of the strut does too. It's not a lever arm like one attached up the LCA (or on the rear link). It'll affect how much it moves with camber/caster a bit but it should be minimal.

I was hoping to go up approx 50%, but it looks like that's not feasible with the ground control kit, so it would be slightly more than double. Worried it's going to overspring the car a bit, although it gets generally decent reviews.
 

Mini7

Go Kart Champion
Location
Charlotte, NC
I will need to think on that. I’m thinking there is still a lever affect acting on the spring despite the shock being mounted to the knuckle, because of the difference in the pivot point.

So I went to a 450lbs square setup front and rear with my Ohlins. 50lbs stiffer than their spec. I still daily my car. The ride is firm but still decent. Especially when you back off the rebound on the shocks. I’m happy with this setup for my dual purpose car.

My plan is to go to 500lbs F/ 650lbs R when I progress to takeoff slicks for the track and get the Ohlins revalved. Depending on handling balance, I may revert back to the stock RSB.
 

bfury5

Go Kart Newbie
Location
CT
Front motion ratio should be almost 1, since the strut attaches directly to the knuckle. If you draw a straight line through the strut it pretty much intersects the middle of the tire contact patch.

I'd definitely be careful about upping spring-rate that much with stock dampers, or even with certain off the shelf stuff. I run 450lb fronts and on the street they're pretty tame if valved correctly. Same with the rear. Seeing as you have an R with more rear weight bias, the rear will need to be a touch stiffer in comparison to a GTI.
 

Mini7

Go Kart Champion
Location
Charlotte, NC
Yeah, I will recalculate suspension frequency with the correct front motion ratio.

We are all really close to the right spring rates IMHO- 500/650 or 450/600 for dual purpose car anyway. The stiffer rear rate will help with rotation as well as resist rear weight transfer under acceleration providing more grip to the front.
with the lower rear MR, the rear could easily be stiffer but I would like a very balanced car which has predicable progressive handling.
 

bfury5

Go Kart Newbie
Location
CT
I think the R and GTI have different rear LCA PN from what I've seen, has anyone measured the one on the R? It'd be nice to confirm that the MR is the same between the two, not sure if the R has things moved at all to accommodate the axles.
 

bfury5

Go Kart Newbie
Location
CT
The distance shouldn't matter much since the knuckle moves as a unit - if the wheel bearing moves up 1inch, the bottom of the strut does too. It's not a lever arm like one attached up the LCA (or on the rear link). It'll affect how much it moves with camber/caster a bit but it should be minimal.

I was hoping to go up approx 50%, but it looks like that's not feasible with the ground control kit, so it would be slightly more than double. Worried it's going to overspring the car a bit, although it gets generally decent reviews.
Did you end up settling on the GC kit, or any other springs?
 

jmblur

Go Kart Champion
Location
Massachusetts
Car(s)
2017 Golf R
Did you end up settling on the GC kit, or any other springs?
Decided not to the GC kit. Leaning towards MSS (if I can find a used set), but holding off on all this stuff for now because I just bought a new house so am STUPID busy trying to prep my current one for sale... not to mention saving money.

Good news though - huge 3 car garage, so I'll actually be able to work on my car indoors instead of on the street (I have a garage now but it's waaaay too tiny to do work in, and the driveway is too sloped for jack stands).
 

bfury5

Go Kart Newbie
Location
CT
Decided not to the GC kit. Leaning towards MSS (if I can find a used set), but holding off on all this stuff for now because I just bought a new house so am STUPID busy trying to prep my current one for sale... not to mention saving money.

Good news though - huge 3 car garage, so I'll actually be able to work on my car indoors instead of on the street (I have a garage now but it's waaaay too tiny to do work in, and the driveway is too sloped for jack stands).
I've heard iffy things about the MSS kits. Some say they were trash, some say they fixed the issues that existed. I don't have any first hand experience with them, but I'd do some due diligence (if you haven't already) on that. 3 car garage sounds like paradise, just need to get a lift in there!
 

jmblur

Go Kart Champion
Location
Massachusetts
Car(s)
2017 Golf R
I've heard iffy things about the MSS kits. Some say they were trash, some say they fixed the issues that existed. I don't have any first hand experience with them, but I'd do some due diligence (if you haven't already) on that. 3 car garage sounds like paradise, just need to get a lift in there!
Yeah, there are a few design revisions - longer front springs, revised rear adjuster design, etc.. If you want to lower the car significantly, it's NOT a good kit for that, and their marketing did a bad job of reflecting that. Since I want a minimal drop from stock ride height, it's a decent option, although I'm hopeful they'll share spring rates (they might not). I like the helper spring in the rear as a way to run higher spring rates without destroying DD ride quality. It will also give me the ability to drop in hypercoil or swift springs to play with spring rates, which is a big benefit (although annoying to do on the front).

As for the garage, it already has a high ceiling and a high lift garage door.... but sadly no lift. The question is do I get a project/weekend car before the lift, or a lift first? I gotta lean towards the car... and for what we're spending on thehouse, that's DEFINITELY at least a few years off right now!
 
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