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Re: Scrub Radius, Wheel Track and Coil Overs
Load through the shock mounting points is higher than spring loads anyway...
1966 GTV
1982 Suzuki "Bathurst" Katana
1995 Cagiva Mito (race kitted 250 powered)
1982 Suzuki "Bathurst" Katana
1995 Cagiva Mito (race kitted 250 powered)
Re: Scrub Radius, Wheel Track and Coil Overs
MR measurements were with the LCA at horizontal without the TB installed but with the shock absorber there to get the angle.Mats wrote:MR depends on rife height, I suspect you did your measurements with the wheel off and the suspension in full droop?
Do you calculate a different MR Mats?
Re: Scrub Radius, Wheel Track and Coil Overs
Don't worry about Mats. He's just being a smart ass
Anyway as you just want to get into the ballpark it's not the las decimal that counts.
The values I've used are
315 mm effective length
250 mm to shock mount
17.5 deg shock inclination.
In my new LCA's I make 3 fastening positions for the shock. This way I can easily soften the suspension for rain by changing the MR.
Anyway as you just want to get into the ballpark it's not the las decimal that counts.
The values I've used are
315 mm effective length
250 mm to shock mount
17.5 deg shock inclination.
In my new LCA's I make 3 fastening positions for the shock. This way I can easily soften the suspension for rain by changing the MR.
- Maurizio
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Re: Scrub Radius, Wheel Track and Coil Overs
I have the same MR from my calcs.
Edit: Micke's typing is faster
What Mats is saying is that the MR is changing, as your suspension moves, your lower arm runs trough a circle segment. In theory the tb setup has no linear stiffness.
Plus the top off your shock stays in the same place, so your helper spring changes also in angle wrt the forces.
The difference though is an second order effect and gets less if you stiffen up the suspension, so for hobbyists neglect-able
Edit: Micke's typing is faster
What Mats is saying is that the MR is changing, as your suspension moves, your lower arm runs trough a circle segment. In theory the tb setup has no linear stiffness.
Plus the top off your shock stays in the same place, so your helper spring changes also in angle wrt the forces.
The difference though is an second order effect and gets less if you stiffen up the suspension, so for hobbyists neglect-able
Banned.. ? Daily donky.. ==> BMW 325d
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
Re: Scrub Radius, Wheel Track and Coil Overs
Just remembered that my car is maybe not the perfect datum either...
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
Re: Scrub Radius, Wheel Track and Coil Overs
No, I don't believe youMicke wrote:Don't worry about Mats. He's just being a smart ass
Any way, has anybody any input about the effect of the scrub radius? Especially the effect of reducing the scrub radius?
I've read some stuff about how the scrub radius effects the braking behavior when the left and right wheels are on surfaces with different grip levels, but what about steering feel???
By the way, cheers to you die hards that entertain my mental wanderings
Re: Scrub Radius, Wheel Track and Coil Overs
A moderate increase in scrub radius is OK. In the 116 I'd say up to ET about 10 or so is still good to drive.
I once had some (I think Mirafiori) rims with huge ET. Probably negative. CAr was very heavy to turn and sensitive to braking surfaces.
My 5 ct conclusion is that if you want to widen the car from stock it's a good idea to so something about the scrub. As long as you keep within stock fenders probably not worth it.
Then only the hubs wont help at all. As long as you want the tire in the position it is (as far out as possible) only the position of the upper and lower ball joints can do the trick.
Then again if you make the LCA much longer you will reduce the scrub radius. But your KPI will go to hell. So you need a new UCA as well.
I once had some (I think Mirafiori) rims with huge ET. Probably negative. CAr was very heavy to turn and sensitive to braking surfaces.
My 5 ct conclusion is that if you want to widen the car from stock it's a good idea to so something about the scrub. As long as you keep within stock fenders probably not worth it.
Then only the hubs wont help at all. As long as you want the tire in the position it is (as far out as possible) only the position of the upper and lower ball joints can do the trick.
Then again if you make the LCA much longer you will reduce the scrub radius. But your KPI will go to hell. So you need a new UCA as well.