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Front end mods... your thoughts on new behavior?

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Thurlowb Avatar
Thurlowb Silver Member Brad Thurlow
Coquitlam, BC, Canada   CAN
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I have just completed the following changes to the front suspension.

1) I went from the 480lb springs to the 550lb springs. This has the effect of lowering the car just a tiny, tiny bit more.
2) replaced my perfectly fine front dampers with a set of Caldwell adjustables. (Sweet!)
3) replaced the lower control arms with negative camber versions.

Went for a test drive...
The car is now extremely twitchy. If you aren’t hanging onto the wheel tightly, the car will jump left or right as it hits small road bumps.
The steering doesn’t tend to return to center anymore. Once you start a turn, the car really likes It! It feels like you have to pull the car out of the turn or it will just keep turning. It is an unusual feeling.

So...some of the characteristics are what I want for autocrossing, but maybe these effects can be mitigated just a bit.

I have some ideas, but want to hear some opinions first.

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Steve64B Avatar
Steve64B Steve Opitz
Phoenix, AZ, USA   USA
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1966 MG MGB
Brad, you need to get the toe reset after adding the negative camber wishbones. The wishbones are primarily responsible for the great turn-in and the twitchiness.

When you next auto-x the car you'll notice a tendency for the front brakes to lock up easier, because now you're riding on the inside edge of the tires. Also, after a bit you'll notice that you're wearing the inside edges of your tires.

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Jim Stabe Avatar
San Diego, CA, USA   USA
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I didn't see resetting the toe on your list. Might want to give it a look



Jim

"If you want me to agree with you then we would both be wrong"

'66 MGB widened 11" with supercharged LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108
Continued in Part 4 http://forum.britishv8.org/read.php?13,40751
Continued in Part 5 http://forum.britishv8.org/read.php?13,48698,48698#msg-48698
Continued in Part 6 http://forum.britishv8.org/read.php?13,61672

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Thurlowb Avatar
Thurlowb Silver Member Brad Thurlow
Coquitlam, BC, Canada   CAN
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Yup.... I have not changed the toe in/out.

Do you think I need more “in”or more “out”?

Brad

As for tear wear, this year past I wore the crap off the outside edges, so I’m hoping that I break even on tire wear this summer.

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Jim Stabe Avatar
San Diego, CA, USA   USA
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My guess is that lengthening the lower control arms would cause additional toe in and create the condition you describe. It's a simple thing to check and adjust, buy or build yourself a set of toe plates.

https://i.ytimg.com/vi/TTkSwuXKWpM/maxresdefault.jpg

https://images-na.ssl-images-amazon.com/images/I/317BP9-RA2L.jpg



Jim

"If you want me to agree with you then we would both be wrong"

'66 MGB widened 11" with supercharged LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108
Continued in Part 4 http://forum.britishv8.org/read.php?13,40751
Continued in Part 5 http://forum.britishv8.org/read.php?13,48698,48698#msg-48698
Continued in Part 6 http://forum.britishv8.org/read.php?13,61672

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Thurlowb Avatar
Thurlowb Silver Member Brad Thurlow
Coquitlam, BC, Canada   CAN
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Makes sense. I left the steering rod ends exactly as they were. Since I’ve moved the lower kingpins outward that combo would create a toe in that wasn’t there before.

Thanks for talking me through this.

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oleanderjoe Avatar
oleanderjoe Platinum AdvertiserAdvertiser Joseph Baba
Fresno, CA, USA   USA
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You should also check your Camber; If I remember, 1975 -80 RB Cars had about 1 Degree Positive Camber ?????, Negative camber arms should have given you about 2 Degrees Neg Camber. (Perfect)
If you need I can post up a drawing on how to do it pretty easily. Let us know.



IN ALL SUBJECTS.: For those who believe, no proof is needed. For those who don’t believe, no proof is possible.

"Strive for perfection in everything. Take the best that exists and make it better. If it doesn't exist, create it. Accept nothing nearly right or good enough"
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Joe Baba 2021


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67motorcat Avatar
67motorcat Steve O
Pinehurst, NC, USA   USA
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1967 MG MGB
Easy to adjust Toe yourself. Just park your cars front wheels on 3 sheets of wax paper under each front wheel.

Grab a tape measure and reference the tread in the same place in front and behind the tires while adjusting tie rods to a few hairs toe in....done thumbs up

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mgblestyle Avatar
mgblestyle Philip Shave
Olympia, WA, USA   USA
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Brad, as others have said, checking the toe is necessary. Also measure the camber--the combination of lowering and negative camber control arms may have resulted in excessive negative camber. I used the 480 lb springs to lower my 1980 and the result was -1/4 to -1/2 degree camber, L/R. In other words, the lowering alone will result in negative camber if you do it with springs. Your description of how the car handles sounds a lot like too much negative camber. Phil

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Coquitlam, BC, Canada   CAN
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Brad, First time posted but I live in Coquitlam and in the midst of redoing the suspension on my B. Finished the body and drive train last year
. Would love to connect and compare and see what you haven done. Email me at michaelswan61@gmail.com if your interested

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Thurlowb Avatar
Thurlowb Silver Member Brad Thurlow
Coquitlam, BC, Canada   CAN
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In reply to # 3645306 by mgblestyle Brad, as others have said, checking the toe is necessary. Also measure the camber--the combination of lowering and negative camber control arms may have resulted in excessive negative camber. I used the 480 lb springs to lower my 1980 and the result was -1/4 to -1/2 degree camber, L/R. In other words, the lowering alone will result in negative camber if you do it with springs. Your description of how the car handles sounds a lot like too much negative camber. Phil

Hopefully, some adjustment to toe-in will tame the car a bit. As is, it might be fine on the autocross course, but I still have to drive it around between races!

As for camber, I'll try to get an accurate measurement of how much negative camber I have actually created. However...if I don't like the answer, what could be done about it? The effect of the lower springs and the (-) camber arms adds up to what it is...there isn't any adjustment in the system. I suppose I could put the taller, softer springs back in...

As it was, I was tearing up the outsides of the front tires...and the tires I ran this past season were not even as soft as my next set will be. So the increased negative camber could only be good for tire wear.

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JoeReed Avatar
JoeReed Joe Reed
Cordova, TN, USA   USA
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1978 MG MGB "Kermit"
In reply to # 3645631 by Thurlowb
In reply to # 3645306 by mgblestyle Brad, as others have said, checking the toe is necessary. Also measure the camber--the combination of lowering and negative camber control arms may have resulted in excessive negative camber. I used the 480 lb springs to lower my 1980 and the result was -1/4 to -1/2 degree camber, L/R. In other words, the lowering alone will result in negative camber if you do it with springs. Your description of how the car handles sounds a lot like too much negative camber. Phil

Hopefully, some adjustment to toe-in will tame the car a bit. As is, it might be fine on the autocross course, but I still have to drive it around between races!

As for camber, I'll try to get an accurate measurement of how much negative camber I have actually created. However...if I don't like the answer, what could be done about it? The effect of the lower springs and the (-) camber arms adds up to what it is...there isn't any adjustment in the system. I suppose I could put the taller, softer springs back in...

As it was, I was tearing up the outsides of the front tires...and the tires I ran this past season were not even as soft as my next set will be. So the increased negative camber could only be good for tire wear.

Reinstall the stock lower control arms?

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Thurlowb Avatar
Thurlowb Silver Member Brad Thurlow
Coquitlam, BC, Canada   CAN
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In reply to # 3645712 by JoeReed
Reinstall the stock lower control arms?

Ha..ha... yes...but that would be giving up on the attempt to make things better. And...I have already proven the prior configuration eats the outside of the tires.

Brad

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lbcnut Avatar
lbcnut Gold Member James Woolf
Nevada City, CA, USA   USA
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1964 MG MGB
In reply to # 3645725 by Thurlowb
In reply to # 3645712 by JoeReed
Reinstall the stock lower control arms?

Ha..ha... yes...but that would be giving up on the attempt to make things better. And...I have already proven the prior configuration eats the outside of the tires.

Brad

Brad, a properly aligned stock system (sounds like that is what you had?) should wear the tires evenly. It sounds like you were toed out before and were trying to fix it by introducing negative camber...

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Thurlowb Avatar
Thurlowb Silver Member Brad Thurlow
Coquitlam, BC, Canada   CAN
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In reply to # 3645733 by lbcnut
Brad, a properly aligned stock system (sounds like that is what you had?) should wear the tires evenly. It sounds like you were toed out before and were trying to fix it by introducing negative camber...

I think the rapid destruction of the outside edges of my tires had more to do with autocrossing than it did with alignment.

However, if I can’t get the car to behave decently between races I am willing to go back to the old lower arms. I sure hope that some toe adjustment will fix the problems. Certainly the old combo was perfect for road use. I’m just trying to get more out of the car on the race course while keeping it pleasant enough on the street....it is a fine line and it is just possible that this current configuration is a bit too far toward track use.

Brad

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