Bump steer

BoostedBlood · 06-12-2009, 07:50 AM

anyone try any these bump steer kits?
Techno Toy Tuning - Your performance parts source for the old school cool!
bump steer is driving me crazy and looking to fix it asap. would like to hear how it worked for others before i do the rackflip, dont feel like replacing hubs if it doesent work out. i have never tryed the balljoint spacers either but seems to me you would lose a little of the benifits of being lowered, that would be my guess. would love to hear your input ^.^

nikn · 06-12-2009, 03:24 PM

I'm not familiar with the products on that site but I would assume that the RCA's should worsen bump steer if anything (because now the steering arms and suspension arms are no longer parrallel). Make sure you get both the RCA and the flip kit thing as having only one is probably not a good idea.

On a side note, the purpose of RCA's usually isn't to eliminate bump steer but rather to change the suspension geometry in a way that increases the resistance to roll (raise roll center).

BoostedBlood · 06-19-2009, 07:35 PM

thanks for input, im going to order the kits next payday and will post and let others know how they work ^^

palos · 06-19-2009, 07:54 PM

Please describe your suspension components that have created the bump steer phenomenon. Coilovers I'm presuming. Perhaps you can provide the ride height of your fenders running perpendicular to the ground, passing through the wheels. Also, what are your toe settings and do you have your front wheels pre-loaded when the alignment is performed?

Thanks in advance.

BoostedBlood · 06-26-2009, 04:53 PM

Im runing a eibach prokit with tokico 5way adjustables, prothane bushings and custom swaybars (1inch ft, 3/4inch in rear) my alignment was done recently with the wheels preloaded(i assume you are talking about haveing the car siting on the turnplates rather than haveing it lifted). i found my sheet finaly but unable to post it at the moment(not at home) but i do think i figured out what is causeing my problem. my car has sat in my shop for about 5 years. i recently pulled it out and fixed the axel that was broke and was keeping me off the road. at that time i also installed some new tires i got from work and didnt think much about it at the time but my rear is 225/45/17 and ft is 215/40/17. though it may look cool with big meaty tires in the back im starting to think thats what is causeing my problem. the only other think i can think of is it has been 5 years since i drove it regularly and perhaps im too used to driving a big suv lol. ill post the alighnment later when i make it home.

palos · 06-26-2009, 08:17 PM

My S/C is somewhat similar. I am using the progressive rate ST springs, Tokico Illumina 5 way adjustable struts, and use a preload bar on the tires when setting the front toe. I haven't experienced bump steer using 205/40-16's on a 16x7.5 wheel or 195/50-15's on a 15x7 wheel.

The 225/45-17's on the rear are massive, probably 1.5 inches taller than stock. I'm surprised they fit without rubbing.

It will be interesting to see the toe specifications.

mr2tim · 07-05-2009, 06:14 PM

Interesting discussion ya'll, I lowered my 89 S/C 3" w progressives (Susp Tech), moved to a 3/4" bar in the front and have not encountered any suspension problems, my old 14" tires are on OEM S/C Alum rims and they wear perfectly.

Is the Mark1 built differently than Mark 2 cars?

BoostedBlood · 07-09-2009, 09:19 PM

i made myself some rcas and a flipkit on my multimill but before i installed them i decided to try something. i put 205/40/17 all around and seemed to eliminate my problem. guess the large tires in rear were too much lol >< as for the differences from 85-86 and 87-89 not sure how different they are but best i remember the struts in back are larger in diameter, not sure if there was any other suspension changes. and cant for the life of me find my alighnment sheet, i will print another when i get some time to put my car back on the rack ><

mr2Peak · 07-16-2009, 02:12 AM

You were experiencing the rear roll center being higher than the front, feels like the back always wants to flip around.

Bump-Steer has nothing to do with your wheel-tire selection. It's a change in toe that happens when the suspension compresses/de-compresses.

If you install the RCA's and don't do something about the angle of the tie-rod, then your bump-steer will be massive.

mr2tim · 07-24-2009, 02:53 PM

Question for the group?

Installed a c-52 behind my S/C when I could not afford the (extremely) expensive rebuild parts from Toyota on the close their ratio S/C E-51 transmission.
(Budget Racer)

I now experience a really cool super tow-in condition (in the rear) under heavy cornering, which under race conditions (slicks) helps with quicker rotatation of the car.

?Is this a Bump-steer? If so, what is the cause?

Jackstand Queen · 07-26-2009, 12:19 AM

I think bump steer occurs when you hit a bump while cornering. And the car lurches, and ass suddenly shifts position.

I think the conditon is aggravated by rigid rear strut control arms and rigid connection at the top of the strut.

Using heim jointed strut camber plates, and rear control arms is supposed to lessen bump steer.

I could be all wrong though. Maybe a racing suspension whiz will come along and correct me. (329 FTW ?)

mr2Peak · 07-26-2009, 12:40 AM

Quote:

Originally Posted by mr2tim

Question for the group?

Installed a c-52 behind my S/C when I could not afford the (extremely) expensive rebuild parts from Toyota on the close their ratio S/C E-51 transmission.
(Budget Racer)

I now experience a really cool super tow-in condition (in the rear) under heavy cornering, which under race conditions (slicks) helps with quicker rotatation of the car.

?Is this a Bump-steer? If so, what is the cause?

A change in toe during compression is bump steer, front or rear. The cause is the change in relative lengths of the tie-rods and lower control arms between the chassis and the hub.

Rear toe-in during cornering would slow rotation because it puts the rotation point behind the car, rear toe-out puts the rotation point inside the chassis making the rotation faster.

328FTW · 07-26-2009, 01:01 AM

Bump steer is a bitch I hate it my sc mkI has it bad at the moment. I'm having trouble figuring it out I think its incorrectly set toe but I've been getting it better and better adjusting the front toe, there is still something in there not right though.

You will find it is normally to do with incorrect toe that worsens as the suspension travels, there are other things as well like worn toe bushings that move around with changing weight, its what went on mine causing dangerous bump steer and handling quirks. If you google it you will get some good info. Its one of those things where you KNOW whats causing it then find its something completely different you can't just point at one thing its a system of things that can cause it.....which sucks as far as diagnosis.

mr2Peak · 07-26-2009, 01:17 AM

Try using the TRD stage 2 alignment

Camber Front: -2 degrees
Camber Rear : -1 1/2 degrees

Caster : +6 degrees

Toe in front: 1/16 in. ( 1/8 in. out for auto cross)
Toe in rear : 1/8 in. ( 1/16 in. out for auto cross)

Should help.

06-12-2009, 07:50 AM	#1 (permalink)
BoostedBlood No Skills Join Date: Jun 2009 Location: Washington USA Posts: 20 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Bump steer anyone try any these bump steer kits? Techno Toy Tuning - Your performance parts source for the old school cool! bump steer is driving me crazy and looking to fix it asap. would like to hear how it worked for others before i do the rackflip, dont feel like replacing hubs if it doesent work out. i have never tryed the balljoint spacers either but seems to me you would lose a little of the benifits of being lowered, that would be my guess. would love to hear your input ^.^

07-16-2009, 02:12 AM	#9 (permalink)
mr2Peak No Skills Join Date: Jan 2008 Location: Bay Area Posts: 16 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	You were experiencing the rear roll center being higher than the front, feels like the back always wants to flip around. Bump-Steer has nothing to do with your wheel-tire selection. It's a change in toe that happens when the suspension compresses/de-compresses. If you install the RCA's and don't do something about the angle of the tie-rod, then your bump-steer will be massive. Last edited by mr2Peak; 07-16-2009 at 02:18 AM.

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06-12-2009, 03:24 PM	#2 (permalink)
nikn Cage Fighter Join Date: Jan 2007 Location: dirty jerzey Posts: 144 Thanks: 11 Thanked 3 Times in 3 Posts iTrader Rating: (5/100% )	I'm not familiar with the products on that site but I would assume that the RCA's should worsen bump steer if anything (because now the steering arms and suspension arms are no longer parrallel). Make sure you get both the RCA and the flip kit thing as having only one is probably not a good idea. On a side note, the purpose of RCA's usually isn't to eliminate bump steer but rather to change the suspension geometry in a way that increases the resistance to roll (raise roll center).

06-19-2009, 07:35 PM	#3 (permalink)
BoostedBlood No Skills Join Date: Jun 2009 Location: Washington USA Posts: 20 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	thanks for input, im going to order the kits next payday and will post and let others know how they work ^^

06-19-2009, 07:54 PM	#4 (permalink)
palos … Join Date: Apr 2009 Posts: 170 Thanks: 0 Thanked 20 Times in 18 Posts iTrader Rating: (0/0% )	Please describe your suspension components that have created the bump steer phenomenon. Coilovers I'm presuming. Perhaps you can provide the ride height of your fenders running perpendicular to the ground, passing through the wheels. Also, what are your toe settings and do you have your front wheels pre-loaded when the alignment is performed? Thanks in advance.

06-26-2009, 04:53 PM	#5 (permalink)
BoostedBlood No Skills Join Date: Jun 2009 Location: Washington USA Posts: 20 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Im runing a eibach prokit with tokico 5way adjustables, prothane bushings and custom swaybars (1inch ft, 3/4inch in rear) my alignment was done recently with the wheels preloaded(i assume you are talking about haveing the car siting on the turnplates rather than haveing it lifted). i found my sheet finaly but unable to post it at the moment(not at home) but i do think i figured out what is causeing my problem. my car has sat in my shop for about 5 years. i recently pulled it out and fixed the axel that was broke and was keeping me off the road. at that time i also installed some new tires i got from work and didnt think much about it at the time but my rear is 225/45/17 and ft is 215/40/17. though it may look cool with big meaty tires in the back im starting to think thats what is causeing my problem. the only other think i can think of is it has been 5 years since i drove it regularly and perhaps im too used to driving a big suv lol. ill post the alighnment later when i make it home.

06-26-2009, 08:17 PM	#6 (permalink)
palos … Join Date: Apr 2009 Posts: 170 Thanks: 0 Thanked 20 Times in 18 Posts iTrader Rating: (0/0% )	My S/C is somewhat similar. I am using the progressive rate ST springs, Tokico Illumina 5 way adjustable struts, and use a preload bar on the tires when setting the front toe. I haven't experienced bump steer using 205/40-16's on a 16x7.5 wheel or 195/50-15's on a 15x7 wheel. The 225/45-17's on the rear are massive, probably 1.5 inches taller than stock. I'm surprised they fit without rubbing. It will be interesting to see the toe specifications.

07-05-2009, 06:14 PM	#7 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 690 Thanks: 2 Thanked 41 Times in 38 Posts My Google Map iTrader Rating: (2/100% )	Interesting discussion ya'll, I lowered my 89 S/C 3" w progressives (Susp Tech), moved to a 3/4" bar in the front and have not encountered any suspension problems, my old 14" tires are on OEM S/C Alum rims and they wear perfectly. Is the Mark1 built differently than Mark 2 cars?

07-09-2009, 09:19 PM	#8 (permalink)
BoostedBlood No Skills Join Date: Jun 2009 Location: Washington USA Posts: 20 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	i made myself some rcas and a flipkit on my multimill but before i installed them i decided to try something. i put 205/40/17 all around and seemed to eliminate my problem. guess the large tires in rear were too much lol >< as for the differences from 85-86 and 87-89 not sure how different they are but best i remember the struts in back are larger in diameter, not sure if there was any other suspension changes. and cant for the life of me find my alighnment sheet, i will print another when i get some time to put my car back on the rack ><

07-24-2009, 02:53 PM	#10 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 690 Thanks: 2 Thanked 41 Times in 38 Posts My Google Map iTrader Rating: (2/100% )	Question for the group? Installed a c-52 behind my S/C when I could not afford the (extremely) expensive rebuild parts from Toyota on the close their ratio S/C E-51 transmission. (Budget Racer) I now experience a really cool super tow-in condition (in the rear) under heavy cornering, which under race conditions (slicks) helps with quicker rotatation of the car. ?Is this a Bump-steer? If so, what is the cause?

07-26-2009, 12:19 AM	#11 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 677 Thanks: 52 Thanked 56 Times in 53 Posts iTrader Rating: (1/100% )	I think bump steer occurs when you hit a bump while cornering. And the car lurches, and ass suddenly shifts position. I think the conditon is aggravated by rigid rear strut control arms and rigid connection at the top of the strut. Using heim jointed strut camber plates, and rear control arms is supposed to lessen bump steer. I could be all wrong though. Maybe a racing suspension whiz will come along and correct me. (329 FTW ?)

07-26-2009, 01:01 AM	#13 (permalink)
328FTW 3vzfe tinkering Join Date: Aug 2008 Location: New Zealand Posts: 1,536 Thanks: 12 Thanked 99 Times in 83 Posts My Google Map iTrader Rating: (0/0% )	Bump steer is a bitch I hate it my sc mkI has it bad at the moment. I'm having trouble figuring it out I think its incorrectly set toe but I've been getting it better and better adjusting the front toe, there is still something in there not right though. You will find it is normally to do with incorrect toe that worsens as the suspension travels, there are other things as well like worn toe bushings that move around with changing weight, its what went on mine causing dangerous bump steer and handling quirks. If you google it you will get some good info. Its one of those things where you KNOW whats causing it then find its something completely different you can't just point at one thing its a system of things that can cause it.....which sucks as far as diagnosis.

07-26-2009, 01:17 AM	#14 (permalink)
mr2Peak No Skills Join Date: Jan 2008 Location: Bay Area Posts: 16 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Try using the TRD stage 2 alignment Camber Front: -2 degrees Camber Rear : -1 1/2 degrees Caster : +6 degrees Toe in front: 1/16 in. ( 1/8 in. out for auto cross) Toe in rear : 1/8 in. ( 1/16 in. out for auto cross) Should help.