Raised spindles on SC

jph83 · 06-10-2003, 03:52 AM

Finally got around to raising the spindles on my bilstein struts and i've got a question for all you experts.

According to my calculations i need to raise the spindle height by 50mm to regain factory settings for a-arm posn. I've got plenty of wheel to a-arm clearance as i'm running 18'' wheels but wondered if there are any reasons why i shouldn't raise them by this amount.
I don't recall anyone raising much more than 35mm in previous threads.
Obviously i will be running a bump steer kit with this setup.

Thanks in advance, Jon.

Wil Ferch · 06-10-2003, 07:37 AM

1.) I never heard of anyone going beyond 35 mm....RSR went up about 12-18 mm. Go too far and ball joint interferes with rim, and doesn't allow 15 or 16" rims to be used.
2.) Why is it "obvious" that a bump steer kit is required?? This whole exercise keeps the original geometry intact.
---Wil Ferch

Chuck Moreland · 06-10-2003, 08:37 AM

"Normal" RSR struts are raised 19mm. 50mm is huge! Ground clearance would be compromised big time. What is your fender height?

Are you lowering the rear a similar amount? You'd have to do surgery on your rear pickups to maintain geometry that low.

Is this a dedicated race car? That height would be impossible on the street. Even for a race car it would be difficult and illegal in many organizations and classes.

jph83 · 06-10-2003, 08:56 AM

Thank for the replies guys,

Will- i am running 380mm dia front discs so i can't run a wheel smaller than 18'' so the ball joint interference is not an issue.

My comment regarding a bump steer kit was made because i am not reprofiling the spindle arm, just raising the spindle in relation to the strut tube. A-arm geometry would be restored but the steering arm would be at a greatly increased angle, thus requiring the use of a bump-steer kit.

Chuck- Ground clearance is not a problem because of an increase in overall wheel/tire diameter (rolling radius). The rear is lowered a similar amount and at the moment i am using stock pickup points but intend to modify them when the oppertunity comes around. it is a race/occasional street car, but i am not affected by any regulations preventing such modifications.

So is the general opinion not to go any further than 35mm?

Any more advice will be greatfully recieved! Thanks, Jon.

Wil Ferch · 06-10-2003, 09:51 AM

RE: Bump steer kit.....
If you're not re-profiling the steering arms to go along with your raised spindles...you're best advised to go ( instead) with the pricey ERP bump steer kit which allows a greater range ( and fine tuning) of bump steer. Remember, the bump steer kit is only a series of washers about 12 mm thick ( to match the available space between the rack and body)..so it would work "perfectly" if your car is lowered 12 mm or about 1/2 inch. Sounds like you're going much further in any case. PEP ( Professionally-Engineered-Products) sells Bilsteins with raised spindles and ( I believe) can properly re-bend the steering arms if the ERP kit is too pricey ( Approx $300+).
---Wil Ferch

jph83 · 06-10-2003, 10:11 AM

Thanks Will- That was the style of bump steer kit i was plannig to use- the type with spherical rose joints instead of the stock track rod end. Like you say, allowing you to fine tune the amount of bump steer produced by raising the spindles more than usual. I already have the rose joints and will machine the other necessary parts when i've raised the spindles.

Anybody got one of those ERP bump steer kits? What did you think of it?

Any other experts care to comment on the proposed 50mm spindle height modification?

Thanks, Jon.

ChrisBennet · ChrisBennet's Garage

Quote:

Originally posted by Wil Ferch
RE: Bump steer kit.....
If you're not re-profiling the steering arms to go along with your raised spindles...you're best advised to go ( instead) with the pricey ERP bump steer kit which allows a greater range ( and fine tuning) of bump steer. Remember, the bump steer kit is only a series of washers about 12 mm thick ( to match the available space between the rack and body)..so it would work "perfectly" if your car is lowered 12 mm or about 1/2 inch. Sounds like you're going much further in any case. PEP ( Professionally-Engineered-Products) sells Bilsteins with raised spindles and ( I believe) can properly re-bend the steering arms if the ERP kit is too pricey ( Approx $300+).
---Wil Ferch [/B]

PEP is the "seatbelt guy" ? Are you aren't thinking of Smart Racing or does PEP do more than seatbelts?
-Chris

Wil Ferch · 06-10-2003, 11:05 AM

Yep...the same PEP, the seatbelt guy....
---Wil

racea911 · 06-10-2003, 11:19 AM

Quote:

Originally posted by Chuck Moreland
"Normal" RSR struts are raised 19mm. 50mm is huge! Ground clearance would be compromised big time. What is your fender height?

Are you lowering the rear a similar amount? You'd have to do surgery on your rear pickups to maintain geometry that low.

Is this a dedicated race car? That height would be impossible on the street. Even for a race car it would be difficult and illegal in many organizations and classes.

Chuck,
I was told that 1973 RSR struts only had the spindles raised 10 mm and were not decambered at all. Your post says they were raised 19mm. If they are raised 19mm and are decambered in any way, I think this would allow me to get a couple of points back in my racing class, because I have non factory raised 15mm spindles and they are decambered. Thanks!

Wil Ferch · 06-10-2003, 12:17 PM

As I mentioned before , I *believe* OEM RSR spindles came in a variety of raised increments from 12 to 19 mm. Common convention is 15 or 18 mm. Perhaps someone linked to a "RSR" Registry or something can comment.
---Wil Ferch

Chuck Moreland · 06-10-2003, 12:43 PM

Quote:

Originally posted by racea911
Chuck,
I was told that 1973 RSR struts only had the spindles raised 10 mm and were not decambered at all.

My supplier provides them raised 19mm, new. I don't know if they come decambered.

Some places modify regular bilstein struts by cutting loose, raising and re-welding the spindles hence all variety of height can be produced.