PDA

View Full Version : What Bump Stops?



Jehu
09-29-2006, 07:34 PM
I got to look at my struts on a lift today.Pulled what was left of the bump stops off in pieces.I had been told i needed new struts. Can i just put new bump stops on the existing struts?I had thought i felt a little drift in the front end and can't really see how just having no bump stops would create it so maybe the whole assembly, cart/shock and hub are junk, they look original, real rusty linkage.. How's $925.00 inc labor sound for front struts, rear shocks and an alignment? They quoted me for KYB but said Sachs would just be a little more.. I know everyone here does all their own work but maybe someone has an idea

Alexlind123
09-30-2006, 12:46 AM
That sounds like an alright price to me, with labor.

genphreak
09-30-2006, 01:03 AM
I got to look at my struts on a lift today.Pulled what was left of the bump stops off in pieces.I had been told i needed new struts. Can i just put new bump stops on the existing struts?I had thought i felt a little drift in the front end and can't really see how just having no bump stops would create it so maybe the while assembly, cart/shock and hub are junk, they look original, real rusty linkage.. How's $925.00 inc labor sound for front struts, rear shocks and an alignment? They quoted me for KYB but said Sachs would just be a little more.. I know everyone here does all their own work but maybe someone has an ideaIf they put KYBs in your car they would have NFI what they are on about. Your springs are highly lowered and need a shock for designed for a higher rated spring. You could install a Sashs kit ($650odd with matched springs and shocks, but you have to add new M5 bumpstops) and then offload your old M-Tech springs to someone. I would go with the Konis and M5 stops myself. It'll be slightly lower and a bit stiffer. Leave the shocks set to soft for at least the first 6 months, they are stiff enough for non-track work even after the break in period. :) Nick

fkong777
09-30-2006, 02:30 AM
that sounds a little pricey.

KYB would cost about $300 retail so they can get it probably at $200

Alignment is generally $80 for 4 wheel alignment but for E34 you can only really do the front since there is no adjustment for the rear. Front end alignment is only about $50.

So maybe you need bump stops at $12 each that's $48..for 4..

I say they will make $600 for labor.. and getting you parts. Not that KYB is bad I never try them but for $900+ I say.. get a quote on labor from competing shops and get your own parts..

Jehu
09-30-2006, 12:35 PM
If they put KYBs in your car they would have NFI what they are on about. Your springs are highly lowered and need a shock for designed for a higher rated spring. You could install a Sashs kit ($650odd with matched springs and shocks, but you have to add new M5 bumpstops) and then offload your old M-Tech springs to someone. I would go with the Konis and M5 stops myself. It'll be slightly lower and a bit stiffer. Leave the shocks set to soft for at least the first 6 months, they are stiff enough for non-track work even after the break in period. :) Nick

I read something http://www.bmwe34.net/e34main/upgrade/suspensions.htm on Bruno's website that said the suggestion that you can't use "regular" sized shocks on a lowwered car is a Myth.

There is a long held myth about so called lowering shocks or shocks designed for lowering springs with reduced travel versus shocks designed for standard or taller springs. The best way to visualize it without physically looking at the shocks side by side is...the only tangible difference is the stroke is shorter in a shock designed expressly for a lowering spring...the throw is shorter. Full jounce position or fully compressed shock position is exactly the same...that is the critical factor for bottoming...wh ere the jounce bumper fully compresses onto the top of the strut collar nut threaded onto the strut housing...that shoulder position is the same for either shock and each shock will identically compress into its cartridge casing. With a standard Boge shock lets say..the throw of the rod internal to the shock is a bit longer..that's all...so the shock is cabable of "extending" farther...at full suspension rebound or when the suspension arms are fully down with a taller spring. With a shorter spring..you don't need a longer throw shock...however..this is the important part...Is putting a standard Boge with longer travel with a lowering spring bad? Absolutely not...you just end up not using the full travel capability of standard shock with a shorter lowering spring... that's all. All the speculation of a standard shock..say Boge..wearing out faster with a lowering spring...is a myth. (From George Mann)


That all seems to say, to me , that struts and shocks designed for stock ride height will work in a lowered car without resulting in raising it or the shocks being too tall and getting crushed the first time you run thru a ditch at 50 MPH.I appreciate the input but i'm hesitant to do anything that would lower the car any more.Its more esthetics with me there. I like the height where it is now and have seen others lower like that and tis just way too low for my taste. Here's a link to a page with a pic of the car linked ; http://www.geocities.com/scott540i/springs.html

My sighting may be inaccurate but his car looks just a bit lower mainly in the back and while the lighting doesn't really allow you to see the space between the tires and the fender it looks just a bit closer than on mine. http://users.adelphia.net/~cpkver8/images/Picture%20a056.jpg

genphreak
10-01-2006, 01:51 AM
That George Mann thing has been around a long time. You will notice that it does not offer any analysis of what the down-sides are. It fails to note any performance difference, though many people driving cars on the street would not notice anyway- they have enough trouble working out if the shocks need replacing, let alone which ones are the correct fitment.

I know they might fit, though a member on the forum (I forget who) did just have a heck of trouble fitting KYBs and ended up pulling them all.

However, for aesethics you don't need the shocks at all :D

Naturally fitting a stock shock with a higher rated spring is possible, but it isn't ideal: no engineer would ever do this, and it is not without good reason; it just won't work so well. That doesn't mean to say its not workable, but the average wide-ass punter (or even most of us) won't know the difference unless we/they are driving from showroom to showroom looking for a new car and experiencing the ride in each.

KYBs are fine for stock, perhaps if you are really budget-minded they (and you) can survive them installed in a semi-lowered car. It is still not the right thing to do w a car as low as ours. Put the wrong shocks/stops on a car with M suspension? I can't see there any choice with this :D

BTW; The pic you posted Jehu was actually fine. The rear is exactly the right M-technic height as seems yours. Peeps often think they are low at the rear as they look at the wheel-arch gap, but it is best to check the rake of the door-sills if you start wondering about a sagging rear.