| makofoto | 02-17-2005 03:45 AM |
Are You Riding On Your Bump Stops, and ...
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Another possibly "stupid'est" question, by Mako ... :p
Anyone think they are hitting/riding their bump stops while Auto Crossing ... and because of this ... increasing their spring rates. Are we getting better AX handling by increasing spring rates ... because it keeps us off of our bump stops?
It sees like a lot of our coil overs have very little travel. Could it be that some of our understeer is caused by getting on the bump stops and losing our suspension?
Anyone try shortening their bump stops to good effect ...
Anyone think they are hitting/riding their bump stops while Auto Crossing ... and because of this ... increasing their spring rates. Are we getting better AX handling by increasing spring rates ... because it keeps us off of our bump stops?
It sees like a lot of our coil overs have very little travel. Could it be that some of our understeer is caused by getting on the bump stops and losing our suspension?
Anyone try shortening their bump stops to good effect ...
| wrx plus | 02-17-2005 06:25 AM |
[QUOTE=makofoto]Another possibly "stupid'est" question, by Mako ... :p
Anyone think they are hitting/riding their bump stops while Auto Crossing ... and because of this ... increasing their spring rates. Are we getting better AX handling by increasing spring rates ... because it keeps us off of our bump stops?
It sees like a lot of our coil overs have very little travel. Could it be that some of our understeer is caused by getting on the bump stops and losing our suspension?
Anyone try shortening their bump stops to good effect ...[/QUOTE]
When you go to after market springs you have to cut the bump stops to half their height and reinstall them, or you WILL bottom out. It is in the instructions for every set of springs i have ever installed.
Coil-overs and "good" springs both have increased progressive rates, for improved handling.
If you are hitting your bump stops, you have a problem, and should fix it before you have a wreck.
Anyone think they are hitting/riding their bump stops while Auto Crossing ... and because of this ... increasing their spring rates. Are we getting better AX handling by increasing spring rates ... because it keeps us off of our bump stops?
It sees like a lot of our coil overs have very little travel. Could it be that some of our understeer is caused by getting on the bump stops and losing our suspension?
Anyone try shortening their bump stops to good effect ...[/QUOTE]
When you go to after market springs you have to cut the bump stops to half their height and reinstall them, or you WILL bottom out. It is in the instructions for every set of springs i have ever installed.
Coil-overs and "good" springs both have increased progressive rates, for improved handling.
If you are hitting your bump stops, you have a problem, and should fix it before you have a wreck.
| Corey | 02-17-2005 07:58 AM |
What bump stops? :p :p
Corey #89 STS
P.S. I've done the zip tie test... I have as much travel as I need. No bottoming.
Corey #89 STS
P.S. I've done the zip tie test... I have as much travel as I need. No bottoming.
| Storm | 02-17-2005 08:03 AM |
Yeah......What he said.....
[QUOTE=Corey]What bump stops? :p :p
Corey #89 STS
P.S. I've done the zip tie test... I have as much travel as I need. No bottoming.[/QUOTE]
Jay Storm
[QUOTE=Corey]What bump stops? :p :p
Corey #89 STS
P.S. I've done the zip tie test... I have as much travel as I need. No bottoming.[/QUOTE]
Jay Storm
| Draken | 02-17-2005 08:30 AM |
I have absolutely no issues with lack of travel with my Tein Flex units on the STi. Not even close to bottoming, or hitting the bump stops. Still running the 10K/8K combo.
Chris H.
Chris H.
| crystalhelix | 02-24-2005 04:23 PM |
I will be running JDM pink springs with Koni yellows. Will I need to do anything with the bump-stops?
| makofoto | 02-24-2005 04:55 PM |
Interesting Tech article on the H&R site about Bump Stops: [URL=http://www.hrsprings.com/site/frames/frametechnical.html]HERE[/URL]
The Tein's (Flex's) have hard bump stops ... I've had Tein Technicians tell me that they've actually replaced their own Tein bump stops with softer Subie or Mitsui bump stops ....
The Tein's (Flex's) have hard bump stops ... I've had Tein Technicians tell me that they've actually replaced their own Tein bump stops with softer Subie or Mitsui bump stops ....
| stretchsje | 03-08-2007 04:29 PM |
Ha, Google found this thread. Bump to the top!
The 2005 STI rides on its bump stops even at stock ride height. It's just barely off the stops while parked, but the weight of a passenger is actually enough to get the car resting on its stops at a traffic light. The bump stops are about 2-3/8" long (60mm), but with a very surprising initial spring rate near 300lb/in. There's a [i]huge[/i] thread probing into this, and how it could be to blame for a lot of the undesirable behavior in the STI's stock suspension:
[url]http://www.iwsti.com/forums/showthread.php?t=65985[/url]
The 2005 STI rides on its bump stops even at stock ride height. It's just barely off the stops while parked, but the weight of a passenger is actually enough to get the car resting on its stops at a traffic light. The bump stops are about 2-3/8" long (60mm), but with a very surprising initial spring rate near 300lb/in. There's a [i]huge[/i] thread probing into this, and how it could be to blame for a lot of the undesirable behavior in the STI's stock suspension:
[url]http://www.iwsti.com/forums/showthread.php?t=65985[/url]
| crystalhelix | 03-08-2007 04:32 PM |
Why would you bump a 2 year old thread?
[IMG]http://www.leelefever.com/archives/cookie.jpg[/IMG]
[IMG]http://www.leelefever.com/archives/cookie.jpg[/IMG]
| stretchsje | 03-08-2007 05:17 PM |
[QUOTE=crystalhelix;17289904]Why would you bump a 2 year old thread?[/QUOTE]
Well, since people always search before posting here, I can assume there haven't been any [i]new[/i] discussions of bump stops and suspension travel since this thread, right?
Chocolate chip cookies FTW.
Anyway, I'm not sure if 2005 STI's riding on their bump stops is new news, but I certainly hadn't read it prior to discovering it myself.
Well, since people always search before posting here, I can assume there haven't been any [i]new[/i] discussions of bump stops and suspension travel since this thread, right?
Chocolate chip cookies FTW.
Anyway, I'm not sure if 2005 STI's riding on their bump stops is new news, but I certainly hadn't read it prior to discovering it myself.
| Mykl | 03-08-2007 08:57 PM |
Yeah, I can actually brake and turn at the same time on my coilovers... couldn't do that so much on the stock struts. ZZYZX FTW
| makofoto | 03-09-2007 02:51 AM |
It's a big help to replace your oem bump stops with hard'ish foam racing stops that are much more progressive then the hard plastic oem stops ... but they won't give you the day to day protection that the oems will if you have a huge crashing "bump."
The progression of bump stops that I went through with my Tein's:
[IMG]http://images15.fotki.com/v168/photos/4/43793/836092/BumpStops-vi.jpg[/IMG]
The progression of bump stops that I went through with my Tein's:
[IMG]http://images15.fotki.com/v168/photos/4/43793/836092/BumpStops-vi.jpg[/IMG]
| BIGSKYWRX | 03-09-2007 11:45 AM |
The H&R article is a good one -Micro Cellular Jounce Bumper :)
Interestingly Subaru changed the rear stops on the 04+ rears- shortening them by ~ 30mm- slightly different shape too.
The oe ones are definitely progressive (and feel more "foamish" than "plastic"- the first couple of "rings" you can easily compress w/ your hand.
Would be nice to get the fellow who tested the Grp N vs oe vs Poly bushings to give some of the different stops the same go round.
Mako how would you rate the ones you tried?
heres some from ground Control
[IMG]http://www.ground-control-store.com/images/fullsize/bumpstop_fs.jpg[/IMG]
Interestingly Subaru changed the rear stops on the 04+ rears- shortening them by ~ 30mm- slightly different shape too.
The oe ones are definitely progressive (and feel more "foamish" than "plastic"- the first couple of "rings" you can easily compress w/ your hand.
Would be nice to get the fellow who tested the Grp N vs oe vs Poly bushings to give some of the different stops the same go round.
Mako how would you rate the ones you tried?
heres some from ground Control
[IMG]http://www.ground-control-store.com/images/fullsize/bumpstop_fs.jpg[/IMG]
| BIGSKYWRX | 03-09-2007 11:49 AM |
Also the oe (WRX anyways) bumpstops are 60mm in the front, rears 02/03 120mm, 04+ 90mm
Would there be any cases where it would benefit if trimming- to trim the lower/firmer section vs the upper softer portion on the oe ones?
Would there be any cases where it would benefit if trimming- to trim the lower/firmer section vs the upper softer portion on the oe ones?
| duncangrant | 03-11-2007 10:59 AM |
Powerflex have published force-deflection data for their foam bumpstops.
Click on 'Catalogue Page' on [URL="http://www.powerflex.co.uk/products.asp?cat=0041&catalog=0141&submit1.x=19&submit1.y=18&submit1=GO"]this page[/URL]
Click on 'Catalogue Page' on [URL="http://www.powerflex.co.uk/products.asp?cat=0041&catalog=0141&submit1.x=19&submit1.y=18&submit1=GO"]this page[/URL]
| BIGSKYWRX | 03-11-2007 12:07 PM |
I'm not seeing the data (says it's provided w/ the stops?) Also wondering what's the deal w/ the ones that list a very wide range of bores.
I called GC the stops (the strut ones) they have are 52mm in length, both firm and soft.
I called GC the stops (the strut ones) they have are 52mm in length, both firm and soft.
| duncangrant | 03-14-2007 11:11 AM |
Click on [B][U]'Catalogue Page'[/U][/B] on [URL="http://www.powerflex.co.uk/products.asp?cat=0041&catalog=0141&submit1.x=19&submit1.y=18&submit1=GO"]this page[/URL]
| BIGSKYWRX | 03-14-2007 07:37 PM |
Got it- thanks :) Interesting- they vary quite a bit in stiffness
| WJM | 03-14-2007 09:00 PM |
riding on bump stops make you faster.
| sciolist | 03-14-2007 09:11 PM |
[QUOTE=crystalhelix;17289904]Why would you bump a 2 year old thread?
[IMG]http://www.leelefever.com/archives/cookie.jpg[/IMG][/QUOTE]
Just for that, you have to go back to the Pinks and Yellows. Our people will be paying you a visit soon. :D
[IMG]http://www.leelefever.com/archives/cookie.jpg[/IMG][/QUOTE]
Just for that, you have to go back to the Pinks and Yellows. Our people will be paying you a visit soon. :D
| silver arrow | 03-14-2007 10:46 PM |
Thanks for bumping this up, my Teins are coming off for a rebuild at the end of the year and I'll try different bumpstops. Mako, did you have your teins revalved. I hate the high speed valving and am thinking about having them revalved when I rebuild.
| makofoto | 03-14-2007 11:36 PM |
Yes ... revalved to match as closely as possible a friends revalved Koni. If you send them to Los Angeles/Tein, you can ask them to revalved them like National Champ Tom Hoppes, etc.
| SWortham | 03-14-2007 11:36 PM |
There is a very good (and lengthy) discussion about this here...
[url]http://www.iwsti.com/forums/showthread.php?t=65985[/url]
At least in the case of the STI, it will almost assuredly ride on its bump stops while autocrossing unless you do something drastic to the suspension to change that.
However, the first progression of contact with the bump stops is very soft so it's not necessarily going to be obvious. But as they compress, they have an exponential spring rate of their own, so it can ruin the dynamics of the car if it relies on them too heavily.
EDIT -- My bad. I completely missed stretch's post above linking to this same thread, haha.
[url]http://www.iwsti.com/forums/showthread.php?t=65985[/url]
At least in the case of the STI, it will almost assuredly ride on its bump stops while autocrossing unless you do something drastic to the suspension to change that.
However, the first progression of contact with the bump stops is very soft so it's not necessarily going to be obvious. But as they compress, they have an exponential spring rate of their own, so it can ruin the dynamics of the car if it relies on them too heavily.
EDIT -- My bad. I completely missed stretch's post above linking to this same thread, haha.
| makofoto | 03-14-2007 11:38 PM |
BS WRX ... I can't rate them ... I was just going for shorter to get more travel.
| stretchsje | 03-15-2007 06:19 PM |
[QUOTE=duncangrant;17350338]Click on [B][U]'Catalogue Page'[/U][/B] on [URL="http://www.powerflex.co.uk/products.asp?cat=0041&catalog=0141&submit1.x=19&submit1.y=18&submit1=GO"]this page[/URL][/QUOTE]
Interesting, most are in the neighborhood of 400lb/in initially. That's really damn firm.
Interesting, most are in the neighborhood of 400lb/in initially. That's really damn firm.
| duncangrant | 03-16-2007 10:32 AM |
[quote=stretchsje;17369577]Interesting, most are in the neighborhood of 400lb/in initially. That's really damn firm.[/quote]
Well, looking at few of the long/soft types such as the SAF005 they start off at around 200N per 6mm or 190 lb/in, which is not insignificant. However its interesting that they seem to go softer at around 1/3 of compression, so over the first inch its averaging about 110lb/in, before getting exponentially stiffer towards full compression.
Also as a general rule of thumb it looks like they compress to around 1/3 of their free length.
Well, looking at few of the long/soft types such as the SAF005 they start off at around 200N per 6mm or 190 lb/in, which is not insignificant. However its interesting that they seem to go softer at around 1/3 of compression, so over the first inch its averaging about 110lb/in, before getting exponentially stiffer towards full compression.
Also as a general rule of thumb it looks like they compress to around 1/3 of their free length.
| BIGSKYWRX | 03-16-2007 10:48 AM |
Be curious to see how they compare w/ the oe ones- the ones you can compress the first couple of rings pretty easily w/ your fingers- it definitely gets firmer as you go down though.
| stretchsje | 03-16-2007 07:32 PM |
[QUOTE=BIGSKYWRX;17376495]Be curious to see how they compare w/ the oe ones- the ones you can compress the first couple of rings pretty easily w/ your fingers- it definitely gets firmer as you go down though.[/QUOTE]
The OE STI bump stops are pretty close to a linear 300lb/in for the first inch. (Start at post 103 in the thread linked above.)
The OE STI bump stops are pretty close to a linear 300lb/in for the first inch. (Start at post 103 in the thread linked above.)
| jamal | 04-02-2007 05:11 PM |
I'm not so sure about this whole "riding on the bumpstops" thing. Here is an 05 STi strut compressed to the bump stop. While we ([email�protected] and I) didn't take any precise measurements, but the car rides higher than this:
[URL=http://img506.imageshack.us/my.php?image=0329072125wf5.jpg][IMG]http://img506.imageshack.us/img506/9240/0329072125wf5.th.jpg[/IMG][/URL]
[URL=http://img506.imageshack.us/my.php?image=0329072125wf5.jpg][IMG]http://img506.imageshack.us/img506/9240/0329072125wf5.th.jpg[/IMG][/URL]
| BIGSKYWRX | 04-02-2007 07:54 PM |
While it might not be in them at oe ride height, it doesn't take too long to get in them. Here's some Koni's in a WRX housing (mind you the Koni has ~ 5mm more stroke than a oe WRX strut). Front struts btw.
first shot is at oe height-
[IMG]http://i83.photobucket.com/albums/j304/BIGSKYWRX/oeheightbump.jpg[/IMG]
second at 20mm of lowering
[IMG]http://i83.photobucket.com/albums/j304/BIGSKYWRX/20mmloweringbump.jpg[/IMG]
3rd one is at 35mm of lowering- clearly on the stops
[IMG]http://i83.photobucket.com/albums/j304/BIGSKYWRX/35mmloweringbump.jpg[/IMG]
Here's the stops I got from GC left is 47mm (and VERY firm), second is 53mm (and firm), third is oe 59mm (and the softest)
[IMG]http://i83.photobucket.com/albums/j304/BIGSKYWRX/comparooegcs.jpg[/IMG]
first shot is at oe height-
[IMG]http://i83.photobucket.com/albums/j304/BIGSKYWRX/oeheightbump.jpg[/IMG]
second at 20mm of lowering
[IMG]http://i83.photobucket.com/albums/j304/BIGSKYWRX/20mmloweringbump.jpg[/IMG]
3rd one is at 35mm of lowering- clearly on the stops
[IMG]http://i83.photobucket.com/albums/j304/BIGSKYWRX/35mmloweringbump.jpg[/IMG]
Here's the stops I got from GC left is 47mm (and VERY firm), second is 53mm (and firm), third is oe 59mm (and the softest)
[IMG]http://i83.photobucket.com/albums/j304/BIGSKYWRX/comparooegcs.jpg[/IMG]
| Mykl | 04-02-2007 10:06 PM |
[QUOTE=jamal;17575431]I'm not so sure about this whole "riding on the bumpstops" thing. Here is an 05 STi strut compressed to the bump stop. While we ([email�protected] and I) didn't take any precise measurements, but the car rides higher than this:
[URL=http://img506.imageshack.us/my.php?image=0329072125wf5.jpg][IMG]http://img506.imageshack.us/img506/9240/0329072125wf5.th.jpg[/IMG][/URL][/QUOTE]
Would you mind taking apart the strut and measuring it? Somebody else has already done that and the link on page one points to the results.
[URL=http://img506.imageshack.us/my.php?image=0329072125wf5.jpg][IMG]http://img506.imageshack.us/img506/9240/0329072125wf5.th.jpg[/IMG][/URL][/QUOTE]
Would you mind taking apart the strut and measuring it? Somebody else has already done that and the link on page one points to the results.
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