Hotchkis or UMI springs
Hotchkis or UMI springs
Street car, cruiser etc. I'm pulling the Belltech drop spindles off of this car and want to put the stocks back on. Its just too low for me. I'd prefer to find a lowering spring in the 1" flavor with decent ride.
Joined: Mar 2001
Posts: 10,425
Likes: 2,089
Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Hotchkis or UMI springs
BMR, Hotchkis, UMI all have similar spring rates up front of roughly 600 lb/in but match that with rear springs ranging from 140 - 200 lb/in advertised. Keep in mind a lot of aftermarket springs are variable rate, so that Hotchkis "140 advertised" is actually 100-140 lb/in. The idea is it cruises soft but quickly perks up when needed. The reality is it will mostly ride on the higher end of the range at 140 lb/in.
I don't know the true specs on the UMI rear spring. They say 130 lb/in in one place of their website, and 200 lb/in in another place of their website. That might hint it is 130-200 lb/in variable rate, but a phone call could confirm. If so, then this would ride rougher just cruising down the road but maybe handle better on a smooth track. The higher spring rate of the UMI might be aimed at people using a dropped panhard bar.
Weight jacks are going to be rough. I would stay away from those for a cruiser.
I don't know the true specs on the UMI rear spring. They say 130 lb/in in one place of their website, and 200 lb/in in another place of their website. That might hint it is 130-200 lb/in variable rate, but a phone call could confirm. If so, then this would ride rougher just cruising down the road but maybe handle better on a smooth track. The higher spring rate of the UMI might be aimed at people using a dropped panhard bar.
Weight jacks are going to be rough. I would stay away from those for a cruiser.
Last edited by QwkTrip; Dec 31, 2023 at 12:22 AM.
Joined: Mar 2001
Posts: 10,425
Likes: 2,089
Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Hotchkis or UMI springs
And here are Eibach spring rates from this thread (dated 2004), https://www.thirdgen.org/forums/susp...ml#post1727822
In the past the exact spring rates for the different eibach kits have been discussed, but nothing really concrete was ever established. With the help of a couple members and eibach tech support I have the actual spring rates for all 3 kits offered for our cars.
Pro Kit: 714 lb/in linear front 1 inch lower front
109/177 lb/in progressive rear 1 inch lower rear
Sportline: 700 lb/in linear front 1.6 inch lower front
80/137 lb/in progressive rear 1.3 inch lower rear
Drag launch: 337/514 lb/in progressive both front sides
80 lb/in linear driver side rear
80/217 in/lb progressive passenger side rear
Eibach says the reason the sportline kit, which is actually lower than the pro kit, is softer is because they use the bumpstops as supplemental spring rate to maintain good ride quality and performance with the lowest drop possible. Hope this helps some of you.
Pro Kit: 714 lb/in linear front 1 inch lower front
109/177 lb/in progressive rear 1 inch lower rear
Sportline: 700 lb/in linear front 1.6 inch lower front
80/137 lb/in progressive rear 1.3 inch lower rear
Drag launch: 337/514 lb/in progressive both front sides
80 lb/in linear driver side rear
80/217 in/lb progressive passenger side rear
Eibach says the reason the sportline kit, which is actually lower than the pro kit, is softer is because they use the bumpstops as supplemental spring rate to maintain good ride quality and performance with the lowest drop possible. Hope this helps some of you.
Re: Hotchkis or UMI springs
Thanks man! Yeah this car won't ever see a track and I think I'd prefer a milder/softer ride. I really want the Hotchkis but dang, they are a little over $100 more for the set.
Joined: Mar 2001
Posts: 10,425
Likes: 2,089
Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Hotchkis or UMI springs
Hey, Nutro. Stumbled across this and thought of you....
Moog-5660 (598 lb/in). $80 for the pair.
You can see the specs here, https://www.moog-suspension-parts.co...il_springs.asp
Not sure how close this is to a Hotchkis front spring but it sure isn't a long way off.
Moog-5660 (598 lb/in). $80 for the pair.
You can see the specs here, https://www.moog-suspension-parts.co...il_springs.asp
Not sure how close this is to a Hotchkis front spring but it sure isn't a long way off.
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Re: Hotchkis or UMI springs
Hey, Nutro. Stumbled across this and thought of you....
Moog-5660 (598 lb/in). $80 for the pair.
You can see the specs here, https://www.moog-suspension-parts.co...il_springs.asp
Not sure how close this is to a Hotchkis front spring but it sure isn't a long way off.
Moog-5660 (598 lb/in). $80 for the pair.
You can see the specs here, https://www.moog-suspension-parts.co...il_springs.asp
Not sure how close this is to a Hotchkis front spring but it sure isn't a long way off.
Joined: May 2001
Posts: 5,244
Likes: 14
From: Sac, CA
Car: '89 GTA
Axle/Gears: 3.27/9-bolt
Re: Hotchkis or UMI springs
Good info in this thread that isn't 20 years old. 
Which Hotchkis springs did you go with? Front/Rear?
Does the Moog 5660 posted actually fit 89 as well? When I look it up says 91-92 and all the truck fitment options.
I have had Eibach Pro Kit up front and Sportline read for many years and while it looks perfect, I'm now looking for any way to get the car up higher again without redoing my low hanging exhaust.
Which Hotchkis springs did you go with? Front/Rear?
Does the Moog 5660 posted actually fit 89 as well? When I look it up says 91-92 and all the truck fitment options.
I have had Eibach Pro Kit up front and Sportline read for many years and while it looks perfect, I'm now looking for any way to get the car up higher again without redoing my low hanging exhaust.
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