Are x1/9 rear coilovers the same as 128's front ?

[stayros32001]

Hi, I own a "Fiat 128" and I want to invest in a coilover set in the near future!
For two reasons: smother riding and to put back wheels at the ground when accelerating. More info here


I saw that in Europe the company D2 Racing Sport has some very decent coilovers for x1/9 and I start googling for pictures to see if they are the same as 128.

I have these two pics as a reference
rear from x1/9:

Strut PAIR Rear - KYB Nitro Gas (Fiat Bertone X1/9 1980-88 + 1973-79) - U8

Strut PAIR Rear - KYB Nitro Gas (Fiat Bertone X1/9 1980-88 + 1973-79) - U8

www.midwest-bayless.com

and front from 128 here:

FIAT 128 127 AUTOBIANCHI A112 ABARTH ZASTAVA 101 YUGO FRONT COILOVERS KIT - Classic Performance Parts

Classic Performance Parts - FIAT 128 127 AUTOBIANCHI A112 ABARTH ZASTAVA 101 YUGO FRONT COILOVERS KIT

classicperformance-parts.com

So they look the same,
Does anyone know if they are the same?

The goal is (if they are the same) to contact to D2 and make same minor adjustments
for example to make sure that these they will fit perfect: https://classicperformance-parts.co...s-kit-shock-top-mount-with-spherical-bearing/
(there is no need to reinvent the wheel and let d2 try to make top mounts if they already exists)

I also have no idea what to do for the rear, that I also will need.




**
to be honest I have found this:

Late X19 rear strut for the 128 front compatability

Been told I can fit late model rear struts in the front of my 75 128.If doable, what mods do I need to perform?..... 1)can I fit the 128 top base mount into this late struts and then just mount them? 2)or do I have to keep the late X19 mounts and then redrill the strut tower base to accept the...

xwebforums.com

but most of the comments are like: do not try this at home!

X19 rear strut isn't the best choice at all... a FWD strut relies on quite stiff extension damping to prevent the front rising under acceleration... I would doubt that x19 inserts (same front and rear) are designed for a stiff extension setting...

so I suppose that I just have to take the "mounting part" and put it at a coilover that it was designed for front wheels?

 

[fastx19]

So, they can be interchanged however..... The will drop the ride height in the 128. So, if your 128 is a bit lower already, then you should be good to go. I used X19 struts in my 128 for multiple uses.

 

[Ulix]

A guy in Germany offers coilovers for front and rear of the 128.

Scuderia Fiat 128 - Ersatzteile

Scuderia Fiat 128 Das Ziel unser Scuderia Fiat 128 liegt in der Freude des Fiat 128 und der gegenseitigen Hilfe bei Ersatzteilsuche, Tipps bei Reparatur, Restaurierung und Tuning

www.fiat128.de

 

[stayros32001]

Really good job from the guy in Germany, but it has the same problem as the classic performance parts. You can not adjust the height from the bottom mount. You have to compress the spring.
D2 has adjustable bottom mounts.
That also means that the are removable from the main structure!, so you can put them in a set of Struts that they was designed to be for the front of the car and they also have the right height, and then to adjust how low you want to go!

So let's say, that the front coils are solved!
The new question now is:
Do we know if the rear bottom mounts are the same with any other car, so us to use them?

I think that the goal is to tell D2: take the bottom mount from x1/9 (rears) and add them to a coilover set with "this" height. (original height of 128)
And then take the bottom from this car (for rear) and put it to a coil with "this" height and thats it! we have made a 128 coilovers set at D2 available

 

[lookforjoe]

Having no idea what 128 rear suspension looks like, I was Looking at this thread - it "appears" the strut tube still uses the same design mount ears - have you physically compared any yourself?

 

[stayros32001]

This is a good reference i think:

FIAT 128 127 AUTOBIANCHI A112 ABARTH ZASTAVA 101 YUGO REAR COILOVERS KIT - Classic Performance Parts

Classic Performance Parts - FIAT 128 127 AUTOBIANCHI A112 ABARTH ZASTAVA 101 YUGO REAR COILOVERS KIT

classicperformance-parts.com

Worst case scenario, I will get these for rear!

 

[Dr.Jeff]

D2 has adjustable bottom mounts.
That also means that the are removable from the main structure!, so you can put them in a set of Struts that they was designed to be for the front of the car and they also have the right height, and then to adjust how low you want to go!

I have always preferred this feature - being able to adjust the position of the lower mount on the strut in addition to adjusting the lower spring perch height. However on the X (and believe also the 128) there is very little room to lower the strut beyond the stock setting before it hits other components. So there is very little to gain from having that feature on these cars. Although if your goal is to raise the car rather than lower it, then the feature will allow you to go much higher.

 

[Dr.Jeff]

Keep in mind there are several features to consider when choosing coilovers, in addition to fitting the car (i.e. having the correct mounts). Such as the dampening characteristics, the spring rates, the overall length of the strut, the type of top mounts, the quality, and more. All of these requirements will be different for every application so you need to determine your specific use of the car first and go from there. Compromising on any of those factors will result in a unsatisfactory outcome.

 

[stayros32001]

there is very little room to lower the strut beyond the stock setting before it hits other components.

WoW! You are life saver! I didn't think of this! So Classic performance parts seams to be the right way!

So there is very little to gain from having that feature on these cars. Although if your goal is to raise the car rather than lower it, then the feature will allow you to go much higher.

The car is my daily driver! (I use also my motorbike) It is an ongoing restomoding project. It has already be equipped with A/C, bigger brakes at front, and disks at rear also, 185/65/14 tires and it is lowered at the back with a "blocks" trick from my mechanic.

The goal is to be as comfort and steady like a train on rails, as it gets!
Ofcource it must lower also so as to meet the rear height.
Good to know, it must handle 85hp.(1500cc ie, more info at first post)

 

[Lowtechprime]

Really good job from the guy in Germany, but it has the same problem as the classic performance parts. You can not adjust the height from the bottom mount. You have to compress the spring.
D2 has adjustable bottom mounts.
That also means that the are removable from the main structure!, so you can put them in a set of Struts that they was designed to be for the front of the car and they also have the right height, and then to adjust how low you want to go!

So let's say, that the front coils are solved!
The new question now is:
Do we know if the rear bottom mounts are the same with any other car, so us to use them?

I think that the goal is to tell D2: take the bottom mount from x1/9 (rears) and add them to a coilover set with "this" height. (original height of 128)
And then take the bottom from this car (for rear) and put it to a coil with "this" height and thats it! we have made a 128 coilovers set at D2 available

I'm a little confused? Classic performance struts are adjusted from the bottom mount..

 

[Dr.Jeff]

I'm a little confused? Classic performance struts are adjusted from the bottom mount..

If I understand your question correctly....
The strut body is threaded all the way to the bottom. Then there are two threaded sections that can be positioned anywhere along the threaded body: the upper one is the typical spring perch (below the spring), the other one is the lower mount for the car's suspension (e.g. the 'upright' or 'spindle'). With that second (lower) section also being threaded the overall ride height can be adjusted independently of the spring height. It is like making the strut body longer or shorter without moving the spring position. So the spring rate (e.g. preload) isn't affected by changing the rife height.

See if this pic helps illustrate it:

The blue portion is where the strut bolts to the car's suspension. And it is threaded inside so the position of it (relative to the strut body) can be adjusted up or down (where he is pointing). This does not affect the spring position (top left portion of pic).

 

[Dr.Jeff]

WoW! You are life saver! I didn't think of this! So Classic performance parts seams to be the right way!



The car is my daily driver! (I use also my motorbike) It is an ongoing restomoding project. It has already be equipped with A/C, bigger brakes at front, and disks at rear also, 185/65/14 tires and it is lowered at the back with a "blocks" trick from my mechanic.

The goal is to be as comfort and steady like a train on rails, as it gets!
Ofcource it must lower also so as to meet the rear height.
Good to know, it must handle 85hp.(1500cc ie, more info at first post)

Double check your car. I am not that familiar with the 128 so it might allow more movement than the X does. But on the X the lower mount can only be raised (to lower the car) about a half inch before the bottom of the strut body hits things.

There is a direct trade-off between comfort and handling; generally speaking in simplest terms, for higher performance handling a stiffer spring is better, but for comfort a softer spring is better. For a daily driver on regular roads a stiff spring is rough riding and uncomfortable. Vice versa, a soft spring offers less ultimate handling. To put it into a little perspective, the typical "sport springs" offered as aftermarket replacements for stock springs are usually 25-30% stiffer than stock (off the top of my head I seem to recall that would be around 175-195 pounds for the X). However race springs can be several hundred percent stiffer than stock (such as 400 to 500 pounds or more). That's a huge difference. Often the coilovers sold have rather stiff springs, but they offer other choices. The dampening effect (hydraulic portion of the strut) needs to match the spring rates.

Usually the more you lower the ride height, the less suspension travel you get (e.g. it will bottom out easier on bumps). The best solution is to use a coilover that has a shorter total (overall) length rather than adjust a longer one to a lower setting.

 

[stayros32001]

There is a direct trade-off between comfort and handling; generally speaking in simplest terms, for higher performance handling a stiffer spring is better, but for comfort a softer spring is better. For a daily driver on regular roads a stiff spring is rough riding and uncomfortable. Vice versa, a soft spring offers less ultimate handling. To put it into a little perspective, the typical "sport springs" offered as aftermarket replacements for stock springs are usually 25-30% stiffer than stock (off the top of my head I seem to recall that would be around 175-195 pounds for the X). However race springs can be several hundred percent stiffer than stock (such as 400 to 500 pounds or more). That's a huge difference. Often the coilovers sold have rather stiff springs, but they offer other choices. The dampening effect (hydraulic portion of the strut) needs to match the spring

Ok, but this problem isn't it solved already with coilover tender springs?

The best solution is to use a coilover that has a shorter total (overall) length rather than adjust a longer one to a lower setting.

I defenately go this way.

 

[Dr.Jeff]

Ok, but this problem isn't it solved already with coilover tender springs?

No. The tender springs are incredibly soft and collapse with just the weight of the car. Their function isn't to be a suspension spring, but merely to expand if the car is raised completely up (i.e. strut fully extended). Many coilovers can extend longer than the length of the main spring. This keeps the main spring from getting loose and possibly unseating from its perch. So the tender springs do not offer any influence on handling or comfort. Although not all coilovers include them, they are an important part of the whole design.

 

[stayros32001]

No. The tender springs are incredibly soft and collapse with just the weight of the car. Their function isn't to be a suspension spring, but merely to expand if the car is raised completely up (i.e. strut fully extended).

I think that you are talking about helper springs.

Tender springs are the most commonly mis-understood of the two and are often confused with helper springs. However, their role is much different; a tender spring is a stiffer spring than a helper spring and does not fully compress at ride height but acts as part of a dual rate spring system. Under low loads, such as normal road driving, the tender spring is used to provide a softer spring rate than if only the main spring was used. Upon compression such as cornering situations, the tender spring closes up becoming inactive, allowing the main spring rate to take over and increase the cornering stiffness of the vehicle and provide a more firm, stable cornering platform.

Helper Springs and Tender Springs - The Difference

There is often a lot of confusion around tender springs and helper springs and the two are often mistaken for one another.

suspensionsecrets.co.uk

 

[stayros32001]

Here is the lower mount. There is no space at all at 128!

 

[Dr.Jeff]

I think that you are talking about helper springs.

Helper Springs and Tender Springs - The Difference

There is often a lot of confusion around tender springs and helper springs and the two are often mistaken for one another.

suspensionsecrets.co.uk

You are correct, technically there is a difference. However the vast majority of aftermarket coilovers include "helper" springs but many describe them as "tender" springs. Hince all the confusion about the terminology (by the way, some sources define those two terms differently than the reference you linked, only making things further confusing).

If they actually offer true tender springs then they usually describe them as "dual rate" coilovers. So be careful when shopping for coilovers as many sellers do not describe things technically correct. If they are true dual rate coilovers with tender springs then they should give the spring rates for both springs. And the rate for each spring needs to be correct for your specific application. A tender spring that is too soft becomes little more than a helper spring. And one that is too stiff becomes redundant to the main spring. Additionally you may see these dual rate coilovers with a third helper spring.

To confuse thing even more, many coilovers will offer a main spring with a "progressive" rate. It is softer at one end than the other. This serves the same function as tender springs; the soft portion of the main spring takes up small bumps and the stiff portion kicks in with further travel. With this design there is no need for a tender spring but there is still a need for a helper spring. These progressive rate springs are also often referred to as dual rate springs.

Because the X1/9 is not a common application for coilover builders to sell, they usually are not available in the more advanced designs. Such as true dual rate with tender springs or progressive springs. Often they take an existing application that is somewhat close to the X and sell it for the X without redesigning the spring rates, dampening characteristics, mounts, or other aspects unique to the X. One such example was recently discussed where the instructions simply said to remove the existing top mount from the coilover as supplied and replace it with a adaptor part sold separately by them. Apparently that was not made clear in the sales literature.

 

[Vuk]

I will chime in as I've been through this exercise with my Yugo. One disclaimer: my suspension is now fully designed and made but not yet road-tested.

128 and Yugo have similar setups with the exception that Yugo features needle bearings in the front strut cups. I decided to get an OSRAV THR25 set which is originally intended for A112, which is quite similar to Yugo in size and engine position. To fit my Yugo properly, I redesigned the top strut cups both in the front and back.

For reference, original OSRAV spring tops look like this:



Maybe it would work for a 128 but it doesn't work for Yugo as (1) the height of the top cone for rear is so short that it rubs against the cup in the top of the spring tower, and (2) the front spring tops do not have much of any remaining length to be bolted through anything more than sheet metal. Yugo has different top spring hats in the front and this solution simply wouldn't work.

The original OSRAV solution in the back mimics the original Fiat setup with the sandwich rubber joint hugging the cup in the top of the spring tower. For -55mm lowering (which is max advertised by OSRAV), this type of strut top mounting is suboptimal as the strut is not positioned at the same angle as originally, continuously exerting force at the side of the cup. Additionally, the original rubber bushings are very soft, and if coilovers are used without the leaf spring, there exists a level of risk that the strut would push out the bottom bushing through the cup in the top of the spring tower (I've heard of a couple of cases of this happening). The key challenge here is to load the top of the spring tower with the coil force and not the rubber bushing itself. Therefore, I designed a top cup featuring a polyurethane universal joint that solves both problems: (1) it translates force to the spring tower and not to the bushing (joint), (2) the joint allows for the strut to naturally attack the top mount at a different angle without any deformation. I've also designed a plate to be welded on top of the spring tower, that also enables mounting of a strut bar, and wheel well reinforcements.



As far as the front goes, the original OSRAV solution cannot be fitted directly to Yugo, so I decided to leverage the rear design with the polyurethane universal joint and add the needle bearing needed to ease steering.



The poly joint is the RockJock's Johnny Joints CE-9112NP, universally used on many 4x4 applications which makes me believe that it is more than sufficient to handle this application. Moreover, the polyurethane joint bushing in these systems acts as no more than a damper, as the joint housing design ensures the springs are exerting force onto the spring tower and not the joint itself.

Now, you could use this design for your 128 rear, especially if you wanted to eliminate the leaf spring. Otherwise, consider the OSRAV set for A112 as another option. I will emphasize that I have personally not had experience with running rear coilovers through factory top rubber bushings so I cannot claim that this causes issues, but I have learned from people designing sport suspensions for the Yugo that it is far from optimal due to the "breathing" in the soft rubber, different strut angle due to lowering, and the force that increases on the bushings (especially if the leaf spring is deleted). If you look closely at the rear coilovers from Classic Performance, you'll see that they added a washer on the top and bottom of the two rubber bushings. This is done exactly to help "sandwich" the soft rubber bushings around the cup in the spring tower and eliminate the possibility that it will be squeezed through the cup. It still does not help the fact that the bottom of those two bushings will be taking quite a bit more load than it is designed for originally, due to the added spring.

Vuk

 

[Lowtechprime]

Componenti Assetto Fiat 127 Autobianchi A112 Stradale Corsa

Vendita e Assistenza per Tuning Auto - Moto - Offroad - Camper, Accessori Interni ed Esterni, Allestimenti Gara, Impianti Audio, Modifiche Estetiche e Meccaniche

www.storextreme.com

Has anyone seen these?

 

[Dr.Jeff]

I will chime in as I've been through this exercise with my Yugo. One disclaimer: my suspension is now fully designed and made but not yet road-tested.

128 and Yugo have similar setups with the exception that Yugo features needle bearings in the front strut cups. I decided to get an OSRAV THR25 set which is originally intended for A112, which is quite similar to Yugo in size and engine position. To fit my Yugo properly, I redesigned the top strut cups both in the front and back.

For reference, original OSRAV spring tops look like this:

View attachment 68132

Maybe it would work for a 128 but it doesn't work for Yugo as (1) the height of the top cone for rear is so short that it rubs against the cup in the top of the spring tower, and (2) the front spring tops do not have much of any remaining length to be bolted through anything more than sheet metal. Yugo has different top spring hats in the front and this solution simply wouldn't work.

The original OSRAV solution in the back mimics the original Fiat setup with the sandwich rubber joint hugging the cup in the top of the spring tower. For -55mm lowering (which is max advertised by OSRAV), this type of strut top mounting is suboptimal as the strut is not positioned at the same angle as originally, continuously exerting force at the side of the cup. Additionally, the original rubber bushings are very soft, and if coilovers are used without the leaf spring, there exists a level of risk that the strut would push out the bottom bushing through the cup in the top of the spring tower (I've heard of a couple of cases of this happening). The key challenge here is to load the top of the spring tower with the coil force and not the rubber bushing itself. Therefore, I designed a top cup featuring a polyurethane universal joint that solves both problems: (1) it translates force to the spring tower and not to the bushing (joint), (2) the joint allows for the strut to naturally attack the top mount at a different angle without any deformation. I've also designed a plate to be welded on top of the spring tower, that also enables mounting of a strut bar, and wheel well reinforcements.

View attachment 68119View attachment 68120View attachment 68121View attachment 68122View attachment 68123View attachment 68124View attachment 68125View attachment 68133

As far as the front goes, the original OSRAV solution cannot be fitted directly to Yugo, so I decided to leverage the rear design with the polyurethane universal joint and add the needle bearing needed to ease steering.

View attachment 68126View attachment 68127View attachment 68128View attachment 68129View attachment 68130View attachment 68131

The poly joint is the RockJock's Johnny Joints CE-9112NP, universally used on many 4x4 applications which makes me believe that it is more than sufficient to handle this application. Moreover, the polyurethane joint bushing in these systems acts as no more than a damper, as the joint housing design ensures the springs are exerting force onto the spring tower and not the joint itself.

Now, you could use this design for your 128 rear, especially if you wanted to eliminate the leaf spring. Otherwise, consider the OSRAV set for A112 as another option. I will emphasize that I have personally not had experience with running rear coilovers through factory top rubber bushings so I cannot claim that this causes issues, but I have learned from people designing sport suspensions for the Yugo that it is far from optimal due to the "breathing" in the soft rubber, different strut angle due to lowering, and the force that increases on the bushings (especially if the leaf spring is deleted). If you look closely at the rear coilovers from Classic Performance, you'll see that they added a washer on the top and bottom of the two rubber bushings. This is done exactly to help "sandwich" the soft rubber bushings around the cup in the spring tower and eliminate the possibility that it will be squeezed through the cup. It still does not help the fact that the bottom of those two bushings will be taking quite a bit more load than it is designed for originally, due to the added spring.

Vuk

Nice conversion. How does the overall length of the A112 coilovers compare to the stock struts?

That RockJock component appears to be a spherical bushing with a large urethane cushion encasing the ball? That would offer the benefits of a spherical joint without the major drawback - harsh ride, vibration, noise. The coilovers from VAS for the X have a similar concept on the top mount; but in that case a urethane piece surrounds a normal spherical joint. So the urethane piece is not part of the joint but just a isolator around it. Unfortunately it is too small to offer much insulation/cushioning effect.

The stock Fiat top mounts are problematic with coilovers and there aren't any good quality replacement ones readily available. So redesigning the complete top mount is worth the effort. Great job on making those top spring cups also.