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BigJimnyMeet (North) 2024 (12 Jan 2024)


BigJimnyMeet 2024

14th July 2024
Parkwood Nr. Leeds

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Re:Recommended suspension kit 2" for New Jimny?

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01 Apr 2020 23:41 #220562 by 300bhpton

Busta wrote: Seems a shame to fit a lift kit, only to have the crossmember sticking down under the car like that robbing ground clearance. I'd be tempted to leave it off. I'm led to believe the rest of the chassis is unchanged from the gen3, which worked fine for 20 years without it.

This would all depend on what you are trying to achieve.

I doubt the cross member is the lowest point and lowering it is unlikely to cause any off road compromises. Happy to be proven wrong. I’m not sure leaving it off completely would be the best thing. It is there for a purpose.

On the flip side as poor lift might give you more clearance. But may reduce off road ability if the suspension travel is compromised.

The easiest way to think of it is. Assume you have 10” of total suspension travel. Sitting on level ground gives you 5” of compression and 5” of droop.

If you simply lift the vehicle (stiffer/longer springs or spring spacers) by 2”. You’ll now have 7” of compression and 3” of droop. But still a total of 10”.

The problem here is. Such limited droop means you’ll be lifting wheels a lot off road. Also most means of lifting that involve heavy duty springs may not compress very well. So you might actually have lost an inch of travel overall.

For off road what we are really wanting is more travel. Longer shocks should allow more droop. So add some +2” shocks and with a lift will return you to the stock 5” of droop. The risk is, a longer shock can bottom out under compression. So some setups use extended bump shocks to limit your compression.

In the above example the longer shocks may have given us the 5” of droop. But we would probably have lost 1” of compression due to the lift springs (6”). So we have gained 1” travel overall. Although an extended bump stop will remove that 1” advantage.

Note the numbers are all made up. Not what the Jimny suspension actually does.

But the key is. You can’t normally increase the compression travel over stock. Not without radical changes. All the increases in suspension travel will come from increased droop. But any setup that tries to retain the maximum compression travel is likely a better balanced setup and may well offer more total suspension travel.

With the 4th gen the front prop will however impact the crossmember. Making a physical barrier to increasing the front drop beyond nominal amounts unless the crossmember is addressed. The rear is a lot easier to increase the droop. But doing so can make the vehicle less balanced off road.

If you plan to off road. Then I personally like a balanced setup.

For the Jimny the kit I like the most so far and what is on my ‘to buy’ list. Is the Raptor kit from Jimnybits. I really don’t want a massive lift unless I was building something extreme that required it.


Apologies I seemed to have ended up rambling a bit..... :)

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02 Apr 2020 09:20 - 02 Apr 2020 09:21 #220575 by DAGZOOK

300bhpton wrote: A lift is not directly related to suspension travel increases. And more flexy suspension doesn’t necessarily mean a lifted vehicle.

i.e.

Lifting a vehicle 40mm has no direct relation to giving you more down travel. So the amount of lift also has no relationship with if the front crossmember will be in the way or not.


Not sure what you mean here bhp, Sure with a body lift (spring spacers etc) you're right, you could lift away without gaining any additional down travel because your factory shock will top out. BUT with a true suspension lift, longer shocks and longer springs you will gain down travel all be it 40-50mm.That'll be enough for the prop to foul on the front crossmember unless you fit a compromise kit like the Trailmaster. The longer shocks if gauged correctly to the vehicle will have the same compressed length as the OEM shocks - So you've gained, not lost anything. If the compressed length of the new shock is the same as the OEM shock, no additional bump stops are required.
Last edit: 02 Apr 2020 09:21 by DAGZOOK.

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02 Apr 2020 10:13 - 02 Apr 2020 10:15 #220577 by 300bhpton

DAGZOOK wrote: Not sure what you mean here bhp, Sure with a body lift (spring spacers etc) you're right, you could lift away without gaining any additional down travel because your factory shock will top out. BUT with a true suspension lift, longer shocks and longer springs you will gain down travel all be it 40-50mm.That'll be enough for the prop to foul on the front crossmember unless you fit a compromise kit like the Trailmaster. The longer shocks if gauged correctly to the vehicle will have the same compressed length as the OEM shocks - So you've gained, not lost anything. If the compressed length of the new shock is the same as the OEM shock, no additional bump stops are required.

I think I slightly misread your post last night.

However, what I was trying to say is. Just because a kit 'lifts' a vehicle. Does not mean it'll give you more articulation or flexy suspension. And in fact some of the best suspension setups (general or other vehicles) don't actually lift the vehicle much or at all.

Also shock length really is irrelevant in terms of 'lifting' a vehicle. And companies that confuse this issue are not helping or worse.

Reading statements such as:
Custom Bilstein B6 Shock Absorbers, extended to suit ride height increase

Would make me question if they understand how suspension works. It certainly doesn't endear me to want to buy their kit. Along with several other things they say in their listing.
Last edit: 02 Apr 2020 10:15 by 300bhpton.

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02 Apr 2020 15:42 - 02 Apr 2020 15:42 #220586 by DAGZOOK

300bhpton wrote:

DAGZOOK wrote: Not sure what you mean here bhp, Sure with a body lift (spring spacers etc) you're right, you could lift away without gaining any additional down travel because your factory shock will top out. BUT with a true suspension lift, longer shocks and longer springs you will gain down travel all be it 40-50mm.That'll be enough for the prop to foul on the front crossmember unless you fit a compromise kit like the Trailmaster. The longer shocks if gauged correctly to the vehicle will have the same compressed length as the OEM shocks - So you've gained, not lost anything. If the compressed length of the new shock is the same as the OEM shock, no additional bump stops are required.

I think I slightly misread your post last night.

However, what I was trying to say is. Just because a kit 'lifts' a vehicle. Does not mean it'll give you more articulation or flexy suspension. And in fact some of the best suspension setups (general or other vehicles) don't actually lift the vehicle much or at all.

Also shock length really is irrelevant in terms of 'lifting' a vehicle. And companies that confuse this issue are not helping or worse.

Reading statements such as:
Custom Bilstein B6 Shock Absorbers, extended to suit ride height increase

Would make me question if they understand how suspension works. It certainly doesn't endear me to want to buy their kit. Along with several other things they say in their listing.


No worries, It's good to have a discussion about it - that's what this forum is all about helping people to make an informed decision.

I'm of the understanding that shock length is very relevant when talking about a true suspension lift. If you were to install spring spacers/larger springs with OEM shocks at a standard length; they'd top out far more frequently. Shocks are designed to operate within a certain range - it's the same when lowering a vehicle. It's not advisable to run a shock absorber that's operating at its max or min extremities, you'll end up with a wacked set of shocks in no time.

This JIMNYSTYLE kit is being developed by Bilstein, the white Gen.4 photographed on the website is the prototype vehicle. This kit isn't just being made for JIMNYSTYLE.. I think they're just being the guinea pig. Bilstein and H&R are an age old combination - reviews online (particularly in the performance sector swear blind by them). It's worth noting that Bilstein shock absorbers come with a lifetime warranty against manufacturing defects i.e leaks and premature failures. I've also had great personal life out of a set of B6 shockers on a sports car - 80k miles still operating as they were on day one :silly: Not often a manufacture gives you that piece of mind.

All down to personal preference at the end of the day. Whatever I do I want to go down the subtle route and just improve the factory set up - If I can find a kit that'll kill the bounciness/body roll and give me a very small advantage off-road in the process - I'll be happy.
Last edit: 02 Apr 2020 15:42 by DAGZOOK.

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02 Apr 2020 16:32 #220587 by DAGZOOK


I've got an update from JIMNYSTYLE on the Bilstein H&R Lift kit - QUOTE:

"The complete kit will lift the Jimny by 40mm (this is the amount of lift we have measured on our Jimny after the suspension has settled), but the dampers themselves are 20mm longer than their OEM counterparts (please see attached a quick picture that we took during our install comparing an OEM front damper to one of our Bilstein front dampers side by side).

The H&R spring rates are aimed at Jimnys that are not excessively loaded. We have done the vast majority of our testing with 1-2 occupants in the car, as the primary purpose of the kit is to improve everyday drivability. We wanted to make sure that the kit was optimised for the 90% of driving that a lot of Jimny owners will be doing, as opposed to the rare occasions where it is treated to more extreme circumstances"


So this kit is aimed at complimenting the Gen.4 without crazy modification - It provides a modest 40mm lift (20mm additional droop + 20mm spring lift). As you can see from the photographs the Bilstein 'monotube' shock absorbers are a greater diameter over the OE allowing the shock to hold more oil and feature a much larger piston - so this shock should stand up to serious abuse both on and off road. The spring rates are being designed for a stock Jimny without excessive additional vehicle weight. Which is where other lift kits seem to fall down... (OME & Tough Dog).
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02 Apr 2020 16:41 #220588 by 300bhpton

DAGZOOK wrote:
No worries, It's good to have a discussion about it - that's what this forum is all about helping people to make an informed decision.

It certainly is and I agree fully :)

DAGZOOK wrote:
All down to personal preference at the end of the day. Whatever I do I want to go down the subtle route and just improve the factory set up - If I can find a kit that'll kill the bounciness/body roll and give me a very small advantage off-road in the process - I'll be happy.

I'm not sure a lift will help body roll in any shape or form. Ride over rough terrain looks to be improved when watching vids on YouTube. However I can't really say I would consider the stock setup to be bouncy or prone to lots of roll. I'd almost say the opposite!

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02 Apr 2020 16:58 - 02 Apr 2020 17:02 #220590 by 300bhpton

DAGZOOK wrote: I've got an update from JIMNYSTYLE on the Bilstein H&R Lift kit - QUOTE:

"The complete kit will lift the Jimny by 40mm (this is the amount of lift we have measured on our Jimny after the suspension has settled), but the dampers themselves are 20mm longer than their OEM counterparts (please see attached a quick picture that we took during our install comparing an OEM front damper to one of our Bilstein front dampers side by side).

The H&R spring rates are aimed at Jimnys that are not excessively loaded. We have done the vast majority of our testing with 1-2 occupants in the car, as the primary purpose of the kit is to improve everyday drivability. We wanted to make sure that the kit was optimised for the 90% of driving that a lot of Jimny owners will be doing, as opposed to the rare occasions where it is treated to more extreme circumstances"


So this kit is aimed at complimenting the Gen.4 without crazy modification - It provides a modest 40mm lift (20mm additional droop + 20mm spring lift).

Not sure I concur with the numbers. A 20mm longer shock will only offer 20mm more droop. But with a 40mm lift you are starting with the shock already extended by 40mm. So even with the longer shock, the amount of down travel is actually -20mm over running stock ride height and stock shocks. Assuming you can achieve full compression and the spring doesn't become bound and/or limited by extended bump stops, then in theory the total travel should have increase by a nominal 20mm. However I'm willing to bet the total travel is probably very akin to stock, rather than an actual improvement in flex or travel.


.

DAGZOOK wrote: As you can see from the photographs the Bilstein 'monotube' shock absorbers are a greater diameter over the OE allowing the shock to hold more oil and feature a much larger piston - so this shock should stand up to serious abuse both on and off road. The spring rates are being designed for a stock Jimny without excessive additional vehicle weight. Which is where other lift kits seem to fall down... (OME & Tough Dog).

Pretty sure OME offer at least 3 different spring rates for their kit, maybe 4. Don't know about Tough Dog. However if they are aiming at the Oz market and overlanding for vehicles with bullbars, winches and roof racks. The design and intent does need to be different.

As for the springs, surely Suzuki also designed theirs with similar ethos in mind as what you describe above?

I'm not knocking the kit or components. I just wonder if it is a kit more for looks than outright performance, at least in an off road sense. I would expect such a setup to end up being slightly stiffer with better damping on rough terrain. But whether this actually translates to better road ride quality I'm unsure.

But I guess time will tell. Although I suspect it isn't the kind of kit I'd probably buy myself. And at the best part of £1000 for only 4 shocks and 4 springs, I'd also suggest it doesn't represent very good vfm either.

As for running larger longer shocks. The last shock swap I did was this, although not on a Jimny.



Umm a shame the forum squishes some photos.... :(
Last edit: 02 Apr 2020 17:02 by 300bhpton.

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02 Apr 2020 17:19 - 02 Apr 2020 17:19 #220591 by DAGZOOK

300bhpton wrote:

Not sure I concur with the numbers. A 20mm longer shock will only offer 20mm more droop. But with a 40mm lift you are starting with the shock already extended by 40mm. So even with the longer shock, the amount of down travel is actually -20mm over running stock ride height and stock shocks. [/quote]

I could be wrong (I'm certainly no mathematician :lol:)

My logic is, 20mm extended shock over OEM - this means that during articulation, the wheel being pushed down is able to travel an additional 20mm? Providing the bump stops don't prevent this. As far as I'm aware this kit doesn't come with additional/larger bump stops. :whistle:
Last edit: 02 Apr 2020 17:19 by DAGZOOK.

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03 Apr 2020 11:10 - 03 Apr 2020 11:11 #220622 by 300bhpton

DAGZOOK wrote: I could be wrong (I'm certainly no mathematician :lol:)

My logic is, 20mm extended shock over OEM - this means that during articulation, the wheel being pushed down is able to travel an additional 20mm? Providing the bump stops don't prevent this. As far as I'm aware this kit doesn't come with additional/larger bump stops. :whistle:

That is correct in terms of total travel.

But when a vehicle is sitting level on the ground the shock isn't fully compressed, it is already part extended.

If you just fitted the longer shocks and kept the stock springs, you will increase the amount of available down travel from a level sitting vehicle. But by lifting the vehicle too, you are removing some/all of this advantage. The longer shock is really there to try and counter the lift. But I suspect they have only gone for a short increase in length, because it is either a standard size shock they have on the shelf. And it doesn't cause the prop to hit the crossmemeber.

A +2" shock would likely have been much more ideal, but would have needed the crossmemeber addressing.

Where this becomes of importance is on uneven terrain. If you have say 3 wheels on fairly level terrain and put one wheel in a hole. This setup will cause the wheel to not drop as far as a stock setup. So you'll end up with a wheel off the ground easier.

It's a bit of s tricky concept to grasp. But is along the lines of what I was saying previously.

If you assume you have 10" of shock travel stock. With the vehicle sitting level you have 5" of droop. So imagine if a hole appeared beneath one wheel. It would be able to drop 5" and remain in contact with the ground. This is important as it keeps the other wheels on the ground too.

With a lift you are not starting in the same position, the vehicle is higher, so you have less available droop (the important bit being, this kit offers more lift than the gain in shock length, i,e. 20 - 40 = -20). If the same hole opened up, the wheel would not be able to drop as far, which would mean you would end up with the wheel in the air. The net result would be on some terrain you'd find you would end up with wheels in the air a lot more and the vehicle would feel less stable. With TCS it isn't the biggest issue in the world as it will keep you going. But on an old pre-traction control Jimny this would cause you to become cross axled a lot easier on mild terrain.

Remember the aim of the suspension is to 'suspend' the body from the axles. It is always pushing up on the body. So even at full flex, this setup is likely to under perform for an aftermarket setup. The lift will of course allow bigger wheels, and more clearance. Which are their own advantages.

I'm not saying this is a bad design or anything. But it is one that for the front suspension at least doesn't actually offer any improvement over stock in terms of off roading, apart from greater clearance. And may actually perform worse in some cases. Although 20mm is not a huge amount, so worse is being a little harsh.

Here is my stock Jimny with the suspension crossed up:



Note the real wheel has dropped quite a lot. And the front has tucked up not too bad, but isn't completely stuffed into the arch, i.e. the top of the tyre is still visible.

At the back you can see the wheel has compressed more so with the top of the tyre going into the arch:


But also note that the front drivers wheel also hasn't dropped anywhere near as much as the rear passenger.

This tells you that in stock trim there is more suspension travel on the rear, in total amount and in both compression and droop. This is pretty normal for most road going 4x4's. It is generally easier to get more travel at the rear.

However it is also worth noting, that while the vehicle looks like has all 4 wheels on the ground. It doesn't, by grabbing the roof above the passenger rear wheel I could rock the vehicle back and forth with ease lifting the rear wheel 2-3+ inches off the ground. When resting you can see it is barely touching:


Real world the TCS would kick in should this actually be an off road obstacle. Without TCS the vehicle would become cross axled and stuck however (requiring momentum to drive through the obstacle).

It is also worth noting this is on level ground, the front is heavier with the engine. Which is why it is the rear wheel that lifts when I rock the vehicle. However off roading you are normally driving forwards, so going up a gradient/hill, should you encounter this, the weight may transfer to the back of the vehicle and lift the front wheel off the ground instead. Which is something you see in quite a lot of the YouTube videos of the Jimny off road.

Lots of people/companies will address this by making the rear suspension have more travel, as it is easy to do on most vehicles. Such as a Land Rover Defender. While this will help in some situations, such as level ground, it doesn't address the fact there is limited droop from the front suspension. Meaning sometimes the vehicle will remain planted, while other times it won't. A balanced setup is normally going to be nicer to drive.

As an example. This is my Land Rover pickup and my brothers 90:





Both vehicles driven by the same driver. And both vehicles have fundamentally the same suspension. Both are running +2 shocks and different springs. In fact if anything the blue 90 might have more droop travel at the rear, as I think the shocks on it are slightly longer in real life. It is also running bigger/taller more aggressive tyres. The key difference is I have done some other things to my front suspension that allow it to make use of the flex (Land Rover front suspension isn't limited by the shock length, but the movement in the arms). This gives me more front travel and a more balanced suspension setup. The results speak for themselves I feel.



Clearly while the stock Jimny is capable, there is room for a lot of improvement in the suspension department (meaning off road use). Which for me is what I'd be looking for when fitting a suspension upgrade. I don't know what Jimnystyle are doing on the rear. I assume longer than stock shocks, but if this is similar to what they are doing at the front. Then you'd end up with a taller vehicle that would likely fair the same or maybe even slightly worse in the above test. If this suits what you want from a vehicle, then fine. But I suspect it is playing more on the "Style" part of their name. Rather than looking to enhance the off road capabilities of the vehicle.
Last edit: 03 Apr 2020 11:11 by 300bhpton.
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03 Apr 2020 12:37 #220625 by Busta
I've just done some quick maths. Assuming the optimal position for the shock is in the middle of its stroke at normal ride height, the optimal shock length for any given lift is X+⅔Y where X is the standard shock closed length and Y is the amount of lift.

So for a 40mm lift (Y=40) on a car with shocks of a 200mm closed length (X=200), the optimal shock length is 200+⅔(40) which is ~227mm.

Assuming the "dead" length of the shocks (accounting for the eyelets on each end, thickness of piston and end stops etc) remains the same, this will give 27mm increase in overall travel, with 13.5mm more travel in each direction relative to the centre position. Bump stops should be extended by the same amount as the increase in closed shock length.

+20mm shocks on a +40mm lift aren't optimal, but you are still gaining 20mm more travel overall. +40mm shocks would be to long and you would lose a disproportionate amount of upwards travel, but gain more droop. Excessive droop looks dramatic in pictures but isn't desirable, especially if the springs dislocate. The aim should be to keep weight on the wheels and the centre of gravity as low as possible.

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03 Apr 2020 13:31 #220627 by Busta
This is assuming that when we talk about a +20mm or +2" shock we are talking about the compressed length. +20 compressed is equal to +40 extended.

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03 Apr 2020 16:00 - 03 Apr 2020 16:01 #220633 by DAGZOOK

Busta wrote: This is assuming that when we talk about a +20mm or +2" shock we are talking about the compressed length. +20 compressed is equal to +40 extended.


Thanks Busta & BHP for the in depth responses - Busta your quick math is impressive. :woohoo:

So from what I have been told from the rep Busta - the Compressed shock length is the same as the OEM setup, this is to eliminate the need to fit extended bump stops. The fully extended length of the shock is 20mm longer (see photograph) So this would confirm what you've both said about gaining 20mm droop but retaining the factory flex (up travel).

It'd be interesting to have the specs for the OME 40mm lift as a comparison - but I could almost guarantee similar results.

I'm learning more and more on this thread and by being in conversation with JIMNYSTYLE. I take back what I had previously said about the Trailmaster kit; Trailmaster have used a 1' longer front shock absorber to prevent down travel causing clashes with the front crossmember - but they've also decreased the compressed length of the front shock (hence why they provide new bump stop extensions) So they've achieved the extra 50mm travel by different means?

I've had further correspondence from the team at JIMNYSTYLE. OPEN QUOTE:

"With regards to the Bilstein dampers, the Bilstein special projects team undertook the design of these and will have chosen the specifications based on their experience. While I can very much appreciate that not extending the dampers further has meant that the amount of suspension droop has not been increased as much as it could have been, the goal was to have the dampers operating in their "sweet spot" with the ride height increase induced by the longer springs."

"With regards to the brake hoses, the factory items are not at all long enough to operate with our kit (as you have already touched upon), which is why we supply extended braided brake lines from Goodridge in the kit. These were a joy to install and the quality of them is absolutely fantastic."

As for the clearance between the prop and the front cross member, this has not proved to be a problem at any stage, having been tested with and without the castor correction bushes installed.

Over the last 7000+ miles we have tried to test the kit in as many environments as possible, from motorways to green lanes and everything in between. On particularly rough surfaces we have used the setup at both normal speeds and speeds we are sure most people would not be doing (all in the name of testing!) and I would not describe the setup as aggressive or firm in its behaviour at all. It's definitely less bouncy and jarring than the standard setup, that's for sure.

If we weren't needing to adhere to such stringent social distancing regulations at the moment then we would be more than welcoming of customers willing to come for a quick test drive in our demo Jimny, but at the moment this will need to wait until the current worldwide issues lessen somewhat.


Close QUOTE
Last edit: 03 Apr 2020 16:01 by DAGZOOK.

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