Tein Flex A

[solidONE]

Originally Posted by Trettiosjuan

Not sure. If wallowing is the suspension riding the bumpstop, then perhaps so, as the HBS won't have the return jolt of the compressed rubber bumpstop releasing its energy.

But if your cornering very hard on high grip, the HBS can't compensate for lack of roll stiffness (too low spring rate or sway bar stiffness) that compromises the bump travel.

How much bumpstop-free bump travel is there on the Z front/rear? If it is anything like the A where there is a full 1" more travel at the rear, I would expect problems in front first....

I didn't take the time to measure the amount of damper stroke, as it was a customer's customer's car so I didn't take my time to measure everything besides preload and ride height. I just installed and adjusted them then drop it off back at their shop. As far as the tire choice goes, I had no say. Apparently he got a really good deal on his wheels and likes the "meaty" look. Way to much tire, IMO, but they were mainly for aesthetics. After a couple hundred miles on the new suspension he brought the car back for me to check and re-torque everything. That's when I had the chance to throw it around a few bends.

At -5 from full stiff it would skip off the bumpstop or "wallow", but no jolt. (And yes, of course I know these dampers are not designed for circuit driving....) At -1 from full stiff it would no longer skip off the bumpstop or "wallow" mid corner. I'm sure if I took the turns harder it will eventually get down to the bumpstops. The ride quality at -1, while firmer, was still pretty damn comfortable. Makes me wonder whether if the japanse spec Flex-Z and A offer more damping for a more "sportier" ride with the same spring rates.

Curious, how much damper stroke is offered in your Flex-A dampers?

[Trettiosjuan]

Flex A damper stroke front/rear is 93/96.5 mm (from Tein UK)
With motion ratios that becomes at the wheel approx 98/129mm respectively. Fairly normal numbers for a double adjustable lowering coilover, from which you would usually need to substract the height of a compressed bump stop so the Flex A is still quite good... From my calc with the weight of the car on the 6/6 springs, the rears sit in the middle of damper stroke which is good, but the fronts sag more than 60%...

[shattered_memory]

Originally Posted by solidONE

Sound like this is worth the extra over the Flex Z. I've thrown around a flex-z equipped FRS at 5 clicks out and the damping, particularly in the rear, felt lacking. It would wallow during hard cornering (from lack of damping). With it jacked up to -1 from full stiff it was a little better. If those hydraulic bump stops works as you describe, then it would probably not have the same problem. Although this is the only complaint I'd have. Over the rough stuff and for normal driving it's soooo compliant. I don't think you can get anything better for the $800 price tag of the Flex-Z. that extra $250 for the extra compression damping at the end of the stroke is probably worth it, I think. I'd have to try for myself to be sure though.

This comment is a little disappointing to me since I just ordered a set of Flex z's. Do you think the flex z improves on the handling compared to stock? I really like the performance of my stock brz suspension and never feel the rear suspension wallow under hard cornering at all. Also, how low was the car that you tested? Thanks.

[churchx]

shattered memory: Zs WILL be better then stock. At DD, and slightly at track, but don't expect miracles, more track focused or higher end offerings on track will outperform it there. So if you pit them against stock, i'd say go for it, at their price they are good. But if you had them in mind for lot of autox/track racing with very grippy tires .. there are better fitting offerings out there.

[solidONE]

Originally Posted by Trettiosjuan

Flex A damper stroke front/rear is 93/96.5 mm (from Tein UK)
With motion ratios that becomes at the wheel approx 98/129mm respectively. Fairly normal numbers for a double adjustable lowering coilover, from which you would usually need to substract the height of a compressed bump stop so the Flex A is still quite good... From my calc with the weight of the car on the 6/6 springs, the rears sit in the middle of damper stroke which is good, but the fronts sag more than 60%...

That's actually a good amount of damper stroke. The rear damper stroke is just about the same as the dampers I'm testing, subtracting the height of the bumpstop there is a little less than 3.5" or 86mm of damper stroke before it starts to make contact. It uses the same rate 6K spring rate as the Flex Z and A coupled with much more aggressive range of damping force adjustment. I've tested them extensively on 255, 225 and 215 wide Hankook RS-3 tires in the canyons, on the race track, and over railroad tracks/speedbumps/pot holes etc. without it ever making contact with the bumpstops. As far as damper stroke available, spring rate and tire grip its same to very similar. Although quality, damping, and also price we're comparing apples to grapes... This does prove my point that increase in compression damping pressure will keep it from bottoming, but I'm sure at the expense of DD ride comfort.

Edit: just some background on who developed these dampers. They are specialist who develop race wining suspension for many platforms for race teams around the world including some very well known JDM companies and not some self proclaimed "wise man" on the Internet that "knows everything". Along with the help of a current race technician working for Ferrari (FSC), who also owns a BRZ and runs the same suspension on his car, developed these dampers that I'm currently testing.

Y'all can listen and buy into his BS, but I'm done dealing with this troll.

[shattered_memory]

Originally Posted by churchx

shattered memory: Zs WILL be better then stock. At DD, and slightly at track, but don't expect miracles, more track focused or higher end offerings on track will outperform it there. So if you pit them against stock, i'd say go for it, at their price they are good. But if you had them in mind for lot of autox/track racing with very grippy tires .. there are better fitting offerings out there.

Thank you for your explanation. I understand the flex z's intentions that it's not a dedicated track setup. I'm just looking for something that is equal or slightly better than stock and I guess Solidone's comment made it seem like it may be worse than stock.

[solidONE]

Originally Posted by shattered_memory

This comment is a little disappointing to me since I just ordered a set of Flex z's. Do you think the flex z improves on the handling compared to stock? I really like the performance of my stock brz suspension and never feel the rear suspension wallow under hard cornering at all. Also, how low was the car that you tested? Thanks.

I'd say with the damping pressure adjusted to the higher ranges (-5 and higher) it will still handle better than a completely stock suspension. We're talking increase in camber front and rear. Just the front plate alone and a mild drop will get you close to -3 degree of camber in the front, along with about double the spring rates from stock. Although it will ride much more comfortable than stock even at full stiff, with enough range to have it riding like a boat, if that's what you are into.

I had his set to -2.5 f and 2.0r, with about a 18mm drop and 5~8mm rake. I was pretty impressed with these $800 dampers.

[solidONE]

Originally Posted by shattered_memory

Thank you for your explanation. I understand the flex z's intentions that it's not a dedicated track setup. I'm just looking for something that is equal or slightly better than stock and I guess Solidone's comment made it seem like it may be worse than stock.

Really? lol If I gave it any more praise you'd think i was working for Tein. But yeah, they're worth the $800 for sure.

[CSG Mike]

Originally Posted by solidONE

I didn't take the time to measure the amount of damper stroke, as it was a customer's customer's car so I didn't take my time to measure everything besides preload and ride height. I just installed and adjusted them then drop it off back at their shop. As far as the tire choice goes, I had no say. Apparently he got a really good deal on his wheels and likes the "meaty" look. Way to much tire, IMO, but they were mainly for aesthetics. After a couple hundred miles on the new suspension he brought the car back for me to check and re-torque everything. That's when I had the chance to throw it around a few bends.

At -5 from full stiff it would skip off the bumpstop or "wallow", but no jolt. (And yes, of course I know these dampers are not designed for circuit driving....) At -1 from full stiff it would no longer skip off the bumpstop or "wallow" mid corner. I'm sure if I took the turns harder it will eventually get down to the bumpstops. The ride quality at -1, while firmer, was still pretty damn comfortable. Makes me wonder whether if the japanse spec Flex-Z and A offer more damping for a more "sportier" ride with the same spring rates.

Curious, how much damper stroke is offered in your Flex-A dampers?

Originally Posted by solidONE

That's actually a good amount of damper stroke. The rear damper stroke is just about the same as the dampers I'm testing, subtracting the height of the bumpstop there is a little less than 3.5" or 86mm of damper stroke before it starts to make contact. It uses the same rate 6K spring rate as the Flex Z and A coupled with much more aggressive range of damping force adjustment. I've tested them extensively on 255, 225 and 215 wide Hankook RS-3 tires in the canyons, on the race track, and over railroad tracks/speedbumps/pot holes etc. without it ever making contact with the bumpstops. As far as damper stroke available, spring rate and tire grip its same to very similar. Although quality, damping, and also price we're comparing apples to grapes... This does prove my point that increase in compression damping pressure will keep it from bottoming, but I'm sure at the expense of DD ride comfort.

Band-aid for the symptom, not a solution for the problem.

If you're going past being critically damped on compression to prevent bottoming out, you have a setup error. Yes, you can indeed prevent the compression event from happening by preventing the spring from compressing, so that the force is, instead, transmitted to the chassis. That is , however, exactly what the suspension is NOT supposed to do. The suspension is there to absorb the road force on the car, not pass it on.

The real fix, is to properly set up the ride height, so that you are no longer bottoming out the damper over bumps, when the damping is critical (or slightly past critical if you want to play it safe).

Side note: maxed damping on the Z is fully useable, but not very comfortable for street driving. You don't have to have a harsh ride to get good handling, but it comes with the territory for any sub-2k damper.

[Trettiosjuan]

So got the springs today and installed them right away.

New Swift spring is green also (they only fit Teins?), nice touch. 178mm instead of 150mm, 7kg instead of 6kg.


Also measured front damper stroke, it is approx 80mm. So 13mm went missing, a good look under the dust boot reveals an very small rubber bump stop, about a third in height of a regular coilover bumpstop...

so much the better considering how the HBS works (see above), but also even more important to get sufficient bump travel before you hit it. Which with the above spring (7kg gives 8mm more) and exactly 7mm preload, bump travel increases 15mm from approx 22mm on the shock (before hitting the above) to approx 37mm, quite a difference! As you can imagine with the increased rate also, the load needed to touch the final bump stop is a lot higher now.

As planned, I removed one collar and the springs sits on on the two remaining ones straight on the wheel carrier. Car is about -30mm in front from stock.


Went for a pretty serious drive doing most types of driving and roads, and now the Flex A are exactly as I hoped for. Front and rear feel much more balanced. Played with damping adjustments, only needed to turn the front 1 click firmer compared to the 6kg spring to get it to my liking (now 6/7 clicks front/rear from full firm). The bridge jump felt much calmer and undramatic at 50mph compared to the RCE yellow where one would bounce of the bumpstops and get launched a bit. I dared to increase speed to 56mph but then it started to bottom out just a bit, still less eventful than the RCE yellow. A clear improvement in (bump) performance driving.
Also the dreaded reference speed bump. Where before it would very noticeably bottom out at 16mph (with the 6kg spring), now at the same speed it was uneventful. I increased speed to 21mph where it just started to bottom out. Like for like, I estimate the speed went up 6mph (15mph to 21mph), a big increase percentage wise. I didn't feel like going faster, it's the kind of speed that starts to feel unnaturally high for a lowered car. Also on back roads, I feel I can push on as much as I like without getting the distinct impression that front bump stroke is limiting the car, and front and rear seem to hit the HBS at the same time. And in other less bumpy circumstances, it still rides a lot better than the stock dampers. So more peformance, better ride, and yet it sits as low as I'd dare (-30/-25 fr/re from stock). All in all very pleased now with the (modded for my chosen rideheight) Flex A, a real upgrade!

[solidONE]

@Trettiosjuan ^ 6/7 click out? Now I'm really curious if these are valved differently than the Flex-Z. When I tested at -5 it still felt quite soft without riding like a boat. And of course the slight bottoming of the rear to the bumpstops cornering at speed. Also the difference between -5 to -1 from full stiff was not very large on the car I tested.

Did you swap out the springs on all 4 corners?

Edit: Okay looking a few pages back you stated that these are the Euro/Jap-spec and not the US-spec dampers. So I'm assuming these provide a bit more damping force especially on the compression side.

[Trettiosjuan]

Sorry, 6 clicks front from full firm in front, 7 rear. Corrected in previous post. Recommended is 8/8(Non-US)

Don't know about other people using a wide range of setting on their shocksI always end up strongly prefering one single setting, often close or spot on recommended setting, irrespective the driving done. 1 click out I feel, more than two either way and it feels awful. Like that on KW (different platform) and these. No idea about the Z... Non rebuildable, perhaps different?

No just in front, rears are original and without preload.

[solidONE]

Very cool! Glad you were able to get them to how you like them with the 7k/6k combo. If only they published the force vs velocity chart of the different specs. I have a feeling I'm right about the compression damping difference, due to the shittier roads in the US compare to the rest of the developed world.

[bfrank1972]

Originally Posted by Trettiosjuan

So got the springs today and installed them right away.

New Swift spring is green also (they only fit Teins?), nice touch. 178mm instead of 150mm, 7kg instead of 6kg.


Also measured front damper stroke, it is approx 80mm. So 13mm went missing, a good look under the dust boot reveals an very small rubber bump stop, about a third in height of a regular coilover bumpstop...

so much the better considering how the HBS works (see above), but also even more important to get sufficient bump travel before you hit it. Which with the above spring (7kg gives 8mm more) and exactly 7mm preload, bump travel increases 15mm from approx 22mm on the shock (before hitting the above) to approx 37mm, quite a difference! As you can imagine with the increased rate also, the load needed to touch the final bump stop is a lot higher now.

As planned, I removed one collar and the springs sits on on the two remaining ones straight on the wheel carrier. Car is about -30mm in front from stock.


Went for a pretty serious drive doing most types of driving and roads, and now the Flex A are exactly as I hoped for. Front and rear feel much more balanced. Played with damping adjustments, only needed to turn the front 1 click firmer compared to the 6kg spring to get it to my liking (now 6/7 clicks front/rear from full firm). The bridge jump felt much calmer and undramatic at 50mph compared to the RCE yellow where one would bounce of the bumpstops and get launched a bit. I dared to increase speed to 56mph but then it started to bottom out just a bit, still less eventful than the RCE yellow. A clear improvement in (bump) performance driving.
Also the dreaded reference speed bump. Where before it would very noticeably bottom out at 16mph, now at the same speed it was uneventful. I increased speed to 21mph where it just started to bottom out. Like for like, I estimate the speed went up 6mph (15mph to 21mph), a big increase percentage wise. I didn't feel like going faster, it's the kind of speed that starts to feel unnaturally high for a lowered car. Also on back roads, I feel I can push on as much as I like without getting the distinct impression that front bump stroke is limiting the car, and front and rear seem to hit the HBS at the same time. And in other less bumpy circumstances, it still rides a lot better than the stock dampers. So more peformance, better ride, and yet it sits as low as I'd dare (-30/-25 fr/re from stock). All in all very pleased now with the (modded for my chosen rideheight) Flex A, a real upgrade!

Very interesting post - this is something to consider for anyone who really wants more bump travel out of these. Problems with droop in this configuration?

Also, an unrelated topic, but I thought I'd ask here since there's activity: noise - how is noise on these for everyone? Dead quiet?

This topic has been discussed in several threads. Some say 'normal' some say 'abnormal'.

Installed my set, they're not Flex A's, but they're the slightly older 'street flex' models. Front right had some noise, tightened the top nut and all good. Rear top nuts were tight, had noise, took them off and checked again, they are tightened at or beyond torque specs (didn't loosen and re-tighten them). Reinstalled and I still get a metallic clunk over bumps/potholes, just like others mention. Not loud or really worrying, but it's certainly there. On second install greased the lower mounts too. Springs have slight preload, everything that I can think of is tightened to spec. Long story short - is this really normal or is something broken? Do I need to disassemble the rear hats? It kind of bugs me...