TRM Coilover Group Buy?

[berny2435]

Don't you mean spring rates?

BC if you are running higher than their suggested spring rate, you would be in the upper 33% of the dampening range (also highest setting via the rebound/compression adjuster)

[Level8drummer]

You would think. But with high rates you don't need that much damping.

Also with their recommended rates I did not need that much damping.

Also I run no preload.

L8d

[techno550]

That's a pretty tall order for a company that won't release shock dynos,

We will. Just call or email and we'll send over the forms to fill out.

have shocks on any winning race cars,

incorrect.
GTS2 SE championship. lap records. etc.

or even addressed why they are good.

They are good because they work well. Many threads on this. The short is that they fill the gap between the "good" street car stuff and the "entry level" pro race car stuff. MCS, JRZ, Ohlins, etc are wonderful on a race car. On a street car, they work well if you can tolerate the maintenance and rebuild interval.

Maybe I am missing something, If I am please educate me.

The target for the TRM was "a Pro level shock engineering wise, with street-compatible rebuild intervals". The result is seals that last a lot longer, but aren't as "free" in the fine movement as something like a JRZ. The adjusters are also "less complicated". Orafice plates can work well, but they are more prone to wear/erode. TRMs have the necessary range of adjustment, but not necessarily the fine granularity you might find on a MCS. I challenge the "advanced" DE guy to be able to tell the difference though.

MCS does nothing but shocks all day long,

And for a double adjustable or beyond, we recommend MCS. If you NEED that level of adjustment, and you have the data system on the race car to go with it, and the engineering support behind it, the extra $XX,XXX in cost for the suspension isn't a concern. If you want something to put on the car for DE, or you are just getting into club racing, the TRM's are just as fast (often faster right out of the box), and easier to find the "happy" zone.

We are also happy to support a car on MCS or JRZ dampers at the track, including data analysis and engineering support.

I am willing to bet it is a night and day difference from the shocks the turbo guys can come up with.

TRM is an engineering firm. The start actually being race car engineering. That got "distracted" by the street car stuff, and the turbo/software was a product of that.
I used my years as a race car engineer on SRP2/LMP675 and formula cars, often with a mix of Professional and Gentlemen drivers to target what made the car fast, and what makes the car fast is being predictable and easy to drive. Is there more left with a well honed "actually fast" car? sure. But amateurs (and a good number of professionals) don't like that knife edge, and if you are tracking an E36 or E46 and not a current F1 car, you might fall into that category somewhat.

The reviews of the TRM's by a large number of people, many with track experience, is that the system does work as intended. It has a wide range of adjustability, and a baseline that puts it in the ballpark. It is fairly quick/easy to get the car to a point where it is easy to drive quickly with minimal effort. A balanced car that communicates well is not always an easy goal to hit, but the TRM suspension does that fairly easily. by the way *this* is why we don't just publish the dynos. The engineering it took to get to this point is inside that.

The jack of all trades is the master of none, so my money goes to MCS by a long shot.

It takes a lot more money to get the MCS option on the car. Double as a starting point. Is it worth double or more? that depends on who you are, what you want, and what you expect to get out of it.

I am willing to bet TRM doesn't even have a shock dyno in house.

We have an AWD chassis dyno in house. We use that a lot. Engines/cars have a lot of variations. Dampers that come to us assembled/dyno'd/etc should not need this. (we carefully selected our manufacturer so this wouldn't be necessary on our end.) That would be like every BMW dealership having a chassis dyno and a 7 post shaker rig. (they don't, btw.) For suspension, we have a "product" on the shelf for E36 and E46. We do a final inspection and check/set things to ease the installation process. All of the core development has been done, and any further testing is on car only at this point (so linear pots and strain gauges), and if we need any dampers run on a dyno, there are plenty around. (including MCS who is only 13 miles away.) We can offer custom valving, and we take it to a shop that stocks a few more shock oils than we do (we keep 2 flavors on the shelf), and we have a full assortment of shims on hand. This only comes up with non-stock geometry or a completely different car/chassis usually, and at that point, we often recommend moving to something like a 3 way MCS or all the way up to a 5 way for bumpy environments. By the nature of our design, we can treat them more like a tightly quality controlled mass produced part like a Bilstein. Which means service is infrequent (almost never?) and just fluid and seals. Ideally, on a MCS or JRZ rebuild, it is also just fluids and seals. Most of the rebuilds (and I've only seen them on cars with massive amounts of track miles on rough tracks) have been fluid and seals only, and were carried out by local damper shops and not shipped back to TRM. We just shipped parts (fresh seals). Protip: If you can fill/service an Ohlins, you have the tools needed to service a TRM.

The TRM's aren't meant to replace the "high end" dampers. They are meant to fill the glaring void between the "good street car stuff" like an off-the-shelf Bilstein strut and the "low end of the high end" like a JRZ RS. (though now the JRZ RS1 somewhat "competes" in this arena, and is very similar to the TRM in its philosophy, just a tad bit more expensive.) There isn't another complete package that fits in that segment or can do what the TRM suspension can do at the same price point.

[Schachmatt]

2 questions for Mike McCoy:

1. Camber Plate adjustment - I believe I read somewhere where the strut had to be lowered in order to adjust camber. If true can you give some details on this procedure?
2. Rear ride height - install instructions say "Ride height, with sufficient preload, is primarily set by the damper length". I'm confused - is the rear weight of the car supported by the dampers or the springs? Would appreciate some detail on how this works.

Thanks.

[techno550]

1. Camber Plate adjustment - I believe I read somewhere where the strut had to be lowered in order to adjust camber. If true can you give some details on this procedure?

With the camber plates, there are 4 screws that lock the adjustment. Two of them are easily accessible, but with the center of the strut at the "back" of the hole, two of them are behind that and under the strut tower sheet metal, thus inaccessible when fully assembled.

To adjust camber there are a few ways to approach it. On race cars, we will add an extra hole or slot. (and often we have to notch the strut tower as well anyway.) If this is done, there is no need to lift the car. (I've also seen some leave out the inaccessible ones, and in some cases add a 3rd to the holes that are accessible. We don't specifically suggest that though, and for most, it is the one time adjustment on the alignment rack, and adds ~60 seconds to the process.)

With everything "stock" and not on an alignment rack: loosen the 3 nuts on the strut hat. lift that corner of the car slightly with a jack to unload the suspension and sag the strut. use a ball end hex head or short bent allen wrench to loosen the two screws on the camber plate that are *under* the strut tower sheet metal. loosen the two that are accessible. slide the camber plate. tighten the two that are accessible, then tighten the two that are under the sheet metal. set the corner down. tighten the 3 strut tower nuts. (note that you need a jack and to loosen the 3 nuts when you adjust using vorshlag plates or the likes as well, but they are the main/only fastening apparatus in that case.)

With everything stock and on an alignment rack: loosen the 6 nuts (3 on each side), lift the front, loosen the two inaccessible bolts, set the car down, loosen and adjust the other accessible bolts to move the struts and tighten when done, and then lift the front again and tighten the inaccessible ones and lower, check and tighten the strut hat nuts.

2. Rear ride height - install instructions say "Ride height, with sufficient preload, is primarily set by the damper length". I'm confused - is the rear weight of the car supported by the dampers or the springs? Would appreciate some detail on how this works.

the weight of the vehicle is supported by the springs. This will always be the case, even with the damper length limiting droop travel.
the damper length prevents droop travel when sufficiently short. (or the spring sufficiently long. frame of reference question there.)
so if we have 700 lb of load on each rear wheel, at 700 lb wheel load equivalent of spring preload, we have no additional squat when we set the car on the wheel. This point is called zero droop. If we go beyond that, we can continue to lower the car with the damper (and continue to preload the spring). Below that point, the spring height sets the ride height as we have squat when the car loads the wheel at rest.

[Level8drummer]

Excellent explanations. So much spring control and adjustability for such an inexpensive setup.

L8d

[Schachmatt]

With the camber plates, there are 4 screws that lock the adjustment. Two of them are easily accessible, but with the center of the strut at the "back" of the hole, two of them are behind that and under the strut tower sheet metal, thus inaccessible when fully assembled.

To adjust camber there are a few ways to approach it. On race cars, we will add an extra hole or slot. (and often we have to notch the strut tower as well anyway.) If this is done, there is no need to lift the car. (I've also seen some leave out the inaccessible ones, and in some cases add a 3rd to the holes that are accessible. We don't specifically suggest that though, and for most, it is the one time adjustment on the alignment rack, and adds ~60 seconds to the process.)

With everything "stock" and not on an alignment rack: loosen the 3 nuts on the strut hat. lift that corner of the car slightly with a jack to unload the suspension and sag the strut. use a ball end hex head or short bent allen wrench to loosen the two screws on the camber plate that are *under* the strut tower sheet metal. loosen the two that are accessible. slide the camber plate. tighten the two that are accessible, then tighten the two that are under the sheet metal. set the corner down. tighten the 3 strut tower nuts. (note that you need a jack and to loosen the 3 nuts when you adjust using vorshlag plates or the likes as well, but they are the main/only fastening apparatus in that case.)

With everything stock and on an alignment rack: loosen the 6 nuts (3 on each side), lift the front, loosen the two inaccessible bolts, set the car down, loosen and adjust the other accessible bolts to move the struts and tighten when done, and then lift the front again and tighten the inaccessible ones and lower, check and tighten the strut hat nuts.

Thanks, I think I have it now. But I have to ask, what drove the need to design the trm camber plates with two inaccessible bolts? Is this design somehow better than the vorshlag design?

... If we go beyond that, we can continue to lower the car with the damper (and continue to preload the spring). ...

I think I was following you (how the adjustable damper controls droop) up until this sentence. I'm still not getting how the rear damper plays a role in setting rear ride height.

And BTW, thanks for your posts here and in various other threads. They are extremely informative.

[propcar]

Indeed. Very informative. Excellent responses and restraint lol

Mike, if I could suggest something. Your site description for these could use a bit of revision. As it sits there's hardly anything at all. A testimonials bit would be good too, I think people question the unknown but with positive reviews its more comforting. Its OK to show off a good product :P

[DBVille]

Indeed. Very informative. Excellent responses and restraint lol

Mike, if I could suggest something. Your site description for these could use a bit of revision. As it sits there's hardly anything at all. A testimonials bit would be good too, I think people question the unknown but with positive reviews its more comforting. Its OK to show off a good product :P

I second this. I read on forums how good these are, and folks at the track talking about them, and I go to the site and find almost no information. I recognize that I can contact someone for specific information, but most folks are looking for something to just read through while they figure out if they want to spend two grand on a system with essentially no description on the web site, or no reviews there.

[techno550]

Thanks, I think I have it now. But I have to ask, what drove the need to design the trm camber plates with two inaccessible bolts? Is this design somehow better than the vorshlag design?

The design was to properly support the upper bearing, and the amount of caster desired dictates that the top of the strut be at the "back" of the hole in the strut tower. It being adjustable would add to the complexity and thus cost to manufacture. It also would make it more difficult to "set" in your garage. It also makes adjustments "on the fly" difficult if there are too many degrees of freedom.

One of the goals was to make a system that was easy to set up and adjust, so we intentionally limited the number of adjustments out of the box. (ex: we recommend a stock front bar and no rear bar. That leaves very little guessing left when trying to figure out what to adjust on a sway bar... there is nothing.)

With only "camber" as the targeted adjustment, in the first go round on setting a car up on track, you might have a few adjustments made. The time (and difficulty) to adjust is the same as the vorshlag plates. With a Vorshlag plate, you still have to jack up the car to move it because you still need to unload it. You still need to loosen the 3 nuts on the strut hat. Lifting a car already on a jack another inch higher and loosening two more screws doesn't seem like an exceptional additional step.

With it being camber only for adjustment, most street car guys set it once (at the alignment shop) and never touch it again. At the track, it doesn't take any longer than a vorshlag plate, and the adjustment is easy. As with the rest of the system, the goal is to make the tire happy. center of the tire hot? too much pressure. Inside edge hot? stand the tire up. outside edge hot? lean the tire in. From there you are free to fine tune the balance via the dampers, spring rates, spring preload, ride height, etc. But I don't see people making multiple camber adjustments at the track on the same day/weekend. Generally you show up with it set where it is needed... or at least really really close. Changing tires/brands you might need an adjustment, but it will be slight, and its rare for me to need to move it more than once.

The vorshlag plate design is quite nice, but possibly overly complicated for the intended use, and the cost is higher than what we wanted to target for this segment. If you want vorshlag plates though, they do work with the TRM coilovers. It is an additional ~$400 iirc. The other option would be to center the strut and make it easier to get to the rear bolts, but then we lose the caster. When we were doing development we looked into this. No additional cost to make these over what we have now, but nobody wanted less caster, and nobody thought the adjustment was anything out of the ordinary with what is now the standard setup.

I think I was following you (how the adjustable damper controls droop) up until this sentence. I'm still not getting how the rear damper plays a role in setting rear ride height.

At zero droop, when you set the car down on the spring, there is no further compression.
OE's use preload to a lesser extent so it can make it difficult to visualize.

I'll use an example where the spring rate == wheel rate, and linear springs, to keep it simple.
If we have a 100 lb/in spring, we may want some preload on it. Otherwise, when we put the 800 lb of car on that wheel, we get 8 inches of movement from full droop to "rest". Now we probably also want to be able to handle bumps that generate at least 2x the load, which would mean we'd need another 800 lb of load on top of the vehicle weight on that corner, so 1600 lb, which would give us 16 inches of travel, or 8 more inches in bump. 100 lb/in is a common OE wheel rate, but 16 inches of wheel travel on a passenger sedan is ... uncommon. The way we get around this is to "pre load" the spring. For the OE approach, if we have already found our target ride frequency dictates a 100 lb/in spring, we then look at total travel desired. if we figure we only want/need 2 inches of droop travel, we can preload the spring 6 inches. (600 lb). now, full droop (wheel off the ground and zero load) to the car sitting on the ground will only move/compress the wheel 2 inches.
If we were to preload the spring 1000 lb, (10 inches), we would not get any movement from "full droop" when we set the car (and its 800 lb wheel load) on the ground. We can even set a 190 lb person in a seat directly positioned above that wheel and it still will not move. it won't be until we exceed that 1000 lb of force threshold that we will start seeing wheel movement.

From that example you can hopefully see some of the how and why of preloading, but also quickly see why OEs also use non-linear springs.

So when preload >= load the car will put on the spring at rest, setting the car on the ground won't move the tire. "full droop" is set by the damper length. From that point, if you shorten the damper more, you lower the car more.

And BTW, thanks for your posts here and in various other threads. They are extremely informative.

Thanks. Glad I can help. Apparently I need a lot more information on the site as well. Hopefully seeing the questions here will help me compile a list of things to better discuss.

[berny2435]

Good information here. Thanks Techno550. couple more questions here

1) RE: the adjustment of compression and rebound together. how would you describe how much the adjustment works with the supplied spring rates?
2.) can you make a tire like the Hankook RS3 start to skip from setting the adjuster near the maximum?
(please note that I don't consider this a bad thing, just shows a range)

Thanks

[techno550]

Good information here. Thanks Techno550. couple more questions here

1) RE: the adjustment of compression and rebound together. how would you describe how much the adjustment works with the supplied spring rates?
2.) can you make a tire like the Hankook RS3 start to skip from setting the adjuster near the maximum?
(please note that I don't consider this a bad thing, just shows a range)

Thanks

1. I'm not sure I understand the question.
2. Yes, you can easily overshoot the damping. The Hankook Ventus RS2 was actually the baseline tire/carcass used for the development. I haven't called to get tire data on the RS3 as I have moved to mostly Michelin/BFG for tires now, but I suspect they didn't drastically change the tire itself between the RS2 and RS3. (I posted RS2 data a long time ago if you have RS3 data for comparison.)

[berny2435]

Okay. That lets me know more about the range on the adjustment. The sidewall of those two tires is pretty similar so I can only guess that if you can over dampen the rs3, you can even more easily over dampen something like the Dunlop z2 which I've found doesn't like as much compression as the rs3v1.

I'm not sure about BFGs. Are you talking about the rival or the Rcomp. Flavors?

[Level8drummer]

Yes, have you found the bfg rival to be fastest of the street tires techno550?

L8d