Dinan rear toe links...just installed!

[bigjae1976]

My first suspension mod...I have a non-EDC stock setup otherwise. I cannot comment on how good they are or are not...need to get an alignment.

First, why go with dinan? Yeah, you can get other bars cheaper and you can even build your own. I've used some TMS adj control arms which are pretty much the same thing as these. I pulled out the rod end of the dinan link and there is a considerable amount of material so you really have a lot of adjustment and a lot of strength (sorry, no pics). This, IMO, is the difference with vrs other brands. I'm sure they are using less expensive rod ends that aren't as long. The dinan part fit perfectly and the difference is in the little things. The link body feels thick and strong...it just looks and feels better.

Second, why this particular upgrade? Dinan claims this piece enhances rear end stability under hard acceleration. As the back end squats, the link flexes can causes toe changes. I would imagine that if there is any steering input, the back end would be even more unstable since you'd potentially have different toe figures on each side.

I felt this at the track with a stock suspension and R6 scrubs(255fr/275rr). Everytime I came out of a tight corner, hard on the acceleration, my back end would kick out or I would have to wait to get on the power. It is very managable but I thought this was only one of two weaknesses in the OEM non-EDC suspension (lack of front camber is the other). The OEM suspension IS excellent, I'm seriously debating whether to install the Dinan Stage II I have in my garage! So I'm hoping this one part cures the rear end twitchiness.

Install...

Was super easy. Took me about an hour. Really, its just loosening two bolts and then retightening 2 bolts. Just need to make sure the rod ends are centered and you tighten down the jam nuts. It helps to try and keep the length of the dinan rods the same as the OEM links.

I will give a quick review on the street tomorrow and over the next couple of days with street tires (OEM PS2s) of course. I will hit the track again on either 4/21 or 5/5 probably with some conti scrubs (275 square). Then I will install the Dinan Stage II and provide another review.

[bigjae1976]

Why is this a "racing only part"? I remember with the E46, the rear camber arms were made to be flimsy on purpose. If there is an impact in the rear, you'd lose a camber arm with the flimsy OEM version...it was designed to bend.

When you installed something more significant, the rest of your suspension (which costs a lot more), subframe, and rear end would absorb the impact. From the looking at the rear subframe, that would be my guess here as well...the OEM toe arm was made to bend under an impact.

[///M Ryder]

Nice work......in for review..................Phil

[THE TECH]

I doubt rod end cost is making up the difference in price. Dinan has an established name, so they think they can charge astronomical prices. The only part that they might make is the bar, but even that is just a CNC'd piece which isn't anything special. Hope they give you the performance you're after.

[bigjae1976]

Originally Posted by THE TECH

I doubt rod end cost is making up the difference in price. Dinan has an established name, so they think they can charge astronomical prices. The only part that they might make is the bar, but even that is just a CNC'd piece which isn't anything special. Hope they give you the performance you're after.

They do engrave a "D" and it is a more polished product. I will admit it is overpriced especially considering that this item is not warrantied. There's no filing, fussing, grinding, banging, hammering, prying, (gulp) torching this thing on...it just goes on and its nice and snug. I do see value in the dinan products because they go on like an OEM part. I've learned the hard way with my E46...you DO get what you pay for. If you cut costs, you're sacrificing something. So you need to decide if its worth sacrificing.

Luckily, I jumped on this one used...I haven't seen too many of these rods being sold used.

Do know that these spherical rod ends don't last nearly as long as the rubber bushing ends. I got 35k miles out of the ends on my E46 rear control arms...I ended up replacing the rod/bearing end with their rubber bushing end.

[klammer]

I've thought about these as well. Looking forward to your impressions, and couldn't agree more that you get what you pay for, especially if you're tracking the car

[Bubbles]

Please keep us posted, I'm very curious of your track impressions.

[bigjae1976]

Right now its terrible! But my alignment is way off...my visual aligning skills aren't so good.

Lesson learned, mark the bolt head...not the washer.

[bigjae1976]

If your rear toe is way out of spec like mine was, you'll get a traction control warning light. So I readjusted it to a manageable level so that the light went out.

Bad news is my suspension guy couldn't do the alignment this evening so no new update other than its terrible right now...since its out of alignment The plan is to get it done tomorrow. What a time for my suspension & tire guy to close his shop

[klammer]

Originally Posted by Bubbles

Please keep us posted, I'm very curious of your track impressions.

+1

[bigjae1976]

I think the right word for the rear end is darty or twitchy on the OEM suspension. I had the car aligned, .09 degrees of toe in on each side in the rear...factory spec (according to the sheet) is .13 - .04 degrees of toe. Your alignment guy will thank you because it makes aligning the rear REALLY fast. Literally takes minutes to set rear toe...a big plus if you DIY alignments. At a minimum, it's almost shade tree mechanic proof.

Street impressions...

There is a difference. When I made a somewhat tight right turn, I feel like I could get on the power sooner and more aggressively without the rear end getting light along with the disconcerting feeling that you are not sure what the rear is doing...twitchy. Even when you accelerate hard from a stop, it just goes straight, no swaying or question where the back end was. At this point, might be a placebo effect but I'm much more confident going around a corner fast. I was running late for hockey so I was driving fast. I drive on a stretch of VERY uneven pavement so the suspension works pretty hard. It just felt better and more planted. I take some banked corners around 80-90mph and then it gets unnerving after that...the back end feels loose...but I took these turns close to 100 and felt very controllable.

Jury is still out on whether or not this is worth $500+...but it seems to be doing what it is advertized to do. I'm glad I got it. I might throw on the Dinan Stage 2 this week for the upcoming weekend at MSR Houston. Stay tuned for track impressions.

[rzm3]

To be honest, I still don't buy how much this link improves rear end stability. Does it make alignment easier? Sure. But the factory link already uses ball joints (not rubber bushings) and uses a very thick piece of aluminium. Just because the OEM part is curved, it does not mean that it flexes a whole lot. Moreover, there are many other bars/joints in the suspension that still uses rubber bushings. I am sure one of the many engineers on this forum can do a quick hand calc of a rectangular curved bar under load.

[bigjae1976]

Originally Posted by rldzhao

To be honest, I still don't buy how much this link improves rear end stability. Does it make alignment easier? Sure. But the factory link already uses ball joints (not rubber bushings) and uses a very thick piece of aluminium. Just because the OEM part is curved, it does not mean that it flexes a whole lot. Moreover, there are many other bars/joints in the suspension that still uses rubber bushings. I am sure one of the many engineers on this forum can do a quick hand calc of a rectangular curved bar under load.

Yes, the factory link is not a rubber bushing but it does have a rubber cover which probably helps the ends last a lot longer.

It could all be in my head but when I didn't feel the rear end getting light about 2/3 of the way around a right turn onto a state highway. That is very subjective. Unless I mount a camera focused on the OEM link its all guess work. I'm not an engineer but the OEM link is a curved H beam (aluminum??) vrs the Dinan link which is a hollow straight rod. I would guess that the dinan link is stronger? Its not an astounding difference. I lucked out and got this pretty cheap used but never installed. Would my feelings be hurt if I had paid $500+ for it? Maybe. I would think that this piece would be of little value if you already have coilovers and numerous other suspension mods.

I don't think this part will really cut the lap times of a professional but it has, so far, made me feel warmer and fuzzier. I think it will cut lap times for inexperienced, non-professionals like myself.

[Orb]

Originally Posted by rldzhao

To be honest, I still don't buy how much this link improves rear end stability. Does it make alignment easier? Sure. But the factory link already uses ball joints (not rubber bushings) and uses a very thick piece of aluminium. Just because the OEM part is curved, it does not mean that it flexes a whole lot. Moreover, there are many other bars/joints in the suspension that still uses rubber bushings. I am sure one of the many engineers on this forum can do a quick hand calc of a rectangular curved bar under load.

I designed my own my M3 replica arm for 335i. I did the calculations and FEA simulations and posted these details some time ago. Not surprising, the OEM will take well over 3 times the corner weight of the car which is what one would expect. The curved part is a very smart design and not obvious. It redirects the load in bending and thus the take larger loads when compared to pure compression (buckling). The curved design also helps with a very good type of compliance and it will do very in a crash as well. The bearing race is Delrin material which has far lower friction than the rod end over the long term. The OEM arm is a very good design in every way.

The Dinan arm calculation in a tension and compression are not good when compared to the OEM. It just buckles in compression so I wondering if anyone has done any calculation at all...LOL. The Dinan arm will deflect more especially under high loads. The OEM has more material so it should make some sense to a few. Dinan is making claims that the OEM arm is not stiff and has rubber bushing. Both are not true at all. If Dinan selected high alloy steel for the tube it would be stiffer than the OEM arm and not much heavier. Clear example of all show and no go. This is very typical in this industry far more than people realize.

FWIW, the M3 sub frame bushings are just okay at best…it would be wise to deal with this one issue as BMW did with the GTS. Tuner Motorsports has racing bushing for every link now.

Sorry to the OP but the truth is better.

[bigjae1976]

Originally Posted by Orb

Sorry to the OP but the truth is better.

Better late than never...where were you a week ago?

Great info. Still gonna try it out and see how it feels but I'll keep my OEM links handy. Your analysis definitely hurts resale value.

[RickyBobby]

The handling issue you are describing is the stock shocks bottoming out and not a fault of the oem arms. When you install sticky tires and power out of corners, the rear is loaded up on the bumpstops resulting in loss of traction.
I complained of this too before moving to proper coilovers.

[bigjae1976]

Originally Posted by RickyBobby

The handling issue you are describing is the stock shocks bottoming out and not a fault of the oem arms. When you install sticky tires and power out of corners, the rear is loaded up on the bumpstops resulting in loss of traction.
I complained of this too before moving to proper coilovers.

Yeah, could be. Still the OEM suspension is still damned good but I'm learning to appreciate the Bilstein PSS coilovers in my 330 more and more.

When I come home from work, I make a right turn and then go up a straight hill. I usually put the car in M mode and let the engine run to redline in 1st and 2nd. This is a good example of my complaint, the traction control will kick in fairly quickly even with smooth application of the throttle. There was no way around it...you just have to go slow and wait for the car to straighten up.

Today, I got on the throttle and no traction control. I definitely could get on the power sooner. Again, could be a placebo effect. No facts...just a feeling.

[j2m]

I'm gonna slap some GC's on my car, but it's because I'm gonna need some serious camber on the rear to fit my 305's and my alignment guy tells me it may throw the tow off too much so he may need the adjustment to correct it.
I'm ALL about the placebo effect though I'll prob think it makes my car way faster

[bigjae1976]

Originally Posted by j2M3

I'm gonna slap some GC's on my car, but it's because I'm gonna need some serious camber on the rear to fit my 305's and my alignment guy tells me it may throw the tow off too much so he may need the adjustment to correct it.
I'm ALL about the placebo effect though I'll prob think it makes my car way faster

My butt is way smarter than my head.

[j2m]

Originally Posted by bigjae1976

My butt is way smarter than my head.

Yeah bro but sometimes my head is so far up my a$$ that I can't tell the difference for the a$$ dyno!?!?

[kaiv]

Such an odd choice for a "first suspension mod"

[bigjae1976]

Originally Posted by kaiv

Such an odd choice for a "first suspension mod"

I'm on a different level...