rev

Just picked up a G Tech Pro meter for testing my cars' 0 to 60 times? Any advice or tips from those who have used one?

I'd also like to determine the cars' rear wheel HP, what's the actual weight for a stock 02 208 CLK55?

Also any advice regarding tire selection to improve the cars' 0 to 60 foot times/launch? This car with an open differential makes off the line skirmishes closer than they should be against less powerful opponents

Thanks!

Improviz

It was inexcusable of MB to put an open diff on a car with this much torque (and more: they're still doing it on the supercharged cars!!). Pretty pathetic that a $26K Mustang GT comes with LSD, but not a $70K+ CLK55...and then, oh, yes, we'll stick ***245's*** back there too...grrr...

Kind of a very, very, very sore spot with me as you can see, but I do love the car. BUT Mercedes would do well to properly equip their performance lineup for, well, better performance in this regard!

Anyway, here's a post of mine detailing the best technique I've found for off the line performance....and of course, 18" E55 rims in back with 265's also help!

https://mbworld.org/forums/showpost....1&postcount=18

Actual weight is around 3450 to 3475 pounds with a full tank.

As to GTECH: well, RTFM, closely, and make sure it's mounted per instructions, precisely. Those things can give wildly optimistic readings if care isn't taken in their mounting, leveling, etc....they go over this in their manual, though...main thing is you want the sucker pretty steady. On mine, I got much better (in terms of accuracy, not numerically!!) results after cramming some little wads of paper into the mounting bracket holes that the pegs go into...this stablized it and kept it more securely coupled to the windshield. And even after this, you may be a bit disappointed when you take it to a strip (mount up your GTECH while there if you do to compare!).

Hope this helps!

rev

Thanks for the info, I do have one question about the tire size though. Seems to me that Harris from Harton, whose supposed to be pretty knowledgeable about these cars, wrote that the E55 rims wouldn't properly fit the CLK55 and that going to 265/35/18s would actually slow the car down. Perhaps he meant in the quarter, but I'm not sure why that is or if that's factual? Any personal experience with the best wheel/tire set up for lowering my 60 foot times? Thanks!

Improviz

I personally have W210 (previous gen, not the new supercharged) E55 18" rims on my car, and have had for quite some time now. I had 265's, am now wearing 275's (same wheel/tire combination as came stock on the W210 E55). Have not taken it to strip yet. However, I have a stretch of road where I do GTECH it; with stock rubber, best 0-60 time I could get (traction limited) was about 5.1.

After switching to the 265's, I got a best of 4.7, with consistent 4.8-4.9. On the one outing I did since getting 275's I got 4.8-4.9, but this was in colder temps than when I did the 4.7 on the 265's, so I anticipate a slight improvement.

rev

Know where I can get a pair of the rear 18" w210 E55 rims, either new, used or quality replicas? Also what is the width on these? Thanks!

Improviz

Your local Mercedes dealer should have them, but they'll be more expensive there...tire rack also sells them:

http://www.tirerack.com/

I believe that width is 9".

rev

Any issues with fit on the 208 CLK55, when going with 18x9s and 275/35s on the rear? Also does the increase in overall diameter cause any problems with the speedometer/ESP system with this change, when leaving the stock 225/45/17s on the front?

Improviz

I haven't had any fitment issues, no rubbing, etc....no problems with ESP either. Overall diameter change is slight, from 24.7" stock to 25.5" with the 275/35-18's (or 24.4" with the 265/35-18's). I use Yokahama AVS ES100's, so these diameters will be different with other brands, so check tirerack.com's spec sheet for any given tire.

Speedo error will of course be introduced, and gearing ratio will also be changed, both slightly. Speedo error at 60 mph is +1.94 mph.

These calculators should help: clicky-click:

Lastly, note that I chose to keep 17's up front to avoid excessive deterioration in ride quality, but what constitutes "excessive" to me might not be so bad to you. So, you could certainly consider going w/18's all the way around....I think that there are some folks on the forum who've done that, try a search.

rev

Thanks, I think I'll be going with the same set up you have! Do you know the proper torque for the lug bolts and the recommended inflation pressures for the 275s?

I've also read that lowering rear tire pressure can help with launching. In your experience does this work on the street and if so what pressure(s) would you recommend?

My objective is to be able to launch the car quicker, try to holeshot my opponents, and shut it down early(win or lose). A lot easier done when you're the car in front ! I don't mind getting spanked if it's by a better(i.e., quicker) machine or driver, but I hate playing catch up because I've wasted good torque and rubber!

On a final note, I was once advised to try using drag radials. The trade off is a very short street life and an increased risk of hydroplaning. Besides that I haven't been able to find any 245's or larger that will fit the stock rims(17x8.5s I think). I'm wondering if anyone here has had any experience with using them on the street and if so could make any recommendations?

Improviz

I use stock inflation and stock torque, both of which are in the owners' manual (forget 'em right now)...

I haven't tried messing around with inflation, but others have; search the archives...I wouldn't recommend dropping below 30 psi and doing much driving, though, so unless this will be at a track, I'd be hesitant to mess with it much, at least not for sustained periods, as it can be dangerous.

Drag radials will help, but as can be seen by reading this blurb from BF Goodrich, I'd be leery about leaving them on for everyday driving! But yes, at the track they will definitely help you get a better hole shot.

Lastly, there are aftermarket limited slip diffs available for these cars, but they ain't cheap...but since the tightasses at Benz inexcusably chose not to equip these cars with them--sickening in light of the fact that $26,000 Mustang GTs have them--it's the only way to get one on the car, at least domestically (Mercedes gallantly offers them to its German customers, but not to us, even though we buy more of their cars, the jerks).

I recently discussed a good launch technique in another thread...were you in that one? I forget...

rev

The LSD is probably the way to go, but for now money is an issue. Please let me know if you get any info on the LSD.

I did recently learn/was told from a guy at tirerack, that some 255/40/17s(which fit the stock rims) have a wider footprint(track width) than some 265/35/18s. I'd hate to spend the extra and end up with that scenario. He also said that the 265/35 was the widest he could recommend for the clk, due to clearance issues with the wider section widths.

Improviz

Hmm, well, if I look at tire rack's spec sheet for the tires I use, I see that they spec the tread width of a 255 at 9.8", the 265 at 10.2", and the 275 at 10.7". The stock 245 is spec'd at 9.4".

I'd be interested in seeing what tire he's talking about, considering that the first number defines the section width, and one would assume that for any given manufacturer, a tire with a 255 mm sectional width would be narrower than one with a 265 mm sectional width...if you get a brand, please let me know.

Does he own one? I've had them on there for three months now, with zero rubbing issues. Now, I don't carry passengers in the rear and am running a stock (i.e., unlowered) suspension, so if you're prone to carrying passengers or lowriders, you might check with the forum; I personally don't know of anyone else who's used 275's, though....

The 255's would probably help somewhat, but I'll tell you that I can pretty effortlessly fry even the 275's off the line, and so would personally recommend at least a 265, but it's your car, and your call!

rev

Thanks for the info! From what I've come up with so far, there is a difference in advertised tread width(even with the same size tire), between the different manufacturers. Do you have any brand recommendations from your experience?

The guy from tirerack said that "when the tire pressure is lowered in a high profile tire, it will distort more than a low profile tire and thereby allow a greater contact patch".

Improviz

Depends...how much do you want to spend? I went with Pilot Sports for the first go-round, but later switched to Yokohama AVS-ES100's, which are pretty much the same thing at about half the price. They're good, but get a bit noisy as they age. They also have a bit more sidewall than the Pilots, which helps prevent curbing, although you still need to be careful of curbs (and potholes, and other crap in the road) with any ULP tire.

These are the only two I've used so far, as I'm pretty happy with the Yokos...I may switch next time around to a bit less-agressive tread pattern, because although they look cool, there isn't much rain here and I don't drive in it in any event, and I'd prefer a bit less noise when the tires wear (although having said that, I am by no means certain that other brands/types will do better in this regard, so don't base your decision on this!). So, it will be an experiment...but it's been fairly recently that I got the Yokos, so I'm staying put for some time.

But anyway, Tirerack has user polls for each tire they offer, and breaks them down into sub categories like wear, noise, ride comfort, etc...they also do their own road tests, but I'd recommend looking at both.

Between those and asking others on the forum, you should be able to zero in on something. There aren't that many in that size to pick from, frankly! I would avoid "all-season" types and stick with "summer" tread for best traction, though...