Rear Tire Size

**Cruzer 8** · 06-07-2007

Will increasing the diameter by 1 inch cause any problems with warranty, or clearance --
will increasing width from 245 to 255 have any adverse effects
I plan on keeping the 17 inch rims

**etyu** · 06-07-2007

You may also want to ask Ynot.

**DansSlk** · 06-07-2007

I would leave the diameter alone if i where you.

255's will be fine for width

**webslinger** · 06-07-2007

Speaking of tires-

Is there a 265 tire that will have the right diameter and work on the stock 18" AMG rims, Dan? Or is 255 better?

Would I have to change the camber with either?

**Cruzer 8** · 06-08-2007

Going to the 255/40 -17 increases the dia from 24.7 to 25.0 inches or a 1.3% increase --I assume this is all right --- but will that size effect the warranty?

VitaminT · 06-08-2007

On my 55 I am running 225/40r18 in the front and 255/35r18 in the rear. I believe the rears are slightly off like posted above 1.3% or something like that and I don't have any issues with ECT. As for warranty concerns Dan will have to answer on that one.

For the guy asking about the 265 tire. If I remember right the AMG rears are 18x8.5. I believe a 8.5" is outside of most manufacturers recommended safe rim width for a 265. You should be able to use a 255 without any problems, but to be honest the 245 will give you a crisper feel as a 255 will have a slightly bulged/protruded sidewall.

Banned · 06-08-2007

Quote:

Originally Posted by Cruzer 7

Going to the 255/40 -17 increases the dia from 24.7 to 25.0 inches or a 1.3% increase --I assume this is all right --- but will that size effect the warranty?

Don´t worry Gene. I´m driving 19´´ and I still have the full warranty. If you´re looking for new shoes, have a look onto SL rims in 8,5 and 9,5x18*. Sometimes they are offered at Ebay very cheap. The only you need are different bolts with 12mm heads instead of 14mm. The 12mm you can order at www.kicherer.net for small money.

*- 18´´ is driving the 55, so you´ll get no problem at all

**webslinger** · 06-08-2007

sounds like 55's for the 55....

**DansSlk** · 06-08-2007

Cruzer - Yeah as Gero says thats nothing to worry about.

Webslinger - Correct 255 should be the max, anymore than that and you could be in for warranty issues cause they will pin it on the unsafe sizing.

**Cruzer 8** · 06-08-2007

Thanks guys -- good info --- I want to keep the 17 rims when you go larger you have to reduce the sidewall width to keep the tires from being to large in diameter and as we all know narrower side walls give a stiffer ride --sounds like I will have 225/45-17 fronts and 255/40-17 on the rears
we are going to have the stock rims permastar treated (powder coated ) in a gold color they will be shiny like chrome
Again thanks

412driver · 06-08-2007

Quote:

Originally Posted by Cruzer 7

Going to the 255/40 -17 increases the dia from 24.7 to 25.0 inches or a 1.3% increase --I assume this is all right --- but will that size effect the warranty?

You had Ms Couch in third grade too. You cipher bad as me. 25.0 take away 24.7=.3 inches. still cipherin on the % thing but ifn I had 100 marbles an 25 were in one pile an one broke and tha .7 part got lost so only tha .3 part was still there. ???????????? would that be 1.3%???????????? I'll git back to ya on that.....

jliu · 06-08-2007

Sounds like your describing it wrong ... are you asking to go 1 in wider ? Going to 265 19s is not a problem.

Just make sure that the DIAMETER is within 5% preferably within 2 1/2%.

Ynot · 06-08-2007

Quote:

Originally Posted by jliu

Sounds like your describing it wrong ... are you asking to go 1 in wider ? Going to 265 19s is not a problem.

Just make sure that the DIAMETER is within 5% preferably within 2 1/2%.

jliu, he's keeping the stock 17"s, so it's going to be 8.5" wide in the rear, going to 265 might not be a proper fit, doubt if you can find 265mm tires for 17"s wheels, it's rare iirc, 255" will offer the best grip and performance w/o over doing it, less than 2% difference is not going to ruin anything.

**Gabus** · 06-08-2007

Here's a nice little tool so you can skip the marbles.....

http://www.miata.net/garage/tirecalc.html

412driver · 06-08-2007

Just when I almost had it ciphered out too. Had to invite mor kin over last night, ran outa toes an fangers. An Bubba kept fallin outa tha chare makin me lose my place...

**webslinger** · 06-08-2007

The larger diameter tire will lower your rpms at speed, and increase your mileage. The downside is that it makes your rear gears taller so your 60ft times and low end "out of the hole" may suffer depending on how much taller the tires are.

06-07-2007	#1 (permalink)
Cruzer 8 Elite SLK World Member Join Date: Jan 2007 Location: Peoria, AZ Vehicle: 07 SL 550 Mars Red Posts: 579 Country: Thanks: 32 Thanked 58 Times in 28 Posts	Rear Tire Size Will increasing the diameter by 1 inch cause any problems with warranty, or clearance -- will increasing width from 245 to 255 have any adverse effects I plan on keeping the 17 inch rims __________________ GENE ---- See My Pic's To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. *To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.* SL 550 Mars Red

06-07-2007	#2 (permalink)
etyu Founding Member #2 / Ambassador Of Good Will Join Date: Jun 2006 Location: Orange County, CA Vehicle: 2008 SLK 55 Posts: 5,309 Country: Thanks: 385 Thanked 283 Times in 174 Posts	You may also want to ask Ynot. __________________ *Eddy* To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Pewter/Beige, PIII package, Airscarf, Hands-Free Communication System, Lighting package Designo Black Leather Cover on e-brake handle, ( To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Bill T), SmartTop v1.0, Kleyman 3BFM (NoRegret Custom), Green Air Filters, *Mod. R170 ant.*, EuroClear sidemarkers w/PIAA PlasmaIon lamps, chromed front & rear turn indicator lamps, PIAA SuperPlasmaGTX front parking lamps, bilateral rear fog lamps enabled.

06-07-2007	#3 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,801 Country: Thanks: 99 Thanked 236 Times in 180 Posts	I would leave the diameter alone if i where you. 255's will be fine for width __________________ One thing you will learn with German cars - If it's simple it ain't happening.

06-08-2007	#5 (permalink)
Cruzer 8 Elite SLK World Member Join Date: Jan 2007 Location: Peoria, AZ Vehicle: 07 SL 550 Mars Red Posts: 579 Country: Thanks: 32 Thanked 58 Times in 28 Posts	Going to the 255/40 -17 increases the dia from 24.7 to 25.0 inches or a 1.3% increase --I assume this is all right --- but will that size effect the warranty? __________________ GENE ---- See My Pic's To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. *To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.* SL 550 Mars Red

06-08-2007	#9 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,801 Country: Thanks: 99 Thanked 236 Times in 180 Posts	Cruzer - Yeah as Gero says thats nothing to worry about. Webslinger - Correct 255 should be the max, anymore than that and you could be in for warranty issues cause they will pin it on the unsafe sizing. __________________ One thing you will learn with German cars - If it's simple it ain't happening.

06-07-2007	#4 (permalink)
webslinger Elite SLK World Member Join Date: Apr 2007 Location: Bay Area, CA Vehicle: '07 SLK55 AMG Other Toys: Honda motorcycle Posts: 552 Country: Thanks: 25 Thanked 22 Times in 14 Posts	Speaking of tires- Is there a 265 tire that will have the right diameter and work on the stock 18" AMG rims, Dan? Or is 255 better? Would I have to change the camber with either?

06-08-2007	#6 (permalink)
VitaminT Elite SLK World Member Join Date: Apr 2007 Location: Alabama Vehicle: 2005 SLK55 Posts: 361 Country: Thanks: 0 Thanked 0 Times in 0 Posts	On my 55 I am running 225/40r18 in the front and 255/35r18 in the rear. I believe the rears are slightly off like posted above 1.3% or something like that and I don't have any issues with ECT. As for warranty concerns Dan will have to answer on that one. For the guy asking about the 265 tire. If I remember right the AMG rears are 18x8.5. I believe a 8.5" is outside of most manufacturers recommended safe rim width for a 265. You should be able to use a 255 without any problems, but to be honest the 245 will give you a crisper feel as a 255 will have a slightly bulged/protruded sidewall.

06-08-2007	#8 (permalink)
webslinger Elite SLK World Member Join Date: Apr 2007 Location: Bay Area, CA Vehicle: '07 SLK55 AMG Other Toys: Honda motorcycle Posts: 552 Country: Thanks: 25 Thanked 22 Times in 14 Posts	sounds like 55's for the 55....

06-08-2007	#10 (permalink)
Cruzer 8 Elite SLK World Member Join Date: Jan 2007 Location: Peoria, AZ Vehicle: 07 SL 550 Mars Red Posts: 579 Country: Thanks: 32 Thanked 58 Times in 28 Posts	Thanks guys -- good info --- I want to keep the 17 rims when you go larger you have to reduce the sidewall width to keep the tires from being to large in diameter and as we all know narrower side walls give a stiffer ride --sounds like I will have 225/45-17 fronts and 255/40-17 on the rears we are going to have the stock rims permastar treated (powder coated ) in a gold color they will be shiny like chrome Again thanks __________________ GENE ---- See My Pic's To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. *To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.* SL 550 Mars Red

06-08-2007	#12 (permalink)
jliu Founding Member Join Date: Jun 2006 Location: Bay Area, SF Posts: 184 Country: Thanks: 0 Thanked 0 Times in 0 Posts	uh Sounds like your describing it wrong ... are you asking to go 1 in wider ? Going to 265 19s is not a problem. Just make sure that the DIAMETER is within 5% preferably within 2 1/2%.

06-08-2007	#14 (permalink)
Gabus Elite SLK World Member Join Date: May 2007 Location: Søgne Vehicle: 96 SLK 230K Other Toys: Volvo L3314N Posts: 442 Country: Thanks: 18 Thanked 68 Times in 48 Posts	Here's a nice little tool so you can skip the marbles..... http://www.miata.net/garage/tirecalc.html __________________ Gabus The Rolls Royce is the Mercedes amongst cars To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.

06-08-2007	#15 (permalink)
412driver Elite SLK World Member Join Date: Mar 2007 Location: Salisbury North Carolina USA Vehicle: 99 SLK230 Other Toys: TOO MANY TOYS Posts: 1,010 Country: Thanks: 0 Thanked 0 Times in 0 Posts	Just when I almost had it ciphered out too. Had to invite mor kin over last night, ran outa toes an fangers. An Bubba kept fallin outa tha chare makin me lose my place...

06-08-2007	#16 (permalink)
webslinger Elite SLK World Member Join Date: Apr 2007 Location: Bay Area, CA Vehicle: '07 SLK55 AMG Other Toys: Honda motorcycle Posts: 552 Country: Thanks: 25 Thanked 22 Times in 14 Posts	The larger diameter tire will lower your rpms at speed, and increase your mileage. The downside is that it makes your rear gears taller so your 60ft times and low end "out of the hole" may suffer depending on how much taller the tires are.

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