View Full Version : Easiest way to measure MM of sway bars


69camaross
07-28-2009, 03:16 PM
I am looking at purchasing a set of used SLP sway bars and need to have the present owner measure them to make sure they are the SLP 35/21mm bars and not the stock 32/19mm bars. What's the best way to measure these using basic tools as I doubt this owner has a dial caliper?

pewter2002
07-28-2009, 04:23 PM
For the rear, take an open ended wrench size 19mm and slip it over a straight part of the bar. It should be snug- an 18mm wont slide over a 19mm bar. A vernier caliper is a pain because the jaws shift and converting SAE to metric is not accurate. For the front, use a paper or fabric tape measure and wrap it around your stock 32mm. Compare that with the "new" one- original one will be smaller, but by how much... I dont think a 35mm wrench would be readily avilable to try first method!

LS1BLKSS
07-28-2009, 04:28 PM
open end wrench is your friend! :)

mitchntx
07-28-2009, 05:53 PM
metric calipers rock!

98RedBird
07-28-2009, 11:28 PM
I would use a digital caliper. They make life easy, you should really pick one up if you don't already have one!

UMI Performance
07-29-2009, 09:12 AM
If using standard calipers multiple the dimension by 25.4 to get a metric reading.

z28mccrory
07-29-2009, 09:15 AM
For the rear, take an open ended wrench size 19mm and slip it over a straight part of the bar. It should be snug- an 18mm wont slide over a 19mm bar. A vernier caliper is a pain because the jaws shift and converting SAE to metric is not accurate. For the front, use a paper or fabric tape measure and wrap it around your stock 32mm. Compare that with the "new" one- original one will be smaller, but by how much... I dont think a 35mm wrench would be readily avilable to try first method!

How is SAE to metric not accurate?

Simply multiply the SAE measurement by 25.4

spy2520
07-29-2009, 11:05 AM
How is SAE to metric not accurate?

Simply multiply the SAE measurement by 25.4

should be accurate enough for this.

z28mccrory
07-29-2009, 11:49 AM
should be accurate enough for this.

Its accurate enough for anything, as its an absolute conversion that doesn't round up or down.

I do Cad/Cam work at a woodworking company, and have to do Metric to SAE and vice versa conversions all day long. It sacrifices no accuracy.

csxfbird
07-29-2009, 01:23 PM
Its accurate enough for anything, as its an absolute conversion that doesn't round up or down.

I do Cad/Cam work at a woodworking company, and have to do Metric to SAE and vice versa conversions all day long. It sacrifices no accuracy.

Better yet, just get a digital caliper that can do both. Quells all worries about inaccurate conversions. (I agree with you, by the way, no accuracy is lost with conversions)

Sam Strano
07-29-2009, 02:29 PM
Or you could just use an adjustable wrench, tighten it to fit the bar and measure the opening...

pewter2002
07-29-2009, 03:29 PM
The digital caliper is definitely the way to go due to the jaws of the vernier caliper opening slightly when removing them to read it. Hence the potential for inaccuracy with my cheap caliper! Someone (SLP?) made a 36.5mm at one point as well.

EchoMirage
07-30-2009, 06:08 AM
depending on the bushings, it could also very well say the size on the side of them. its probably in SAE, but you can tell which is bigger that way anyway. are you getting bushings with it, or just the bar? can you ask him to give you the old bushings with it, just to see if the size is on it?

deelong4002
07-30-2009, 06:18 AM
yeah i use 25.4 mm/1inch every single day. It is understood as the absolute conversion. If it's not accurate, my machinists are doing stuff very very wrong then......

Mike454SS
07-30-2009, 11:44 AM
should be accurate enough for this.

Stop posting and go back to school.

Mike454SS
07-30-2009, 11:51 AM
converting SAE to metric is not accurate

you too...stop posting and go back to school

00 Trans Ram
07-30-2009, 02:24 PM
I think the operative statement here is "using basic tools". Calipers and such aren't usually basic. At least, not for me - since I don't have any!

Use a tape measure. Measure the circumference. Here's what you're looking for:

Diameter = Circumference (inches.decimal, inches and fraction)
19mm = 2.349, just larger than 2 5/16
21mm = 2.596, just larger than 2 9/16
32mm = 3.956, just larger than 3 15/16
35mm = 4.327, almost exactly 4 5/16

z28mccrory
07-30-2009, 05:22 PM
I cant believe there is almost a full page of replies about something as simple as measuring a sway bar, lol.

Here is an idea... go to a local Napa and ask them if you can use a set of calipers for a second. They use them to measure seals and bearings when the part numbers aren't legible... so they have a pair under the counter.

pewter2002
07-30-2009, 09:05 PM
you too...stop posting and go back to school

Wow, one poorly written statement and I've got tech enthusiasts, machinists and a passive/aggresive cyber bully jumping all over a partial statement. I should def watch what I post more carefully like Mike454SS (Massachussets plates) does! You know, asking people where to get tint locally, duh!, POSTS ON WHERE TO GET REAR ANTI RATTLE CLIPS THEN ANSWERING YOUR OWN POST... I guess you are quite the details man, but as long as the repairs to your wrecked (twice!!!) 2000 pewter Camaro LOOK good, you're happy. Perhaps some DRIVING SCHOOL is in order for you! Oh yeah, the douchebag that door -dinged you, a real careless jerk! What happened after was classic passive/aggressive- minimal confrontation at the time- then lay into him on a forum - real hubris haha! Classic bully too, no real, in your face confrontation, just putting him in his place on the net- pathetic. Your contribution to THIS thread was nil, it's just your M.O. To everybody thanks for the correction, to Mike454SS, waiting to catch YOUR next marvellous post(959 and counting). If it is of interest, most will try to reply/help. If it isn't they will probably move on to the next one without comment...

Mike454SS
08-01-2009, 01:25 AM
You know, you're right, I was rude...but please be sure about your "Facts" before you post them. 1 inch is EXACTLY 25.4 mm, so that conversion leaves absolutely no margin of error, and is very straightforward with a calculator.

I'm not going to bother to reply to the rest of your message, it's FAR more uncalled for than anything I said to you.