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Wed Jul 06, 2005 12:35 pm

Has anyone ever found a gear to correct the stock VW speedo for larger tires? Ive got 700R15's on the front of mine, and would like to have a correctly reading speedo.

I had heard the S. Beetle speedo has a different gear set in it that gets close to correcting for a 27-28" tire.

TIA

Wed Jul 06, 2005 2:14 pm

I have the same issues since I put on 7.00x15's. There are alot of those radar speed sites here in OC so I've come to find the speedo is 10 or 11 mph off what actual radar clocked me at.

Wed Jul 06, 2005 3:14 pm

I dont even have my speedo hooked up. I got tired of the speedo cable going out. I have been driving this car for so long, I just drive by rpm. Seems to work, have not been caught by the cameras yet. But there is a place here in Phoenix that will calibrate my speedo, I think they said about $120. Hope this helps,Later,Mitch.

Wed Jul 06, 2005 3:23 pm

Mine is off about 10mph also. I also have 700s.

Wed Jul 06, 2005 3:28 pm

$120. BUCKS! holy hell! I'll do the math in my head before I spend that much!

Wed Jul 06, 2005 3:35 pm

dgpilot15 wrote: $120. BUCKS! holy hell! I'll do the math in my head before I spend that much!

Thats why I just live with it.

Quote: Mine is off about 10mph also. I also have 700s

I have the same tires, off about the same. I usaully just go with the flow of traffic, keeps me out of trouble. Later,Mitch.

Wed Jul 06, 2005 4:14 pm

Just a thought...but you could use a bicycle speedo that has a wireless transmitter. for about 20 bucks....Digital stuff... :D Gotta lov it...

Wed Jul 06, 2005 5:16 pm

I did the whole calculation thing and found mine to be off something like 13.3 percent. So at 60mph I was really doing like 38pmh. At 10 mph 11.3 mph. I had a local officer clock me to verify my figures. I'm just going to repaint the face.

A couple of Hints.

Hint 1: Find out how far off your speedo is.
Drive on the highway for 10 miles (according to mile markers) and note how far your odometer advances. Divide the odo reading by 10 and that will tell you what percentage your speedo is off.

Example: If you drive 10 miles and your odometer advances 8.75 miles, 8.75 / 10 = .875. So your speedometer is reading 87.5% slow.

Wed Jul 06, 2005 8:14 pm

or you could stick your finger in your mouth, then hold it out the window. j/k :D

Thu Jul 07, 2005 12:36 pm

Here is a reasonably good speed calulator. The stock VW tire for my 65 was 5.60x15.

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

Thu Jul 07, 2005 11:38 pm

Thanks for all the replies. I know how much Im off. Ive used GPS in the car. What Im after is a way to correct my VW speedo.

Fri Jul 08, 2005 2:23 pm

Mine is of also wrong, one day I spotted one of those unmanned radar trailers the cops around here set up. All this thing does is tell you how fast you're going, no cameras or anything. Any way the thing said I was going 37 speedo said 44 thats about 20% fast ( big and little tires ) so now I know that 80 on the speedo is a about 65mph. The pecentage never changes, at 40 I'm going 32mph, it's just like calculating tips. After a while it becomes natural you don't even think about it.
Bill

Fri Jul 08, 2005 10:43 pm

One way for certain would cal your speedo now, and allow you to recal anytime you get the urge in the future, but it's not low-buck. www.dakotadigital.com This place sells electronic speedometers (lots of places do) but they also have a universal sending unit system and a device for infinately adjusting to pretty much whatever you feel like. Imp558

SGI-5 Universal Speedometer Signal Interface $79.95
SEN-4165 Magnetic Speed Pick-up Coil $29.95
Speedos from them appear to be about $150 and up, cheaper elsewhere

Tue Jul 26, 2005 12:51 am

Back to the top.

Anyone corrected a VW speedo?

Thanks for the info on other options. At this point I want to correct my VW speedo.

Tue Jul 26, 2005 3:33 am

Check into hotrod speedos... Stewart Warner etc make regearable speedos....

The VDO stock ones are a bit toughter to tinker with.

Tim

Sun Aug 07, 2005 7:40 pm

Try giving George at Gilmore Global Instruments Co. in Houston, TX a call. He set up my Dolphin mechanical speedo to read correctly off of the VW front hub.
Price was reasonable and service was simply fantastic.
Their phone no. is: 1-800-999-6632 or 713-946-9133.
Bill K

Tue Mar 23, 2021 3:48 pm

vwclass11 wrote: I dont even have my speedo hooked up. I got tired of the speedo cable going out. I have been driving this car for so long, I just drive by rpm. Seems to work, have not been caught by the cameras yet. But there is a place here in Phoenix that will calibrate my speedo, I think they said about $120. Hope this helps,Later,Mitch.

I know it's been a long time but I'm around the Desert Ridge area in Phoenix--any chance that person is still around? Mine has 35 inch tires and I'm trying to find out if a speedo can be recalibrated to that big of a change

Wed Mar 24, 2021 3:51 am

I believe (haven't tried it) by varying the length of the hair spring on the speedo needle you can adjust the speedo to read correctly. This would be a trial and error thing for us regular guys. It would not correct the odometer though. If you send it to someone this I believe is what they will do.

A while back someone posted a link to a site that sells a little gearbox that has different gear ratios available to install between the cable and the speedo. This would correct both the speedo needle and the odometer. I don't recall what thread I saw it in.

Wed Mar 24, 2021 5:57 am

Here is what I have done in the past.
I was running 235-75 tires on the front and the speedo was off about 10%. My car was a '74, so it had the 100mph speedo. I found an older speedo with a 90mph face on it, disassembled both of them, and used the 100mph face on the 90mph guts.
It corrected the speed, but the odometer was still off.

Wed Mar 24, 2021 7:37 am

Just a thought, but why not change out the speedo for a gps unit. That’s what I run in my Thing and it’s always right. No trial and error, and doesn’t matter what size tires you run.