| [ Total Views: 477 | Total Replies: 6 | Thread Id: 20591 ] |
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 sleeper
Wolfsburg Wizard
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| posted on March 24th, 2004 at 12:53 PM |
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speedo reading?
hi there....
anyone will be able to tell me by how much my speedo is out as i changed my tyres at the front from 165 to 135 size....
and assume the reading is now affected....is it more ....or less??????
cheers
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BiX
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| posted on March 24th, 2004 at 01:16 PM |
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what profile are the new tires and what profilea are the old ones?
I have no sympathy for my car, only the wallet that pays for it!
Go hard or go home!!!!
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sleeper
Wolfsburg Wizard
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| posted on March 24th, 2004 at 02:34 PM |
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old ones 165
new ones 135
still in 15...
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Split nut
Seriously Crusin Dubber
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| posted on March 24th, 2004 at 03:03 PM |
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Those numbers quoted don't appear to be profiles. The numbers on your tyres should be something like 165/65/R15 or 135/50/R15. The middle number is
the profile mesurement. It will tell you the distance from the rim to the outer limit of the tread.
The first number is the width of the tyre and the last is the rim size.
The higher the profile the larger the tyre which means the speedo will show a speed slower than true and vice versa.
Hope this makes sense.
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AdrianH
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| posted on March 24th, 2004 at 06:06 PM |
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With 165s if your speedo was reading 50 mph, you were doing 50 mph, with 135s and the speedo reading 50 mph you would be doing 46.15 mph Roughly 8%
less than the speedo reads.
Thats based around them being std 165/85/15 and 135/85/15
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blutopless2
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| posted on March 25th, 2004 at 08:43 AM |
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did you buy the tyres from a dealer (like goodyear/bob jane) etc?? as they should have informed you if it would effect the speedo reading, especially
if you have asked for a specific tyre size and profile. my preivous dealings with tyre people is that they will recalculate the profile if you change
the width and have told me if the speedo reading will change, but usually standard tyres are made to compensate for this.
see.... air and water do mix 
1974 1300
1997 MK3 Golf GL
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sleeper
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| posted on March 25th, 2004 at 02:05 PM |
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ok...old size was 165-65-15
new one is 135-sr-15
michelin has fitted the new ones at the front as i kept the back ones....mmmm...
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battybat
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| posted on March 25th, 2004 at 04:22 PM |
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so how do you work out the speeds then?
I'm running 195/70/14's at the front and 205/70/14's at the back (if i remember right) and I have absolutely NO idea how fast i'm going
http://www.dtsband.com - Rock and Roll is NOT dead
My other car is a scooter, and it's in even more bits than my beetle. One day they will both be back together.......
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AdrianH
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| posted on March 25th, 2004 at 06:16 PM |
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Ive got an excell spreadsheet that graphs gear ratios, rpm vs. speed, its got additional calcs on tyre size, and relative speeds. If anyone wants it,
or wants to host it on a web site somewhere email me at debbiehill@ihug.co.nz
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