The service manual specifies 175/70 R 13 82T for the 1500 Si hatch back.
175/70 R 13 for the 1500 DX hatchback and 165/70 R 13 for the base 1300
hatch. This is also what is listed on the web site of Goodyear for that
car. Are you sure your car has the original tire size?

Dan Knaus wrote:
>
> I believe the tire sizes given below are for the non-SI versions. I
> just went outside and looked at my '87 SI - the tires are 185/60R14s
> and I haven't changed sizes. My manual is in the garage, but again,
> the the non-SIs have 13 inch tires, the SI has 14 inch.
>
> Dan
>
> On Sat, 09 Aug 2003 16:24:25 GMT, Randolph <trash@junkmail.com> wrote:
>
> >I have the Honda service manual for the 1987 Civic (US model) and it
> >confirms what the previous poster said. 175/70R13 82T to be precise.
> >
> >
> >
> >David L wrote:
> >>
> >> According to Tirerack (www.tirerack.com), the original tire size for the '87
> >> Civic Si hatchback is 175/70-13.
> >>
> >> Not really good at math, but there is another website
> >> (www.miata.net/garage/tirecalc.htm) which gives the calculations you're
> >> looking for in different size tires. Based on the change to 185/65-15 your
> >> speedometer would read 8% too slow. When your speedometer reads 60mph
> >> you're actually traveling at 64.8mph.
> >>
> >> If you want to change to a 15" tire, get the 195/50-15. That would only
> >> make your speedometer read .1% too slow, so if your speedometer reads 60mph
> >> you're actually traveling at 60.1mph. You can also opt for 185/60-14 which
> >> would read .4% too slow so when your speedometer reads 60mph you're actually
> >> traveling at 60.3mph. All of the above info was gathered from the two
> >> websites quoted.
> >>
> >> It'll probably be more trouble that what it's worth to try and change the
> >> speedo. Upgrade to the appropriate corresponding tire size instead.
> >>
> >> Hope this helps,
> >> -Dave
> >>
> >> "Tina Venne" <TinaVenne@comcast.net> wrote in message
> >> news:f959jv0rgaa731mf5avckpqu4ac1c780ko@4ax.com...
> >> > Can anyone tell me what the original size tires were from the factory
> >> > on the 1987 Civic Si?
> >> >
> >> > If someone is good at math, can you tell me what the speed difference
> >> > would be, as indicated on the speedometer, between this stock size and
> >> > the currently installed P185-65-R15 at, say, 60mph?
> >> >
> >> > Also, where can one obtain the driven gear (or whatever it is called)
> >> > that would correct the speedometer for the above current tire size?
> >> >
> >> > Thanks a bunch.