Speedo reads 80mph at 5000 revs

JT · **Posted:** Sun Mar 07, 2010 9:28 pm

Now then

Can't find or remember the thread that it was on recently but I said that my speedo read 80mph when my tacho was at 5000 revs and Hairy and I think, Lampy didn't think that was right or that something was wrong, well it definately reads like that and has done from day one ;-)

, confirmed it today while out and the actual speed at 5000 revs according to the satnav is 72mph :thumbs:

So what does your speedo read at 5000 revs ? :dontknow:

bodysnatcher · **Posted:** Sun Mar 07, 2010 9:34 pm

my speedo is only out by 3 mph to my satnav. which is pretty acurate considering my ol van was out by nearly 10 mph..

wonder wat the average deviation is on our bikes speedo's .. be interesting to find out..

Largest of Als · **Posted:** Sun Mar 07, 2010 9:46 pm

JT wrote:

Now then

Can't find or remember the thread that it was on recently but I said that my speedo read 80mph when my tacho was at 5000 revs and Hairy and I think, Lampy didn't think that was right or that something was wrong, well it definately reads like that and has done from day one ;-)

, confirmed it today while out and the actual speed at 5000 revs according to the satnav is 72mph :thumbs:

So what does your speedo read at 5000 revs ? :dontknow:

Sounds about right.. as long as you're in top gear...

Will double check in the morning on the way to work..

Al

625martin · **Posted:** Sun Mar 07, 2010 9:52 pm

I think (correct me if wrong) a speedo has to be accurate to within plus 10% so must not indicate a speed slower than the vehicle is actually doing. So I would say that you're bang on the limit there JT.
Mine reads bang on to my sat nav (not sure how accurate sat navs are) but reads slower than most others I've compared it with, but I think thats simply luck after fitting white dial faces.
Perhaps the more mathematically minded will work out the actual revs required for 80 mph given gear ratios and tyre sizes etc.
ps. I hope this test was carried out on a private road JT :wickedgrin:

JT · **Posted:** Sun Mar 07, 2010 9:58 pm

625martin wrote:

I think (correct me if wrong) a speedo has to be accurate to within plus 10% so must not indicate a speed slower than the vehicle is actually doing. So I would say that you're bang on the limit there JT.

My speedo reads +8 not -8 Martin so it's ok, I'll never be speeding, I'll have mph in the bag :thumbs:

, as long as I stick to the speed limits that is :twisted:

cheers

hairy · **Posted:** Sun Mar 07, 2010 11:54 pm

JT wrote:

confirmed it today while out and the actual speed at 5000 revs according to the satnav is 72mph :thumbs:

Mine has always read 76mph at 4K

At 5K i'm around 88mph :dontknow:

17 38 gearing

JT · **Posted:** Mon Mar 08, 2010 7:06 am

I'm on standard gearing.
Mind you, the air pressure is different with you lot innit, that's probably got something to do with it and why you all talk kiinda funny :lol:

Cheers

steve31174 · **Joined:** Tue Oct 27, 2009 9:47 am **Posts:** 4

Hi,
I found out on a ride yesterday that my speedo is about 10mph slower than my actual speed.
Is there anything i can do to fix this, or is it buy new parts time ?
Thanks,
Steve.

(yellow xjr sp also)

JT · **Posted:** Mon Mar 08, 2010 1:42 pm

steve31174 wrote:

Hi,
I found out on a ride yesterday that my speedo is about 10mph slower than my actual speed.
Is there anything i can do to fix this, or is it buy new parts time ?
Thanks,
Steve.

(yellow xjr sp also)

Yeah, people tend to find that the Yellow ones go faster than they thouhgt :twisted:

zigzag · **Posted:** Mon Mar 08, 2010 3:33 pm

JT wrote:

steve31174 wrote:

Hi,
I found out on a ride yesterday that my speedo is about 10mph slower than my actual speed.
Is there anything i can do to fix this, or is it buy new parts time ?
Thanks,
Steve.

(yellow xjr sp also)

Yeah, people tend to find that the Yellow ones go faster than they thouhgt :twisted:

funny you should mention that jt :wickedgrin:

edge · **Posted:** Mon Mar 08, 2010 6:21 pm

As i happened upon a Camera van last week I hope that my speedo over reads :lol:

Largest of Als · **Posted:** Mon Mar 08, 2010 7:48 pm

Largest of Als wrote:

JT wrote:

So what does your speedo read at 5000 revs ? :dontknow:

Will double check in the morning on the way to work..

Al

Aye.. Top Gear + 5000prm = 80 (Indicated)

Al

625martin · **Posted:** Mon Mar 08, 2010 9:52 pm

JT wrote:

625martin wrote:

I think (correct me if wrong) a speedo has to be accurate to within plus 10% so must not indicate a speed slower than the vehicle is actually doing. So I would say that you're bang on the limit there JT.

My speedo reads +8 not -8 Martin so it's ok, I'll never be speeding, I'll have mph in the bag :thumbs:

, as long as I stick to the speed limits that is :twisted:

cheers

Err I fink thats wot I wrote JT :scratch:

- plus 10% at indicated 80mph means youre doing 72mph actually :smarmy:

JT · **Posted:** Mon Mar 08, 2010 10:26 pm

Just checking :eusadance:

ratty · **Posted:** Mon Mar 08, 2010 11:09 pm

wgaf

just cane it :thumbs:

TEX · **Posted:** Wed Mar 10, 2010 3:19 pm

Mine reads 78 MPH at 5000 rpm

with 18 / 38 sprockets :thumbs:

gwb · **Posted:** Wed Mar 10, 2010 3:54 pm

Just been out to the garage

5K = 0 mph

mechman · **Posted:** Thu Mar 11, 2010 1:42 pm

5000 rpm = 87ish indicated for me

gwb · **Posted:** Sat Mar 13, 2010 5:41 pm

gwb77 wrote:

Just been out to the garage

5K = 0 mph

Just been out on the road
5K = 85 mph
4k = 69 mph
6k = 100 ish
too many golfs in the way to try 7K

noname · **Posted:** Sun Mar 14, 2010 3:47 pm

steve31174 wrote:

Hi,
I found out on a ride yesterday that my speedo is about 10mph slower than my actual speed.
Is there anything i can do to fix this, or is it buy new parts time ?
Thanks,
Steve.

(yellow xjr sp also)

same as mine, up against my mates if mine says 30 theirs are showing about 34 and at 60 they're reading about 65, on showing 80 theirs are reading just under 90 etc

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Speedo reads 80mph at 5000 revs

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