Forum

[Lord-Toady]

Hi I thought I was doing well on my 500 Bullet getting up to good speeds on it but it my mate behind me was saying I was riding slower than I thought I was. Tonight I bit the bullet and strapped a sat nav on (sacrilege!) and low and behold my cheapo smith 80mph replica over reads by 10mph. 30mph is actually 20, 40 30, 50 40 etc so I have been riding around really slow. I think I need to pay £50 for a proper one from hitchcocks the same one but without Smiths on it, are they good and accurate it says they are tested?

[dean6553]

I've got the same cheap replica, I had someone follow me in a car with an accurate speedo and I then worked out mine over reads by 20% (i.e. 30 mph on the clock is actually 24 mph, 40 on the clock is actually 32 mph, etc). I can live with that as I just mentally compensate (if you really wanted to you could put some very thin paint lines on the outside of the glass to signify the actual speeds). Much cheaper than paying the extra.

[Lord-Toady]

The problem is its a bit psychological I get the bike up to 50mph and it feels bloody fast then I look at the speedo and it says 60 and to get that needle say 70 (60mph) I would have to go full throttle. So far the needle has not been at 70 for fear of blowing the engine up!

[Chris Tindal]

If you're willing to shell out, then a reconditioned original Smiths chronometric is not a bad move, the contrast is considerable.

[Craig]

I use to self calibrate mine and move the face to suite..they are always a constant amount out so measure true but show false..inho easy way was with the old stick on spedo dial but perhaps not looks so good...cheers all..

[Aethelric]

Mine is calibrated in kph. Tested against GPS it's around 25% out. Quite handy though. 100kph should be 62.5mph but the GPS says 50mph.

SO I simply divide the kph reading by 2 to get the real speed in mph.

[Adrian]

If you do take up Chris' suggestion and get a genuine chronometric Smiths speedometer you'll need to ensure it is correctly calibrated, or else you will be spending quite a bit of money and still be getting incorrect readings! They come with various different calibration figures usually between 1400 and 1700 depending on their intended bike's tyre size and speedo drive gearbox ratio. All but the older Indian Bullets will have a front wheel drive speedo with a 2:1 replica Smiths gearbox (earlier ones have rear wheel speedo drive same as the Redditch-built bikes). With the tyre date from the tyre manufacturer's web site you can calculate the circumference and thus the number of revolutions the tyre will turn in a mile.



Assuming a 3.25" x 19" Avon (AM26) front tyre with an 82" circumference, that will rotate 772.68 times in one mile (when new). Run that through a 2:1 gearbox and you're after a speedo calibrated to 1545 or very close. For a 90/90 x 19 tyre, 1582.



A good speedo repair person can always re-calibrate a chronometric to suit while overhauling/repairing. If you're in Sussex I would suggest Philip Woods in Littlehampton, he has done a good job with a number of chronometrics for me.



The other option is a Puca Smiths digital version of the old speedos for about the same as you would pay buying a used original and getting it overhauled, which you can calibrate yourself.



http://www.puca.co/productC.html



A.

[daveh]

I found I could lever the back off the speedo, pull the needle off and then push it back on at a different angle. It's fiddly, and you should make sure you test the calibration before putting everything back together.

[Chris L]

I'm just thinking about buying a Indian maid speedo and had Braeburn about them not beening very accurate but didn't think they would be that bad . As the meteor miner has only got 17 " wheels so wil be a lot worse than 20% out . NO MORE Speeding tickets! Not sure which way to go now as part books have the same part numbers for 19" wheels as 17" wheels ?

[Adrian]

Braeburn???



Most Indian speedos are calibrated for 19" wheels, but the early EFI Classic C5 models had 18" front wheels, which is a bit closer. However, while you could use an Indian speedo as a temporary measure, it would be better to have a working chronometric in that Meteor Minor. I admit I would be tempted by 19" wheels, but there would be added expense if you have to factor in a new set of 19" wheel-friendly mudguards - not sure about the back one, but the original front mudguard wouldn't be big enough.



A.