Skull Posted July 11, 2005 Share Posted July 11, 2005 So I can tell my speedometer is way off after having gone to a 16-tooth front sprocket. Can anyone point me to what the speedometer-vs.-actual relationship is? Quote Link to comment Share on other sites More sharing options...
devilisht2003 Posted July 11, 2005 Share Posted July 11, 2005 at 80 you are doin 70 Quote Link to comment Share on other sites More sharing options...
Redbird Posted July 11, 2005 Share Posted July 11, 2005 ~15% Keep in mind that's including the 7% or so error that comes stock. Quote Link to comment Share on other sites More sharing options...
davesXX01 Posted July 11, 2005 Share Posted July 11, 2005 By the math method, 4000 rpm, 6th gear, 17t sprocket = 68mph 4000 rpm, 6th gear, 16t sprocket = 64mph This does not include any error in the spedo. I have an excellent Excel spread sheet that allows changes in gear sizing, showing speed vs rpm in all gears but have no clue how to post it, anybody help a brother out? Dave Quote Link to comment Share on other sites More sharing options...
Hobicus Posted July 11, 2005 Share Posted July 11, 2005 Shit, Dave... I keep forgetting to do that. Upload it to your gallery, then link to it. Quote Link to comment Share on other sites More sharing options...
StPeteXX Posted July 11, 2005 Share Posted July 11, 2005 By the math method, 4000 rpm, 6th gear, 17t sprocket = 68mph 4000 rpm, 6th gear, 16t sprocket = 64mph This does not include any error in the spedo. +1. I noticed about a 4mph difference also. Rich Quote Link to comment Share on other sites More sharing options...
Motor Psycho Posted July 11, 2005 Share Posted July 11, 2005 WWW.SPEEDOHEALER.COM Quote Link to comment Share on other sites More sharing options...
TOXXIC Posted July 12, 2005 Share Posted July 12, 2005 I think the difference is greater than thought. I always compare my 16 tooth indicated speed to the actual speed on my GPS, massive differences over 100 MPH. Anyway, I'm thinking of gearing back up to a 17 tooth since I'm also putting extra miles on the odometer. Quote Link to comment Share on other sites More sharing options...
arcticflipper Posted July 12, 2005 Share Posted July 12, 2005 That sounds a bit slow - 68 Mph and 4000 rpm? Should it not be more like 74 Mph at 4000 rpm? Only reason I know is caus I got caught dong 4000 rpm in a 35 Mph lane... Well I remember the RPm, @ 4000 I was doing 120 km/h that's a nice R1500.00 = $220 fine...... The gain or loss on the speedo due to a smaller size front sprocket, is this on a digital or a analog speedo? Can't say that I've ever come accross this, sounds like it's pretty common though... The 1 tooth down in front is equal to +-3 at the back, thus if you add or drop 3 on the rear sprocket will it also have the same influance on the clock ??? as mentioned earlier on. Quote Link to comment Share on other sites More sharing options...
davesXX01 Posted July 12, 2005 Share Posted July 12, 2005 Artic, sorry man, to get 74 mph, 6th gear @ 4000 rpm you would need an 18 front AND a 44 rear sprocket! The calculations I use are with a 24.8 diameter rear tire per Bridgestone O.E. BT-57. If anybody wants I will post up my charts (with Rich's help) for all to see! Dave Quote Link to comment Share on other sites More sharing options...
Obby Posted July 12, 2005 Share Posted July 12, 2005 Artic, sorry man, to get 74 mph, 6th gear @ 4000 rpm you would need an 18 front AND a 44 rear sprocket!The calculations I use are with a 24.8 diameter rear tire per Bridgestone O.E. BT-57. If anybody wants I will post up my charts (with Rich's help) for all to see! Dave That's about the speed I get out of 6th using a 44T rear. I would like to lower the rev's even more as I commute 65miles a day on the freeway. Looking for a 42T rear now. Quote Link to comment Share on other sites More sharing options...
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