Question: 43 Tooth Rear Sprocket Change

[steelhead]

My friend changed his rear sprocket from a 40 tooth to a 43 (Vortex brand). Nothing was done with the front sprocket.

My question is whether the speedometer reading will be affected, and to what degree? Will it run faster or slower? Any suggestions when installing this new rear sprocket?

Thanks,
SteelHead

 

[PaNDeM1C]

I have a 43 in the rear and when you install it you'll certainly notice a huge OOOMPH!!!

I love my set-up.

You will notice the change from stock if you do that slight modification...

Ok, yeah, it'll make the busa wheelie much easier!!! lol!

 

[PaNDeM1C]

Oh... yes. The speedometer WILL change some. I did a road test and my speedo was off minus 10mph or so. In other words if you see yourself doing 90mph you're actually doing around 82mph. I did a speed test on I20 from Anniston AL to Atlanta w/ my father driving and me on my busa... he told me my actual speeds...

So.... figure -10 or -9mph if you go with a 43 rear.

 

[PaNDeM1C]

DARN!!

Another note: When I did that speed test I was probably in 5th or 6th so maybe that speed test won't matter as far as the rear sprocket is concerned. I'm not sure.
Anyway... when we did the speed test I was around 10-8mph OVER the actual speed of my father's Ford F150 truck. And, yeah, we did it on an open stretch of road where I could look over at him safely and not worry about dying!!! Still, like I said, I'm not sure if the sprocket change matters at interstate speeds in the higher gears or not. But.... you have my info on what I know. Use it.

 

[forceofnature]

I have the 16/ 43 setup and I think I am close to 15 mph off.

 

[steelhead]

Thanks for the tips Pandemic and ForceofNature!

 

[PaNDeM1C]

I'm pretty confident that the 43 in the rear is about 10mph off (higher/faster).

I was around 10mph faster on the freeway than my father.... I was around 71 and he said he was around 60. I made sure we tested properly, too! It was a real road test..............

We did a few tests, too... they were all around the same. I was nearly 10mph faster than his truck. So take that into consideration.

GO W/ THE 43 REAR!!! IT ROCKS!!!! You'll love the new found BLAST of acceleration it'll give you!!!! You can always get a speedohealer if the difference in speed/miles matters that much to you...........

 

[forceofnature]

Yeah what Pandemic says on 43 tooth. It rocks, I cant go 190 mph anywhere safely so I dont mind sacrificing top end for acceleration.

If I ever make it to Maxton I may swap out the 43 back to the 40.

 

[proud dad]

AT 17/40 gearing, speedo at 60,GPS AT 57.
17/42 gearing,speedo at 60,GPS at 54..............speedo at 100,GPS at 90
I'm 10 - 11% off up to 100.17/43 would be off a little more.

 

[xzvs]

Ya i dropped to 16t in the front and its off by a good margin
use my gps for speedo now .

 

[manatrader]

I have the 43 on the back 17 in the front and yes its off, made the adjustment with the speed o healer. I was about 11.5% off.

 

[Super Trucker]

If can afford a speedohealer, I would recommend it. Some say just use GPS for actual speed, but keep in mind your odometer is off also. So 10% is adding 100 miles per 1000 that you ride.

 

[big jim]

I am running 16/41 and off about 11%

 

[TXBusa05LE]

Anything need to be done w/ the chain when using the 43 tooth?

 

[dadofthree]

Same chain 13 MPH difference in 6th gear at 10K

 

[Luvanicebum]

A speedohealer would definately pay for itself in the miles saved at resale.

 

[Somebody1010]

i have a 43 rear and stock front and i am off 11.2 percent.

 

[johnnycrash]

(Luvanicebum @ Jun. 20 2007,22:09) A speedohealer would definately pay for itself in the miles saved at resale.

+1 That speedo error (odometer error) adds up after awhile. I got mine for about $100 and the top speed memory recall is nice to have.

I'm running 17/44 right now - can't remember the correction I used with my SH - I used the correction calculator on the SH website.