4th gear speed
RE: 4th gear speed
sounds interesting, wish I could help but my shoulder is outta commision until friday, what I do know is I have a CV carb .010 over cylinders and it goes over 120. if you are still interested I can test it out this weekend and see what sprockets I have. I also have a 16 inch rear wheel
Thread Starter
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Elite HDF Member
Joined: Mar 2005
Posts: 4,092
Likes: 1
From: St. Petersburg Florida
RE: 4th gear speed
Yes, that would be cool. I am kinda interested what RPM's you are running at 70mph and perhaps 120mph if you are inclined. What sprockets are you running?
ORIGINAL: 74_ironhead
sounds interesting, wish I could help but my shoulder is outta commision until friday, what I do know is I have a CV carb .010 over cylinders and it goes over 120. if you are still interested I can test it out this weekend and see what sprockets I have. I also have a 16 inch rear wheel
sounds interesting, wish I could help but my shoulder is outta commision until friday, what I do know is I have a CV carb .010 over cylinders and it goes over 120. if you are still interested I can test it out this weekend and see what sprockets I have. I also have a 16 inch rear wheel
Tourer
Joined: May 2006
Posts: 267
Likes: 1
From:
RE: 4th gear speed
can anyone else not take their bike above like 50-55 for long period of time.....I cant do 65 down the highway and it starts coughing out of the carb and its at about 3400 if i remember right....anyone know what could cause this or if i could get different sprokets to change the ratio?
RE: 4th gear speed
Ok, so here is the difference between our two bikes:
....................Piniongear 24T front 51T rear............Skjold 24T front 43T rear.....74 21T front 51T rear
3rd gear at 45 mph= 3500 rpms....................................3000rpm... ..........................2500 rpms
4th gear at 50 mph= 3600 rpms....................................2500rpm... ..........................2000 rpms
4th gear at 60 mph= 4300 rpms....................................3000rpm... ..........................2500 rpms
4th gear at 70 mph= 5300 rpms....................................3500rpm... ..........................3000 rpms
4th gear at 100 mph
=................................................. .......................................5000 rpms
ok I did some testing too, I added my 21T front and 51T rear. My rear tire size is 130/90/16 it's 25" tall and 80" around. If you need anything else let me know.
....................Piniongear 24T front 51T rear............Skjold 24T front 43T rear.....74 21T front 51T rear
3rd gear at 45 mph= 3500 rpms....................................3000rpm... ..........................2500 rpms
4th gear at 50 mph= 3600 rpms....................................2500rpm... ..........................2000 rpms
4th gear at 60 mph= 4300 rpms....................................3000rpm... ..........................2500 rpms
4th gear at 70 mph= 5300 rpms....................................3500rpm... ..........................3000 rpms
4th gear at 100 mph
=................................................. .......................................5000 rpmsok I did some testing too, I added my 21T front and 51T rear. My rear tire size is 130/90/16 it's 25" tall and 80" around. If you need anything else let me know.
Thread Starter
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Elite HDF Member
Joined: Mar 2005
Posts: 4,092
Likes: 1
From: St. Petersburg Florida
RE: 4th gear speed
Hmmmmm, something is not right here. With a 21T/51T sprocket set, you should have the higest RPMs between the three of us. Both Piniongear and my bikes have been regeared down to lower our RPM's for cruising. My bike and Piniongear's front sprockets are the largest you can put on an Ironhead. My 43 rear is the smallest available which makes my 1st gear feel like 2nd, and my 4th gear like having a 5th. You pretty much are running the stock sprocket set with give you the fastest acceleration of our 3 bikes.
ORIGINAL: 74_ironhead
Ok, so here is the difference between our two bikes:
....................Piniongear 24T front 51T rear............Skjold 24T front 43T rear.....74 21T front 51T rear
3rd gear at 45 mph= 3500 rpms....................................3000rpm... ..........................2500 rpms
4th gear at 50 mph= 3600 rpms....................................2500rpm... ..........................2000 rpms
4th gear at 60 mph= 4300 rpms....................................3000rpm... ..........................2500 rpms
4th gear at 70 mph= 5300 rpms....................................3500rpm... ..........................3000 rpms
4th gear at 100 mph =................................................. .......................................5000 rpms
ok I did some testing too, I added my 21T front and 51T rear. My rear tire size is 130/90/16 it's 25" tall and 80" around. If you need anything else let me know.
Ok, so here is the difference between our two bikes:
....................Piniongear 24T front 51T rear............Skjold 24T front 43T rear.....74 21T front 51T rear
3rd gear at 45 mph= 3500 rpms....................................3000rpm... ..........................2500 rpms
4th gear at 50 mph= 3600 rpms....................................2500rpm... ..........................2000 rpms
4th gear at 60 mph= 4300 rpms....................................3000rpm... ..........................2500 rpms
4th gear at 70 mph= 5300 rpms....................................3500rpm... ..........................3000 rpms
4th gear at 100 mph
=................................................. .......................................5000 rpmsok I did some testing too, I added my 21T front and 51T rear. My rear tire size is 130/90/16 it's 25" tall and 80" around. If you need anything else let me know.
RE: 4th gear speed
I don't know what to tell you. I did all the same things you did and thats what I came up with. maybe it's engine size in piniongear and carburators on ours?? or maybe it's the rear wheel. the tach drive could also be affecting it because of a smaller rear tire. right now thats my best guess. what size tire are you using? and could my tach be off b/c of a smaller wheel?
Thread Starter
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Elite HDF Member
Joined: Mar 2005
Posts: 4,092
Likes: 1
From: St. Petersburg Florida
RE: 4th gear speed
I am using a 16 inch rear tire and I believe Piniongear's sporty is also 16" as well.
ORIGINAL: 74_ironhead
I don't know what to tell you. I did all the same things you did and thats what I came up with. maybe it's engine size in piniongear and carburators on ours?? or maybe it's the rear wheel. the tach drive could also be affecting it because of a smaller rear tire. right now thats my best guess. what size tire are you using? and could my tach be off b/c of a smaller wheel?
I don't know what to tell you. I did all the same things you did and thats what I came up with. maybe it's engine size in piniongear and carburators on ours?? or maybe it's the rear wheel. the tach drive could also be affecting it because of a smaller rear tire. right now thats my best guess. what size tire are you using? and could my tach be off b/c of a smaller wheel?
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
RE: 4th gear speed
My rear tire is the standard 4.50x18 inch wheel. The OD of the 18 inch and the 16 inch are probably close to the same dimension I'm sure.
ironhead74.........a smaller OD tire will result in slower speed per rpm. In effect, it lowers your overall gear ratio.
ironhead74.........a smaller OD tire will result in slower speed per rpm. In effect, it lowers your overall gear ratio.
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From:
RE: 4th gear speed
Hi all,
done me own "paper" calcs with the ratios indicated, they give me this:
tyres: 16" x 5.00 = 26" diam, same as 18" x 4.00... Being foreigner, don't know how many inches in a mile, so done the calcs in km and changed that to miles:
-59/34 x 51/24 = 1.73 x 2.12 = 3.66 overall ratio
at 6000 rpm, rear wheel spins 1639 revs per minute x diameter x phi x 60mn = 204 km/h = 126 mph
-59/34 x 43/24 = 1.73 x 1.79 = 3.09 overall ratio
at 6000 rpm, rear wheel spins 1941 revs per minute x diameter x phi x 60mn = 241 km/h = 150mph
-59/34 x 51/21 (std XLH ratio) = 1.73 x 2.42 = 4.18 overall ratio
at 6000 rpm, rear wheel spins 1435 revs per minute x diameter x phi x 60mn= 178 km/h = 111mph
I can see a tuned street sportster pulling the 1st set,
2nd set is more like a Salt Flats gearing??? specially considering 6000rpm is not top notch for a Sportster
Patrick
done me own "paper" calcs with the ratios indicated, they give me this:
tyres: 16" x 5.00 = 26" diam, same as 18" x 4.00... Being foreigner, don't know how many inches in a mile, so done the calcs in km and changed that to miles:
-59/34 x 51/24 = 1.73 x 2.12 = 3.66 overall ratio
at 6000 rpm, rear wheel spins 1639 revs per minute x diameter x phi x 60mn = 204 km/h = 126 mph
-59/34 x 43/24 = 1.73 x 1.79 = 3.09 overall ratio
at 6000 rpm, rear wheel spins 1941 revs per minute x diameter x phi x 60mn = 241 km/h = 150mph
-59/34 x 51/21 (std XLH ratio) = 1.73 x 2.42 = 4.18 overall ratio
at 6000 rpm, rear wheel spins 1435 revs per minute x diameter x phi x 60mn= 178 km/h = 111mph
I can see a tuned street sportster pulling the 1st set,
2nd set is more like a Salt Flats gearing??? specially considering 6000rpm is not top notch for a Sportster
Patrick
