What happens if I go from a 70 to a 65 tooth pulley?
#11
04-23-2015, 09:59 AM
Ultimate HDF Member
Hard to say whether you would like it or not...you would have to try it and see. 93 down bikes have a lower geared primary...so you would wind up with gearing similar to what a 94 up bike has stock. 70 tooth bikes had a 132 tooth belt and 65 tooth bikes had a 130 tooth belt...so it is very likely you will have to change the belt.
http://community.jpcycles.com/articl...e-pulleys.aspx
http://www.harley-davidsonforums.com...oth-count.html
http://community.jpcycles.com/articl...e-pulleys.aspx
http://www.harley-davidsonforums.com...oth-count.html
#12
04-23-2015, 10:33 AM
#13
04-23-2015, 10:43 AM
Club Member
#14
04-23-2015, 02:13 PM
Seasoned HDF Member
#15
04-23-2015, 05:10 PM
Seasoned HDF Member
Join Date: Dec 2004
Location: Texas! Ya mean there's someplace else?
Posts: 11,065
Received 1,297 Likes
on
484 Posts
The following users liked this post:
Prodigal_Sun (06-07-2020)
#16
04-24-2015, 04:22 AM
Road Master
#17
04-24-2015, 04:43 AM
Club Member
The following users liked this post:
Hillsidecycle.com (04-04-2021)
#18
03-28-2021, 02:29 PM
Stage I
#19
03-30-2021, 07:28 AM
I bought my 1990 Glide new, which came with a 61T rear pulley as stock, because it was an International spec model. I have since installed a stock US 70T one (with longer belt)! Why? because the original gearing was very long/tall and IMHO hurt rideability. I now have a 107" engine and feel no need to change my gearing. Your stage 1 doesn't add anything to your performance that needs any change IMHO.
You can use the tooth counts of the two pulleys to analyse the change the 65T will give. Your torque to the rear wheel will be reduced 65/70 = 93% of stock gearing, which will probably counter any small improvements your stage 1 gives you. Yes, you will need a shorter belt.
As for top end gain, it is unlikely there will be any. Our bikes are very over-geared as stock, to help them meet EPA regulations (or equivalent in the case of my bike when new). At 5,000rpm your bike has a theoretical speed of 128mph. Changing to a 65T will increase that to 70/65 x 128 = 138mph, however it is unlikely to be able to do either of those, as it doesn't have the power available to do those speeds!
Your gearing will be changed in the same way, so the rpm at a given road speed in top gear will be reduced to 93% of what it is at present. If you currently cruise at say 3,000rpm then engine speed will be reduced to 3,000 x 93/100 = 2,790rpm.
You can use the tooth counts of the two pulleys to analyse the change the 65T will give. Your torque to the rear wheel will be reduced 65/70 = 93% of stock gearing, which will probably counter any small improvements your stage 1 gives you. Yes, you will need a shorter belt.
As for top end gain, it is unlikely there will be any. Our bikes are very over-geared as stock, to help them meet EPA regulations (or equivalent in the case of my bike when new). At 5,000rpm your bike has a theoretical speed of 128mph. Changing to a 65T will increase that to 70/65 x 128 = 138mph, however it is unlikely to be able to do either of those, as it doesn't have the power available to do those speeds!
Your gearing will be changed in the same way, so the rpm at a given road speed in top gear will be reduced to 93% of what it is at present. If you currently cruise at say 3,000rpm then engine speed will be reduced to 3,000 x 93/100 = 2,790rpm.
This is for 70 tooth rear sprocket
This is for 65 tooth rear sprocket
Last edited by RLH3175; 03-30-2021 at 07:34 AM.
