changing to US gearing ?

N

nutah

Guest
the standard Buell gearing on my X1 is
55-29 UK gearing
but there is also the option of
61-27 US gearing

the US Buell ratio pulleys are a bit hard to find & can be expensive
(be careful as Buell Blast pulleys are a different width)


Sportster rear pulley (part no.40246-91) has 61 teeth
this will fit BUT you need to enlarge the central big hole by about 3mm internal Dia.

i only changed the rear pulley on mine which gives 1/2 US gearing , but a marked improvement in bottom end response :D

be aware though this alters your speedo , it will be around 10% optimistic

for full US gearing front & rear pulley , you are going to need a US spec speedo .
or one of these electrical speedometer adjusters.. HealTech Electronics Ltd. - Makers of the SpeedoHealer, GIpro, X-TRE, FI Tuner Pro, OBD Tool

Speedo Healer V4
 
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Re: changing to US gearing ?

Hi Nutah,

I have discussed changing gearing on Harleys here on HDH so it is interesting to see how Buells have been affected. My 1990 FLHS originally had a 61T rear pulley, compared with a US spec 70T (which it now has). There were a raft of other differences when compared with US spec bikes of the time, all prompted by the effing Swiss who still have more stringent noise regulations than most of the rest of the World.

Changing from 61 to 70 gives a reduction in overall gearing of approx 14% and a corresponding increase in torque to the rear wheel, which is why it is so worthwhile.

In the case of your Buell the UK gearing of 55:29 gives 1.897:1, compared with US spec of 2.259:1. Thats a whopping 19% difference! Think of the cost of trying to get that extra performance by conventional tuning! If you are able to buy a US spec front pulley and complete your transformation the only consolation I can offer is that it will give a very cheap boost in performance!

Your original gearing gave approx 25.5 mph/1,000rpm and the US will give just over 21. Your current gearing has given you an 11% increase in rear wheel torque, which is where that improvement has come from!
 
Re: changing to US gearing ?

Thanks Graham , that's very interesting info :D
 
Re: changing to US gearing ?

nutah said:
Thanks Graham , that's very interesting info :D
Click to expand...

It's a pleasure! My Firebolt seems to have satisfactory performance for this ole dodderer, so I haven't been tempted to mess with that, but I have modified the overall gearing on both Glide and Dyna, 14% and 19% respectively.
 
Re: changing to US gearing ?

Interesting - why have different gearing for different countries?:eek:
 
Re: changing to US gearing ?

not sure TBH Foby, unless it's the difference in motorway/freeway speeds ?
 
Re: changing to US gearing ?

Foby said:
Interesting - why have different gearing for different countries?:eek:
Click to expand...

Essentially there are different noise and emissions standards around the World (California eg is different to the rest of the USA). Recent Harleys have 6-speed boxes to yet further reduce engine speed, hence noise, at the road speeds the noise monitoring is conducted at. In Europe the Swiss have even more demanding noise limits than most other countries, hence Nutah's Buell had higher gearing than US spec, just as my Glide did back in 1990.
 
Re: changing to US gearing ?

Yeh they look nice bits of kit Maverick, bit expensive for my pockets though
 
Re: changing to US gearing ?

My 1200 Lightning has got a 55 and 29. Is it really worth changing? How is the cruise?
 
Re: changing to US gearing ?

Is it the best option or should I go to a 70 rear?
 
Re: changing to US gearing ?

I had both the full US-gearing on bikes as well as the part US-gearing and it's certainly worth the money!

To be honest though, cruising is less of a joy but fuck me it lifts the frontwheel up like it's going out fashion! :60277EB7B04744289C0
 
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