Author Topic: SC Box  (Read 1731 times)

Offline jfligg

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SC Box
« on: 11.04. 2009 13:14 »
Hi Guys
  I was wondering if anyone has used a SC box on the road?  I was wondering what the ratios are like?  I am doing a rough build of my Cafe Racer project and I think I will use that gearbox.  Thanks Jeff

Offline dpaddock

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Re: SC Box
« Reply #1 on: 11.04. 2009 19:46 »
Scrambles ratios are not my first choice for a cafe racer, chiefly because of the wider jump between top and third gear relative to the STD set (32.5 pct vs. 21.0 pct). However, the 2-to-3 jump is better than the STD; 24 vs. 31 pct.
The SC internal ratios are:
    1st (bottom) - 2.343
    2nd - 1.754
    3rd - 1.325

'57 Spitfire

Offline snowbeard

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Re: SC Box
« Reply #2 on: 11.04. 2009 20:04 »
I found this when I was first researching my SC.T2 box.

I have no comparison yet, but I don't mind my box for the road.  of course I also don't really know that it hasn't been changed...
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Offline alanp

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Re: SC Box
« Reply #3 on: 23.04. 2011 17:44 »
I used to run a DBD34 Gold Star with an SC box after suffering an RRT2 in city traffic. The big advantage for me was the first gear lower than the RRT2 but not as low as the standard box. I found it excellent in city traffic surrounded by traffic lights and multiple stop/starts to get out of town. However, out of town the drop to 3rd gear from 4th was not as close and useful as the standard box and not in the same league as the RRT2 out of town.
Personally, I think the standard box is a good compromise for a 4 speed box. However, the latest Nova 5 speed with its road biased ratios would be a better way to spend money on a gearbox change.
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Offline Rocket Racer

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Re: SC Box
« Reply #4 on: 26.06. 2015 06:19 »
I've just purchased an SC box, for around twice what I'd expect to pay for a STD box but a small fraction of a 5 or 6 speed.
According to my calculations it should give me a solid workable 1500rpm rev range in each gear. Being more evenly spread.
I've always found the jump from 2nd to 3rd a problem in the STD box, but in solving this I'm loosing the close 3rd to 4th.
As the bike is practically just doing short sprint races of around 4 laps we still need a decent 1st gear so we can get off the line hard with a wheel in the air.
Hope to trial this in the spring at the Barry Sheene Hampton Downs meeting; as the bike hauls two people around I'm hoping the ratio's will suit the rig, certainly worth a punt, nothing ventured...
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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