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General Category >> Rubber Side Down! >> Gearing - 5th too close to 4th
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Message started by Jasbee on 03/06/16 at 17:49:03

Title: Gearing - 5th too close to 4th
Post by Jasbee on 03/06/16 at 17:49:03

I figure gears 1 to 4 on the S40 are perfect, but the gap between 4th and 5th is too narrow, the difference is just 8%. And the bike could easily cope with a taller 5th. At present it does 24 KPH per 1000 RPM in 5th which means at max power (5400 revs) the bike is doing just 130 KPH (sorry about the unit but I'm from metric Australia). In 4th it is doing 120 KPH at max power, and at a modest rev limit of 6000 it is doing 133 in that gear. So 4th is your highway 'power' gear.

5th should then be more like 26 KPH/ 1000 RPM, or 140 KPH at max power. But there's no easy way to alter just 5th. I read the topic on chain drive conversion, but no way would I give up the belt drive, and that of course only enables you to raise all 5 gears. As a compromise I might consider replacing the 140/80 rear tyre with a 140/90 which would raise all gears by ~ 5%. I believe some owners may have done that, if so, how did the gearing now feel? But I suspect that's too small a change to have much affect.

Title: Re: Gearing - 5th too close to 4th
Post by Gus on 03/06/16 at 18:05:52

No one has ever been able to figure out why Suzuki has never changed the gearing for 5th. But yeah, the gearing stinks.
Is 5% enough to justify the cost of a new tire? Not to me. I might try it when it's time for a new tire.
Some here (a couple) have converted to Kawasaki pulley's on one end or the other. Maybe Dave will chime in with some input on that. He's one of the savage guru's here and more than willing to answer questions and post links. Here is the link to Dave's bike build if you haven't seen it already. It's very informative reading with lots of pics.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1358099938

Title: Re: Gearing - 5th too close to 4th
Post by Kris01 on 03/06/16 at 20:06:38

I'm running a 140/90. It's very "worth it"!

I've also tried the Kawasaki pulley with no success. It makes a weird noise which I suspect is the belt teeth not engaging the pulley correctly/smoothly.

So now I'm left with a chain conversion. I'm considering something around a 2.65:1 ratio. It's not too tall but not too short. It should prove acceptable on 40 mph backroads AND 65 mph highways.

Title: Re: Gearing - 5th too close to 4th
Post by KennyG on 03/06/16 at 20:06:53

I recently switched from the factory stock rear tire to a Shenko 230 130/90-15 rear tire. I haven't ridden enough since the change to feel a noticeable difference, but 5% can only help at highway speeds.

I am anxious to put my GPS on after this rainy week is over and see if the speedometer is now closer to being accurate than it was.

Kenny G

Title: Re: Gearing - 5th too close to 4th
Post by Kris01 on 03/06/16 at 20:09:54

Kenny, according to my $10 bicycle speedo that is adjustable for different tire sizes, my 140/90 is about 1-2 mph off. The 140/80 was waaaay off.

Title: Re: Gearing - 5th too close to 4th
Post by Dave on 03/07/16 at 03:46:25

447D667C3F3E0F0 wrote:

Kenny, according to my $10 bicycle speedo that is adjustable for different tire sizes, my 140/90 is about 1-2 mph off. The 140/80 was waaaay off.

Stock speedos vary.....the one on my rescue bike matched the GPS exactly with the stock IRC tire.

The change to a 130/90-15 will make a 1% change in gearing and won't make a noticeable difference in gearing or handling...the tire is very close in size to the stock 140/80-15. The change to a 140/90-15 will make a 4% change, and it is very noticeable both in gearing - but also in the more stable handling.

Changing to a Kawasaki front pulley makes an 8% reduction in engine rpm....changing both results in a 13.7% reduction in engine rpm.

Title: Re: Gearing - 5th too close to 4th
Post by Dave on 03/07/16 at 03:51:04

526B706A2928190 wrote:

You really should send me your pulley so I can look at it. The pulley works fine for everyone else.....I have about 4,000 miles on my double pulley conversion and I have never had any problems with it. MMRanch and a few others are running the front pulley and have put a lot of miles without any problems.

You either have something wrong with your pulley.....or there was something on the bike not working correctly.

Title: Re: Gearing - 5th too close to 4th
Post by Serowbot on 03/07/16 at 07:16:28

My try at the pulley mod did the same as Kris...
Big time whirring sound,... almost like hitting the rumble strips on the highway...

Versy has it now...

Title: Re: Gearing - 5th too close to 4th
Post by Art Webb on 03/07/16 at 08:50:27

5th is as low as it is so the bike won't be totally out of it's powerband on the freeway
I agree this is sort of dumb, as you can use 4th for passing, but that's corporate thinking for you
I found my topo speed in 4th and 5th to be identical, in 4th the engine ran out of breath, in 5th it ran out of grunt, but a higher 5th would be more comfortable while also sparing the engine and burning less fuel
Only excuse I can think of is suzukin still thinks the speed limit is 55 ;D