Need help with gear ratio

[REOFL]

I just had my vtx1800f tiked by The Trike Shop of Daytona (Roadsmith). My top speed is only ~75-80 MPH at <b>5700 rpm</b>. The kit came with a 3.55 DANA 30 differential. What ring and pinion would I need to get me back to 70- MPH at 3000 rpm? Tires are now 16" the OEM final primary drive ratio was 3.09 with 18" wheels. <br />
<br />
I used a full tank of gas bring the bike home 90 miles 4.2 gallons with the current gear ratio, 21.5 mpg, was getting ~40 to 42 mpg.<br />
<br />
REOFL

 

[jim peacock]

First think I would do is get a hold of your installer and talk to them about what can be done.
If you mess with it,it could void your warrenty.

 

[jfingalls]

REOFL, I think Jim gave you the best advice. If you have not talked to Dick (owner) at The Trike Shop about this try him. He is about the smartest Trike guy I have ever met. If he can't help, I will be surprised. By the way, call him or drive over in your car if you are getting that kind of mileage :>)

 

[Chumbly]

IMO your gear ratio isn't different enough to produce that much reduced speed. I'd wonder about the clutch slipping or some such thing. Any strange grinding or squealing noises? Chumbly-<img src="images/smilies/confused.gif" border="0" alt="" title="huh??" class="inlineimg" />

 

[REOFL]

Went back to the ROADSMITH installer and they had me check the gearing (count of one wheel turn gave be about 3.5 drive shaft revolutions 3.55 seems to be what RoadSmith has determined to be the best ratio through trial and error during design).

I took it back out on a test drive with a GPS to check the speedo and the speedo read about 5 mph slower than the GPS {in 1st 3000 rpm gave me 24 mph, 2nd 3000 rpm gave me 35 mph, 3rd 3000 rpm gave me 45 mph, 4th 3000 rpm gave me 54 mph and 5th 3000 rpm gave me 64 mph.} So guess the combination of smaller wheels 18" to 16" and final drive 3.09 to 3.55 plus the 5 mph speedo error puts me in a safe zone for cursing on the highway (couldn't get to a highway to check out 70 mph, will try this weekend); definitely lost some top end, but never go much over 75 anyway.

Looks like I just lacked experience/ the new feel of a trike and the fact that the VTX F model isn't a good trike candidate, due to the compromising of some Honda design parameters.

I do experience the "shudder" (shakes the hell out of the handle bars) below about 2500 rpm that goes away above 3000 rpm. May try a heavier duty clutch, I think I read somewhere on the posts that some of the shudder may be from the extra weight and the clutch not engaging smoothly, anyone have any experience here?

Definitely need the 6% rake kit as the trike wobbles at slow speeds, below 30-45 mph, then steadies out and drive smoothly above that.

 

[kj5ix]

The ratio seems right or darn close, and you do need the rake kit installed. It will help all the way around.

 

[Baz]

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<img src="images/misc/quote_icon.png" alt="Quote" /> Originally Posted by <strong>REOFL</strong>
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<div class="message">Went back to the ROADSMITH installer and they had me check the gearing (count of one wheel turn gave be about 3.5 drive shaft revolutions 3.55 seems to be what RoadSmith has determined to be the best ratio through trial and error during design).<br />
<br />
I took it back out on a test drive with a GPS to check the speedo and the speedo read about 5 mph slower than the GPS {in 1st 3000 rpm gave me 24 mph, 2nd 3000 rpm gave me 35 mph, 3rd 3000 rpm gave me 45 mph, 4th 3000 rpm gave me 54 mph and 5th 3000 rpm gave me 64 mph.} So guess the combination of smaller wheels 18" to 16" and final drive 3.09 to 3.55 plus the 5 mph speedo error puts me in a safe zone for cursing on the highway (couldn't get to a highway to check out 70 mph, will try this weekend); definitely lost some top end, but never go much over 75 anyway.<br />
<br />
Looks like I just lacked experience/ the new feel of a trike and the fact that the VTX F model isn't a good trike candidate, due to the compromising of some Honda design parameters. <br />
<br />
I do experience the "shudder" (shakes the hell out of the handle bars) below about 2500 rpm that goes away above 3000 rpm. May try a heavier duty clutch, I think I read somewhere on the posts that some of the shudder may be from the extra weight and the clutch not engaging smoothly, anyone have any experience here?<br />
<br />
Definitely need the 6% rake kit as the trike wobbles at slow speeds, below 30-45 mph, then steadies out and drive smoothly above that.</div>

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</div>The above is starting to look about right to me but 3400 rpm I, think is peak torque on the VTX ( correct me if I'm wrong ) therefore I would like to see 3400/3600 rpm @ 100 kph (60mph)<br />
As Iv'e said in earlier discussions a lot of the shudder can be tuned out by fueling changes. ie richen the mixture via a Cobra FI 2000 ( or a Power commander 2nd choice ) You will I suspect pick up heaps of torque & gain a much more efficient and therefore rideable Trike. Baz :yes:<br />
ps if your clutch is in good order & correctly adjusted a so called heavy duty unit will just shift the problem else where.<br />
.