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Discussion Starter · #1 ·
Hi,

I'm purchasing a Catrike "Road" with 3 - 20" wheels and will be upgrading it's performance to at least that of my Burley Django.

The question I have for you science geeks out there is rolling resistance. One would think with 3 tires contacting the ground there would be more resistance than with 2, however with the weight being distributed at 3 points the nip at each point would be smaller, thus the resistance would be roughly the same. I plan on using 20x1'" Primo "Racers" at 110 psi.

IF IF IF this is true, and the wind resistance is less (the seat is at a 45.0 angle about 4" off the ground), I should see sustainable speeds of 20+ mph (the Burley runs 19 mph).

Thanks
 

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There's TMV

TMV = too many variables. Rolling resistance is a combination of casing flex and the "rebound impact" of the tires having to "climb over" surface irregularities in the road. Three tires are going to be climbing over 50% more irregularities, but each tire's casing flex is going to be less. Plus, with a trike you've got possible issues from the fixed wheels not being in exactly the same plane and therefore having extra drag. One thing's for sure, 20 in wheels are higher rolling resistance than larger wheels. Whether casing flex is a bigger problem than surface irregularities would depend on both how smooth the road is and how stiff the casings are. Also, just because the bike is lower doesn't mean it's faster, as it could be a lot "dirtier" due to the extra wheel and it could be that you couldn't apply as much power to the wheels due to the recumbent position. No way to tell how this all comes out.
 

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Discussion Starter · #3 ·
Kerry Irons said:
TMV = too many variables. Rolling resistance is a combination of casing flex and the "rebound impact" of the tires having to "climb over" surface irregularities in the road. Three tires are going to be climbing over 50% more irregularities, but each tire's casing flex is going to be less. Plus, with a trike you've got possible issues from the fixed wheels not being in exactly the same plane and therefore having extra drag. One thing's for sure, 20 in wheels are higher rolling resistance than larger wheels. Whether casing flex is a bigger problem than surface irregularities would depend on both how smooth the road is and how stiff the casings are. Also, just because the bike is lower doesn't mean it's faster, as it could be a lot "dirtier" due to the extra wheel and it could be that you couldn't apply as much power to the wheels due to the recumbent position. No way to tell how this all comes out.

Good points. Though this is one of the lowest riding HPV's, it is also wider than any bicycle and it would be adversly effected on uneven surfaces. The trike will be ridden exclusively on bicycle trails as it would be suicide to bring it out into traffic. The trails here are kept in good repair so that shouldn't be an issue. I may need to invest in converting the front wheels to bladed spokes. I'm not sure it will make much difference with the rear wheel as it is tucked neatly behind the seat. There is also the option of a front fairing which would clean up the air a bit.

The orientation of the pedals to the seat and the seat angle is similar to that of the Burley. Everything is just dropped down lower between the wheels and there's been no problem putting power into the Burley. It's just a few mph less than my carbon road bike.

Like you say, we'll see.
 
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