Any experiences with Lightning P-38 or F-40?

[HiYoSilver]

Some think these things are the best since slided bread, others seem to think they are bone breakers?

Anyone ridden one and have an option to share?

[BlazingPedals]

I've never owned one, but I've ridden a few. Unfaired (P-38 incarnation,) they're a little bit faster than a V-Rex, probably because they're lower and lighter. I would expect with the nosecone/bodysock they would be about as fast as a lowracer.

They also have a reputation for broken frames. The most common failure mode is cracking just behind the head tube. Tim Brummer admits that the design is a compromise in favor of low weight, and that the frames can be expected to break eventually. At least steel frames are relatively easy to repair!

[HiYoSilver]

thanks. What are the most reliable fast bents now?

[sch]

Fast bents have to be qualified is to which type. Air resistance is the biggest factor controlling higher speeds, so bents with layed back cockpits will be faster then bents with more uprite position. Low racers are very layed back, but monotubes such as Baccheta and Volae can be configured for a nearly the same layed back position.
Overall weight will controll acceleration and hill climbing, lighter is always faster there. Once up to speed, weight is much less important than aerodynamics on level. Ease of fairing is a factor, as the fuller the fairing coverage the lower the drag. Baccheta type high wheelers are harder to fair well compared with lower bikes. A front faired
Toureasy will give a Baccheta/Volae sans fairing a battle and easily outcoast them down longer hills in my experience. My Rotator Pursuit coasts right with a friends Baccheta Aero. Not sure what you mean by reliable, unless referring to frame breaking. No information as to that but it is not limited to P38s. My Ti Pursuit was recalled to replace the monotube: originally 1.75" OD, new tubing 2.125" OD because of several weld failures where the BB shell coved into the monotube. Steve

[paulw]

Air resistance is NOT the major factor in recumbent speed unless you only ride dead flat roads. In addition, aerodynamics only start to have real effects at 20 mph (in still air.) Recreational riders, particularly newbies, never reach speeds high enough to benefit from the aero designs, except downhill. They're quickly passed on the next up hill and left behind.

This whole issue of selling recumbents "because they're faster" is misleading. Only SOME recumbents are faster.

I have a P-38. It's a practical and clever mix of comfort and speed.

Average speed of any bicycle/'bent in the real World is determined by how fast you can push it up hills. (unless you only ride on flat ground.)

I am as fast on my P-38 as riders 10 years younger on their road bikes.
Without going into lengthy detail, it's because the P-38 has a stiff frame and isn't too heavy for hill climbing. Coupled to that, it has a fairly aerodynamic design. With the small zzipper fairing, Lightning claim it's about 10% faster than a DF. That seems to be the case when I'm riding with DF groups.

To select a fast recumbent, look at those that have stiff frames or bracing around the BB. Then select for lightness.

(The above is my opinion backed by testing same weight 'bents over the same route and riding with fit DF riders on high quality, lightweight bikes.)

[lowracer1]

"Air resistance is NOT the major factor in recumbent speed unless you only ride dead flat roads. In addition, aerodynamics only start to have real effects at 20 mph (in still air.) Recreational riders, particularly newbies, never reach speeds high enough to benefit from the aero designs, except downhill. They're quickly passed on the next up hill and left behind."


I'm not sure which statements to start disagreeing with here first.

Air resistance IS the major factor in recumbent speed, on flats, downhill and uphill.

When do you ever ride in still air? With a 7 mph headwind, aerodynamics already come into play if you can pedal 13mph into that headwind.
If a newbie gets passed on an uphill it is because they don't have the engine to use the superior aerodynamics on the uphill.
Hill attacks on a recumbent are totally different to an attack on an upright bike. Hills can be crested much quicker when a sufficient high speed run can be made at the base of the hill. By powering up the hill when already at a high rate of speed, less power needs to be applied to maintain a plus 20mph clip up a hill than if grinding up it a 10mph.
If you can't get a good run at the hill, then its back to the power of the engine and the desire to beat the road bike to the top.

Most newbies don't go out and buy high performance racing recumbents to begin with. An EZ-1 or rans rocket is not a high performance aerodynamic bike and isn't going to beat a lightweight roadbike up a hill. The rider on these bikes shouldn't have the desire to go that fast to worry about being dropped by roadbikes on the uphill. If the rider was concerned about such things, a faster design bike would have been bought. So with this remark I will agree that only some recumbents have the platform design to be faster and sold as so by reputation.

I really don't see a p-38 as being anywhere near as fast as a lowracer, but the f-40 on the otherhand keeps up just fine and with an equal engine can be much faster than a stock or tailfaired lowracer. This is due to superior aerodynamics of the f-40.

"To select a fast recumbent, look at those that have stiff frames or bracing around the BB. Then select for lightness"

In general, this statement is true, but not mandatory. A recumbent made with plate steel would be very stiff........... fast? no

ON my vk-2, the boom became somewhat loose on a ride and I could see and feel the boom swaying from side to side and up and down enough that it would make the chain rub on the front derailleur in every pedal stroke. Did it slow me down much? nope... I don't think so.


"Lightning claim it's about 10% faster than a DF. That seems to be the case when I'm riding with DF groups."

Uh......... forgive me if I'm wrong, but if you are riding WITH Df groups, then you aren't 10 percent faster. If you are 10% faster, than you should be a mile in front of the group, not drafting and riding the same pace. Now if your engine is 10% less than the other DF riders, then this statement makes sense. The bike helps keep you with the stronger riders.

[steveknight]

air resistance has been tested with fairings in a wind tunnel. they really only started making a difference at around 18mph. then it was a 10% difference.